Four- to six-year follow-up of primary THA using contemporary titanium tapered stems.

Tapered cementless femoral components have been used in total hip arthroplasty constructs for more than 20 years. In the past 5 to 10 years, these stems have gained popularity in the United States. The purpose of this study was to evaluate the results of the authors' initial experience using a contemporary tapered, proximally porous-coated, titanium femoral component at 4 to 6 years of follow-up. Eighty-eight patients underwent 100 total hip arthroplasties using the Summit stem (DePuy, Warsaw, Indiana) and a cementless acetabular component. Average age at the time of surgery was 61.6 years. Patients were prospectively followed for 4 to 6 years or until death. Patients were evaluated clinically using Harris Hip Scores and the need for revision. Radiographs were evaluated for femoral loosening and osteolysis. At final follow-up, no hips had been revised for femoral or acetabular loosening. Two hips required revision for dislocation and 1 for early femoral fracture. Bony ingrowth was seen in all but 2 femoral components. There was 1 instance of proximal femoral osteolysis and none distally on radiographs (cross-linked polyethylene was used in 73% of cases). There were 2 cases of severe stress shielding. One percent of cases had an early fracture (too tight) and 1% subsided without ingrowth (too loose). One patient reported significant thigh pain that did not limit activity. At final follow-up, the Summit femoral component demonstrated durable results at 4 to 6 years. Stability of the implant without femoral fracture is paramount.