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Louisville Orthopaedic Clinic

The Journey II Total Knee System: A Step Ahead – An Evolutionary New Design

Richard “alex” sweet ii, md, kate s. hamilton, pa-c, richard a. sweet, m.d. (retired 2022).

HOW THE NORMAL KNEE WORKS: It is a common misconception that the human knee functions as a simple hinge joint, with straight up and down flexion and extension. In reality the motion of the knee is much more complex, with six degrees of motion (not just the two of a hinge). As the knee bends and straightens, it also rotates internally and externally and slides front to back. Traditional total knee replacement designs have never been able to recreate the complex movement necessary for the knee to feel and function normally, especially in the high demand situations of a physical job or performing athletics.

journey knee prosthesis

The Journey II Total Knee Medial Pivot Design The “ Normal Feeling ” Knee Replacement

The Journey II Knee is a revolutionary new knee replacement design. It incorporates several new design changes, the most significant of which is Medial Pivot design. These design changes include:

MEDIAL PIVOT DESIGN: A revolutionary new concept. It is the first true major design advancement in knee replacement surgery in decades. The Medial Pivot Design is the first TKR design to incorporate all 6 degrees of motion of the natural knee. It does so by creating a “cupped” almost ball-in-socket articulation between the plastic and the femur on the medial side of the joint (blue arrow) and a flat articulation between the plastic and the femur on the lateral side joint (red arrow). The resultant kinematics (mechanics) are such that the “ball in socket” articula-tion on the inside of the joint keeps the femur centered in one spot as the knee bends, while the “flat” articulation on the outside of the knee allows lateral femur to glide backwards and rotate like the normal knee. The result: normal kinematics are restored in the Medial Pivot Design TKR.

GREATER STABILITY: An added inherent benefit of the medial ball-in-socket “cupping” of the Medial Pivot design is that it improves front-to-back knee stability vs that of the conventional TKR. Given that the ACL is sacrificed in all TKR surgery, the added front-to-back stability of the Medial Pivot design is a crucial improvement.

NORMAL ANATOMY RESTORED: The Journey II re-establishes the subtleties of normal joint line anatomy (which are altered by the arthritis process and not corrected by conventional TKR surgery.

journey knee prosthesis

IMPROVED QUADRICEPS STRENGTH: The Journey II, as opposed to other TKR designs, moves the contact point between the femur and the tibia forward to its normal position (blue arrow right as compared to orange arrow of traditional TKA designs). Reestablishing this forward contact point results in increased quadriceps strength (like being on the long end of a teeter-totter) GREATER RANGE OF MOTION: The Journey II design changes the anatomy of the back of the femoral component to mimic that of the normal knee (blue arrow left). The result is to provide for an extra 15 degrees of flexion versus what is expected in a conventional TKR. The cumulative result of these design changes of the Journey II TKR is that patients experience a knee replacement with improved kinematics, speedier recovery, better ultimate range of motion, enhanced stability, and ultimate functional ability for high demand situations at full recovery.

Design Limitations of Past Conventional TKRs Conventional knee replacements work well at what they are designed to do: rid the patient of arthritis and provide a new artificial knee that will function adequately. As TKR surgery has expanded into younger more active age groups who place a higher demand on their new knee, the goal of only eliminating arthritic pain is no longer sufficient. Design limitations of the conventional knee replacement that can inhibit the return to normal functioning and can lead to patient dissatisfaction include: 1. ABNORMAL KINEMATICS: The knee is NOT a hinge. A conventional knee replacement forces the knee to flex and extend like a hinge on a door, with a straight simple up and down motion. The normal knee, however, does not function like a hinge. Instead, as it bends and straightens, there is flowing rotation and front to back sliding to its kinematics. Only the Journey II TKA recreates these kinematic movements. 2. ALTERED ANATOMY: With conventional knee replacement surgery, anatomy of the knee is altered in several ways. When looking at a normal knee from the front, the joint line is not perpendicular to the tibia as it is with conventional TKR surgery, but instead is at a slight angle with the inside of the joint being slightly lower than the outside. To compensate, the femur must be correspondingly rotated to keep the ligaments balanced. This can lead to abnormal forces on the knee, creating sensations of instability, dissatisfaction, and potential early failure of the knee replacement. 3. DIMINISHED QUADRICEPS STRENGTH: In conventional TKR surgery the contact point between the femur and tibia is shifted towards the back of the knee. This shift causes abnormal (called “paradoxical”) motion to occur when the knee starts to bend. The mechanical effect is that the strength of the quadriceps muscle is weakened. This is of clinical importance as a patient with a conventional TKR attempts to squat, climb steps, or perform other high demand activities.

Results of Conventional TKR Surgery Design Limitations: The result of the limitations noted above is that the ligaments and capsule of the knee see an altered knee anatomy, altered knee kinematics, and a weakened quadriceps muscle. This can cause a range of problems from:

  • A patient perceiving a subtle sensation that the knee does not “feel normal”
  • More significant problems such as less range of motion, reduced stability, a weak knee/quadriceps complex, intermittent soreness/swelling, problems with stair climbing, and difficulties engaging in recreational activities and vigorous work.

Conclusion The Journey II TKA is truly a revolutionary step forward in the design of total knee implants. With proper surgical technique and in the hands of a well-trained surgeon, the Journey II knee can produce results superior to the traditional total knee design. It is our goal as your surgical team to continue to improve our surgical techniques and to look for new advances in technology that allow us to give you the best result possible.

Louisville Orthopaedic Clinic

4130 Dutchman's Lane, Suite 300,Louisville 40207 (502) 897-1794

1425 State St., ,New Albany 47150 (812) 920-0408

journey knee prosthesis

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Journey II Implant

Partial knee replacement.

Bone and ligament sparing partial knee replacement

journeyuni

First, let's discuss what is meant by the term minimally invasive surgery or MIS. To be clear, MIS is still a surgical procedure and therefore carries the same risks associated with other surgeries.

However, because it uses specially designed surgical instruments, MIS wth the JOURNEY UNI implant is able to prepare the bones of your knee and then properly place your new implant using a smaller incision than traditional knee replacement. Also, because the implant only replaces one compartment of your knee, there is less bone removed and typically less disturbance to the tissue surrounding the knee than in traditional knee replacement surgery.

According to the American Academy of Orthopaedic Surgeons, partial knee replacement patients usually spend less time in the hospital, have less blood loss, and return to normal activities sooner than do total knee replacement patients. Partial knee replacement patients may also experience better early flexion, less pain after surgery and more natural feeling outcome.

Potential benefits of JOURNEY UNI knee replacement compared with total knee replacement

  • No disruption of the knee cap
  • Less blood loss
  • Possibility for less post-operative pain
  • Faster rehab/recovery time
  • Better early range of motion

Important: Individual results may vary.

Important safety notes

Individual results of joint replacement vary. Implants are intended to relieve knee pain and improve function, but may not produce the same feel or function as your original knee. There are potential risks with knee replacement surgery such as loosening, wear and infection that may result in the need for additional surgery. Patients should not perform high impact activities such as running and jumping unless their surgeon tells them that the bone has healed and these activities are acceptable. Early device failure, breakage or loosening may occur if a surgeon's limitations on activity level are not followed.

Talk to your doctor to determine what treatment may be best for you.

  • //orthoinfo.aaos.org/topic.cfm?topic=A00585
  • Laurencin CT, Zelicof SB, Scott RD, Ewald FC. Unicompartmental versus total knee arthroplasty in the same patient. A comparative study. Clin Orthop Relat Res. 1991; (273):151-156
  • Based on the JOURNEY UNI surgical technique

All information provided on this website is for information purposes only. Every patient's case is unique and each patient should follow his or her doctor's specific instructions. Please discuss nutrition, medication and treatment options with your doctor to make sure you are getting the proper care for your particular situation. If you are seeking this information in an emergency situation, please call 911 and seek emergency help.

All materials copyright © 2020 Smith & Nephew, All Rights Reserved.

journey knee prosthesis

OXINIUM ◊ Technology

Important safety notes:, only replace what is damaged, knee anatomy.

The knee joint is the point at which the femur bone of the thigh meets the tibia bone of the lower leg. All the components of the knee - bones, cartilage, synovial membrane, ligaments, tendons and muscles - must work together properly for the knee to move smoothly. Cartilage is a protective cushioning that keeps the bones from rubbing against one another. In a healthy knee, a thin, smooth tissue liner called the synovial membrane releases a fluid that lubricates the knee, reducing friction as the bones move. In an arthritic knee, the cartilage between the femur (thigh bone) and the tibia (shin bone) gets worn away, causing the two bones to scrape against each other. When this happens, the joint can become pitted, eroded and uneven, often resulting in pain, stiffness and instability. While this type of arthritis damage often happens throughout the entire joint, for some patients it can be localized in a single compartment of the knee. If the damage is localized to a single compartment, treatment with partial knee replacement may be an option. Because the JOURNEY ◊ UNI implant only replaces the damaged bone and cartilage of a either the medial or lateral compartment of your knee, the rest your natural knee's structure is retained.

Potential benefits of partial knee replacement compared with total knee replacement

(Results may vary)

  • No disruption of the knee cap 1
  • Less blood loss 2
  • Possibility for less post-operative pain 2
  • Faster rehab/recovery time 2
  • Better range of motion 3

? Understanding the procedure

Description of the journey ◊ uni partial knee implant procedure.

  • An incision is made to expose the damaged joint
  • The end of the femur and top of the tibia are shaped to accommodate the JOURNEY UNI Knee components
  • Trial components are placed to ensure proper alignment
  • Once properly aligned, the trial components are removed
  • The femoral and tibial JOURNEY UNI components are implanted
  • The incision is closed.

