Department of Orthopaedic Surgery, Faculty of Medicine, Siriraj Hospital, Mahidol University, Bangkok, Thailand.
Institute of Health Policy, Management and Evaluation, University of Toronto, Toronto, Ontario, Canada.
PLoS One. 2023 Feb 3;18(2):e0281237. doi: 10.1371/journal.pone.0281237. eCollection 2023.
Knee flexion angle (KFA) is one of the most critical factors for evaluating patient functional outcomes after total knee arthroplasty (TKA). Preoperative KFA and intraoperative drop leg test are both accepted as predictors of postoperative KFA after TKA. Preoperative testing performed after anesthesia helps overcome pain-related limitations; however, the KFA measurement timepoint that best predicts KFA at 6 months after TKA has not yet been established.
This prospective cohort study recruited patients who underwent unilateral primary TKA at Siriraj Hospital (Bangkok, Thailand) during August 2012 to August 2017. We recorded KFA at the pre-anesthetic phase, post-anesthetic phase, intraoperation using drop leg test, and at 6-months post-operation. Pearson's correlation coefficient was used to evaluate correlation between different measurement timepoints and 6 months after surgery. Those same relationships were evaluated for overall patients, and for patients with KFA <90° (poor KFA), 90-120° (average KFA), and >120° (high KFA).
A total of 165 patients with a mean age of 68.7 years were recruited. Pre-anesthetic KFA measurement had the highest positive correlation with the 6-month KFA (r = 0.771, p<0.05). Post-anesthetic measurement and intraoperative drop leg KFA measurement had moderate positive correlation (r = 0.561, p<0.05) and low positive correlation (r = 0.368, p<0.05) with the 6-month KFA, respectively. The average KFA group had the highest positive correlation between pre-anesthetic KFA measurement and the 6-month KFA (r = 0.711, p<0.05). Predicted 6-month KFA (degrees) adjusted for pre-anesthetic KFA is 45.378 + [0.596 x pre-anesthetic KFA (degrees)] (r = 0.67, p <0.05).
Pre-anesthetic KFA demonstrated the highest correlation with the final KFA at six months after unilateral primary TKA, especially in the patients who had a preoperative KFA within 90-120°.
膝关节屈曲角度（KFA）是评估全膝关节置换术（TKA）后患者功能结果的最关键因素之一。术前 KFA 和术中垂腿试验均被认为是预测 TKA 后术后 KFA 的指标。在麻醉后进行的术前测试有助于克服与疼痛相关的限制；然而，尚未确定在 TKA 后 6 个月时最佳预测 KFA 的 KFA 测量时间点。
本前瞻性队列研究招募了 2012 年 8 月至 2017 年 8 月在泰国曼谷诗里拉吉医院接受单侧初次 TKA 的患者。我们记录了麻醉前、麻醉后、术中使用垂腿试验和术后 6 个月的 KFA。使用 Pearson 相关系数评估不同测量时间点与术后 6 个月之间的相关性。对于所有患者以及 KFA<90°（差的 KFA）、90-120°（平均 KFA）和>120°（高 KFA）的患者，评估了这些相同的关系。
共招募了 165 名平均年龄为 68.7 岁的患者。麻醉前 KFA 测量与术后 6 个月 KFA 呈高度正相关（r = 0.771，p<0.05）。麻醉后测量和术中垂腿 KFA 测量与术后 6 个月 KFA 呈中度正相关（r = 0.561，p<0.05）和低度正相关（r = 0.368，p<0.05）。平均 KFA 组的麻醉前 KFA 测量与术后 6 个月 KFA 呈最高正相关（r = 0.711，p<0.05）。调整麻醉前 KFA 后预测的 6 个月 KFA（度）为 45.378+[0.596 x 麻醉前 KFA（度）]（r = 0.67，p<0.05）。
在单侧初次 TKA 后 6 个月，麻醉前 KFA 与最终 KFA 的相关性最高，尤其是在术前 KFA 为 90-120°的患者中。
