Purpose of the study: The aim of the retrospective study was to analyse the medium-term results of the cementless hip prosthesis St. Nabor.
Method: 46 patients with complete postoperative and radiographic documentation were available for clinical review. The average follow-up was eight years and five months (range from eight years, one month to ten years). The average age at the last follow-up was 60 years. Ten patients showed severe coxarthritis and 32 patients a dysplasia of the acetabulum before surgery. Two patients suffered from a severe osteonecrosis of the femoral head and two patients had fractures of the acetabulum or femoral neck, respectively.
Results: The medium-term follow-up for the acetabular component showed a survival rate of 97.8%. The radiographic data visualized one loosening as a result of a low grade infection, 18 months after surgery. There was no migration of the acetabular component according to Sutherland et al. and no protrusion was found. None of the acetabular components showed radiolucent lines or was loose according to radiographic criteria. In comparison to the first post-operative radiograph, 26 of the hips were found with a significant reduction of lacunae, twelve of them showed a complete absence at last follow-up. The overall Harris hip score averaged 92 points (range 58 to 100 points) for the entire group. 41 (92%) of all hips were rated as excellent or good. Two hips (4%) of all hips were rated as fair and two hips (4%) were rated as poor.
Conclusion: The high rate of good and satisfying results in medium-term follow-up proves this St. Nabor acetabular component system to be an excellent implant in total hip arthroplasty for younger patients with or without dysplasia.