Abstract：Objective To investigate the preliminary results and complications of a tapered proximal femur modular stem in total hip arthroplasty (THA).Methods From October 2010 to December 2011,tapered proximal femur modular stems were used for THA in 50 patients (56 hips).There were 14males and 36 females,at a mean age of 61 years (range,25-82 years).Forty-four patients had unilateral THA and six bilateral THA.Hip osteoarthritis secondary to developmental dysplasia of the hip occurred in 15 patients,femoral neck fractures in 12,avascular necrosis of the femoral head in 10,primary hip osteoarthritis in nine,rheumatoid hip arthritis in two,malunion of femoral neck fracture in one,and femoral head fracture combined with posterior dislocation of the hip in one.The adopted femoral component was a tapered proximal femur modular stem.Femoral head-acetabulum interface composed metal-polyethylene in 34 hips,ceramics-polyethylene in 12 hips,and ceramics-ceramics in 10 hips.There were 48 hips with standard femoral head (28 mm) and eight hips with non-standard femoral head (＞28 mm).Results Mean period of follow-up was 11 months (range,6-19 months) and two patients (two hips) were lost to follow-up.Harris hip score improved from 36 points (range,4-71 points) preoperatively to 89 points (range,55-98 points) at the final follow-up.There was one patient with mild pain in the thigh,one moderate pain,but none severe or critically severe pain at the final follow-up.At the final follow-up,no migration or loosening of the implanted prostheses occurred; periprosthetic bone ingrowth fixation on the femoral side was achieved in 53 hips and fibrous stable fixation in one hip ; apart from one hip of ＜ 2 mm prosthetic subsidence,the remained revealed no subsidence of the prostheses.Intraoperative complications included acetabulum perforation in one hip and periprosthetic femoral fracture in one hip.Conclusion The short-term results are satisfactory,but the potential risk of fretting/corrosion and even breakage at the modular stem junction remains.
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