Wignadasan Warran, Magan Ahmed, Kayani Babar, Fontalis Andreas, Chambers Alastair, Rajput Vishal, Haddad Fares S
Department of Trauma and Orthopaedic Surgery, University College Hospital, London, UK.
Department of Orthopaedic Surgery, The Princess Grace Hospital, London, UK.
Bone Jt Open. 2024 Nov 6;5(11):992-998. doi: 10.1302/2633-1462.511.BJO-2024-0139.
While residual fixed flexion deformity (FFD) in unicompartmental knee arthroplasty (UKA) has been associated with worse functional outcomes, limited evidence exists regarding FFD changes. The objective of this study was to quantify FFD changes in patients with medial unicompartmental knee arthritis undergoing UKA, and investigate any correlation with clinical outcomes.
This study included 136 patients undergoing robotic arm-assisted medial UKA between January 2018 and December 2022. The study included 75 males (55.1%) and 61 (44.9%) females, with a mean age of 67.1 years (45 to 90). Patients were divided into three study groups based on the degree of preoperative FFD: ≤ 5°, 5° to ≤ 10°, and > 10°. Intraoperative optical motion capture technology was used to assess pre- and postoperative FFD. Clinical FFD was measured pre- and postoperatively at six weeks and one year following surgery. Preoperative and one-year postoperative Oxford Knee Scores (OKS) were collected.
Overall, the median preoperative navigated (NAV) FFD measured 6.0° (IQR 3.1 to 8), while the median postoperative NAV FFD was 3.0° (IQR 1° to 4.4°), representing a mean correction of 49.2%. The median preoperative clinical FFD was 5° (IQR 0° to 9.75°) for the entire cohort, which decreased to 3.0° (IQR 0° to 5°) and 2° (IQR 0° to 3°) at six weeks and one year postoperatively, respectively. A statistically significant improvement in PROMs compared with baseline was evident in all groups (p < 0.001). Regression analyses showed that participants who experienced a larger FFD correction, showed greater improvement in PROMs ( = 0.609, p = 0.049; 95% CI 0.002 to 1.216).
This study found that UKA was associated with an approximately 50% improvement in preoperative FFD across all three examined groups. Participants with greater correction of FFD also demonstrated larger OKS gains. These findings could prove a useful augment to clinical decision-making regarding candidacy for UKA and anticipated improvements in FFD.
虽然单髁膝关节置换术（UKA）中残留的固定屈曲畸形（FFD）与较差的功能结局相关，但关于FFD变化的证据有限。本研究的目的是量化接受UKA的内侧单髁膝关节关节炎患者的FFD变化，并研究其与临床结局的相关性。
本研究纳入了2018年1月至2022年12月期间接受机器人手臂辅助内侧UKA的136例患者。研究包括75例男性（55.1%）和61例女性（44.9%），平均年龄为67.1岁（45至90岁）。根据术前FFD程度将患者分为三个研究组：≤5°、5°至≤10°和>10°。术中使用光学运动捕捉技术评估术前和术后的FFD。在术后六周和一年时测量临床FFD。收集术前和术后一年的牛津膝关节评分（OKS）。
总体而言，术前导航（NAV）FFD的中位数为6.0°（四分位间距3.1至8），而术后NAV FFD的中位数为3.0°（四分位间距1°至4.4°），平均矫正率为49.2%。整个队列术前临床FFD的中位数为5°（四分位间距0°至9.75°），术后六周和一年时分别降至3.0°（四分位间距0°至5°）和2°（四分位间距0°至3°）。所有组的患者报告结局量表（PROMs）与基线相比均有统计学意义的改善（p<0.001）。回归分析表明，FFD矫正幅度较大的参与者，其PROMs改善更大（=0.609，p=0.049；95%可信区间0.002至1.216）。
本研究发现，UKA与所有三个研究组术前FFD改善约50%相关。FFD矫正程度较大的参与者OKS得分增加也更大。这些发现可能有助于临床决策中关于UKA候选资格以及FFD预期改善的判断。
