Duke-NUS Medical School, Singapore, Singapore.
Department of Orthopaedic Surgery, Singapore General Hospital, Singapore, Singapore.
Knee Surg Sports Traumatol Arthrosc. 2018 Jun;26(6):1723-1727. doi: 10.1007/s00167-017-4749-6. Epub 2017 Oct 9.
The primary aim of this study was to evaluate the influence of postoperative fixed flexion deformity (FFD) on the clinical outcomes 10 years after unicompartmental knee arthroplasty (UKA). The secondary aim was to identify predictors for the occurrence of postoperative FFD.
Patients who underwent UKA between 2003 and 2007 were prospectively followed up for 10 years. A total of 172 patients were categorized into 3 groups based on the amount of postoperative FFD: (1) 0° or less (Min-FFD), (2) 1°-9° (Mid-FFD), and (3) 10° or more (Max-FFD). Functional outcome was quantified using Knee Society Function Score (KSFS), Knee Society Knee Score (KSKS) and Oxford Knee Score (OKS).
At 10 years after UKA, the mean KSKS and OKS were 6 ± 5 (95% CI 6-18, p = 0.050) and 5 ± 2 (95% CI 0-9, p = 0.041) points lower in patients with Max-FFD than those with Min-FFD. Other clinical outcomes were not different between groups. Patients with a higher preoperative body mass index (OR 1.122 per unit increase, 95% CI 1.006-1.253, p = 0.040) or worse preoperative FFD (OR 1.108 per unit increase, 95% CI 1.022-1.201, p = 0.013) were at increased risk of having postoperative FFD of 10° or more at 10 years after UKA.
The clinical relevance of this study was to demonstrate the long-term negative correlation between severe postoperative FFD and functional outcome and, therefore, the importance of achieving good knee alignment after UKA. The authors recommend that FFD should be fully corrected intra-operatively if possible while preserving knee balance and stable dynamic function through full range of motion.
Prognostic level II.
本研究的主要目的是评估单髁膝关节置换术后固定屈曲畸形（FFD）对术后 10 年临床结果的影响。次要目的是确定术后 FFD 发生的预测因素。
前瞻性随访 2003 年至 2007 年间接受 UKA 的患者 10 年。根据术后 FFD 的量，将 172 例患者分为 3 组：（1）0°或以下（Min-FFD）；（2）1°-9°（Mid-FFD）；和（3）10°或以上（Max-FFD）。使用膝关节学会功能评分（KSFS）、膝关节学会膝关节评分（KSKS）和牛津膝关节评分（OKS）量化功能结果。
UKA 后 10 年，Max-FFD 组患者的平均 KSKS 和 OKS 分别比 Min-FFD 组低 6±5 分（95%CI 6-18，p=0.050）和 5±2 分（95%CI 0-9，p=0.041）。各组间其他临床结果无差异。术前体重指数较高的患者（每单位增加的 OR 1.122，95%CI 1.006-1.253，p=0.040）或术前 FFD 较差的患者（每单位增加的 OR 1.108，95%CI 1.022-1.201，p=0.013）术后发生 10°或以上 FFD 的风险增加。
本研究的临床意义在于证明了严重术后 FFD 与功能结果之间存在长期的负相关，因此，UKA 后获得良好的膝关节对线至关重要。作者建议，如果可能，术中应充分纠正 FFD，同时通过全范围运动保持膝关节平衡和稳定的动态功能。
预后 II 级。
