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Case Reports in Orthopedics
Volume 2017, Article ID 1230412, 5 pages
Case Report

Mobile Bearing Total Knee Arthroplasty for Valgus Knee Osteoarthritis with Permanent Patellar Dislocation: A Case Report and Review of the Literature

Department of Orthopaedic Surgery, Kobe University Graduate School of Medicine, 7-5-1, Kusunoki-cho, Chuo-ku, Kobe, Hyogo 650-0017, Japan

Correspondence should be addressed to Tomoyuki Matsumoto; pj.en.noid.4m@nustam

Received 16 November 2016; Accepted 15 March 2017; Published 29 March 2017

Academic Editor: Andreas Panagopoulos

Copyright © 2017 Kohei Kamada et al. This is an open access article distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.


Permanent patellar dislocation with tibiofemoral joint osteoarthritis is a relatively rare condition. To treat this condition, total knee arthroplasty with proximal or distal realignment of the extensor mechanism has been reported. We report a challenging case of an 80-year-old woman diagnosed with permanent patellar dislocation with tibiofemoral joint osteoarthritis treated by a mobile bearing total knee arthroplasty utilizing navigation system. Lateral retinaculum release was performed to improve patellar tracking; other proximal or distal realignment of the extensor mechanism was not necessary. Postoperative radiographs show stable patellar tracking and recurrent patellar dislocation was not observed. This clinical case indicates that the implant’s precise alignment and rotation during total knee arthroplasty could settle anatomical abnormalities of permanent patellar dislocation and the mobile bearing insert could contribute to stabilizing patellar tracking.