Ceramic femoral head in highly cross-linked polyethylene cup. 5 year results of a randomized trial.

Background: Although few methods are used to estimate polyethylene liner wear from radiographs of total hip replacements, there is no consensus with regard to the accuracy of these methods. Highly cross-linked polyethylene (XLPE) is reported to have low rates of linear wear in the literature. However, there are not reports about wear rate of ceramic head in hxple cup at 5 years postoperatively, evaluated by Dorr method. We evaluated the wear rate of HXPLE, within the first five years after implantation using manual techniques of Dorr.

Material And Methods: We evaluated 143 patients (93 males and 50 females) with one design of uncemented acetabular component, a 40-mm (77 hips) or 44-mm (66 hips) ceramic femoral head and the annealed highly cross-linked crossfire polyethylene (X3) insert used in combination with Secur-Fit Advanced stems at a mean follow-up of 5 years. Selection of these femoral heads was based on several factors, including the perceived risk of dislocation, the outer diameter size of the acetabular component, and liner availability. Measurements of linear wear were performed by experienced surgeons with Dorr method and analyzed using the first-to-last method. Standard radiographs were used to detect periprosthetic osteolysis. Clinical records were used to determine all demographic data (age, height, weight, gender, months of follow-up, etc.).

Results: For the entire cohort, the median linear wear rate was 0.0438 mm per year at 5 years and there was no any revision due to loosening, no liner fracture, and no patient with symptomatic corrosion. The head size was selected intraoperatively based on the size of the acetabular component and presumed risk of dislocation. There was no hip with pelvic or femoral osteolysis. The median linear wear rate was 0.0461 mm (±0.0183) and 0.0409mm (±0.0118), respectively, at head diameters of 40 and 44 mm. We found no association between femoral head size and the linear wear rate. This sentence can be excluded from here CONCLUSIONS: This acetabular component and HXLPEs with large ceramic heads had low rates of linear wear. Large ceramic femoral heads did not lead to liner fracture, loosening, or symptomatic trunnion corrosion in this patient population. However, we recommend longer clinical follow-up studies and caution in the routine use of larger ceramic femoral heads in other, younger patient populations.

Key Words: Ceramic femoral heads, Highly cross-linked polyethylene, Large heads, Total hip arthroplasty.