We report catastrophic early failure of a cemented total hip replacement comprising a modular femoral component with a Zirconia ceramic head and an acetabular component of cross-linked ultra-high molecular-weight polyethylene (Hylamer). Between 1995 and 1999 we implanted 29 hips in 26 patients with a mean age of 49.2 years. Survivorship analysis in this group revealed a failure rate of 67.6% at five years. All hips which failed did so because of aseptic loosening with progressive osteolysis or radiolucencies. We therefore recommend early and regular review of all patients with this combination of implants and early revision surgery in order to avoid massive bone loss.
We performed a prospective, randomised trial comparing three treatments for displaced intracapsular fractures of the hip in 280 patients aged 65 to 79 years. The mean patient survival was significantly higher in the group undergoing reduction and internal fixation (79 months) compared with that with a cemented Thompson hemiarthroplasty or a cemented Monk bipolar hemiarthroplasty (61 months and 68 months, respectively). After three years, 32 of 93 patients (34.4%) who had undergone fixation had local complications, necessitating further intervention in 28 (30%). There were no significant differences in the functional outcome in survivors, who were reviewed annually to five years. Either reduction and internal fixation or cemented hemiarthroplasty may be offered as alternative treatments for a displaced intracapsular fracture in a mobile and mentally competent patient under the age of 80 years. The choice of procedure by the patient and the surgeon should be determined by the realisation that the use of internal fixation is associated with a 30% risk of failure requiring further surgery. If this is accepted, however, hemiarthroplasty is avoided, which, in our study has a significantly shorter mean survival time. The use of a bipolar prosthesis has no significant advantage.
We performed a randomised prospective trial to compare a cemented unipolar prosthesis (Thompson) with a cemented bipolar prosthesis (Monk) in the treatment of displaced intracapsular fractures of the hip in patients over 80 years of age. Patients with a mental test score of less than 5/13 were excluded but the mortality was still about 30% at one year in both groups. We therefore feel that subjective criteria such as the level of pain and the return to the preinjury state are of paramount importance. Two years after operation there was no statistical difference between the rate of complications in the two groups. After adjusting for confounding factors such as differences in the level of function before injury between the groups, the degree of return to the preinjury state was significantly greater (p = 0.04) when using the unipolar prosthesis, which is one-quarter of the price of the bipolar. We cannot therefore justify the use of an expensive bipolar prosthesis in patients over 80 years of age.
