[ABG Cementless THR: Description of the Implant, Medium-term Results.]

The authors present medium-term clinical results and radiographic evaluation of the implantation of cementless ABG total hip replacement. The implant is made from titanium alloy with a press-fit acetabular cup. The outer surface of the cup is coated with hydroxyapatite. Primary stability of the stem is guaranteed by its anatomical shape, secondary stability by the hydroxyapatite coating in the metaphyseal part of the implant. Evaluation covers a group of 19 patients who showed up to the clinical and radiographic follow-up. Average age at the time of implantation was 52 years (ranging between 31 and 65). The most frequent indication was in 11 cases primary coxarthrosis, in 5 cases necrosis of the head of the hip joint. Four times the operation was indicated for secondary postdysplastic osteoarthritis of the hip joint. Clinical results were evaluated according to Harris questionnaire. Excellent result was achieved in 10 patients (50 %), good result in 6 patients (30 %). Radiographic finding was evaluated on the basis of Gruen criteria using radiographs in 2 projections. The most frequent finding was a good secondary stability of the cup and metaphyseal stem with cortex hypotrophy in zones 2 and 6. In one case we encountered certain signs of loosening of acetabular cup. One THR was re-implanted due to aseptic loosening. Average period of follow-up was 4 years and 6 months. Key words: cementless THR, hydroxyapatite, pressfit principle.