Post-operative protocol

  • Ice and elevation to reduce pain and swelling in your knee
  • A continuous passive motion machine that will promote the return of your knee's range of motion
  • Walking with a walker or crutches on your first day after surgery

What to expect

  • On average, this type of surgery takes approximately one to three hours, depending on your individual circumstances.
  • Usually you'll be ready to return to your room after one to three hours in recovery.
  • After surgery, your pain may be managed via intravenous therapy and/or a pain pump and/or injection and/or pills given by mouth.
  • Depending on your situation, you may be able to walk with the aid of a walker or cane the day after surgery.
  • Increased pain, redness or swelling
  • Incision drainage
  • Prolonged nausea or vomiting
  • Chest pain or shortness of breath
  • Tenderness in the calf or thigh of the operated leg
  • Most patients are ready to drive a car about eight weeks after surgery, but not unless your surgeon authorizes it.
  • Recovery varies greatly based on individual factors but most patients resume normal activities in about 12 weeks following surgery.

All information provided on this website is for information purposes only. Every patient's case is unique and each patient should follow his or her doctor's specific instructions. Please discuss nutrition, medication and treatment options with your doctor to make sure you are getting the proper care for your particular situation. If you are seeking this information in an emergency situation, please call 911 and seek emergency help.

All materials copyright © 2019 Smith & Nephew, All Rights Reserved.

Knee Replacement VERILAST Knee JOURNEY◊ II VISIONAIRE◊ Patient Matched Technology Partial Knee Replacement JOURNEY◊ II UNI Partial Knee Replacement ZUK◊

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ORTHOPAEDICS

Journey ii ◊ rox ◊ total knee solution with conceloc ◊ and oxinium ◊ technologies.

Combining cemented and cementless technologies for a reverse hybrid approach, we bring to the stage our latest and greatest in joint reconstruction

journey knee prosthesis

Remix your reconstruction

Surgeons continue to pursue solutions in TKA to both improve patient satisfaction - by making the knee feel more normal - and reduce some of the most common failure modes such as tibial aseptic loosening, instability and infection. 1,2 However, current implant designs have not addressed both objectives and literature still cites that up to 20% of patients are not satisfied. 3-5

We mix things up on our approach to TKA, combining the anatomic design and normal kinematics 6-10 of JOURNEY II TKA with the cutting-edge technology of CONCELOC Advanced Porous Titanium and the unrivalled material science 11-17 of OXINIUM Oxidized Zirconium, to build the foundation for outcomes you ’ ll want on repeat.

We call it our greatest hits. You’ll call it a best -in-class knee construct.

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Product Features

Show videos, reference materials, clinical evidence, medical education, related products.

* Compared to non-JOURNEY II knees

We thank the patients and staff of all the hospitals in England, Wales and Northern Ireland who have contributed data to the National Joint Registry. We are grateful to the Healthcare Quality Improvement Partnership (HQIP), the NJR Steering Committee and staff at the NJR Centre for facilitating this work.

The views expressed represent those of Smith+Nephew and do not necessarily reflect those of the National Joint Registry Steering Committee or the Health Quality Improvement Partnership (HQIP) who do not vouch for how the information is presented.

The data used for this analysis was obtained from the National Joint Registry (“NJR”), part of the Healthcare Quality Improvement Partnership (“HQIP”).

HQIP, the NJR and/or its contractor, Northgate Public Servi ces (UK) Limited (“NPS”) take no responsibility (except as prohibited by law) for the accuracy, currency, reliability and correctness of any data used or referred to in this report, nor for the accuracy, currency, reliability and correctness of links or references to other information sources and disclaims all warranties in relation to such data, links and references to the maximum extent permitted by legislation including any duty of care to third party readers of the data analysis.

For detailed product information, including indications for use, contraindications, precautions and warnings, please consult the product’s applicable Instructions for Use (IFU) prior to use.

journey knee prosthesis

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  • v.13(1); 2023

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Original research

Comparison of the journey ii bicruciate stabilised (jii-bcs) and genesis ii total knee arthroplasty for functional ability and motor impairment: the capability, blinded, randomised controlled trial, iain mcnamara.

1 Norfolk and Norwich University Hospital, Norwich, UK

2 University of East Anglia, Norwich, UK

Valerie Pomeroy

Allan b clark.

3 Norwich Medical School, University of East Anglia, Norwich, UK

Graham Creelman

4 Mental Health Act Review Panels, Norfolk and Suffolk, UK

Celia Whitehouse

5 Department of clinical neurosciences, University of Cambridge, Cambridge, UK

Toby O Smith

6 Faculty of Medicine and Health Sciences, University of East Anglia, Norwich, UK

Juliet High

7 Norwich Clinical Trials Unit, Norwich, UK

Ann Marie Swart

8 Health Sciences, University of East Anglia, Norwich, UK

Celia Clarke

Associated data.

bmjopen-2022-061648supp001.pdf

Data are available on reasonable request. Reasonable requests for data will be considered by the trial team.

To determine if a newer design of total knee replacement (TKR) (Journey II BCS) produces superior patient-reported outcomes scores and biomechanical outcomes than the older, more established design (Genesis II).

Patients were recruited from an NHS University Hospital between July 2018 and October 2019 with surgery at two sites. Biomechanical and functional capacity measurements were at a University Movement and Exercise Laboratory.

Participants

80 participants undergoing single-stage TKR.

Interventions

Patients were randomised to receive either the Journey II BCS (JII-BCS) or Genesis II TKR.

Primary and secondary outcome measures

Primary outcome was the Oxford Knee Score (OKS), at 6 months. Secondary outcomes were: OKS Activity and Participation Questionnaire, EQ-5D-5L and UCLA Activity scores, Timed Up and Go Test, 6 min walk test, lower limb kinematics and lower limb muscle activity during walking and balance.

This study found no difference in the OKS between groups. The OKS scores for the JII-BCS and Genesis II groups were mean (SD) 42.97 (5.21) and 43.13 (5.20) respectively, adjusted effect size 0.35 (-2.01,2.71) p=0.771

In secondary outcome measures, the Genesis II group demonstrated a significantly greater walking range-of-movement (50.62 (7.33) vs 46.07 (7.71) degrees, adjusted effect size, 3.14 (0.61,5.68) p=0.02) and higher peak knee flexion angular velocity during walking (mean (SD) 307.69 (38.96) vs 330.38 (41.40) degrees/second, adjusted effect size was 21.75 (4.54,38.96), p=0.01) and better postural control (smaller resultant centre of path length) during quiet standing than the JII-BCS group (mean (SD) 158.14 (65.40) vs 235.48 (176.94) mm, adjusted effect size, 59.91 (–105.98, –13.85) p=0.01.).

Conclusions

In this study population, the findings do not support the hypothesis that the Journey II BCS produces a better outcome than the Genesis II for the primary outcome of the OKS at 6 months after surgery.

Trial registration number

ISRCTN32315753 .

STRENGTHS AND LIMITATIONS OF THIS STUDY

  • This is a two arm, superiority, observer-blind, participant-blind and clinical staff-blind, randomised control trial.
  • It uses a wide variety of patient reported outcomes measures and biomechanical measurements to determine if one implant is superior to the other
  • The required sample size was achieved with only one person lost to follow-up.
  • A potential limitation is the relatively large number of secondary outcomes.
  • The surgeons all had a much greater familiarity with the implantations of Genesis II implants.

Original protocol for the study is mentioned here: https://trialsjournal.biomedcentral.com/articles/10.1186/s13063-020-4143-4 .

Introduction

Despite total knee replacement (TKR) being a recommended surgical treatment for end-stage knee osteoarthritis, 1 up to 34% of all patients following TKR have poor functional outcomes. 2–6 With estimates of osteoarthritis of the knee affecting one in eight people in the USA 7 and 250 million individuals worldwide 8 the number of patients with intrusive symptoms after surgery is significant.

Multiple changes in implant design have been introduced to try to improve patient outcomes and while some implant design alterations have led to improvements in patient-reported outcome measures (PROMS) 9–11 and kinematics 12 13 not all have led to differences. 14–20

The Genesis II (Smith & Nephew, Memphis, Tennessee, USA) TKR has been reported to have good survivorship and patient satisfaction 13 21 and is commonly used in the UK 22 An evolutionary design, the Journey II BCS (JII-BCS; Smith & Nephew), also manufactured by Smith and Nephew, has been developed to improve kinematic outcome compared with the Genesis II by using a bicruciate design. 23 This design change has been supported by encouraging fluoroscopic studies. However, to date, no randomised controlled trials (RCTs) have been conducted to assess if there is a difference in the outcome compared with its predicate design. 24

This trial aimed to assess whether the JII-BCS would produce better patient reported and movement outcomes than the Genesis II.

The published protocol included the aims for investigating: the rotational profile around the native knee and following TKR; and patients’ experiences and surgeons’ experiences. 25 These findings will be reported in subsequent manuscripts.

Trial design, randomisation, blinding to intervention allocation, ethics and registration

A two-arm, superiority RCT comparing the JII-BCS knee implant (experimental intervention) to the Genesis II knee implant (control intervention) was performed. The trial was observer-blind, participant-blind and clinical staff-blind. Only the operating surgeon and theatre team knew which implant was used for an individual participant.

Trial participants were assigned to either the JII-BCS or Genesis II group using a computer-generated, 1:1 randomisation schedule stratified by site and age (<60 years = younger; ≥60 years = older). 26 27 Group allocation was revealed using REDCap, 28 29 the interactive web-randomisation system, to a member of the research team who was not involved in either the clinical care or assessments of any participant. Allocation was concealed from the surgical team until after the preoperation baseline measures were completed.

Sample size

The sample size was calculated from the Oxford Knee Score (OKS, primary outcome measure). 30 The RCT was powered at 80% with a 5% significance level to detect a minimally important clinical difference of five points 31 32 with an SD of 7.4 points. 33 Accounting for an estimated attrition rate of 10% at 6 months postsurgery the estimated sample size was 80 participants (40 per group).

