Introduction and purpose: This study analyzes the clinical and radiographic results of two generations of the same uncemented acetabular component.

Materials and methods: The analysis comprised 83 Harris-Galante I (HGI) shells (with a 32 mm femoral head) and 93 Harris-Galante II shells (HGII) (with a 28 mm femoral head. Mean follow-up was 12.5 + 2.52 years for the HGI shells and 7.8 + years for the HGII ones. PE wear was assessed by means of image digitalization and computer software (AutoCAD).

Results: There were two cases of loosening amongst the HGI shells (Kaplan-Meier 96.9%) and one among the HGII ones (98.3%) (p = 0.7107). 4 PE replacements had to be performed due to wear in the HGI (90.7%). There were three dislocations of the PE insert in the HGI shells ( 79.7%) and one in the HGII ones (97.9%) (p = 0.883). Acetabular osteolysis was observed in 7 cases, out of which 5 were HGI and 2 HGII,. The osteolysis was related to a higher initial settling on the PE (position zero) ( p = 0.0062), a higher mean wear rate (p = 0.001), and a higher wear rate at the end of follow-up (p = 0.002). Position zero was 0.15 + 0.04 mm for HGI shells and 0.11 + 0.02 for HGII ones (p < 0.001). The mean wear rate was 0.13 + 0.23 mm/year and 0.11 + 0.09 respectively (p = 0.740). PE insert dislocation appeared after an average of 117 + 60.3 months, with a position zero of 0.15 mm for dislocated shells and y 0.13 mm for non-dislocated ones. The respective mean wear rates were 0.94 mm and 0.10 mm (p = 0.001).

Conclusions: Stable radiographical fixation was observed in the majority of shells of both generations. Osteolysis was related with higher wear. The second generation shows a lower position zero which leads to less wear at the end of follow-up, but not to a lower mean wear rate.

Introduction and purpose: This study analyses the long-term results and the polyethylene wear rate of a first-generation hemispherical porous shell.

Materials and methods: 40 Tri-Lock shells were analyzed associated to an ACS (DePuy) PE insert implanted between 1988 and 1992. The PE had been gamma sterilized in air. The mean follow-up until revision or last control was 9.3 years (range: 3.1–15.0). PE wear was assessed by means of image digitalization with an Auto-CAD 14R software after 6 weeks (position zero), 6 and 12 months and, then, once a year. All cases were associated to a Profile stem.

Results: All shells showed themselves to be radiographically osseointegrated. 7 cases had acetabular osteolysis (Kaplan-Meier survival: 74.1% at 13 years). The appearance of osteolysis was related to a higher average wear rate (p=0.0021) and a higher wear rate at the end of follow-up (p=0.0147). 11 cases showed a breakage of the PE (Kaplan-Meier survival: 61.69+29.9% at 13 years). These breakages appeared on average after 60.1 months. The distance between the axis of the femoral head and that of the shell on the initial radiograph (position zero or initial settling) was 0.6018 in cases with breakage and 0.2338 in cases with no breakage (p=0.009). PE breakage was related to a higher mean wear rate (p< 0.0001) and the verticalization of the shell (p=0.0016).

Conclusions: Although all Tri-Lock cups were osseoin-tegrated, the breakage of the ACS insert was an usual finding, which was related with a higher initial settling of the PE, a higher mean wear rate and the verticalization of the shell.