Background: High volumetric wear of polyethylene was the main factor in periprosthetic bone resorption and the failure of historic metal or ceramic on polyethylene hip resurfacing prosthesis. Metal on metal devices reduce the wear substantially and may solve this problem. The present study describes the clinical and radiographic results of our first 300 hips treated with the Birmingham Hip Resurfacing (BHR, Midland Medical Technologies, U.K.).

Methods: Between September 1998 and May 2003, 300 BHR were implanted in 262 patients. The patients had an average age of 49 years, 56% were men, 58% had a diagnosis of a CDH, 19% of osteoarthritis and 11% of avascular necrosis. Clinical and radiographic follow-up was performed at three months postoperatively and yearly thereafter.

Results: The average duration of follow-up was 2.4 years (1 to 5 years). We achieved a follow-up rate of 97%. Mean Harris Hip Score increased from 51 points pre-operatively to 91–92 points after one to five years, Total range of motion increased from 136 to 220. 6 prostheses had to be revised due to malposition (2), infection (2), neck fracture (1) and inguinal pain (1). Acetabular radiolucencies were observed in 3% in one zone, femoral radiolucencies in 5% in one to three zones around the stem. No patient showed radiolucency lines in all zones or migration.

Conclusions: In our opinion the cementless press fit cup, the low wear metal-on-metal bearing and the conservative implantation technique of the BHR at least fundamentally improves the known disadvantages of the historic Resurfacings. Our preliminary experience is encouraging, but has to be proofed in long-term observations.

Aims: Do the short term results, histopathological þndings and metal ion concentration predict a better outcome of modern metal-on-metal Hip Resurfacings (BHR) in comparison with historic metal-on-polyethylene Resurfacings? Methods: Comparison of 241 BHR arthroplasties with a follow up from 6 months to 4 years with long time results of 305 WHR; of 7 BHR and 3 MetaSUL capsule tissue histologyñs and chromium and cobalt serum concentrations of 67 BHR patients and 32 patients after MetaSUL THR implantation. Results: We achieved mean Harris Hip Scores of 90–92 in our BHR series with no radiological signs of aseptic loosening and a revision rate of 1.7% after approx. 18 months in opposition to 8% of the WHR after 2 years. The BHR capsule tissue showed wear particles in only 2 of 7 cases in opposition to MetaSUL joints, where in every case wear particles were detectable. We found no statistical difference in metal ion serum levels between BHR and Meta-SUL joints. Conclusions: In our opinion the cementless press þt cup, the low wear metal-on-metal bearing and the conservative implantation technique of the BHR at least fundamentally improves the known disadvantages of the historic Resurfacings which may predict better long term results.

Aims: In opposition to stemmed THR, Hip Resurfacing offers considerable advantages like bone preservation, however a correction of the pathological rotation and offset of the upper femur in higher grade CDH cases is not possible during implantation without subtrochanteric osteotomy. The aim of this study is the comparison of short term clinical and radiological results of Hip Resurfacing in higher grade CDH without osteotomy and primary osteoarthritis to examine if the clinical results are affected because of this disadvantage. Methods: Comparison of the clinical and radiological results of 38 BHR arthroplasties with acetabular bone grafting in CDH cases Eftekhar grade B and 76 BHR in primary osteoarthritis, AVN or Epiphyseolysis capitis femoris cases with a follow up from 6 months to 3 years. Results: Up to one year postoperatively the BHR with acetabular grafting showed slightly lower Harris Hip Scores than the primary osteoarthritis cases with differences up to 5 points. In opposition to that the range of motion and the number of positive Trendelenburg signs were not different. Also a difference in the rate of complications was not detectable. Conclusions: In our opinion the slightly slower rehabilitation of BHR with acetabular grafting in higher grade CDH depended on the partial weight bearing over 3 months postoperatively and the higher number of cases with an affected contralateral hip but not on the resultant pathology.