Participants, setting and recruitment

Full eligibility criteria are provided in the published protocol. 25 In brief, participants were aged at least 18 years and met the clinical and radiological criteria for a single-stage TKR. People were excluded if they: had a fixed-flexion deformity of at least 15° or non-correctable varus/valgus deformity of at least 15°; had inflammatory arthritis or previous septic arthritis; had previous surgery to the collateral ligaments of the affected knee; had a contralateral TKR implanted less than 1 year earlier; had severe comorbidity that could present an unacceptable safety risk or were pregnant; were a private patient; were likely to be living outside the clinical centre catchment area at 6 months postsurgery or were enrolled on another clinical trial.

Patients were recruited at a university teaching hospital with surgery conducted at two sites. Outpatient physiotherapy was conducted in a single hospital. The Movement and Exercise Laboratory at the associated University (MoveExLab) was the setting for measures of functional capacity and biomechanics.

All participants received routine NHS care for people with TKR irrespective of the implant received. This included following a standard postoperative rehabilitation of outpatient physiotherapy centred on knee strength and range of motion (ROM) exercises within the first 6 weeks after surgery. Patients received the same physiotherapy protocols and classes.

Experimental intervention

Participants in the experimental group received the JII-BCS. The JII-BCS is a dual-cam post designed to substitute for both the anterior cruciate ligament and posterior cruciate ligament. In addition the femoral and tibial components are asymmetric and the polyethylene insert is a medially concave and laterally convex shape. The device is designed to provide guided motion, and thus improve knee kinematics, and increase anteroposterior stability throughout knee flexion.

Control intervention

  • Participants in the control group received the Genesis II (Smith and Nephew), posterior stabilised (PS) TKR. The design features specific to the implant and a lateralised trochlear groove to improve patellar contact and tracking, an externally rotated femoral implant design and an anatomically shaped tibial baseplates.

Surgical techniques

All four surgeons had extensive experience, at least 5 years, of the Genesis II implant. All undertook cadaveric training on the JII-BCS and declared that they were competent in the surgical technique having completed their operative learning curve before starting the trial. Both implants are uncoated, cemented implants. The surgical procedure followed the standard manual surgical approach and technique through a medial parapatellar approach in all cases with intramedullary femoral and tibial rods to provide the alignment of the components. Patella resurfacing was used in both groups.

Data collection schedule

Data collection time points for the primary outcome measure were: at least 1 day before surgery (baseline), 7±2 days after surgery (1 week postoperatively), 6–8±2 weeks after surgery (2 months), 6 months±4 weeks after surgery (outcome, primary time point). Secondary outcomes were collected at baseline, 2 months and 6 months. Any differences from these time points are provided in the outcome measures section.

Outcome measures

Primary outcome measure.

The OKS was the primary outcome measure. This is a 12-question patient self-assessment of knee function and pain 30 with values ranging from 0 (worst outcome) to 48 (best outcome).

Secondary outcome measures

  • The Oxford Knee Score Activity and Participation Questionnaire (OKS-APQ), which complements the OKS by assessing everyday activity and social participation. 34 The overall score is from 12 to 60 with 12 being the best outcome.
  • The EQ-5D-5L is a self-report questionnaire consisting of five questions and a Visual Analogue Scale. Higher values indicate better quality of life. 35
  • The UCLA Activity score (UCLA) to assess physical activity self-rating scale ranged from 0 (complete inactivity) to 10 (participation in impact sport).
  • Timed Up and Go Test (TUG)—seconds to rise from chair, walk 3 m and return to sitting; mean of three trials. 36 The reported minimal detectable change after TKR is 2.27 s. 37 A lower value indicates better function.
  • Six min walk test—metres walked in 6 min around a 20 m circuit. 38 39 The reported minimal detectable change from baseline after TKR is 26 metres. 40 A higher value indicates greater function.
  • Modified Star-Excursion Test 41 (cm/leg length) where larger values indicate better balance.

For these simultaneous measures, participants wore shorts and were bare-footed. Reflective sensors were placed in accordance with the Plug-In Gait model (Vicon) for the lower limb and three-dimensional motion data were collected, at 100 HZ, with eight wall-mounted infrared cameras (Vicon Motion System, Oxford, UK). Three embedded force plates (BERTEC, Ohio, USA) were used to collect kinetic data at 2000 Hz for walking tasks and 100 Hz for balance tasks. Surface electromyographic sensors (EMG: Delsys) were placed bilaterally on the Vastus Medialis, Vastus Lateralis, Tibialis Anterior, Bicep Femoris and lateral head of the Gastrocnemius following SENIAM guidance. EMG data were collected at 2000 Hz.

For walking tasks, participants were asked to walk in a straight line along a 10 m walkway at their self-selected speed. For double stance balance activities, participants were instructed to stand with their feet shoulder-width apart. For single stance balance activities, participants were instructed to stand on one leg with hands-on-hips. Three trials of 10 s were recorded for each activity.

For the stair ambulation task, participants were asked to complete six ascents and six descents all unaided, leading with the operated limb for three trials and the non-operated limb for the remainder. The stairs had four steps. The first step was 16.5 cm, and the others were 15 cm high. Handrails were available if participants needed support.

Movement data were processed in accordance with the Vicon Plug-in Gait Model (Oxford Metrics, Oxford, UK). Raw EMG was filtered with pass bands at 10 and 500 Hz, rectified and low pass filtered using a fourth order Butterworth with a 10 Hz cut-off. Walking data were normalised to 101 data points for the gait cycle. Three trials of tasks were used to create a mean for each measure per participant. Values were extracted using a purpose-built MATLAB script. Data were processed by motion analysis experts in the research team.

The JII-BCS is expected to provide more normal kinematics during knee movement than Genesis II due to the design changes discussed earlier. Other authors have indicated that the femo-tibial relationship may be more normal during deep knee bend 42 and more stable during walking 43 Accordingly, people with the Journey prosthesis may 44 45 or may 43 have greater knee ROM, may walk faster, 46 47 and may have a longer stride length 46 47 than people receiving a comparison knee replacement. In addition, greater stability of the femur on the tibia could produce greater knee flexion angular velocity as dynamic knee loading could be more normal. However, there is only one non randomised study of 18 patients comparing the JII-BCS directly with the Genesis II. 45 Based on the available literature, the hypothesis driving the kinematic investigation was that people receiving the JII-BCS compared with those receiving the Genesis II would have greater walking velocity, step-length symmetry (resulting from longer stride length), knee ROM and peak knee flexion angular velocity.

  • Walking speed (metres/second). A higher value indicates better performance
  • Step length symmetry during walking. Step length ratio was calculated as ((2xOp)/Op+NOp))−1); where Op is the step length of the operated leg and NOp is the step length of the non-operated leg. Zero indicates perfect symmetry and best performance.
  • Knee ROM during walking (degrees). Higher values indicate better performance.
  • Peak knee flexion angular velocity during walking (degrees per second). This was inadvertently omitted from the statistical analysis plan (SAP). Higher value indicates better performance.
  • Double stance support (% of gait cycle). It was planned to measure cadence, (steps/min), step length (m) and stride length (m). However, there is redundancy with the temporal-spatial gait parameters of walking speed and step length symmetry which are included in the primary movement performance measures.
  • Peak extension and flexion moments of operated knee during the gait cycle (Nm/kg).
  • Hip and ankle ROM during walking.
  • Peak knee flexion angular velocity during stepping up onto a stair.
  • Percentage of gait cycle for peak activation of Vastus Medialis, Vastus Lateralis, Tibialis Anterior, Biceps Femoris and Lateral head of Gastrocnemius (% of gait cycle).
  • Balance measures were derived from kinetic data (from force plates) during standing still: single stance on the operated lower limb for 10 s with eyes open (yes/no) and duration maintained; resultant centre of pressure path length (COP cm) in double stance with eyes closed; and resultant COP velocity (cm/s) in double stance with eyes closed.

Clinical context and adverse events

Data on length of hospital stay and complications related to the surgery (eg, anaesthesia-related problems, bleeding, morbidities) were collected from a notes review. At each visit, participants were asked about their pain medication and if they had received additional treatment since their surgery/previous visit and what this entailed. Any need for revision surgery was recorded. All adverse events identified were tracked until resolution.

The SAP was finalised and agreed prior to database lock and analysis was completed blinded to group allocation ( online supplemental file ). For all outcomes the hypothesis tests and 95% CIs were two sided; and a p<0.05 was considered significant. An intention-to-treat analysis was conducted that is, all randomised participants regardless of their eligibility or adherence were analysed according to the treatment they were randomised to receive. The analysis was undertaken by the Trial Statistician using Stata V.16.

Supplementary data

For the primary outcome, the mean OKS at 6 months was compared between the control and experimental groups using a general linear model adjusting for site and age (<60 years/≥60 years). An adjusted analysis was conducted using the same model but adjusting for the OKS at baseline. The model assumptions were checked graphically, and sensitivity analysis done using a non-parametric bootstrap using 5000 repetitions.

All the other outcomes were analysed separately at 2 months and 6 months using the same general linear model specified above and a corresponding adjusted analysis. The exception was ability to balance for 10 s. This was analysed using a logistic regression model adjusting for site and age.

Patient and public involvement

A patient representative, who had previously undergone knee replacement surgery, was involved in the protocol development, assessment of the burden of the intervention and time taken to participate in the research and oversight of the trial as a member the trial management group. The representative also contributed to the planning and writing of research dissemination materials.

Participants were recruited between July 2018 and October 2019. Last follow-up visits were in October 2020 with some impact and delayed visits due to COVID-19.

In the published protocol, 25 the analysis plan included a per-protocol and safety analysis. This was not undertaken as the implants were used as intended so these populations would be the same as the intention-to-treat population.

Flow of participants through the trial

In total, 105 of 153 people screened were eligible to take part, 16 declined participation and eight were excluded for other reasons. Therefore, 81 of 153 people (53%) were recruited. All participants in the Genesis II group (n=40) received their allocated intervention. In the JII-BCS group (n=41), one participant withdrew prior to surgery (postrandomisation exclusion). Full details are in the Consolidated Standards of Reporting Trials (CONSORT) flow chart ( figure 1 ).

