Purpose: The purpose of this study was to determine the greater than 20 year survivorship of the PCA total hip arthroplasty (THA) in patients with severe hip osteoarthritis.

Method: A prospective follow-up of 315 consecutive patients treated with a PCA cementless THA in patients with hip osteoarthritis was performed. Patients had postoperative assessments and radiographs every two years. Overall THA, femoral stem and acetabular cup revisions and Kaplan-Meier survivorship was determined. Revision rates and survivorship was also investigated across gender.

Results: The mean age of our patients was 61 years old (range 20 to 86) with 47% female patients. 226 cases used a 26mm articulation and 89 cases a 32mm articulation. At 23 years follow-up, 188(60%) patients were alive with retained implants while 85(27%) were deceased with still implants that were functioning well. Forty-two cases (13%) were revised (30 sockets, 13 stems), five of which later deceased. The 20 year Kaplan Meier survivorship for the overall THA, stem component and acetabular cup were 86%, 97% and 90% respectively. Survivorship of the acetabular cup for 26mm and 32mm articulations was 92% and 85% respectively (p=0.016). Females had a worse THA survivorship than males, 82% and 91% respectively (p=0.036).

Conclusion: The PCA cementless THA has performed well beyond 20 years with 26 mm articulations doing better than 32 mm, and male gender associated with better outcomes. The authors postulate that polyethylene thickness is key to predicting failure.

Introduction: Patients following resurfacing frequently remark about the natural feel of the resurfaced hip joint in contrast to those with total hip arthroplasty. Possible reasons for this include the larger femoral head size, conservation of bone and superior biomechanics of the implant with more accurate restoration of femoral offset, leg length and femoral anteversion.

Our aim was to assess femoral offset and leg length following hip resurfacing and hybrid THR (uncemented acetabulum) performed by the same surgeon.

Methods: A consecutive group of patients were identified (35 resurfacing and 25 hybrid). AP pelvis radiographs were evalulated, films with evidence of malrotation or inadequate imaging of the femur were excluded, leaving 21 resurfacing and 15 hybrid. Comparison was made between the pre-op and post-op films together with the contralateral hip on the same film. Patients with hip dysplasia or significant pathology in the contralateral hip were excluded. Magnification of the films was measured by comparison of the templated diameter of the implanted femoral head and the acutal diameter of the implant. To allow comparison between pre-op films a measurement was taken between the obturaror foraminae.

All films were analysed by the same investigator using the technique described by Jolles et al (J Arthroplasty 2002). A horizontal line was drawn between the base of the teardrop on both sides, and perpendicular lines drawn from the back of the teardrops. The anatomical femoral axis was drawn and femoral offset measured from this. The centre of rotation of the femoral head was determined by templating and the acetabular offset obtained.

Distance from tip of the greater trochanter to the centre of the femoral head in the axis of the femur was determined on pre and post-op films, as this shows little variation with rotation of the femur. Leg length was measured from the horizontal line to the tip of the greater trochanter together with the angle between the femoral axis and the horizontal to correct for abduction of the hip.

Results: Mean total femoral offset compared to the contralateral side was −1.3mm (SD 5.3) and −3.2mm (SD 6.5) for the resurfacing and hybrid groups respectively. No significant difference was detected in leg length or other measurements.

Discussion and Conclusion: No significant differences were demonstrated between femoral offset or leg length in the resurfacing and hybrid arthroplasty groups. This study does not support the hypothesis that resurfacing produces more accurate restoration of hip biomechanics than hybrid total hip arthroplasty.