Abstract
Bipolar femoral head replacement (BHP) was performed on 9 hips of 7 rheumatoid arthritis (RA) patients. The average age was 60.6 years (range 29-81), average disease duration was 18.4 years (range 1-42), and average postoperative follow-up period was 50.8 months (range 20-90). We analyzed the clinical results using the hip score of the Japanese Orthopaedic Association (JOA score) and Fujibayashi's classification. Köhlerline-cup (KC) and tear drop line-cup (TC) length and CE angles were measured on X-ray images for the evaluation of medial and upward migration. CE angle' was defined for the 4 cases with the bone graft on the accetabular edge.
The JOA score, especially the JOA pain score, and Fujibayashi's class improved significantly (p<0.05) postoperatively. KC length decreased and TC length increased in 77.8% (7 of 9 hips). Two joints in two patients with marked upward migration dislocated postoperatively. No statistically significant correlations of medial or upward migration with CE angle or CE angle' were found.
The authors conclude that bipolar femoral head replacement might not be indicated for some patients with RA.
