Total hip arthroplasty in ankylosing spondylitis: Outcome in 340 patients

Objective. The longterm outcome of total hip arthroplasty (THA) in ankylosi ng spondylitis (AS) remains unclear. Concern has been expressed regarding j oint survival, given that recipients are young and active. We present outco me data on 340 THA after a mean followup of 14 years. Methods. The 6.7% of patients (n = 309:237 contactable) who had undergone T HA were identified from our database of 4569 subjects. Responses were recei ved from 166 subjects (112 men, 54 women, M:F = 2:1) who were assessed for employment status and outcome [i.e., pain, mobility, satisfaction, disease activity (BASDAI), function (BASFI), and global well being (BAS-G)]. A nonT HA AS control group was matched for age, sex, and disease duration. Results. The mean age at AS disease onset for THA recipients was 19.5 yrs c ompared to 24.4 yrs for the total database (p < 0.05). The mean age at the first THA was 40.0 yrs. Of the 340 THA, 276 were primary (bilateral in 66%) and 64 were revisions. The mean followup for THA was 14.0 yrs (range 1-52) . Overall, for the 340 THA, the patients considered outcome to be very good in 85%. In relation to the matched control group, THA patients were compar able for BASDAI, but had poorer function (p < 0.05) and lower global well b eing (p < 0.05). Of the 80 men under 60 years of age, 39 (49%) were employe d compared to 49 (68%) of the control group (p < 0.01). Survival of origina l THA and revisions after 10, 15, and 20 yrs was 90%, 78%, 64%, respectivel y (originals), and 73%, 55%, 55%, respectively (revisions). Conclusion. The longterm outcome of THA in AS is outstanding. THA recipient s have a younger age at onset than nonrecipients. The longterm survival cha racteristics of THA in young patients with AS is excellent.