gms | German Medical Science

Objectives: Classification of possible causative factors of nontraumatic osteonecrosis of the femoral head (ONFH), including systemic steroid administration and habitual alcohol intake, is largely dependent on information obtained from routine interviews at the time of diagnosis. We aimed to examine whether reevaluation of causative factors using a more careful interview based on a questionnaire would change the previous classification in patients with nontraumatic ONFH.

Methods: The participants included 401 patients with nontraumatic ONFH who came to our hospital for regular follow-up between February 2011 and March 2015. Careful medical interview using a questionnaire sheet (about 20 min per patient) was designed to investigate the patients' past histories regarding systemic steroid administration and habitual alcohol intake in detail, according to which the ONFH was reclassified into four subgroups (steroid-associated, alcohol-associated, steroid/alcohol-associated, idiopathic). We then compared the reclassified proportions in the subgroups with those obtained at the time of diagnosis (retrieved from medical records for this study).

Results and Conclusion: Based on the results of the careful medical interview, 97 of the 401 ONFHs (24.2%) were classified into different subgroups. Of 401 patients, 43.4% were now considered steroid-associated, 31.7% alcohol-associated, 17.7% steroid/alcohol-associated, and 7.2% idiopathic. The steroid-associated ONFH group displayed a decrease in proportion from 54.9% to 43.4%, whereas the steroid/alcohol-associated ONFH group increased from 2.5% to 17.7%.

Our study suggests that the conventional classification of nontraumatic ONFH according to possible causative factors may be uncertain so long as the factors depend on information obtained solely from a simple routine medical interview.