An external file that holds a picture, illustration, etc.
Object name is bmjopen-2022-061648f01.jpg

Consolidated Standards of Reporting Trials (CONSORT) diagram.

Participant characteristics

There were no discernible baseline differences between the groups ( table 1 ).

The baseline characteristics of participants

EQ-5D-5L is a measure of health-related quality of life, in the range of −0.109 (worst possible state) and 1.0 (perfect health), anchored at 0 (death).

EQ-VAS is a health state assessment ranging between 0 and 100, in which 0 is worst imaginable health state and 100 is best imaginable health state.

OKS is a 12-item knee function assessment, ranging from 0 (worst score) to 48 (best score).

Timed Up and Go Test—seconds to rise from chair, walk 3 m and return to sitting; mean of three trials. A lower value indicates better function.

Six min walk test—metres walked in 6 min around a 20 m circuit A higher value indicates greater function.

The UCLA Activity score to assess physical activity self-rating scale ranged from 0 (complete inactivity) to 10.

*Thirt-nine participants.

†Thirt-eight participants.

Primary outcome comparison: 6 months postoperatively

The OKS scores for the JII-BCS and Genesis II groups were mean (SD) 42.97 (5.21) and 43.13 (5.20), respectively. There was no significant difference between the groups: adjusted effect size 0.35 (−2.01,2.71) p=0.771 ( table 2 ).

Oxford Knee Scores (OKS, primary outcome), from baseline to 6 months after surgery (primary time point)

Journey II BCS (JII-BCS)

*Adjusted for strata used in randomisation and for baseline scores.

APQ, Activity and Participation Questionnaire; VAS, Visual Analogue Scale.

Secondary outcome comparisons: 6 months postoperatively

Patient-reported outcome questionnaires.

There were no differences between the two groups for any of the secondary patient reported outcomes ( online supplemental tables S1 ).

Walking and balance functional ability

There was no difference between the JII-BCS and Genesis II groups in the time to complete the TUG Test or the distance covered in the 6 min walk test ( online supplemental table S2 ). The Star-Excursion Test was attempted by all participants but 59% of participants at baseline, 59% at follow-up and 63% at outcome were unable to complete it ( online supplemental table S3 ). Therefore, statistical analysis was not undertaken.

Movement performance during walking and balance

The primary movement performance measures are reported in table 3 . In summary at 6 months postsurgery, the Genesis II group had a significant advantage for knee ROM and peak knee flexion angular velocity during walking. There were no differences between the groups for walking speed or peak flexion angular knee velocity on stair climbing.

Movement performance primary measures during walking from baseline to 6 months postsurgery (primary time point): walk speed, step length symmetry, knee range of motion (ROM) and peak knee flexion angular velocity

Step length symmetry—step length ratio calculated as ((2xOp)/Op+NOP))−1); where Op is the step length of the operated leg and NOP is the step length of the non-operated leg. Zero indicates perfect symmetry and best performance.

Bold text is used to denote values achieving statisitcal significance

Data for all secondary movement performance measures are provided in online supplemental tables S4–S8 . The only difference between groups that reached statistical significance was for COP path length in double stance with eyes closed ( online supplemental table S7 ). The mean (SD) values for the Genesis II and JII-BCS groups were 158.14 (65.40) mm and 235.48 (176.94) mm, respectively. Adjusted effect size was −59.91 (–105.98, –13.85) p=0.01 in favour of the Genesis II group.

Postoperative clinical context

There were no between-group significant differences for: length of stay, change in pain medication from randomisation or physiotherapy received ( online supplemental tables S9 and S10 ).

Adverse events

One patient with a JII-BCS developed acute swelling and pain in the knee and was systemically unwell at 4 months postoperatively. The joint aspiration demonstrated turbid fluid and an exchange of the polyethylene spacer and retention of the femoral and tibial components (Debridement And Implant Retention) was performed with postoperative antibiotic treatment. Subsequent microbiology was negative so infection was never conclusively demonstrated. The numbers and type of complications are reported in online supplemental table S11 .

The findings do not support the hypothesis that the JII-BCS produces a better outcome than the Genesis II for the primary outcome of the OKS at 6 months after surgery. No differences between groups were also found for: other patient-reported outcomes; measures of balance and walking function; hip and ankle ROM; knee moments during walking; double support time during walking and percentage of gait cycle for peak muscle activation. However, significant advantages for the control group (Genesis II) were found for: operated knee range-of-movement and peak knee flexion angular velocity during walking, and postural control (COP path length).

While some investigators have demonstrated differences between generations of knee designs 12 not all modern generation TKR designs have demonstrated an improvement in outcomes when compared with their predecessors. 15–20 48 One possible reason for this is that the predecessor is already producing good results and therefore is difficult to improve on. Regarding the JII-BCS, at the time of writing, only Bialy et al 45 have directly compared the Genesis II and the JII-BCS. Their study was non randomised and consisted of 18 patients between the two groups. They reported a greater supine range of movement of the JII-BCS compared with the Genesis II when measured with a long arm goniometer. They also reported an improvement in functional knee scores and stability when balancing. Their conclusions were that the JII-BCS restores more normal anatomy and kinematics which is correlates into the improvements that they found. None of the other papers reporting outcomes of the JII-BCS compared the JII-BCS to the Genesis II, none used a randomised design and none used methodology or outcomes that could be compared with the methodology used in this trial. 42–46 However, on the basis of the available literature, we measured outcomes that would be expected to be difference on the basis of the available literature, walking velocity, step-length symmetry (resulting from longer stride length), knee ROM and peak knee angular velocity.

Within our trial, we found differences in some biomechanical measures of motor impairment but not for others; patient-reported outcomes; and, walking and balance function. It is possible that knee range-of-movement during walking, walking symmetry, peak knee flexion angular velocity during walking and postural control (COP path length) are detecting motor impairment improvement for the Genesis II group and/or because statistical significance was a result of testing multiple outcomes. The latter explanation is clearly possible but knee range-of-movement is greater for people reporting good outcome after knee replacement than for those reporting poor outcome. 49 Moreover, knee range-of-movement has been found to be the main biomechanical effect of TKR 50 and to improve over time while other biomechanical measures do not. 50 51 Likewise, postural control improves over time 52 53 and approaches healthy control values. 52 Importantly, gait symmetry is an indicator of walking control 54 and, while of borderline statistical significance (p=0.05) can possibly detect differences following insertion of different prostheses. Peak knee angular velocity during walking is also an indicator of walking control 55 and has been found to change beneficially after insertion of the Genesis II prosthesis. 50 These findings indicate that secondary, in-depth, analysis of the biomechanical data should be undertaken.

A potential limitation is the relatively large number of secondary outcomes. However, this is also a strength as it ensured comprehensive examination of the potential impact of TKR on functional ability, motor impairment and health-related quality of life. Another potential limitation is that the surgeons all had a much greater familiarity with the Genesis II implants. However, all surgeons were very experienced with the Genesis II implant with at least 10 years of experience implanting the device. All surgeons received thorough training with the JII-BCS and the surgical technique and instrumentation are similar for both devices with only one additional femoral cut being necessary for the JII-BCS compared with the Genesis II. A key strength of this trial is that the required sample size was achieved with only one person lost to follow-up. Other strengths include minimisation of selection bias through a robust randomisation procedure and use of double blinding to minimise interpretation bias.

The lack of difference between implant designs is important for patients, surgeons, healthcare providers and implant companies. For the patient and surgeons, reassurance can be gained that older designs, with proven track record of function and survivorship, can provide the same patient reported and functional outcome as more modern designs. For the healthcare providers, older implants are often less expensive and, in the absence of clinical benefit with and demonstrable longevity, if the additional expenditure on more modern designs is avoided for the hundreds of thousands of patients undergoing surgery worldwide the cost savings are potentially significant. Finally, for the implant companies, it is more likely than not than implant design has reached a point when non-implant-related factors play a more important role in patient outcome. The future of design and innovation may come in the form of more modern surgical techniques such as robotic assisted implantation to assist in placing the knee in a more kinematically sympathetic position which in turn may allow the newer design philosophies to positively influence outcome. It is possible, only then in combination with modern surgical techniques, that improvements in patient outcomes can be realised but well-constructed surgical trials will need to answer such questions.

This study demonstrated no difference between the Genesis II and its successor the JII-BCS for PROMS, walking function, temporal-spatial gait parameters, balance ability and lower limb kinematic results at 6 months follow-up. However, significant advantages were seen in for the Genesis II in the operated knee range-of-movement, peak knee flexion angular velocity during walking and postural control.

Supplementary Material

Acknowledgments.

The team would like to thank all the participants and families who gave their time to be part of this study; Antony Colles, Martin Pond and the NCTU data management team; Estelle Payerne; Amanda Thacker; NNUH sponsorship team and the safety monitoring committee members, Prof Marcus Flather and Prof Simon Donell. Also: Mr Charles Mann, Mr Nish Chirodian, Mr David Calder, Dr Nicola Hancock, Nursing and clinic staff at the Spire Hospital and NNUH, Prof Andoni Toms and the Radiology department at NNUH and Addenbrooke’s hospital, Cambridge, Dr Simon Horton and Dr Anne Killett

Twitter: @tobyosmith

Contributors: IM and VP drafted this paper. IM is the guarantor. All authors (IM, VP, ABC, GC, CW, JW, BH, TOS, JH and AMS) contributed to revisions of the manuscript, read and approved the final manuscript. All authors (IM, VP, ABC, GC, CW, JW, BH, TO, JH and AMS) contributed to the development of the trial protocol as well as conception or design of the work; the acquisition, analysis or interpretation of data for the work.

Funding: This work was supported by an investigator initiated grant from Smith and Nephew, with both types of knee replacements supplied at the same cost.

Disclaimer: The funders had no role in the design of the study, the data collection, the data analysis, interpretation of data, or writing of the manuscript.

