Takao Masaki, Nishii Takashi, Sakai Takashi, Sugano Nobuhiko
Departments of Orthopaedic Surgery (M.T. and T.S.) and Orthopaedic Medical Engineering (T.N. and N.S.), Osaka University Graduate School of Medicine, Osaka, Japan
Departments of Orthopaedic Surgery (M.T. and T.S.) and Orthopaedic Medical Engineering (T.N. and N.S.), Osaka University Graduate School of Medicine, Osaka, Japan.
J Bone Joint Surg Am. 2016 Sep 21;98(18):1548-54. doi: 10.2106/JBJS.15.01073.
Inadequate soft-tissue tension in total hip arthroplasty is regarded as one cause of dislocation or abductor muscle weakness. The purpose of the present study was to assess how the postoperative discrepancy in limb offset (consisting of both femoral offset and acetabular offset) affects soft-tissue tension compared with other factors among patients with unilateral hip disease undergoing total hip arthroplasty.
A total of 89 consecutive patients underwent mini-incision total hip arthroplasty involving an anterolateral or posterior approach and with use of a computer navigation system. Soft-tissue tension was measured by applying traction amounting to 40% of body weight with the joint positioned at 0°, 15°, 30°, and 45° of flexion. The separation between the cup and the prosthetic head was measured using the navigation system.
The cup-head separation differed significantly for varying angles of flexion (p < 0.001), with the greatest distance noted at 15° of flexion (mean and standard deviation, 11 ± 5 mm). Stepwise multiple regression analysis showed that postoperative limb-offset discrepancy, an anterolateral approach, and preoperative abduction range of motion were correlated with the cup-head separation at 15° of flexion. Postoperative limb-offset discrepancy was negatively correlated with the cup-head separation at 0°, 15°, and 30° of flexion.
Postoperative limb-offset discrepancy significantly affected the soft-tissue tension in total hip arthroplasty at varying degrees of flexion. This indicated that it is important to restore normal limb offset without overlengthening to obtain adequate soft-tissue tension in total hip arthroplasty.
Therapeutic Level IV. See Instructions for Authors for a complete description of levels of evidence.
全髋关节置换术中软组织张力不足被认为是脱位或外展肌无力的原因之一。本研究的目的是评估在接受全髋关节置换术的单侧髋关节疾病患者中，与其他因素相比，术后肢体偏移（包括股骨偏移和髋臼偏移）差异如何影响软组织张力。
共有89例连续患者接受了采用前外侧或后外侧入路并使用计算机导航系统的微创全髋关节置换术。通过在关节处于0°、15°、30°和45°屈曲位时施加相当于体重40%的牵引力来测量软组织张力。使用导航系统测量髋臼杯与假体头之间的间距。
髋臼杯与假体头之间的间距在不同屈曲角度下差异显著（p < 0.001），在屈曲15°时距离最大（均值和标准差，11 ± 5 mm）。逐步多元回归分析显示，术后肢体偏移差异、前外侧入路和术前外展活动范围与屈曲1
