2023 ISAKOS Biennial Congress Paper
Does the Severity of Preoperative Patellofemoral Joint Degeneration Influence the Clinical Outcome of Total Knee Arthroplasty without Patella Resurfacing?
Paul Nardelli, MD, Innsbruck AUSTRIA
Sabrina Neururer, Dipl.-Ing., Innsbruck AUSTRIA
Kerstin Gruber, cand. med., Innsbruck AUSTRIA
David Wippel, MD, Innsbruck AUSTRIA
Nadine Kogler, cand. med., Innsbruck AUSTRIA
Sebastian Ender, MD, Innsbruck AUSTRIA
Hermann Leitner, Innsbruck, Tyrol AUSTRIA
Benedikt Koller, MD, Zams AUSTRIA
Martin Fischer, MD, Zams AUSTRIA
Dietmar Dammerer, Prof. Dr.med.univ., MSc, PhD, Krems AUSTRIA
Michael C. Liebensteiner, MD, PhD, Innsbruck, Tyrol AUSTRIA
Innsbruck Medical University, Innsbruck, Tyrol, AUSTRIA
FDA Status Cleared
Summary
It is recommended that patella resurfacing be applied in patients with severe Iwano Stage 3 or 4 patellofemoral osteoarthritis during TKA.
Abstract
Objective
To determine whether the preoperative degree of degeneration of the patellofemoral joint really affects the outcome of total knee arthroplasty (TKA) surgery without a patella button and thus to establish a parameter that might serve as guiding factor to decide whether or not to perform retropatellar resurfacing.
Methods
Application of a retrospective-comparative design on the basis of arthroplasty registry data that included patients with primary TKA without patella resurfacing. Patients were allocated to the following groups based on preoperative radiographic stage of patellofemoral joint degeneration: a) mild patellofemoral osteoarthritis (Iwano Stage 1-2) and b) severe patellofemoral osteoarthritis (Iwano Stage 3-4). For patient-reported outcome measurement the Western Ontario and MacMaster Universities Osteoarthritis Index (WOMAC) score was taken once preoperative and once 1-year postoperative (0: best, 100 worst). In addition, implant survival was calculated from the arthroplasty registry data.
Results
In 1209 primary TKA without patella resurfacing, 3-year survival was 97.4% and 92.5% in patients with preoperative mild and severe patellofemoral osteoarthritis, respectively (p=0.002). Five-year survival was 95.8% vs. 91.4% (p=0.033) and 10-year survival was 93.3% vs. 88.6% (p=0.033). Postoperative WOMAC total and WOMAC subscores did not differ significantly between groups, but potentially suffered from type 2 error.
Conclusions
From the study findings it is concluded that patients with preoperative severe patellofemoral osteoarthritis have significantly higher risks for reoperation than do those with preoperative mild patellofemoral osteoarthritis – when treated with TKA without patella resurfacing. Hence, it is recommended that patella resurfacing be applied in patients with severe Iwano Stage 3 or 4 patellofemoral osteoarthritis during TKA.