Two-staged exchange arthroplasty with an antibiotic-impregnated PMMA cement spacer in-between two stages has a success rate of 85% to 95% in eradication of infection. Use of vancomycine in high doses has a high potential for complications due to nephrotoxicity. The aim of this study was to evaluate the results of two-staged exchange arthroplasty in infected hip arthroplasty using low-dose vancomycine-impregnated PMMA cement as an interim spacer between stages. Thirty-five (20 females, 15 males, average age: 60) patients with a confirmed infected total hip arthroplasty who were treated between 1999 and 2005 were the subjects of the study. In the first stage after removal of the prosthesis and debridement, a spacer made of 40 grams of PMMA cement impregnated with 1 gr vancomycine was placed in the infected joint space. Postoperatively, patients were treated with 6 weeks of intravenous antibiotics in consultation with an infectious disease consultant. When CRP and ESR returned to normal levels, revision surgery with cementless components was performed. The average follow-up after the second stage was 4 years. The ESR and CRP decreased significantly before the second stage with this treatment protocol (from 81.28 to 17.54 mm/h p<
0.001 and 10.05 to 0.64 mg/dl respectively, p<
0.001). The mean interval between the two stages was 193.3 days. A second debridement was needed in 4 patients (10.8 %) because they did not respond to treatment. Two patients (5.4 %) had recurrent infections after reimplantation and underwent a resection arthroplasty. None of the patients suffered from antibiotic toxicity. Two-stage exchange arthroplasty using a low dose vancomycine-impregnated cement spacer was an effective method in treating infected hip replacements. With using a lower dose than previously reported, we were able to avoid antibiotic toxicity while effectively treating our patients with the same success rate.
As expected, the generated forces at the bike pedal were low (20–25% body-weight) calling for little muscle activity and low compressive joint forces. However, with a mean maximum flexion angle of 131.5°, the observed motion ranges were higher than expected. Prostheses not designed for high flexion activities could lose tibio-femoral contact during cycling with detrimental effects on wear. Still, the measured range of rotation in the transverse plane indicates that despite its posterior-stabilized design rotation is taking place with approximately the same amount as it occurs in normal subjects. This may have detrimental effects on the post at the tibial plateau and could explain the previously observed rotational damage patterns on retrieved posterior stabilized TKA specimens. Data are suggesting that leisure activities should be considered to determine the appropriate TKA design. This study will provide useful data for future design and wear testing scenarios.
We have reviewed 54 patients who had undergone 61 total hip replacements using bulk femoral autografts to augment a congenitally dysplastic acetabulum. There were 52 women and two men with a mean age of 42.4 years (29 to 76) at the time of the index operation. A variety of different prostheses was used: 28 (45.9%) were cemented and 33 (54.1%) uncemented. The graft technique remained unchanged throughout the series. Follow-up was at a mean of 8.3 years (3 to 20). The Hospital for Special Surgery hip score improved from a mean of 10.7 (4 to 18) pre-operatively to a mean of 35 (28 to 38) at follow-up. The position of the acetabular component was anatomical in 37 hips (60.7%), displaced less than 1 cm in 20 (32.7%) and displaced more than 1 cm in four (6.6%). Its cover was between 50% and 75% in 34 hips (55.7%) and less than 50% in 25 (41%). In two cases (3.3%), it was more than 75%. There was no graft resorption in 36 hips (59%), mild resorption in 21 (34%) and severe resorption in four (6%). Six hips (9.8%) were revised for aseptic loosening. The overall rate of loosening and revision was 14.8%. Overall survival at 8.3 years was 93.4%. The only significant factor which predicted failure was the implantation of the acetabular component more than 1 cm from the anatomical centre of rotation of the hip.