Multicentric and prospective study of the Summit cementless stem.

Abstract

We assess early clinical and radiographic results of a multicentric and prospective study of 485 Summit porous-coated stems implanted in 5 hospitals. Of the patients, 171 had a hydroxyapatite (HA) coating and 314 had non-HA porous-coated stems. The mean follow-up was 4.2 years (range 2.5-6 years). The median size of the stem was 5. A standard femoral offset stem was used in 366 hips (75.5%) and a high femoral offset in 119 hips (24.5%). Dislocation was the most frequent postoperative complication (16 hips). Clinical results according to the Harris scale were 30.17 points (range 10-52) before surgery and 95 points (range 90-100) at the last follow-up evaluation. All stems were radiographically osseointegrated. Femoral stem position was neutral in 395 hips (81.4%), and femoral canal filling was related with implant position. No stem subsidence greater than 5 mm has been found in any hip. No osteolysis was found around the femoral stem. No differences have been found between HA coating and non-HA porous-coated stems. Although the present follow-up in this series is too short to allow definite conclusions, the Summit stem with and without HA coating has provided excellent short-term results.