Hybrid primary total hip arthroplasty: a 5- to 9-year followup study.

One hundred fifty-two hips were reviewed at a minimum of 5 years after hybrid primary total hip arthroplasty using uncemented porous coated acetabular components and cemented femoral stems to determine the intermediate term durability of this method of fixation. Five hips (3.6%) have been revised: 1 for dislocation (0.7%), 1 for cup loosening (0.7%), and 3 for femoral loosening (2.2%). Clinical results proved to be extremely reliable in this series with 78% of the patients reporting no pain and 19.7% reporting slight or occasional pain. Radiographic evidence of polyethylene wear was evident in more than 1/2 of cups, but significant osteolysis or component loosening was not commonly seen on the cup side. On the femoral side incomplete radiolucencies were present in 31%, and focal osteolysis in 12.2%, nearly always proximally in Zones 1 and 7. These intermediate term results compare favorably on the femoral side and very favorably on the acetabular side to prior reported series. These results support the continued use of this combination of fixation methods for primary arthroplasty, but polyethylene wear and its effects remain a concern regarding the long term performance of these arthroplasties.