Medial Rotation Knee ™
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Medial Rotation Knee™ System Clinical Data Summary Physiological Stability and Mobility for the Active Knee Without Compromise

Contents 1 Summary Overview of Clinical Data 2 Key Literature 6 Manufactured by MatOrtho Limited 19/20 Mole Business Park | Randalls Road | Leatherhead | Surrey | KT22 7BA | UK T: +44 (0)1372 224 200 | info@MatOrtho.com For more information visit: www.MatOrtho.com © MatOrtho Limited 2018 All rights reserved. No part of this publication may be reproduced or transmitted in any form or by any means, electronic or mechanical, including photocopy, recording or any information storage and retrieval system. 2 | Medial Rotation Knee™ System | Clinical Data Summary

In normal healthy knees the shapes of the medial and lateral tibial condyles are different: the medial side is concave; the lateral side is convex. Stability is provided collectively by the collateral ligaments (MCL and LCL), both cruciate ligaments (ACL and PCL) and the menisci. The resulting pattern of movement during flexion is asymmetric: the medial condyle is stable throughout the range of motion, but on the lateral side there is limited freedom to move anterior-posterior (tibia with respect to femur). The anatomy of the patellofemoral articulation is also asymmetric: the femoral...

features a physiologically lateralised trochlea14,15 and, true to design intent, when compared to patients with no TKR and patients with a PS knee, patients with the MRK™ exhibited similar amount of lateral translation of the patella in flexion as patients without a TKR, whereas patients with the PS knee did not15. Choosing not to replace the patella has not been shown to influence outcomes for this knee design with the trochlea being identified as the more important feature16. Nevertheless, the unique saddle-shaped patella, which can rotate to match the femur for a fully conforming...

Australian Orthopaedic Association National Joint Replacement Registry (AOANJRR) The AOANJRR has sufficient data to present revision rates for some TKR devices up to 17 years post operation. The overall revision rate for all TKRs is 3.6% at 5 years, 5.3% at 10 years and 8.4% at 17 years for indication of osteoarthritis, which accounts for 97.6% of procedures26 The MRK™ was not used in Australia until 2006 and the AOANJRR has recorded 459 MRK™ procedures. Just 8 knees have been revised, providing a revision rate of 1.9% (95%CI: 0.9-3.7), which means that the MRK™ is on track to have one of...

2 Key Literature Knee Arthroplasty with a Medially Conforming Ball-and-socket Tibiofemoral Articulation Provides Better Function. Hossain F, Patel S, Rhee SJ, Haddad FS. Clin Orthop Relat Res. 2011; 469(1)55-63 Abstract Background: A knee design with a ball-and-socket articulation of the medial compartment has a femoral rollback profile similar to the native knee. Compared to a conventional, posterior-stabilized knee design, it provides AP stability throughout the entire ROM. However, it is unclear whether this design difference translates to clinical and functional improvement....

Tibiofemoral Kinematic Analysis of Knee Flexion For a Medial Pivot Knee. Moonot P, Mu S, Railton GT, Field RE, Banks SA. Knee Surg Sports Traumatol Arthrosc. 2009; 17(8):927-34. Abstract Knee arthroplasties are designed to accommodate flexion, axial rotation and anteroposterior (AP) translation. Axial rotation during extension varies, with some rotating platform devices allowing unrestricted rotation while some conforming fixed-bearing designs almost none. The purpose of this study was to examine in vivo kinematics of a fixed-bearing medial rotation-type arthroplasty (MRK) during...

Patellar Tracking: A Comparison of an Implant with a Lateralised Trochlear Groove Compared to a Conventional Posterior Stabilised Design. Rhee SJ, Hossain F, Konan S, Ashby E and Haddad F. J Bone Joint Surg Br 2012; 94-B no. SUPP IX 90 Abstract Aim: The aim of our study was to assess lateral tracking of the patella with differing designs of Total Knee Arthroplasty (TKA) and compare to that of the native patella. Method: A modified caliper was used to measure the width and position of the patella relative to the femur at different degrees of knee flexion. The relationship of the patella...

The Early Radiological Follow-up of a Medial Rotational Design of Total Knee Arthroplasty. Amin A, Al-Taiar A, Sanghrajka AP, Kang N, Scott G. Knee 2008; 15(3)222-6 Abstract The objective of this study was to investigate the hypothesis that the increased constraint of a medial rotational knee promotes earlier loosening of the prosthesis. All patients with a Freeman-Samuelson 1000 knee arthroplasty (medial pivot design), (group 1), or a Freeman-Samuelson Modular knee arthroplasty, (group 2), with a minimum follow-up of 2 years (mean follow-up 4 years) were identified from our unit's...

Knee Arthroplasty with a Medial Rotating Total Knee Replacement. Midterm Clinical Findings: A District General Experience of 38 Cases. Jonas SC, Argyropoulos M, Al-Hadithy N, Korycki M, Lotz B, Deo SD, Satish V. The Knee. 2015; 22(2): 122-125. Abstract Background: The Medial Rotating Knee replacement (MRK™) was first used in 1994, reporting high rates of satisfaction. It is designed to replicate natural knee kinematics and improve stability and function. There are limited studies on the mid-term clinical outcomes, in particular in a district general hospital (DGH) environment. This is the...