ObjectiveTo evaluate the middle- and long-term effectiveness of primary total hip arthroplasty (THA) in patients with chronic autoimmune inflammatory diseases. MethodsBetween January 1990 and June 2006, 42 patients (51 hips) with chronic autoimmune inflammatory diseases underwent THA. There were 15 males (18 hips) and 27 females (33 hips) with an average age of 36.9 years (range, 22-70 years). The locations were the left side in 29 hips and the right side in 22 hips. Of 42 cases, there were 11 cases of systemic lupus erythematosus (13 hips), 16 cases of rheumatoid arthritis (22 hips), and 15 cases of ankylosing spondylitis (16 hips). The causes of THA included avascular necrosis of the femoral head in 26 cases (34 hips), ankylosis of the hip in 15 cases (16 hips), and fracture of the femoral neck in 1 case (1 hip). The Harris score was 32.49 ± 9.50. The physical component summary (PCS) and mental component summary (MCS) of short form 36 health survey scale (SF-36) scores were 25.53 ± 4.46 and 42.28 ± 6.27, respectively. ResultsAll incisions healed primarily. All 42 patients were followed up 5-21 years (mean, 9.1 years). At last follow-up, the Harris score was 89.25 ± 8.47; PCS and MCS of the SF-36 were 51.35 ± 4.28 and 55.29 ± 8.31, respectively; and significant differences in the scores were found between pre- and post-operation (P lt; 0.05). Complications included limp (4 cases), prosthesis dislocation (2 cases, 2 hips), periprosthetic fracture (1 case, 1 hip), aseptic loosening (2 cases, 2 hips), and ectopic ossification (3 cases, 3 hips). ConclusionTHA seems to be a good choice for patients with chronic autoimmune inflammatory diseases.