Anterior dislocation following primary total hip replacement by the posterior approach - Aetiology and treatment

Abstract

Objective: Review of 5 patients after anterior dislocation of prosthesis following primary total hip replacement done from the posterior approach. Patients and Methods: The implanted prosthesis included 3 hybrid hips and 2 cementless hips. Results: The mean age of the patients was 60 years. Dislocation occurred between 2 to 25 days after operation. All dislocations were treated by closed reduction. The hips were unstable in extension, adduction and external rotation. Special splints were designed to protect the hips in the 'safety zone' of flexion, abduction, and internal rotation. After an average protection period of 2.7 weeks, all hips were stable after a mean follow-up of 31 months. Total anteversion angle was measured under fluoroscopy in 3 hips and this ranged from 50°to 75°. Conclusion: Anterior dislocation was proposed to be associated with excessive anteversion of the components. The special rehabilitation method was effective for treating anterior dislocation, even for sub-optimally positioned components.

我們報告5例經後路切入全髖關節置換術後前脫位個案。病人平均年齡為60歲。植入假體包括3例混合型及2例非骨水泥假體。脫位於術後2至25日發生。所有脫位都是以閉合性復位。髖關節在後伸、內收及外旋時顯得不定。我們設計了特別的支架以保護髖關節在屈曲、外展及內旋安全區。經過平均保護時間2.7週後，所有髖關節平均隨訪31個月內均保持穩定。我們以C型臂來量度其中3例全髖的總前傾角，數值為50º至75º。過度前傾的假體被認為與前脫位有關。即使假體位置並不理想，我們特別設計的康復方法也可以有效地處理前脫位的問題。