Abstract
Objective: We had performed bipolar hemi-arthroplasty for osteoarthritis of the hip, with the technique of ace-tabular reaming until 1991. We studied the long-term results of this procedure radiographically.
Materials and methods: 62 patients (70 hips) were followed up for at least eight years after bipolar hemi-arthroplasty without cement. The diagnosis of all patients was osteoarthritis of the hip, which mainly came from dysplasia of the hip. The patients consisted of 13 men and 49 women. The average age at the operation was 43 years old (36–74 years old). The average duration of follow-up was 11 years (8–14 years). Smooth-surface press-fit type stem (Omnifit, Osteonics) was implanted for all cases. Focal osteolysis around component, the migration of the outer head and the subsidence of stem, were evaluated radiographically. By reviewing serial A-P radiographs, the first recognition of osteolysis and the extension of the lesion were researched.
Results: The mean migration of the outer head was 3.0mm medially and 9.1mm superiorly. The mean subsidence of stem was 7.2mm at final follow-up. The ace-tabular focal osteolysis was identified in 31 hips (44 %) and was first recognized at average 3.1years(1–9years) postoperatively. The femoral focal osteolysis was identified in 33 hips (47%) and was first recognized at average 2.3 years (1–9years) postoperatively. After the first recognition of osteolysis, the lesion was progressively spreading, especially on femoral side.
Conclusion: From these results, bipolar hemi-arthroplasty with the technique of acetabular reaming should not be indicated for osteoarthritis of the hip. This procedure causes osteolysis, which is progressive, and the migration of the outer head so often that it is difficult to preserve acetabular bone stock.
The abstracts were prepared by Nico Verdonschot. Correspondence should be addressed to him at Orthopaedic Research Laboratory, University Medical Centre, PO Box 9101, 6500 HB Nijmegen, The Netherlands.
