Multicentric and prospective study of the Summit cementless stem

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.