Grit-blasted titanium femoral stem in cementless primary total hip arthroplasty: a 5- to 10-year multicenter study

A total of 133 cementless primary total hip arthroplasties using the Zweymuller-Alloclassic grit-blasted titanium tapered stem were performed in 3 institutions. The patient cohort was divided into 2 subgroups, nonselected and selected, on the basis of excellent bone stock and age (<65 years old at surgery). Acetabular components were all cementless, and bearing surfaces were all alumina-ceramic on polyethylene. After a 7.3-year average follow-up period (range, 5-10 years), 118 primary femoral replacements in 109 patients could be reviewed fully. Mean age at surgery was 55.7 years (range, 27-84 years). According to the Merle d'Aubigne and Charnley rating system, clinical results were graded excellent and good in 89% of hips and fair in 11%. Radiologically, early subsidence >2 mm could be detected in 4 hips (3.4%). Calcar atrophy and spot welds were noted in 77% and 82% of hips. Femoral osteolysis granuloma was noted in 4 hips (3.4%). There has been no stem fracture and no ceramic head breakage. The survivorship at 10 years with definite femoral aseptic loosening (radiographic failure) as the endpoint was 100% (95% Wilson confidence interval, 78.4%-100%; worst scenario, 95.4%). A significant difference between the nonselected and selected patient subgroups was observed only for early reoperation (P =.03) and proximal stress shielding (P =.01). Press-fitting but not filling the femoral canal with a rough titanium, straight, tapered femoral component represents, at intermediate follow-up, a promising cementless option in primary total hip arthroplasty.