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

ABSTRACT

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.