This retrieval analysis study consisted of two goals. The first goal was to determine if there was a difference in the corrosion and fretting damage along the taper interface between large femoral heads in comparison to monopolar hemiarthroplasty heads. The second goal was to examine if the diameter of monopolar hemiarthroplasty heads can influence corrosion and fretting damage along the taper interface. This retrieval analysis compared the corrosion and fretting behaviour of 40 mm femoral heads (n = 13) to monopolar hemiarthroplasty heads (n = 17 for a diameter < 50 mm; n = 6 for a diameter ≥ 50 mm) such that all implants had a minimum implantation period of three months, a 12/14 mm taper, and the heads and stems consisted of CoCr alloy. The 40 mm heads articulated with a polyethylene cup whereas the monopolar hemiarthroplasty heads articulated with cartilage. The 40 mm heads were manufactured from one company whereas the monopolar hemiarthroplasty heads were manufactured from four different companies. Corrosion and fretting damage were assessed using a previous technique [1]. Table 1 lists the patient information and reasons for revision whereas Table 2 provides the implant information. The Mann Whitney U test and the Kruskal-Wallis test were performed for identifying significant differences for corrosion and fretting scores that were not normally distributed (α = 0.05). An unpaired student's t-test was conducted for comparing the head corrosion scores for the two head size groups of monopolar hemiarthroplasty implants since these scores were normally distributed.Introduction
Patients and Methods
