From Anderson Orthopaedic Research Institute, Alexandria, VA.
J Am Acad Orthop Surg. 2018 Apr 1;26(7):e158-e163. doi: 10.5435/JAAOS-D-16-00802.
Unicompartmental knee arthroplasty (UKA) is an effective alternative to total knee arthroplasty (TKA) for the management of unicondylar osteoarthritis. Historical contraindications limit patients' eligibility for UKA. However, recent reports have suggested that some contraindications may not be absolute. This study evaluates preoperative flexion contracture with regard to UKA.
This study was a retrospective review of 53 patients with preoperative flexion contracture between 11° and 20° who underwent fixed-bearing UKA and a matched cohort of 53 patients who underwent cruciate-retaining TKA.
Preoperatively, the average flexion contracture was 13.8° in the UKA group and 14.1° in the TKA group (P = 0.42). Mean preoperative motion was greater in the patients treated with UKA (106°) than in those treated with TKA (97°; P < 0.001). Postoperatively, patients who underwent UKA had greater motion than patients who underwent TKA had (121° versus 113°; P < 0.01). Residual flexion contracture was greater in the UKA group (4.1°) than in the TKA group (2.1°; P = 0.02). The two groups demonstrated similar improvements in Knee Society clinical scores (P = 0.32). However, patients treated with UKA demonstrated higher Knee Society functional scores, compared with patients treated with TKA (86 versus 75; P = 0.03).
Although residual flexion contracture was worse after UKA, this group had similar clinical improvement, greater postoperative motion, and greater function scores, compared with the matched TKA group. Preoperative flexion contracture >5° may not be an absolute contraindication to UKA.
The contraindications to UKA regarding flexion contracture may not be as absolute as previously thought. Larger, prospective studies are needed to generalize these findings to a wider population.
单髁膝关节置换术（UKA）是治疗单间室骨关节炎的有效方法，可替代全膝关节置换术（TKA）。既往的禁忌证限制了 UKA 的适用人群，但近期的研究报告表明，一些禁忌证可能并非绝对。本研究评估了术前膝关节屈曲挛缩与 UKA 的关系。
本研究为回顾性研究，纳入了 53 例术前膝关节屈曲挛缩 11°~20°的患者，其中 26 例行固定平台 UKA，27 例行保留交叉韧带 TKA。
UKA 组术前平均膝关节屈曲挛缩 13.8°，TKA 组为 14.1°（P = 0.42）。UKA 组患者术前膝关节活动度（平均 106°）大于 TKA 组（平均 97°；P < 0.001）。术后，UKA 组患者膝关节活动度大于 TKA 组（平均 121°比平均 113°；P < 0.01）。UKA 组的残余膝关节屈曲挛缩程度（4.1°）大于 TKA 组（2.1°；P = 0.02）。两组患者的膝关节学会临床评分（KSS）均有改善（P = 0.32）。但 UKA 组的膝关节学会功能评分（KSS-FS）高于 TKA 组（86 分比 75 分；P = 0.03）。
尽管 UKA 术后残余膝关节屈曲挛缩程度更差，但与 TKA 组相比，该组患者临床改善相似，术后膝关节活动度更大，膝关节功能评分更高。术前膝关节屈曲挛缩>5°可能不是 UKA 的绝对禁忌证。
既往认为 UKA 禁忌证中膝关节屈曲挛缩的限制并非绝对。需要开展更大规模的前瞻性研究，以将这些发现推广至更广泛的人群。
