Abstract
Since the universal failure of first generation smooth threaded cups in primary total hip arthroplasty (THA), the screw-in concept of cementless acetabular cup fixation has been largely abandoned. We hypothesised that grit-blasted titanium conical cement free threaded cup shows stable long-term fixation. 198 Alloclassic total hip arthroplasties were performed in 179 patients, mean age 66 years old (22–85). 193 hips were analyzed after a mean follow-up of 10 years (1–25 years).
Results were excellent or good in 184 hips (95%). Postel-Merle d'Aubigne score increased from 10.3 (range 1 to 15) pre-operatively to 16.7 (12 to 18) points and 151 hips (78%) were pain free at last FU. Radiographic signs indicating successful cup osseointegration were noted in 92% of hips. Polyethylene wear > 0.1mm/year was observed in 6 hips (3%). The main cause of re-operation/revision surgery was recurrent dislocation (9/17cases, 53%). 2 threaded cups were revised for any reason and the revision per cent observed acetabular component years was 0.10 at 10 years average FU. 20 year-survival of the metal back was 98.8% (77.2–99.9%) and 100% (79.6–100%) for revision for any reason and revision for aseptic loosening, respectively. Despite minimum PE thickness of 6.5mm and use of alumina ceramic 28mm heads, conventional polyethylene liner wear was the weak link of the acetabular reconstruction;
This study shows excellent long-lasting bone anchorage through bone on-grown of grit-blasted titanium threaded cup. Despite universal outstanding longevity in the worldwide literature, CSF threaded cups were retrieved from the European market in March 2017 due to insufficient sales, indicating that evidence base medicine may not be the major criteria influencing surgeons' choice.
