Tsubosaka Masanori, Matsumoto Tomoyuki, Takayama Koji, Nakano Naoki, Kuroda Ryosuke
Department of Orthopaedic Surgery, Kobe University Graduate School of Medicine, 7-5-1, Kusunoki-cho, Chuo-ku, Kobe, 650-0017, Japan.
Int J Surg Case Rep. 2017;37:200-204. doi: 10.1016/j.ijscr.2017.06.036. Epub 2017 Jun 29.
There are few specific reports of late medial instability after total knee arthroplasty (TKA). We described two cases of late medial instability of the knee due to hip disease with osteoarthritis or rheumatoid arthritis after TKA, which required revision TKA.
An 82-year-old woman experienced right femoral neck fracture due to a fall that required conservative treatment at age 77 years and underwent left TKA at age 80 years. A 68-year-old woman underwent left TKA at age 54 years, right TKA at age 64 years, and left THA at age 67 years. Both cases required revision TKA with constrained knee prostheses due to the severe medial instability. Hip-knee-ankle (HKA) angle, range of motion (ROM), Knee Society score (KSS) and functional score (FS) were evaluated pre- and postoperatively. Their respective HKA angle improved from 134° and 155° preoperatively to 184° and 179° postoperatively. KSS improved from -4 and 53 points to 59 and 100 points, respectively. FS improved from -10 and 58 points to 25 and 90 points, respectively. In the 82-year-old woman, ROM did not improve from -10-90° to -20-90°. On the other hand, in the 68-year-old woman, ROM improved from 0-110° to 0-125°. The late medial instability in the current case report was partly due to a similar mechanism underlying the long leg arthropathy and coxitis knee caused by hip joint degeneration.
Constrained prostheses were applied for both patients, providing moderately good short-term results.
全膝关节置换术（TKA）后晚期内侧不稳定的具体报道较少。我们描述了两例TKA后因髋部疾病伴骨关节炎或类风湿关节炎导致的膝关节晚期内侧不稳定病例，这两例均需要翻修TKA。
一名82岁女性在77岁时因跌倒导致右股骨颈骨折，接受了保守治疗，80岁时接受了左膝TKA。一名68岁女性在54岁时接受了左膝TKA，64岁时接受了右膝TKA，67岁时接受了左髋THA。由于严重的内侧不稳定，两例均需要使用限制性膝关节假体进行翻修TKA。术前和术后评估了髋-膝-踝（HKA）角、活动范围（ROM）、膝关节协会评分（KSS）和功能评分（FS）。她们各自的HKA角术前分别为134°和155°，术后改善至184°和179°。KSS分别从-4分和53分提高到59分和100分。FS分别从-10分和58分提高到25分和90分。在82岁女性中，ROM未从-10-90°改善至-20-90°。另一方面，在68岁女性中，ROM从0-110°改善至0-125°。本病例报告中的晚期内侧不稳定部分归因于髋关节退变引起的长腿关节病和膝关节炎的类似机制。
两名患者均应用了限制性假体，短期结果中等良好。
