Abstract
Introduction
The purpose of this study was to evaluate the in vivo migration patterns of a polished femoral component cemented line-to-line using EBRA –FCA.
Methods
The series included 164 primary consecutive THAs performed in 155 patients with a mean age of 63.8 years. A single prosthesis was used combining an all-polyethylene socket and a 22.2 mm femoral head. The monoblock double tapered femoral component made of 316-L stainless steel had a highly polished surface (Ra 0.04 micron) and a quadrangular section (Kerboull(r) MKIII, Stryker). The femoral preparation included removal of diaphyseal cancellous bone to obtain primary rotational stability of the stem prior to the line-to-line cementation. Stem subsidence was evaluated using EBRA-FCA software which accuracy is better than ± 1.5 mm (95% percentile), with a specificity of 100% and a sensitivity of 78% for detection of migration of more than 1.0 mm, using RSA as the gold standard.
Results
At the minimum 15-year follow-up, 73 patients (77 hips) were still alive and had not been revised at a mean of 17.3 ± 0.8 years, 8 patients (8 hips) had been revised for high polyethylene wear associated with periacetabular osteolysis, 66 patients (69 hips) were deceased, and 8 patients (10 hips) were lost to follow-up. Among the 8 revision procedures, the femoral component was loose in 3 cases. A total of 1689 radiographs were digitized of which 263 were excluded by the software for lack of comparability, leaving 142 hips with adequate follow-up evaluation data. At last follow-up, the mean subsidence of the entire series was 0.63 ± 0.49 mm (0 – 1.94 mm). When using a 1.5 mm threshold, 4 of the 142 stems were considered to have subsided.
