Martin, BR, Pegg, EC, van Duren, BH orcid.org/0000-0003-1877-8227 et al. (4 more authors) (2019) Posterior Bearing Overhang Following Medial and Lateral Mobile Bearing Unicompartmental Knee Replacements. Journal of Orthopaedic Research, 37 (9). pp. 1938-1945. ISSN 0736-0266
Abstract
This study explores the extent of bearing overhang following mobile bearing Oxford unicompartmental knee replacement (OUKR) (Oxford Phase 3, Zimmer Biomet). The Oxford components are designed to be fully congruent, however knee movements involve femoral rollback, which may result in bearing overhang at the posterior margin of the tibial implant, with potential implications for; pain, wear, and dislocation.
Movement is known to be greater, and therefore posterior overhang more likely to occur, with; lateral compared to medial implants, anterior cruciate ligament deficiency, and at extremes of movement.
24 medial, and 20 domed lateral, OUKRs underwent sagittal plane knee fluoroscopy during step‐up and forward lunge exercises. The bearing position was inferred from the relative position of the femoral and tibial components. Based on the individual component sizes and geometry the extent the posterior part of the bearing which overhung the posterior part of the tibial component was calculated.
There was no significant posterior overhang in knees with medial implants. Knees with lateral domed implants exhibited overhang at flexion angles beyond 60°, the magnitude of which increased with increasing flexion angle, reaching a maximum of 50% of the bearing length at 140° (range 0‐140°). This demonstrates a clear difference between the kinematics, and prevalence and extent of posterior bearing overhang between medial and lateral OUKRs.
Metadata
Item Type: | Article |
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Authors/Creators: |
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Copyright, Publisher and Additional Information: | © 2019 Orthopaedic Research Society. Published by Wiley Periodicals, Inc. This is the peer reviewed version of the following article: Martin, B. R., Pegg, E. C., Duren, B. H., Mohammad, H. R., Pandit, H. G., Mellon, S. J. and Murray, D. W. (2019), Posterior Bearing Overhang Following Medial and Lateral Mobile Bearing Unicompartmental Knee Replacements. J. Orthop. Res., which has been published in final form at https://doi.org/10.1002/jor.24339. This article may be used for non-commercial purposes in accordance with Wiley Terms and Conditions for Self-Archiving. Uploaded in accordance with the publisher's self-archiving policy. |
Keywords: | unicompartmental knee replacement; mobile bearing; posterior bearing overhang |
Dates: |
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Institution: | The University of Leeds |
Academic Units: | The University of Leeds > Faculty of Medicine and Health (Leeds) > School of Medicine (Leeds) > Institute of Rheumatology & Musculoskeletal Medicine (LIRMM) (Leeds) > Orthopaedics (Leeds) |
Depositing User: | Symplectic Publications |
Date Deposited: | 03 Jun 2019 10:04 |
Last Modified: | 06 May 2020 00:38 |
Status: | Published |
Publisher: | Wiley |
Identification Number: | 10.1002/jor.24339 |
Related URLs: | |
Open Archives Initiative ID (OAI ID): | oai:eprints.whiterose.ac.uk:146737 |