Competing interests: The trial was funded by Smith and Nephew via an unrestricted grant, administered by the Sponsor NNUH. Funding was used within NNUH for running the trial. Funds were provided via NNUH to UEA for the members of the trial team based in the movement and Exercise Laboratory (MoveExLab) at UEA and the clinical trials unit (CTU) based at UEA for statistics, and trial and data management.

Patient and public involvement: Patients and/or the public were involved in the design, or conduct, or reporting, or dissemination plans of this research. Refer to the Methods section for further details.

Provenance and peer review: Not commissioned; externally peer reviewed.

Supplemental material: This content has been supplied by the author(s). It has not been vetted by BMJ Publishing Group Limited (BMJ) and may not have been peer-reviewed. Any opinions or recommendations discussed are solely those of the author(s) and are not endorsed by BMJ. BMJ disclaims all liability and responsibility arising from any reliance placed on the content. Where the content includes any translated material, BMJ does not warrant the accuracy and reliability of the translations (including but not limited to local regulations, clinical guidelines, terminology, drug names and drug dosages), and is not responsible for any error and/or omissions arising from translation and adaptation or otherwise.

Data availability statement

Ethics statements, patient consent for publication.

Not applicable.

Ethics approval

This study involves human participants and was approved by East of England – Cambridge Central Research Ethics Committee (reference 16/EE/0230). Participants gave informed consent to participate in the study before taking part.

Journey-Deuce bicompartmental knee arthroplasty with the addition of computer navigation achieves good clinical outcomes and implant survival at 10 years

Affiliations.

  • 1 Fiona Stanley Fremantle Hospitals Group, Perth, WA, Australia. [email protected].
  • 2 Orthopaedic Research Foundation of Western Australia, Alma St, Fremantle, Perth, WA, Australia. [email protected].
  • 3 HFRC Rehabilitation Clinic, 117 Stirling Highway, Nedlands, WA, 6009, Australia.
  • 4 School of Human Sciences (Exercise and Sport Science), University of Western Australia, Crawley, WA, 6009, Australia.
  • 5 Orthopaedic Research Foundation of Western Australia, Alma St, Fremantle, Perth, WA, Australia.
  • 6 Fiona Stanley Fremantle Hospitals Group, Perth, WA, Australia.
  • 7 School of Surgery (Orthopaedics), University of Western Australia, Crawley, Perth, WA, 6009, Australia.
  • PMID: 33974113
  • DOI: 10.1007/s00167-021-06579-8

Purpose: To report 10-year outcomes and survivorship in patients undergoing bicompartmental knee arthroplasty (BCKA) using the Journey-Deuce prosthesis in a consecutive prospective case series.

Methods: Between November 2006 and November 2009, 41 patients with a mean age of 69.6 years (range 51-86) underwent 51 bicompartmental knee arthroplasties with the Journey-Deuce knee prosthesis. All patients presented with symptomatic medial and patellofemoral compartment osteoarthritis, with intact cruciate ligaments and a preserved lateral compartment on plain radiographs and Magnetic Resonance Imaging. Clinical assessment was undertaken pre-surgery and at 1, 2, 5 and 10 years post-surgery using the Oxford Knee Score (OKS), EuroQol Group 5-Dimension self-reported questionnaire (EQ-5D) and maximal active range of motion (ROM).

Results: 30 patients (37 knees) were followed-up at a mean time of 11.4 years (SD 1.1; range 10.5-14.0). Eight patients (ten knees) were deceased and three could not be contacted at final review. No major component revision was performed. Pre-operative OKS 25.4 (SD 5.2; range 15-40), knee flexion 116.4° (SD 10.3°; range 100°-140°) and EQ-5D 70.5 (SD 19.9; range 25-95). 10-year OKS 43.5 (SD 4.1; range 32-48), knee flexion 127.3° (SD 11.1°; range 105°-144°) and EQ-5D 77.4 (SD 9.3; range 60-100). The OKS (p < 0.0001), EQ-5D (p = 0.024) and active knee flexion ROM (p < 0.0001) all significantly improved from pre-surgery to 1-year post-surgery, with no further significant changes in these scores between any post-operative time period up until 10 years. 32% (7/22) of tibial and 45% (10/22) of femoral components showed progressive radiolucencies between 2 and 5-year and 10-year follow-up.

Conclusions: This is the largest cohort of patients having undergone BCKA (with the Journey-Deuce prosthesis) with longest follow-up described in the literature. At 10 years, patients presented with significantly improved clinical outcomes, comparable to other surgical arthroplasty options. No major component revision was performed. Progressive radiolucencies were noted in 32% of tibial and 45% of femoral components without corresponding clinical signs of loosening.

Level of evidence: Level III.

Keywords: Arthroplasty; Bicompartmental; Journey-Deuce; Knee.

© 2021. Crown.

  • Aged, 80 and over
  • Arthroplasty, Replacement, Knee*
  • Follow-Up Studies
  • Knee Prosthesis*
  • Middle Aged
  • Osteoarthritis, Knee*
  • Range of Motion, Articular
  • Treatment Outcome

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A prosthesis driven by the nervous system helps people with amputation walk naturally

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A person wears a prosthetic leg with a circuit board while walking up stairs in a lab.

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State-of-the-art prosthetic limbs can help people with amputations achieve a natural walking gait, but they don’t give the user full neural control over the limb. Instead, they rely on robotic sensors and controllers that move the limb using predefined gait algorithms.

Using a new type of surgical intervention and neuroprosthetic interface, MIT researchers, in collaboration with colleagues from Brigham and Women’s Hospital, have shown that a natural walking gait is achievable using a prosthetic leg fully driven by the body’s own nervous system. The surgical amputation procedure reconnects muscles in the residual limb, which allows patients to receive “proprioceptive” feedback about where their prosthetic limb is in space.

In a study of seven patients who had this surgery, the MIT team found that they were able to walk faster, avoid obstacles, and climb stairs much more naturally than people with a traditional amputation.

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“This is the first prosthetic study in history that shows a leg prosthesis under full neural modulation, where a biomimetic gait emerges. No one has been able to show this level of brain control that produces a natural gait, where the human’s nervous system is controlling the movement, not a robotic control algorithm,” says Hugh Herr, a professor of media arts and sciences, co-director of the K. Lisa Yang Center for Bionics at MIT, an associate member of MIT’s McGovern Institute for Brain Research, and the senior author of the new study.

Patients also experienced less pain and less muscle atrophy following this surgery, which is known as the agonist-antagonist myoneural interface (AMI). So far, about 60 patients around the world have received this type of surgery, which can also be done for people with arm amputations.

Hyungeun Song, a postdoc in MIT’s Media Lab, is the lead author of the paper , which appears today in Nature Medicine .

Sensory feedback

Most limb movement is controlled by pairs of muscles that take turns stretching and contracting. During a traditional below-the-knee amputation, the interactions of these paired muscles are disrupted. This makes it very difficult for the nervous system to sense the position of a muscle and how fast it’s contracting — sensory information that is critical for the brain to decide how to move the limb.

People with this kind of amputation may have trouble controlling their prosthetic limb because they can’t accurately sense where the limb is in space. Instead, they rely on robotic controllers built into the prosthetic limb. These limbs also include sensors that can detect and adjust to slopes and obstacles.

To try to help people achieve a natural gait under full nervous system control, Herr and his colleagues began developing the AMI surgery several years ago. Instead of severing natural agonist-antagonist muscle interactions, they connect the two ends of the muscles so that they still dynamically communicate with each other within the residual limb. This surgery can be done during a primary amputation, or the muscles can be reconnected after the initial amputation as part of a revision procedure.

“With the AMI amputation procedure, to the greatest extent possible, we attempt to connect native agonists to native antagonists in a physiological way so that after amputation, a person can move their full phantom limb with physiologic levels of proprioception and range of movement,” Herr says.

In a 2021  study , Herr’s lab found that patients who had this surgery were able to more precisely control the muscles of their amputated limb, and that those muscles produced electrical signals similar to those from their intact limb.

After those encouraging results, the researchers set out to explore whether those electrical signals could generate commands for a prosthetic limb and at the same time give the user feedback about the limb’s position in space. The person wearing the prosthetic limb could then use that proprioceptive feedback to volitionally adjust their gait as needed.

In the new Nature Medicine study, the MIT team found this sensory feedback did indeed translate into a smooth, near-natural ability to walk and navigate obstacles.

“Because of the AMI neuroprosthetic interface, we were able to boost that neural signaling, preserving as much as we could. This was able to restore a person's neural capability to continuously and directly control the full gait, across different walking speeds, stairs, slopes, even going over obstacles,” Song says.

A natural gait

For this study, the researchers compared seven people who had the AMI surgery with seven who had traditional below-the-knee amputations. All of the subjects used the same type of bionic limb: a prosthesis with a powered ankle as well as electrodes that can sense electromyography (EMG) signals from the tibialis anterior the gastrocnemius muscles. These signals are fed into a robotic controller that helps the prosthesis calculate how much to bend the ankle, how much torque to apply, or how much power to deliver.

The researchers tested the subjects in several different situations: level-ground walking across a 10-meter pathway, walking up a slope, walking down a ramp, walking up and down stairs, and walking on a level surface while avoiding obstacles.

In all of these tasks, the people with the AMI neuroprosthetic interface were able to walk faster — at about the same rate as people without amputations — and navigate around obstacles more easily. They also showed more natural movements, such as pointing the toes of the prosthesis upward while going up stairs or stepping over an obstacle, and they were better able to coordinate the movements of their prosthetic limb and their intact limb. They were also able to push off the ground with the same amount of force as someone without an amputation.

“With the AMI cohort, we saw natural biomimetic behaviors emerge,” Herr says. “The cohort that didn’t have the AMI, they were able to walk, but the prosthetic movements weren’t natural, and their movements were generally slower.”

These natural behaviors emerged even though the amount of sensory feedback provided by the AMI was less than 20 percent of what would normally be received in people without an amputation.

