Abstract
Purpose of the study: This series included 50 consecutive cases of titanium hydroxyapatite coated cups impacted directly on live bone of the neoacetabulum after removal of a loosened cup implanted and reviewed at more than ten years.
Material and methods: The goal was to insert a titanium hydroxyapatite-coated cup on the largest quantity of healthy cancellous bone in the neocavity without using a graft and without worrying about the future height of the center of rotation nor the medial offset. The shortened impaction related to the neoacetabulum formed by the loosening could be compensated for by descending the femoral stem a bit further. This method of acetabular revision was performed for 75 hips before 1993. At more than ten years follow-up, four hips were lost to follow-up, 20 patients had died, and one case of early suppuration was noted. The series thus included 50 cups in 48 patients (22 men and 26 women, mean age 67 years at revision surgery). The Charnley classification was: A:21, B:22, C:7. Mean follow-up was 11 years. The SOFCOT staging was: I=0, II=33, III=14, IV=3. AAOS I=0, II=32, III=18, IV=0. The number of prior cup replacements: 0=46, 1=4. Approach: trochanterotomy (n=44), femorotomy (n=0), posterolateral alone (n=6). Mean cup diameter 60 (range 48–68). Femoral stems changed = 20. Preoperative PMA = 12 and postoperative PMA = 16.
Results: Among the 50 hips, 48 exhibited optimal fixation without lucent line or bone defect. One patient presented a partial lucent line and one had revision at nine years. At five years, all cups (100%) were in place and at ten years 98%. There were no cases of pelvic fracture and only three stage IV hips.
Discussion: The advantages of this method are to avoid the use of a graft or frozen head, and the generally immediate/rapid weight bearing. This series raises the question of whether it is advisable to replace the new cup in the position of the paleoacetabulum. These implants can be improved with screwed cups onto which a double-mobility cup can be press-fit. This technique has enabled weight-bearing in conditions which otherwise would not have been possible for these frail elderly patients.
Conclusion: In light of this consecutive series reviewed at more than ten years, we have decided to continue this approach.
Correspondence should be addressed to SOFCOT, 56 rue Boissonade, 75014 Paris, France.
