These studies once again show that truly long term outcome can be identified only when the follow up is also over a long period. These studies came from tertiary centers mostly and may be biased toward the severe cases. The patients were adult hospital attendees. Hence, the study is biased towards those with severe disease and hospital follow up. Seventy two percent of all patients in this series needed total hip replacement.
Some recent studies suggest more favorable figures.
However, the mean duration of disease in this cohort is shorter than those in other studies and only follow up will confirm if this trend continues. The median age of the patients was 17.7 years and the median duration of disease was 7.1 years. Only 5 patients were in class III and 1 patient in class IV, in their cohort of 124 patients. The mean duration of follow up was 7.1 years. The patients with active or stable disease had higher scores than those with inactive disease or in remission.