应力位X射线片与单髁置换后膝关节对位对线的关系

Correlation of knee joint alignment correction between valgus stress and postoperative radiography after unicompartmental knee arthroplasty

背景:应力位X射线片对于单髁置换术中力线的矫正有一定参考价值,但对于胫股关节半脱位的矫正程度仍不明确,且目前多数医疗机构并不重视这一术前检查。目的:研究置换前应力位X射线片上膝关节内翻畸形和半脱位的矫正程度与单髁置换后X射线片表现的相关性。方法:回顾性研究2018年1月至2021年1月牛津单髁手术患者共37例50膝,观察其临床效果,测量置换前下肢全长片、置换前外翻应力位片及置换后下肢全长片上的髋膝踝角、胫股关节面角及冠状面胫股半脱位值,并分析各指标间的相关性。结果与结论:(1)应力位X射线片及置换后X射线片上,髋膝踝角、胫股关节面角及冠状面胫股半脱位值均较置换前X射线片有所纠正,差异有显著性意义(P<0.05)。(2)相关性分析发现,应力位上胫股关节面角矫正值与置换后髋膝踝角矫正值呈正相关(r=0.420,P<0.05),应力位下冠状面胫股半脱位矫正值与置换后冠状面胫股半脱位矫正值呈正相关(r=0.754,P<0.05)。(3)因而,膝关节单髁置换可纠正置换前膝关节内翻畸形和冠状面胫股关节半脱位,且矫正程度可应用置换前外翻应力位X射线片进行有效预测。

BACKGROUND:Stress radiographs had a certain reference value for the correction of the lower limb alignment in unicompartmental knee arthroplasty,but the extent of tibiofemoral subluxation correction was still unclear.In addition,most medical centers did not pay enough attention to this examination.OBJECTIVE:To clarify the correlation between the degree of correction of knee varus deformity and subluxation on the stress radiographs and the X-ray appearance after unicompartmental knee arthroplasty.METHODS:We retrospectively analyzed the patients who undertook unicompartmental knee arthroplasty from January 2018 to January 2021.Totally 37 patients with 50 knees were included.The clinical outcome,and the radiographic assessment including the hip-knee-ankle angle,joint line convergence angle and coronal tibiofemoral subluxation value were assessed on pre-and post-operative full-length radiographs,as well as preoperative valgus stress radiographs.The correlations in-between these factors were analyzed.RESULTS AND CONCLUSION:(1)Compared with preoperative radiographs,hip-knee-ankle angle,joint line convergence angle and coronal tibiofemoral subluxation were significantly corrected in valgus stress and postoperative radiographs(P<0.05).(2)Pearson correlation analysis showed that the correction of joint line convergence angle on the valgus stress radiographs was positively correlated with the correction of hip-knee-ankle angle after unicompartmental knee arthroplasty(r=0.420,P<0.05),while the correction of coronal tibiofemoral subluxation at valgus stress radiographs was also positively correlated with the correction of postoperative coronal tibiofemoral subluxation(r=0.754,P<0.05).(3)Thus,unicompartmental knee arthroplasty can correct the varus deformity and coronal tibiofemoral joint subluxation of the knee joint,and the degree of correction can be effectively predicted by preoperative valgus stress radiographs.