“One of the main findings here is that a small increase in neural feedback from your amputated limb can restore significant bionic neural controllability, to a point where you allow people to directly neurally control the speed of walking, adapt to different terrain, and avoid obstacles,” Song says.

“This work represents yet another step in us demonstrating what is possible in terms of restoring function in patients who suffer from severe limb injury. It is through collaborative efforts such as this that we are able to make transformational progress in patient care,” says Matthew Carty, a surgeon at Brigham and Women’s Hospital and associate professor at Harvard Medical School, who is also an author of the paper.

Enabling neural control by the person using the limb is a step toward Herr’s lab’s goal of “rebuilding human bodies,” rather than having people rely on ever more sophisticated robotic controllers and sensors — tools that are powerful but do not feel like part of the user’s body.

“The problem with that long-term approach is that the user would never feel embodied with their prosthesis. They would never view the prosthesis as part of their body, part of self,” Herr says. “The approach we’re taking is trying to comprehensively connect the brain of the human to the electromechanics.”

The research was funded by the MIT K. Lisa Yang Center for Bionics and the Eunice Kennedy Shriver National Institute of Child Health and Human Development.

Hugh Herr, who wears two prosthetic legs, speaks to someone holding a prosthetic leg.

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Press mentions.

Researchers at MIT have developed a novel surgical technique that could “dramatically improve walking for people with below-the-knee amputations and help them better control their prosthetics,” reports Timmy Broderick for STAT . “With our patients, even though their limb is made of titanium and silicone, all these various electromechanical components, the limb feels natural, and it moves naturally, without even conscious thought," explains Prof. Hugh Herr. 

Financial Times

A new surgical approach developed by MIT researchers enables a bionic leg driven by the body’s nervous system to restore a natural walking gait more effectively than other prosthetic limbs, reports Clive Cookson for the Financial Times . “The approach we’re taking is trying to comprehensively connect the brain of the human to the electro-mechanics,” explains Prof. Hugh Herr.  

The Washington Post

A new surgical procedure and neuroprosthetic interface developed by MIT researchers allows people with amputations to control their prosthetic limbs with their brains, “a significant scientific advance that allows for a smoother gait and enhanced ability to navigate obstacles,” reports Lizette Ortega for The Washington Post . “We’re starting to get a glimpse of this glorious future wherein a person can lose a major part of their body, and there’s technology available to reconstruct that aspect of their body to full functionality,” explains Prof. Hugh Herr. 

The Guardian

MIT scientists have conducted a trial of a brain controlled bionic limb that improves gait, stability and speed over a traditional prosthetic, reports Hannah Devlin for The Guardian . Prof. Hugh Herr says with natural leg connections preserved, patients are more likely to feel the prosthetic as a natural part of their body. “When the person can directly control and feel the movement of the prosthesis it becomes truly part of the person’s anatomy,” Herr explains. 

The Economist

Using a new surgical technique, MIT researchers have developed a bionic leg that can be controlled by the body’s own nervous system, reports The Economist . The surgical technique “involved stitching together the ends of two sets of leg muscles in the remaining part of the participants’ legs,” explains The Economist . “Each of these new connections forms a so-called agonist-antagonist myoneural interface, or AMI. This in effect replicates the mechanisms necessary for movement as well as the perception of the limb’s position in space. Traditional amputations, in contrast, create no such pairings.”  

The Boston Globe

Researchers at MIT and Brigham and Women’s Hospital have created a new surgical technique and neuroprosthetic interface for amputees that allows a natural walking gait driven by the body’s own nervous system, reports Adam Piore for The Boston Globe . “We found a marked improvement in each patient’s ability to walk at normal levels of speed, to maneuver obstacles, as well as to walk up and down steps and slopes," explains Prof. Hugh Herr. “I feel like I have my leg — like my leg hasn’t been amputated,” shares Amy Pietrafitta, a participant in the clinical trial testing the new approach.

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JOURNEY ◊ II AKS implant feel

The right "feel" often starts with the right design.

journey knee prosthesis

To most of us, total knee implants all look very similar. With the exception of color (the OXINIUM ◊ alloy used in JOURNEY ◊ II implants is black while the cobalt chrome used in other implants is silver), it can take an experienced eye to see the subtle differences in size and shape between two implants. However, as subtle as the differences may seem, they can often have a profound impact on how an implant feels to the patients after surgery.

Fortunately, JOURNEY II implants were designed using a concept called PHYSIOLOGICAL MATCHING ◊ . This unique process begins with proprietary human simulation software that virtually recreates the exact internal shapes and angled forces that act on the knee through each phase of motion. This detailed information helped Smith & Nephew engineers create an implant that replicates as closely as possible the complex, natural rotation of the knee.

Important safety note

Individual results of joint replacement vary. Implants are intended to relieve knee pain and improve function, but may not produce the same feel or function as your original knee. There are potential risks with knee replacement surgery such as loosening, wear and infection that may result in the need for additional surgery. Patients should not perform high impact activities such as running and jumping unless their surgeon tells them that the bone has healed and these activities are acceptable. Early device failure, breakage or loosening may occur if a surgeon's limitations on activity level are not followed.

Talk to your doctor to determine what treatment may be best for you.

All information provided on this website is for information purposes only. Every patient's case is unique and each patient should follow his or her doctor's specific instructions. Please discuss nutrition, medication and treatment options with your doctor to make sure you are getting the proper care for your particular situation. If you are seeking this information in an emergency situation, please call 911 and seek emergency help.

All materials copyright © 2020 Smith & Nephew, All Rights Reserved.

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Great Big Story

Great Big Story

How This Action Sports Star Built His Own Prosthetic Leg

Posted: January 2, 2024 | Last updated: July 10, 2024

Embark on an extraordinary journey with Mike Schultz, a former pro racer turned prosthetic innovator, who refused to let adversity define him. After a life-altering snowmobile accident led to amputation, Mike designed his own prosthetic leg to get back on the track. Witness the birth of the revolutionary Moto Knee and Moto Foot, as Mike's ingenuity redefines possibilities for amputees worldwide.

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  • JOURNEY UNI KNEE IMPLANT – UNLIKE ANY OTHER

Over the years, we have received feedback from our patients about how Movement Orthopedics has helped them. We are proud to share some of these patient testimonials below.

OXINIUM ◊  Technology

If it is determined that a JOURNEY UNI implant is right for you, the femoral – or thighbone portion – of your implant may be made from OXINIUM Oxidized Zirconium – a patented and award winning metal alloy that Smith & Nephew spent more than a decade developing. The JOURNEY UNI is the only partial knee implant marketed that features this remarkable material. During manufacture, OXINIUM implants undergo a process that transforms the implant’s surface into a hard, ceramicised metal; a combination that offers the smooth, hard surface of a ceramic, as well as the strength and durability of a metal. Because of this unique combination, OXINIUM implants are more than twice as hard cobalt chrome implants (the material most commonly used in knee implants) and therefore more than twice as resistant to the kind of scratching that can cause an implant to wear out before its time.

Important Safety Notes:

Individual results of joint replacement vary. Implants are intended to relieve knee pain and improve function, but may not produce the same feel or function as your original knee. There are potential risks with knee replacement surgery such as loosening, wear and infection that may result in the need for additional surgery. Patients should not perform high impact activities such as running and jumping unless their surgeon tells them that the bone has healed and these activities are acceptable. Early device failure, breakage or loosening may occur if a surgeon’s limitations on activity level are not followed.

Talk to your doctor to determine what treatment may be best for you.

All information provided on this website is for information purposes only. Every patient’s case is unique and each patient should follow his or her doctor’s specific instructions. Please discuss nutrition, medication and treatment options with your doctor to make sure you are getting the proper care for your particular situation. If you are seeking this information in an emergency situation, please call 911 and seek emergency help.

All materials copyright © 2020 Smith & Nephew, All Rights Reserved.

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Ieee spectrum, follow ieee spectrum, support ieee spectrum, enjoy more free content and benefits by creating an account, saving articles to read later requires an ieee spectrum account, the institute content is only available for members, downloading full pdf issues is exclusive for ieee members, downloading this e-book is exclusive for ieee members, access to spectrum 's digital edition is exclusive for ieee members, following topics is a feature exclusive for ieee members, adding your response to an article requires an ieee spectrum account, create an account to access more content and features on ieee spectrum , including the ability to save articles to read later, download spectrum collections, and participate in conversations with readers and editors. for more exclusive content and features, consider joining ieee ., join the world’s largest professional organization devoted to engineering and applied sciences and get access to all of spectrum’s articles, archives, pdf downloads, and other benefits. learn more about ieee →, join the world’s largest professional organization devoted to engineering and applied sciences and get access to this e-book plus all of ieee spectrum’s articles, archives, pdf downloads, and other benefits. learn more about ieee →, access thousands of articles — completely free, create an account and get exclusive content and features: save articles, download collections, and talk to tech insiders — all free for full access and benefits, join ieee as a paying member., the best bionic leg yet, a surgical procedure and muscle-sensing electrodes allow neural control of a prosthetic limb.

a gym setting with a focus on a person walking up stairs with a prosthetic leg on

A neural interface allowed people with prosthetic limbs to move faster and more naturally.

For the first time, a small group of patients with amputations below the knee were able to control the movements of their prosthetic legs through neural signals—rather than relying on programmed cycles for all or part of a motion—and resume walking with a natural gait. The achievement required a specialized amputation surgery combined with a non-invasive surface electrode connection to a robotic prosthetic lower leg. A study describing the technologies was published today in the journal Nature Medicine .

“What happens then is quite miraculous. The patients that have this neural interface are able to walk at normal speeds; and up and down steps and slopes; and maneuver obstacles really without thinking about it. It’s natural. It’s involuntary,” said co-author Hugh Herr , who develops bionic prosthetics at the MIT Media Lab . “Even though their limb is made of titanium and silicone—all these various electromechanical components—the limb feels natural and it moves naturally, even without conscious thought.”

