Vermont Orthopaedic Clinic, Rutland, Vermont.
Swift Institute, Sparks, Nevada; Colorado Joint Replacement, Denver, Colorado.
J Arthroplasty. 2024 Aug;39(8S1):S70-S79. doi: 10.1016/j.arth.2024.05.007. Epub 2024 May 10.
Anatomic patellar components for total knee arthroplasty (TKA) have demonstrated favorable in vivo kinematics. A novel failure mechanism in TKA patients with an anatomic patellar component was observed prompting an investigation to identify patient- and implant-related factors associated with suboptimal performance.
A retrospective evaluation was performed comparing 100 TKA patients with an anatomic patellar component to 100 gender-, age-, and body mass index-matched patients with a medialized dome component. All surgeries were performed with the same posterior-stabilized TKA system with minimum of 1-year follow-up. Several radiographic parameters were assessed. A separate computational evaluation was performed using finite-element analysis, comparing bone strain energy density through the patella bone remnant.
Patients with an anatomic patellar component had significantly higher rates of anterior knee pain (18 versus 2%, P < .001), chronic effusions (18 versus 2%, P < .001), and superior patellar pole fragmentation (36 versus 13%, P < .001) compared to those with a dome component. Radiographically, the anatomic group demonstrated more lateral patellar subluxation (2.3 versus 1.1 mm, P < .001) and lateral tilt (5.4 versus 4.0 mm, P = .013). Furthermore, there were more revisions in the anatomic group (7 versus 3, P = .331). On computational evaluation, all simulations demonstrated increased bone strain energy density at the superior patellar pole with the anatomic patella. Resection thickness <13 mm resulted in over 2-fold higher strain energy density, and negative resection angle of 7° resulted in 6-fold higher superior pole strain energy.
Patients with an anatomic patellar component showed higher rates of anterior knee pain, chronic effusion, and superior pole fragmentation compared to patients with a dome patella, with higher superior patellar pole strain energy confirmed on computational evaluation. Avoiding higher resection angles and excessive patellar resection may improve the performance and survivorship of the anatomic patella.
全膝关节置换术（TKA）的解剖型髌骨组件已证明具有良好的体内运动学效果。在使用解剖型髌骨组件的 TKA 患者中观察到一种新的失效机制，促使我们进行研究以确定与髌骨组件性能不佳相关的患者和植入物相关因素。
我们对 100 例使用解剖型髌骨组件的 TKA 患者和 100 例性别、年龄和体重指数匹配的使用内侧化穹顶组件的患者进行了回顾性评估。所有手术均采用相同的后稳定 TKA 系统进行，随访时间至少为 1 年。评估了几个影像学参数。使用有限元分析对髌骨骨残端的骨应变能密度进行了单独的计算评估。
与穹顶组件组相比，解剖型髌骨组件组患者的前膝疼痛发生率（18%比 2%，P<0.001）、慢性积液发生率（18%比 2%，P<0.001）和髌骨上极碎裂发生率（36%比 13%，P<0.001）显著更高。影像学上，解剖型组显示髌骨外侧半脱位（2.3 毫米比 1.1 毫米，P<0.001）和外侧倾斜（5.4 毫米比 4.0 毫米，P=0.013）更明显。此外，解剖型组有更多的翻修手术（7 例比 3 例，P=0.331）。在计算评估中，所有模拟均显示，在解剖型髌骨中，髌骨上极的骨应变能密度增加。切除厚度<13 毫米会导致应变能密度增加两倍以上，切除角度为负 7°会导致髌骨上极的应变能增加 6 倍。
与穹顶髌骨组相比，解剖型髌骨组患者的前膝疼痛、慢性积液和髌骨上极碎裂发生率更高，计算评估证实髌骨上极的应变能更高。避免更高的切除角度和过度切除髌骨可能会改善解剖型髌骨的性能和存活率。
