Total Hip Arthroplasty with Modular Stem for Dysplastic Hips in South Asian Population

Background: Optimum component positioning and orientation is required to optimize the functional result during total hip arthroplasty for dysplastic hips. Methods: Sixty-two patients (66 hips) including 33 males and 29 females underwent total hip arthroplasty using modular stem prosthesis at an average age of 40.6 years (range 17 to 49 years). Nineteen hips were classified as Type I, 24 hips as Type II, 13 hips as Type III and 10 hips as Type IV dysplastic hips according to Crowe's classification. Eighteen hips (27.2%) underwent sub trochanteric osteotomy and 23 hips (34.8%) required adductor tenotomy at the time of surgery. Results: Sixty-one patients (65 hips) were available for the latest follow up. The median follow-up was 57.4 months (range12 to 100 months). The mean Harris Hip Score was 90.6 (range 72 to 96), which was significant improvement from the preoperative Score of 44.8 (range 38 to 62). The clinical outcome was graded as excellent in 39, good in 13, fair in 7 patients and poor in 2 patients respectively. Only one hip (1.5%) had underwent revision surgery for the stem at 18 months following the index surgery. Postoperative dislocation following a fall was seen in one hip of a female patient who was operated on both sides. The radiographs revealed that all the remaining 65 hips had stable femoral component and the osteotomy sites were healed. The Kaplan-Meier survivorship with revision as endpoint (including open reduction for dislocation) was found to be 96.4% at 100 months (95% Confidence Interval; 86.3-99.1). Conclusion: This study in South-Asian patients using the modular stem strengthened the premise that cementless modular total hip arthroplasty provides a satisfactory outcome in treating secondary osteoarthritis due to dysplastic hips.