术前外翻应力位X线片预测Oxford单髁关节置换术后下肢力线变化的临床研究

A clinical study on preoperative valgus stress radiography for evaluating alignment changes of the lower limb after Oxford unicompartmental knee arthroplasty

目的探讨术前外翻应力位X线片在预测Oxford内侧单髁关节置换术矫正膝内翻力线的作用和价值。方法收集2013年9月至2014年6月,我院收治的50膝Oxford内侧单髁关节置换术治疗的膝关节内侧间室骨关节炎患者的资料。对患者术前进行外翻应力位X线片及膝关节的负重正侧位、髌骨轴位、双下肢全长X线片。测量膝关节面角(femoro tibial facet angle,FTFA)及髋膝踝角(hip knee ankle angle,HKAA),分析单髁关节置换术后HKAA的变化和外翻应力位FTFA变化的特点及相关性。结果本组患者术前HKAA平均(175.7±3.7)°,术后HKAA平均(178.4±3.6)°,术后较术前矫正(2.8±2.5)°(P<0.05)。负重位FTFA平均(2.9±1.8)°,外翻应力矫正下FTFA平均(0.2±1.1)°,外翻应力矫正(2.7±1.5)°。术后HKAA变化角度与外翻应力位FTFA变化角度呈正相关,相关系数为0.612(P<0.05)。外翻应力能矫正组,术前HKAA平均(177.5±3.0)°,术后HKAA平均(180.5±3.2)°,矫正(2.9±2.4)°。外翻应力不能完全矫正组,术前HKAA平均(173.5±3.3)°,术后HKAA平均(176.1±2.2)°,矫正(2.6±2.8)°。结论术后HKAA变化角度与外翻应力位FTFA变化角度呈正相关,术前外翻应力位X线片测量FTFA变化可以预测Oxford单髁关节置换术后下肢力线变化。外翻应力位能矫正的术前内翻畸形,单髁关节置换术后膝关节力线更满意。

Objective To investigate the signiifcance and value of preoperative valgus stress radiography for predicting the correction of the varus alignment after Oxford unicompartmental knee arthroplasty （ UKA ）.Methods The data of the patients （ 50 knees ） with medial compartmental osteoarthritis （ OA ） who underwent Oxford UKA from September 2013 to June 2014 were retrospectively reviewed. Full-length weight-bearing radiographs of the lower limbs were obtained preoperatively. Weight-bearing anteroposterior （ AP ） radiography and valgus stress radiography in the supine position were also performed preoperatively. The femoro tibial facet angle （ FTFA ） and hip-knee-ankle angle （ HKAA ） were assessed. The characteristics and correlation of the changes of HKAA and FTFA after UKA were analyzed.Results The mean preoperative HKAA was （ 175.7 ± 3.7 ） °, which was increased to （ 178.4 ± 3.6 ） ° postoperatively, with a correction of （ 2.8 ± 2.5 ） ° （P 〈 0.05 ）. The mean FTFA under weight-bearing conditions was （ 2.9 ± 1.8 ） °, which was （ 0.2 ± 1.1 ） ° on valgus stress radiographs, with a correction of （ 2.7 ± 1.5 ） °. A positive correlation existed between the changes of postoperative HKAA and FTFA under valgus stress, and the correlation coefifcient was 0.612 （P 〈 0.05 ）. The mean preoperative and postoperative HKAA were （ 177.5 ± 3.0 ） ° and （ 180.5 ± 3.2 ） ° in the corrected group under valgus stress, with a correction of （ 2.9 ± 2.4 ） °. The mean preoperative and postoperative HKAA were （ 173.5 ± 3.3 ） ° and （ 176.1 ± 2.2 ） ° in the uncorrected group under valgus stress, with a correction of （ 2.6 ± 2.8 ） °.Conclusions A positive correlation exists between the changes of postoperative HKAAand FTFA under valgus stress. Based on the changes of FTFA on preoperative valgus stress radiographs, the alignment changes of the lower limb after Oxford UKA can be predicted. For the patients with preoperative varus deformities which can be corrected with valgus stress radiography, the knee alignment will be more satisfactory after UKA.