The analysis of Affecting Factors for the Dissociation of the Polyethylene Liner in Cementless Harris-Galante Acetabular Component

PURPOSE: This study was performed to evaluate the factors associated with dissociation of the polyethylene liner with using a Harris-Galante I or II acetabular component in a stably positioned acetabular cup. MATERIALS AND METHODS: Between January 1998 and February 2007, 32 cases underwent revision of the acetabular component due to osteolysis, wear of the polyethylene liner or locking mechanism failure around the acetabulum in spite of stable positioning. 5 cases were primarily operated on using the type I Harris-Galante Hip Prosthesis and 27 cases used the type II. We divided the 32 cases into the two groups: Group I (18 cases) was composed of cases with the existence of polyethylene liner (PE) dissociation and Group II (14 cases) had no dissociation. The analyzed factors were age, gender, body weight, the type and the size of the acetabular cup, the thickness of the polyethylene liner, the duration of the time interval from the primary surgery, the inclination and ante-version of the acetabular cup, the wear rate of the PE liner, the degree of the osteolysis around the acetabulum and the existence of failure of the locking mechanism in the acetabular component. Statistical analysis was performed using the Mann-Whitney test (SPSS 12.0). RESULTS: Statistical significance was noted only for the wear rate of the PE liner (Group I: 0.40+/-0.19 mm/year, Group II: 0.19+/-0.08 mm, p=0.002) and the existence of failure of the locking mechanism (Group I: 16 cases (88.9%), Group II: 6 cases (42.9%), p=0.006). CONCLUSION: According to this study, the dissociation of the PE liner was influenced by the wear rate of the PE liner and the existence of failure of the locking mechanism in the acetabular component. In order to prevent PE liner dissociation, improvement of the locking mechanism and the PE liner system are essential.

The hemispherical porous acetabular component fixed by press-fit technique and additional screws

Seventy consecutive primary total hip arthroplasties in which a Harris-Galante porous-coated acetabular component had been used from October, 1986 to December, 1989 were reviewed for 5 to 9 years follow-up. We performed the retrospective, clinical and radiological analysis of the hemispheric, porous-coated, cementless acetabular component using press-fit and screw fixation. No component had detectable migration or any other position change. No acetabular fractures and no screw problems were noted. Initial peripheral gaps were observed in 11 cases (16%). Twelve cases had a postoperative polar gap less than 0.5 mm which were stabilized at 2 years postoperatively. Radiolucent line was present in at least one zone in 53% of cases and occurred most frequently in zones 1 and 3. No continuous radiolucent line greater than 2 mm was seen in any zone and radiolucent lines were stabilized 2-3 years postoperatively. Twelve hips (17.1%) had osteolysis of the acetabulum. No acetabular component was revised because of aseptic loosening. Revision arthroplasties were performed in 9 hips during follow-up. We concluded that the hemispheric porous-coated, acetabular components using press-fit and screw fixation had good results with a 5 to 9-year follow-up.