Abstract:
Background: There is little data on the magnitude and factors for functional leg lengthening after primary total knee arthroplasty (TKA). Questions/Purpose: We sought to determine the incidence of and risk factors for functional leg lengthening after primary TKA. Methods: We retrospectively reviewed consecutive unilateral primary TKAs at a single institution from 2015 to 2018. Of the 782 TKAs included, 430 (55%) were performed in women; the mean age was 66 years, and the mean body mass index was 29 kg/m2. Preoperatively, 541 (69%) knees were varus deformities and 223 (29%) were valgus deformities. Hip to ankle biplanar radiographs were obtained preoperatively and 6 weeks postoperatively for all patients. Two independent researchers measured leg length, coronal plane deformity, lateral knee flexion angle, and overall mechanical alignment on all preoperative and postoperative radiographs. Results: The mean overall ipsilateral functional leg lengthening was 7.0 mm. Seven hundred knees (90%) were overall functionally lengthened, including 462 (59%) knees lengthened >5 mm and 250 (31%) knees lengthened 10 mm or more. A valgus deformity and coronal plane deformity of 10° or more were significant risk factors for increased functional lengthening. Patients with severe valgus deformities (>10°) had the largest amount of functional lengthening, at a mean of 13.5 mm. Conclusion: After primary TKA, 90% of limbs are functionally lengthened, including roughly one-third over a centimeter. Valgus knee deformities and severe deformities (>10°) were significant risk factors for increased limb lengthening.
摘要:
背景:关于初次全膝关节置换术(TKA)后功能性腿延长的幅度和因素的数据很少。问题/目的:我们试图确定原发性TKA后功能性腿延长的发生率和危险因素。方法:我们回顾性回顾了2015年至2018年在单个机构中连续的单侧原发性TKAs。包括782个TKA,430例(55%)在女性中进行;平均年龄为66岁,平均体重指数为29kg/m2。术前,内翻畸形541例(69%),外翻畸形223例(29%)。所有患者术前和术后6周获得髋至踝部双平面X光片。两名独立研究人员测量了腿长,冠状平面畸形,膝关节外侧屈曲角度,以及所有术前和术后X光片的整体机械对齐。结果:同侧功能性腿延长平均为7.0mm。七百只膝盖(90%)整体功能延长,包括462(59%)个膝盖延长>5毫米和250(31%)个膝盖延长10毫米或更多。外翻畸形和10°或更大的冠状平面畸形是功能延长增加的重要危险因素。严重外翻畸形(>10°)的患者功能延长量最大,平均13.5毫米。结论:原发性TKA后,90%的肢体功能延长,包括大约三分之一厘米。膝关节外翻畸形和严重畸形(>10°)是肢体延长增加的显著危险因素。