The approach relies on surgery at the amputation site to create what the researchers call an agonist-antagonist myoneural Interface , or AMI. The procedure involves connecting pairs of muscles (in the case of below-the-knee amputation, two pairs), as well as the introduction of proprietary synthetic elements.

The interface creates a two-way connection between body and machine. Muscle-sensing electrodes send signals to a small computer in the prosthetic limb that interprets them as angles and forces for joints at the ankle and ball of the foot. It also sends information back about the position of the artificial leg, restoring a sense of where the limb is in space, also known as proprioception .

“The particular mode of control is far beyond what anybody else has come up with,” said Daniel Ferris , a neuromechanical engineer at the University of Florida; Ferris was not involved in the study, but has worked on neural interfaces for controlling lower limb prostheses. “It’s a really novel idea that they’ve built on over the last eight years that’s showing really positive outcomes for better bionic lower legs.” The latest publication is notable for a larger participant pool than previous studies, with seven treatment patients and seven control patients with amputations and typical prosthetic legs.

To test the bionic legs, patients were asked to walk on level ground at different speeds; up and down slopes and stairs; and to maneuver around obstacles. The AMI users had a more natural gait, more closely resembling movement by someone using a natural limb. More naturalistic motion can improve freedom of movement, particularly over challenging terrain, but in other studies researchers have also noted reduced energetic costs, reduced stress on the body, and even social benefits for some amputees.

Co-author Hyungeun Song , a postdoctoral researcher at MIT, says the group was surprised by the efficiency of the bionic setup. The prosthetic interface sent just 18 percent of the typical amount of information that’s sent from a limb to the spine, yet it was enough to allow patients to walk with what was considered a normal gait.

Next Steps for the Bionic Leg

AMI amputations have now become the standard at Brigham and Women’s Hospital in Massachusetts, where co-author Matthew Carty works. And because of patient benefits in terms of pain and ease of using even passive (or non-robotic) prosthetics, this technique—or something similar—could spread well beyond the current research setting. To date, roughly 60 people worldwide have received AMI surgery above or below either an elbow or knee.

In principle, Herr said, someone with a previously amputated limb, such as himself , could undergo AMI rehabilitation, and he is strongly considering the procedure. More than 2 million Americans are currently living with a lost limb, according to the Amputee Coalition, and nearly 200,000 lower legs are amputated each year in the United States.

On the robotics side, there are already commercial leg prosthetics that could be made compatible with the neural interface. The area in greatest need of development is the connection between amputation site and prosthesis. Herr says commercialization of that interface might be around five years away.

Herr says his long-term goal is neural integration and embodiment: the sense that a prosthetic is part of the body, rather than a tool. The new study “is a critical step forward—pun intended.”

  • You Want a Prosthetic Leg With a Tesla Coil and Spark Gaps? No Problem ›
  • An Open-Source Bionic Leg ›
  • Bionic ‘Feeling’ Leg Makes Walking Easier, Reduces Phantom Limb Pain ›

Greg Uyeno is a freelance science journalist based in New York City. He has been an editor, copyeditor, reporter and writer for a wide range of mediums, ages and audiences.

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Notice to membership, windows on arm is here to stay, related stories, “nothing about us without us”, mind-controlled prosthetic hands grasp new feats, their bionic eyes are now obsolete and unsupported.

Novel surgery meets bionics in breakthrough for limb amputation

journey knee prosthesis

CAMBRIDGE, Massachusetts ‒ Leg amputations haven't changed much in a very long time.

Civil War-era textbooks describing them look pretty similar to contemporary ones, said Dr. Matthew Carty, a staff surgeon at Brigham and Women's Hospital in Boston. "You could even dial it back as far as 2,000 years ago," he said, and the standard approach to limb amputation wouldn't be "all that different."

But in recent years, a small number of surgeons, including Carty, have been trying to find better methods.

Collaborating with Hugh Herr, an MIT technologist and double-amputee, Carty developed a new surgical approach, linking pairs of muscles involved in flexing and turning the ankle.

Now, the two have a new paper, published Monday in the journal Nature Medicine , showing their success with seven patients. All had both the surgery, called AMI (for agonist–antagonist myoneural interface) and a bionic prosthetic.

The combination, the study shows, allows the seven to walk naturally, at a normal pace, even up stairs and on uneven surfaces, as if the legs were their own.

Amy Pietrafitta, 47, of Plymouth, Massachusetts, was one of the seven.

"This gives me so much mobility, I love it," said Pietrafitta, a para athlete who runs marathons, dances, is a member of The Boston I.C.E. Storm sled hockey team and will compete in the 2024 World Coastal Rowing Championships in Italy in September.

But she was only able to use the bionic lower leg in Herr's MIT lab at the K. Lisa Yang Center for Bionics. Now she's back to her regular prosthetic.

"It did make me a little teary eyed," she said of leaving the bionic leg behind. "It's slightly heart-breaking."

A different way to amputate

In the AMI surgery, muscles typically involved in flexing and extending the ankle are linked, as are those involved in inverting and turning out the ankle.

About 60 patients worldwide have received the amputation procedure since the pair developed it about a decade ago, Carty said.

The surgery takes about twice as long as a typical amputation ‒ about 3 hours as opposed to 90 minutes ‒ but isn't much more technically complicated, he told USA TODAY. It doesn't need to be done at an academic medical center. Any modern hospital is good enough, he said.

"Our hope is this or something like this becomes the standard way of doing amputations around the world," Carty said.

The AMI can also be done after an amputation ‒ even years later ‒ as a revision surgery, as long as the needed muscles haven't atrophied.

Herr, who had his own amputation surgery in 1982 after a climbing accident, said he is interested in getting an AMI procedure himself, though only one of the two muscle pairs remains functional.

Bionic limbs

Movements with the bionic limb are much more natural thanks to the AMI, Pietrafitta and Herr said.

With a regular prosthetic, "your foot fights you back," Pietrafitta told USA TODAY. She's adapted to the pushing she gets from her passive prosthetic, but the bionic one felt much more like a part of her.

She was able to go on point dancing ballet and stay up even longer on the bionic foot than her natural one. "That was amazing. That brought tears to my eyes as well," she said.

Today's most advanced prosthetics typically use electronics to move a synthetic ankle, propelling the person forward. The person essentially has to respond to the signals from their prosthetic.

By contrast, the device Herr developed includes electrodes placed on the skin above the point of amputation, outside the muscles paired by the surgery, and is responsive to them. When the muscle normally involved in lifting the ankle contracts, the prosthetic ankle lifts up, when its opposite muscle contracts, the ankle flexes.

Connecting to the person's own muscles also allows them to sense where their prosthetic limb is in space in a way that is not possible with standard surgery and devices, Herr, Carty and Pietrafitta said.

Eventually, Herr said, he hopes to replace surface electrodes with implanted small magnetic spheres that can more accurately track the movements of the muscle pairings with higher fidelity to better control the prosthesis.

The combination of the AMI surgery with the bionics is particularly powerful, said Dr. Benjamin "Kyle" Potter, who was not involved in the study, but who does similar research and is the incoming chairman of the department of orthopedic surgery at Penn Medicine in Philadelphia.

"The magic here is really in the surgery," said Potter, who recently left the Walter Reed National Military Medical Center after 23 years. "What they've demonstrated here is that, although customized, a relatively simple bionic limb can help the patients walk better."

The research proves that natural walking won't require $1 million worth of technology, Potter said. "The synergy of the novel surgery with a prosthesis that can harness that power is probably the real breakthrough here."

The best thing about the surgery, Carty said, is that it enables amputees to take full advantage of available technological advances.

"Longer term, as this experimental technology moves from the lab hopefully to the commercial realm, they will have access to technology that they will be albe to use better than a standard amputee can," Carty said. Herr expects it will take about five years for the bionic limb to become commercially available.

A long, painful journey with a happy ending

Pietrafitta was injured on June 9, 2014, when superheated water fell on her at her job as a restaurant server. She was burned over a quarter of her body, including her torso and left leg.

She had skin grafts and surgeries to reconstruct her damaged leg but was left with something called complex regional pain syndrome.

On a 50-point scale, complex regional pain syndrome is said to register at about a 42 , higher than pregnancy and double the pain of a toothache. "It's called the suicide disease because you can't live in that kind of pain forever," Pietrafitta said.

Her doctor eventually determined said she needed an amputation because her injured leg was no longer functional, but her insurance company kept turning her down for the surgery, saying her pain syndrome made her a poor candidate. For more than two-and-a-half years, she and her doctors fought with the insurance company before a judge finally allowed Carty to give her the AMI amputation on Feb. 27, 2018.

Before the surgery, she took multiple oxycontin, diazepine, clonidine and zoloft every day to cope with the pain. She hasn't needed any since her recovery. "It's been amazing. I have no pain at all," she said. "From one extreme to the other."

She's able to stand in the shower again and even flip her long hair forward and back without falling. If she ever trips, it's because of her natural foot.

"I feel like I still have my limb," she said. "I know I'm an amputee, but my brain forgets in a way, because it feels like so natural."

Herr has long sought to "rebuild bodies, to give persons back after amputation their full limb restoration, where they view the synthetics not an an external tool but as part of their bodies, as self," he said in a call last week with reporters.

"This study is a critical step forward, pun intended, toward that embodiment."

Karen Weintraub can be reached at [email protected].

