The fixation of porous-coated femoral stems. A radiographic study of 113 cases with a 4 to 8 year follow up

Porous-coated anatomic uncemented total hip arthroplasty. A 10-17-year follow-up

A total of 91 PCA total hip arthroplasties were analysed with a mean follow-up of 13.5 years. Thirty-one cups and six stems were revised. If the patients excluded from the follow-up study are included (113 hips), the cumulative probability of having revision of any prosthetic component for any cause was 16.0% (0.1%-31.9%) at 14 years in the "best case" scenario. Thigh pain (17 hips) was correlated with unstable fixation. Radiographic loosening occurred in 21 cups and 12 stems. Cup loosening was related to acetabular polyethylene wear equal to or more than 2mm per year and also to cup size and thereby polyethylene thickness. Stem loosening was related to poor femoral canal filling. Fifty hips had femoral osteolysis which was related to polyethylene wear of more than 2 mm, poor femoral filling and unstable fixation. (Hip International 2005; 15: 78-84).

Behavior of the femoral stem in the Bihapro hip prosthesis

This study evaluated the hydroxyapatite-coated femoral stem of the Bihapro hip prosthesis (Biomet Ltd, Bridgend, United Kingdom) using radiography, TC-99 scintigraphy, and bone densitometry. Thirty stems with >2 years of follow-up (mean: 31 months) were evaluated. No loosening or changes in the position of the implant were seen, and the mean subsidence was 2.2 mm. Radiography revealed a densification in the metaphyseal zone with reconstruction of the trabecular lines in 21 cases, while in 22 patients, radiolucent lines in the distal area of the femoral component were observed. Scintigraphy showed a diaphyseal normo-captation in 19 cases and a hypercaptation <1.4 with a mean index of 1.1 in 10 patients. Metaphyseal hypercaptation >1.4 was seen in 24 patients. Bone densitometry revealed increased density in the metaphyseal zones in 29 patients with a periprosthetic/normal bone quotient of 1.4.