Pre-existing patellofemoral disease does not affect 10-year survivorship in fixed bearing unicompartmental knee arthroplasty
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The purpose of this study was to assess 10-year functional outcome and survivorship analysis of patients with significant radiographic evidence of patellofemoral joint arthritis treated with fixed bearing unicompartmental knee arthroplasty.
Two hundred and sixteen patients (263 knees) that underwent UKA from 2003 to 2005 for a mean of 10.5 ± 2.1 years were prospectively followed up. Preoperative radiological assessment of the patellofemoral joint state was assessed according to the Ahlback classification by an independent assessor and radiographically significant patellofemoral disease was defined as grade 2 or more. Patients with significant bone-on-bone contact in the patellofemoral joint were excluded.
Of the 263 knees, 222 (84.4%) had normal patellofemoral joint state and 41 (15.6%) radiologically significant patellofemoral disease. At 10 years’ follow-up, the normal and patellofemoral groups had similar OKS (20 ± 7 vs 20 ± 8, n.s.) and KSS scores (79 ± 20 vs 81 ± 20, n.s.), respectively. There were 12 revision surgeries in the normal group and the most common indication for revision was progression of contralateral compartment osteoarthritis (6 of 12 cases). There was only one revision in the patellofemoral group and it was due to progression of contralateral compartment osteoarthritis (n.s.). When all secondary surgeries to the operated knee were considered as failures, the 10-year survival rate was 95.1% (CI 95%: 92.2–97.7%).
The presence of significant preoperative radiological patellofemoral disease does not affect long-term implant survival and patients have excellent functional outcomes 10 years postoperatively. These patients should not be contraindicated from undergoing unicompartmental knee arthroplasty.
Level of evidence
KeywordsUKA Patellofemoral Unicompartmental Arthroplasty Survivorship
LW analysed the data and wrote the paper. CYJ contributed significantly to statistical design and data analysis. CHC collected and managed the data. PHN revised and approved the manuscript. TKJ revised and approved the manuscript. CSL revised and approved the manuscript. LNN revised and approved the manuscript. YSJ conceived the study, revised and approved the manuscript.
This study was approved by the Singhealth Centralised Institutional Review Board (CIRB) committee (CIRB:2016/2144).
Compliance with ethical standards
Conflict of interest
No benefits in any form have been received or will be received from a commercial party related directly or indirectly to the subject of this article.
All authors and their immediate family did not receive any financial payments or other benefits from any commercial entity related to the subject of this article.
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