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[Outcome after total hip arthroplasty performed for rapidly progressive hip destruction].

PURPOSE OF THE STUDY
Rapidly progressive destruction of the hip joint occurs in approximately 5 to 10% of patients with degenerative hip disease. The cause and natural history remain unclear, but total hip arthroplasty is almost always necessary. We performed a retrospective analysis to determine the particular clinical and radiological features of this condition and to assess long-term outcome after total hip arthroplasty.


MATERIAL AND METHODS
One hundred total hip arthroplasties were performed between 1984 and 1988 in patients with rapidly progressive hip destruction (67 women and 11 men, mean age 71 years). The transtorchanteric approach was used in all cases to implant cemented Charnley-Kerboull prostheses. Mean follow-up was 7 years 10 months.


RESULTS
There were seven complications: two nonunions of the trochanter, three extensive periprosthetic ossifications, one case of recurrent dislocation, and one late hematogenous infection. At last follow-up, the Merle d'Aubigné classification showed an excellent or very good functional result in 95 hips. Stable fixation was observed for 94 acetabular implants and 97 femoral implants. Six acetabular implants showed signs of loosening: certain=1, probable=4, potential=1. Three femoral implants showed signs of loosening: certain=1, potential=2. All the femoral loosenings were associated with acetabular loosening. Four hips required revision surgery: one for nonunion of the trochanter, one for septic loosening, two for aseptic loosening.


DISCUSSION
This series confirmed the radiological and clinical definitions of rapidly progressive hip destruction and demonstrated the reliability of pathological examination of the femoral head and joint capsule. Among the different hypotheses put forward to explain this condition, neither overloading nor use of antiinflammatory drugs would appear to be operating in this series. We were unable to confirm or infirm the micro-crystalline or vascular origin of this condition. Nevertheless, the vascular phenomena observed in the femoral head could be compared with those observed in ischemic joint disease. Arthroplasty led to major blood loss (2706 ml, hematocrit 35). This appears to be higher than observed for arthroplasty performed with the same technique in patients with the usual form of degenerative hip disease. Excepting this fact, the complications observed and the clinical results as well as the longevity of these implants suggest that arthroplasties performed for rapidly degenerative hips are not substantially different from those performed for common degenerative hip disease.