Christ Alexander B, Baral Elexis, Koch Chelsea, Shubin Stein Beth E, Gonzalez Della Valle Alejandro, Strickland Sabrina M
Hospital for Special Surgery, 535 East 70th Street, New York, NY 10021, United States.
Knee. 2017 Oct;24(5):1233-1239. doi: 10.1016/j.knee.2017.06.015. Epub 2017 Aug 6.
Patellofemoral arthroplasty (PFA) can be a successful, bone-sparing treatment for isolated patellofemoral arthritis. However, progression of tibio-femoral arthritis or incorrect indications may predispose patients to early conversion to total knee arthroplasty (TKA). The purpose of this study was to review the clinical cases and perform retrieval analysis of PFA conversions to TKA at our institution.
Twenty one patellofemoral arthroplasties in 18 patients that were converted to TKA were identified through our implant retrieval registry. Sixteen implants were available for review by biomechanical engineers, who recorded surface markings, wear patterns, and integrity of fixation. Patient charts were reviewed and time to conversion, tourniquet time, conversion implant, additional surgeries, infections, and Kellgren & Lawrence grade of the tibio-femoral joint on pre-operative radiographs were recorded.
PFAs converted to TKAs at our institution were implanted for an average of 2.7years. The most common reason for conversion was pain, but most patients had significant tibio-femoral arthritis, as indicated by an average Kellgren & Lawrence grade of 2.6. The average tourniquet time for these conversions was 67min. These patients underwent an average of one additional surgery per PFA converted, and the infection rate of these conversions was approximately 14%.
Success of PFA depends upon correct patient selection rather than implant failure or wear. Conversion of PFA to TKA is technically similar to primary TKA, with similar post-operative pain relief and range of motion. However, infection rates and complications requiring further surgery are more consistent with results seen in revision TKA.
IV.
髌股关节置换术（PFA）对于孤立性髌股关节炎而言，可能是一种成功的、保留骨质的治疗方法。然而，胫股关节炎的进展或适应证选择不当可能使患者易于早期转换为全膝关节置换术（TKA）。本研究的目的是回顾临床病例，并对我院PFA转换为TKA的情况进行检索分析。
通过我们的植入物检索登记系统，确定了18例患者中21例已转换为TKA的髌股关节置换术。16个植入物可供生物力学工程师检查，他们记录了表面标记、磨损模式和固定的完整性。查阅患者病历，记录转换时间、止血带使用时间、转换植入物、额外手术、感染情况以及术前X线片上胫股关节的Kellgren & Lawrence分级。
在我院转换为TKA的PFA平均植入时间为2.7年。转换的最常见原因是疼痛，但大多数患者有明显的胫股关节炎，平均Kellgren & Lawrence分级为2.6。这些转换手术的平均止血带使用时间为67分钟。每例转换为TKA的PFA患者平均还接受了一次额外手术，这些转换手术的感染率约为14%。
PFA的成功取决于正确的患者选择，而非植入物失败或磨损。PFA转换为TKA在技术上与初次TKA相似，术后疼痛缓解和活动范围也相似。然而，感染率和需要进一步手术的并发症与翻修TKA的结果更为一致。
IV级
