A Radiological Study of Rapidly Destructive Coxarthropathy

Rapidly destructive coxarthropathy (RDC) is a clinical concept propounded by Postel and Kerboull. RDC is characterized by joint destruction progression within a year, although the etiology of this disorder remains unknown. We evaluated 21 hips in 20 patients radiologically diagnosed with RDC. All patients underwent a total hip arthroplasty. The average age at surgery was 75 years. The affected side was more osteoporotic in all patients, and the pelvic angle, which indicates the spinopelvic alignment, was distributed below the normal range, i.e., the posterior tilt was more than the normal range. The affected side showed a higher center-edge (CE) angle and anterior-acetabular head index (AAHI) than the unaffected side, possibly due to severe head collapse. Our result supported that osteoporosis and/or mechanical factors influence the course of RDC. More investigations such as biochemical and immunopathological analyses would be necessary to clarify the etiology of RDC, which could be a terminal stage of some lesions.