Osteolysis and loosening, despite great changes in bearing materials, continue to be a problem in total hip replacements (THR). Hybrid fixation, proposed in 1989 to aid such problems, has not completely solved them.2 There are times during surgery that an alternative to the routine, predetermined technique is needed. Recent alterations in cementless femoral and/or cemented acetabular fixation have produced promising clinical returns and have shown improvement in dealing with linear wear and osteolysis....
Materials and Methods
Between 1987 and 2005, a retrospective review of all THR cases using 2 independent series of hybrid and reverse hybrid cementing techniques was performed. Four hundred fifty-nine hips received a hybrid replacement, and 54 hips received a reverse hybrid replacement. A match-case analysis (n=54 hips in each series) was done between the hybrid and reverse hybrid cohorts, including gender, primary diagnosis, age, and body mass index (average follow-up, 5.8 years; range, 2-16.8 years)....
Of the 54 hips (n=54 patients) in the hybrid group, 8 patients died with a well-functioning arthroplasty (range, 2.7-16.9 years) and none were lost to follow-up. Five hybrid THRs (9.3%) were revised. Two (3.7%) underwent revision for a loose acetabular component caused by pelvic osteolysis, 2 (3.7%) for a loose femoral component, and 1 (1.9%) for a fractured femoral stem.
One hip (1.9%) had a partially loose acetabular cup but was not revised. Of the 54 hips (n=54 patients) in the reverse hybrid group, 4 patients died with a well-functioning arthroplasty (range, 2.3-14.6 years) and none were lost to follow-up. One patient underwent a revision procedure due to a loose femoral stem. No patients in the reverse hybrid group reported significant postoperative complications, including residual polyethylene wear, osteolysis, or evidence of acetabular aseptic loosening....
Discussion
To determine the best mode of acetabular fixation, one must not only evaluate the fixation but the bearing surface and polyethylene wear as well. The bearing surfaces and wear are small; therefore, fixation is paramount.
Although midterm results for hybrid THR have been satisfactory, problems associated with high polyethylene wear, femoral loosening, and increased pelvic/focal osteolysis are cause for concern. Unfortunately, the polyethylene was not the same....
Conclusion
This study shows that the reverse hybrid THR, although unusual, is a successful alternative to hybrid THR when a need arises and institutional resources allow. With the exclusion of varying patient demographics (gender, body mass index, age, and primary diagnosis), the reverse hybrid series of 54 hips accounted for excellent postoperative hip performance, mobility, and survivorship, showing clinical outcomes better than the hybrid series following a minimum 2-year follow-up retrospective review. However, because of the overall difficulty in cementing the acetabular cup, the ease and predictability of the cementless fixation, and now the options of modular bearing surfaces, cementless fixation for the acetabular cup must be considered the gold standard...
Tidak ada komentar:
Posting Komentar