IMAGES

  1. Journey II Knee Prosthesis

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  2. Three-compartment knee prosthesis

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  3. Journey Bi-Cruciate Stabilised (BCS) knee replacement system

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  4. Three-compartment knee prosthesis

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  5. Smith & Nephew Releases JOURNEY II XR Total Knee Arthroplasty

    journey knee prosthesis

  6. Three-compartment knee prosthesis / fixed-bearing

    journey knee prosthesis

VIDEO

  1. Knee Replacement Method with Implant Survival Rate of 20-30 Years by Dr Soumya Chakraborty

  2. My Weight Loss Journey/ knee flare up again!

  3. Transtibial final gait procedure of below knee amputee

  4. Bionis

  5. Knee Arthroscopy positioning and Portals by Dr Prathmesh Jain

  6. Artificial Below knee leg madular systam without belt #artificial #prosthetics #ottobock #leg

COMMENTS

  1. JOURNEY II TKA

    JOURNEY II Total Knee Arthroplasty. Total knee arthroplasty patients report unmet levels of satisfaction, particularly for more active or demanding activities. 1,2 The JOURNEY II System is designed to help patients rediscover their normal through a smoother recovery, *3,4 improved function *4-8 and higher patient satisfaction *2,4-6. Brochure.

  2. JOURNEY II XR Bi-Cruciate Retaining Knee System

    JOURNEY II XR Bi-Cruciate Retaining Knee System. While JOURNEY II TKA has been shown to restore anatomical shape, position and motion, 1-4 the JOURNEY II XR system goes a step further by allowing the ACL to be retained. An anatomical design is intended to help a smoother recovery, improved function and higher patient satisfaction *1-11.

  3. JOURNEY II UK Unicompartmental Knee System

    Partial knees treat only the affected part of the knee, while allowing the patient to keep their healthy ligaments. JOURNEY II UK System combines clinically successful features to present a third-generation, unicompartmental knee platform featuring: Intraoperative sizing flexibility. OXINIUM Technology bearing surface. Tissue-conscious design.

  4. JOURNEY II Active Knee Solutions: Knee Replacement Surgery

    The JOURNEY II AKS difference. One of the most remarkable breakthroughs in design of total knee replacements has been the creation of the JOURNEY II Active Knee Solutions. Designed using the latest in human simulation software, and built using some of the most wear-resistant materials available, this unique implant was designed to address two ...

  5. JOURNEY II

    The JOURNEY II BCS Knee. Recent advances in biomedical engineering software have opened a new chapter on high performance knee implants. One remarkable breakthrough has been the creation of the JOURNEY II BCS knee, a second-generation knee replacement that combines the stability and natural motion of the human knee with new low-friction materials that may extend the life of the implant.

  6. The Journey II Total Knee System: A Step Ahead

    Conclusion. The Journey II TKA is truly a revolutionary step forward in the design of total knee implants. With proper surgical technique and in the hands of a well-trained surgeon, the Journey II knee can produce results superior to the traditional total knee design. It is our goal as your surgical team to continue to improve our surgical ...

  7. McKinley Orthopedic

    The JOURNEY II BCS Knee . Recent advances in biomedical engineering software have opened a new chapter on high performance knee implants. One remarkable breakthrough has been the creation of the JOURNEY II BCS knee, a second-generation knee replacement that combines the stability and natural motion of the human knee with new low-friction materials that may extend the life of the implant.

  8. JOURNEY II XR

    The JOURNEY II XR implant addresses durability with a combination of two wear reducing materials - the proprietary OXINIUM metal alloy and a highly cross-linked plastic insert - that were designed to address wear on both surfaces of the implant. Because it is twice as hard as cobalt chrome, the most commonly used metal in knee implants ...

  9. Smith+Nephew announces first surgery for its JOURNEY™ II Medial Dished

    Minor adaptations in implant design bicruciate-substituted total knee system improve maximal flexion. Poster presented at: 2nd World Arthroplasty Congress; 19-21 April, 2018 ; Rome, Italy . *Based ...

  10. McKinley Orthopedic

    The JOURNEY UNI is the only partial knee implant marketed that features this remarkable material. During manufacture, OXINIUM implants undergo a process that transforms the implant's surface into a hard, ceramicised metal; a combination that offers the smooth, hard surface of a ceramic, as well as the strength and durability of a metal. ...

  11. JOURNEY II Partial Knee Implant

    Today, partial knee replacement with the JOURNEY UNI knee implant is a minimally invasive surgical procedure that may provide several key benefits to patients whose arthritis is confined to a single compartment of their knee, have a moderately active lifestyle and are within normal weight ranges. First, let's discuss what is meant by the term ...

  12. The Journey Bicruciate Knee Replacement: Design Modifications ...

    The Journey-I total knee replacement was designed to improve knee kinematics but had several complications including early dislocation. The Journey-II modification was introduced to reduce these while maintaining high function. To assess whether the modified Journey-II prosthesis has succeeded in it …

  13. CAPAbility: comparison of the JOURNEY II Bi-Cruciate Stabilised and

    CAPAbility is a pragmatic, blinded, two-arm parallel, randomised controlled trial recruiting patients with primary osteoarthritis due to have unilateral TKR surgery across two UK hospitals. Eligible participants (n = 80) will be randomly allocated to receive either the JOURNEY II or the GENESIS II BCS knee prosthesis. Baseline measures will be ...

  14. JOURNEY II Knee Replacement Technology: Knee Implant Wear

    Just like the surfaces of your natural knee joint, friction created when the surfaces of a knee implant rub together can cause these surfaces to wear down over time. This type of implant wear is a leading cause of knee replacement failure. Conventional wisdom indicates that most knee implants should be expected to last 10 to 15 years before ...

  15. Understanding Uni Knee Implant

    The JOURNEY UNI surgical procedure allows your surgeon to access, remove and accurately replace only the damaged surface of your knee - leaving your healthy bone intact. Below is a brief description of the procedure: An incision is made to expose the damaged joint. The end of the femur and top of the tibia are shaped to accommodate the ...

  16. JOURNEY II ROX

    The opening act for JOURNEY II ROX Solution has been shown to restore the anatomical shapes, position and motion of a normal knee;6-10providing improved clinical outcomes and higher patient satisfaction*10,18-22. Normal shapes: Featuring an anatomic, asymmetric femur/tibia,8,10,23 concave medial tibial surface8,9,23and a convex lateral tibial ...

  17. Comparison of the Journey II bicruciate stabilised (JII-BCS) and

    Other authors have indicated that the femo-tibial relationship may be more normal during deep knee bend 42 and more stable during walking 43 Accordingly, people with the Journey prosthesis may 44 45 or may 43 have greater knee ROM, may walk faster, 46 47 and may have a longer stride length 46 47 than people receiving a comparison knee ...

  18. Surgical Technique for JOURNEY II BCS JOURNEY II CR

    Implant Compatibilities 64 JOURNEY™ II TKA Total Knee System. 2 JOURNEY™ II BCS contributing surgeons: Johan Bellemans, MD, PhD ... The knee should drop passively into full extension. Under varus/valgus stress, 1-2mm of laxity should be observed throughout the ROM (ie, 0, 30, 60, 90 and 120º).

  19. Journey-Deuce bicompartmental knee arthroplasty with the ...

    Purpose: To report 10-year outcomes and survivorship in patients undergoing bicompartmental knee arthroplasty (BCKA) using the Journey-Deuce prosthesis in a consecutive prospective case series. Methods: Between November 2006 and November 2009, 41 patients with a mean age of 69.6 years (range 51-86) underwent 51 bicompartmental knee arthroplasties with the Journey-Deuce knee prosthesis.

  20. Rotational mismatch between femoral and tibial components ...

    The JOURNEY bi-cruciate stabilized (BCS) knee system (Smith & Nephew, Memphis, TN, USA) was released in 2005. ... Malrotation of the fixed-bearing posterior stabilized total knee prosthesis causes a postoperative rotational mismatch between the femur and tibia. Knee Surg Sports Traumatol Arthrosc. 2020; 28: 3810-3820.

  21. Knee Replacement

    Knee Replacement. Knee replacement (also called knee arthroplasty) is a type of surgery that replaces all or part of the knee with a man-made implant. It is intended for people with severe knee damage from injury or advanced arthritis. The type of knee arthroplasty a person receives depends on the extent of the damage to the joint.

  22. A prosthesis driven by the nervous system helps people with amputation

    "This is the first prosthetic study in history that shows a leg prosthesis under full neural modulation, where a biomimetic gait emerges. No one has been able to show this level of brain control that produces a natural gait, where the human's nervous system is controlling the movement, not a robotic control algorithm," says Hugh Herr, a professor of media arts and sciences, co-director ...

  23. JOURNEY II Knee Replacement Technology: Knee Implant Feel

    JOURNEY II AKS implant feel The right "feel" often starts with the right design. To most of us, total knee implants all look very similar. With the exception of color (the OXINIUM alloy used in JOURNEY II implants is black while the cobalt chrome used in other implants is silver), it can take an experienced eye to see the subtle differences in size and shape between two implants.

  24. How This Action Sports Star Built His Own Prosthetic Leg

    Embark on an extraordinary journey with Mike Schultz, a former pro racer turned prosthetic innovator, who refused to let adversity define him. After a life-altering snowmobile accident led to ...

  25. JOURNEY UNI KNEE IMPLANT

    The JOURNEY UNI is the only partial knee implant marketed that features this remarkable material. During manufacture, OXINIUM implants undergo a process that transforms the implant's surface into a hard, ceramicised metal; a combination that offers the smooth, hard surface of a ceramic, as well as the strength and durability of a metal. ...

  26. The Best Prosthetic Leg Yet, Thanks to a Neural Interface

    A surgical procedure and muscle-sensing electrodes allow neural control of a prosthetic leg. Hugh Herr from MIT Media Lab created a new system in which amputees get a surgical procedure to connect ...

  27. Designing mobility: Engineering students create adjustable prostheses

    JMU Engineering students Parker Agan, Will Bradford, Megan Caulfield, Abby Charleston, Matrix Chen, Jack Nordstrom, Danny Tyra, Emily Vierrether, and Jack Zhao embarked on a capstone project with a clear mission: to design a comfortable, well-fitting, below-the-knee prosthesis capable of adjusting in length and volume, ideally growing with a child.

  28. Amputation advance: novel AMI surgery meets bionics

    New research shows how the combination of a novel surgery and a bionic prosthetic allows patients with an amputated leg to walk naturally. ... A long, painful journey with a happy ending.