不置换髌骨膝关节置换术后髌骨不稳的原因及预防

The etiologies and prevention of patellar instability after unresurfaced total knee arthroplasty

目的探讨全膝关节置换术后髌骨不稳的原因和预防措施。方法1997年9月至2005年4月对94例（105膝）膝骨关节炎患者行全膝关节置换术。术前膝外翻14例，膝内翻80例，力线正常者11例。所用假体包括可旋转铰链型膝假体RK10例14膝，活动衬垫型膝假体TACK40例43膝，GEMINI假体44例48膝，所有患者均不置换髌骨。术前、术后在屈膝30。髌骨轴位片上测量髌骨的排列。结果术前有膝外翻和髌骨不稳者术后髌骨不稳的发生率分别为28．6％和29．5％，使用RK、TACK、GEMINI假体的患者髌骨不稳的发生率分别为28．6％，20．9％和16．7％。4例有明显股骨或胫骨假体旋转异常。结论膝关节置换术后出现髌骨不稳定的原因包括患者术前状态、假体设计、假体位置不良等。选择合适的假体，熟练掌握手术技巧，能明显减少膝关节置换术后髌骨轨迹异常。

Objective To investigate the etiologies and prevention of patellar instability after total knee arthroplasty （TKA）. Methods From September 1997 to April 2005, 94 patients （105 knees ） underwent TKA without patellar resurfacing. All of them were osteoarthritis. Ten patients （ 14 knees ） were performed with Rotation Knee （RK） prostheses. Forty patients were performed with mobile bearing TACK prostheses, and 44 patients with GEMINI prostheses. Subluxation and tilt of patella were evaluated by X-rays before or after operation. Results The incidence of patellar instability after operation was 28.6% in patients who had genu valgus deformity, and was 29. 5% in whom had patellar instability preoperative. The incidence of patellar instability in RK, TACK, and GEMINI group was 28.6%, 20.9%, and 16. 7% respectively after operations. Four patients had obvious femoral or tibial components malrotation. Conclusions The etiologies of patellofemoral instability include pre-operative conditions, prosthetic design, and improper positioning of the prosthetic component. So the suitable component design and skillful operative technique will help the surgeon to avoid this complication.