Fatigue fractures which originate at stress-concentrating voids located at the implant-cement interface are a potential cause of
Aims. To assess the early subsidence rate of the femoral stem for patients who had collarless Corail total hip replacement. Methods. Consecutive data was collected retrospectively between August 2007 and December 2009 for patients who had collarless Corail total hip replacement. Radiographic assessment of the degree of subsidence, calcar resorption, stem angulation, canal fill ratio and loosening of the stem were measured. Post operative pain, dislocation and stem revision surgery were also evaluated. Results. 48 patients were identified, providing 51 hips for the study. There were 22 male and 26 female. The mean age 64.2 years (range 38-77). Post-operative radiographs were taken at day 1, 6 weeks and one year post-operatively (range 10-18 months, mean 12.7). Significant subsidence was defined as 3 or more millimetres, we identified two patients with subsidence between 3-5mm, one patient with 6mm and two patients with 10mm subsidence at one year post-operatively. In the 5 patients with subsidence post-operatively, all significant subsidence occurred within the first 6 weeks. Canal fill ratio was measured in all patients; in the non-subsided group the ratio was an average of 72% in the lower third of the stem and 84% in the middle third. In the subsided group 75% in the lower third of the stem and 81% in the middle third, which we felt was clinically insignificant. There was no dislocation or revision for
Introduction. Total hip arthroplasties (THAs) in young patients are associated with high failure rates. We always use cemented total hip implants, however, in cases with acetabular bone stock loss we perform bone impaction grafting. Our purpose was to evaluate the outcome of 69 consecutive primary cemented total hips in patients younger than 30 years followed between 2 to 18 years. Methods. Between 1988 and 2004, 69 consecutive primary cemented THAs (mainly Exeters) were performed in 48 patients (32 women, 16 men) younger than thirty years. Average age at time of operation was 25 years (range, 16 to 29 years). Twenty-nine hips (42%) underwent acetabular bone impaction grafting because of acetabular bone loss. Mean follow-up was 10 years (range, 2 to 18 years). Revisions were determined, Harris Hip Score (HHS), and Oxford Hip Questionnaire Score (OHQS) were obtained and radiographs were analyzed. Survival was calculated using the Kaplan-Meier method. Results. No patients were lost to follow-up, but 3 patients (4 hips) died during follow-up, none of whom had underwent revision. Eight revisions were performed: 3
Post-mortem retrieval of canine, cemented femoral components was analysed to assess the performance of these implants in the dog as a model for human total hip replacement (THR). Mechanical testing and radiological analysis were performed to determine the stability of the implant and the quality of the cement. Thirty-eight implants from 29 dogs were retrieved after time intervals ranging from 0.67 to 11.67 years. The incidence of aseptic loosening was 63.2%, much higher than in human patients (6% in post-mortem studies). Failure of the femoral implants began with debonding at the cement-metal interface, similar to that in implants in man. The incidence of aseptic loosening was much lower in bilateral than in unilateral implants. Significant differences were observed for three different designs of implant. While the dog remains the animal model of choice for THR, results from this study provide insight into interspecies differences in the performance of implants. For example, the performance of THR in dogs should be compared with that in young rather than in elderly human patients.
