The German Hip Outcome Score: validation in patients undergoing surgical treatment for femoroacetabular impingement.

To cross-culturally adapt and validate the Hip Outcome Score (HOS) for use in German-speaking patients undergoing surgical treatment for femoroacetabular impingement.After cross-cultural adaptation (German-language version of the HOS [HOS-D]), the following metric properties of the questionnaire were assessed in 85 consecutive patients (mean age, 33.4 years; 36 women) undergoing hip arthroscopy or surgical hip dislocation: feasibility, reliability, internal consistency, and construct validity (correlation with Western Ontario and McMaster Universities Arthritis Index, Oxford Hip Score, Short Form 12, and University of California, Los Angeles activity scale). We calculated floor and ceiling effects taking the minimal detectable change into account.The activities of daily living subscale of the HOS-D could be scored in all cases and the sport subscale in all but one. The HOS-D scores were highly reproducible with intraclass correlation coefficients of 0.94 for the activities of daily living subscale and 0.89 for the sport subscale. Internal consistency was confirmed by Cronbach α values >0.90 for both subscales. Correlation coefficients with the other measures ranged from -0.08 (Mental Component Scale of Short Form 12) to -0.90 (Western Ontario and McMaster Universities Arthritis Index function subscale).The HOS-D is a reliable and valid self-assessment tool for patients undergoing surgical femoroacetabular impingement treatment. By use of the HOS, comparisons between studies and treatment regimens involving either German- or English-speaking patients are now possible.Level I, testing of previously developed diagnostic criteria in a series of consecutive patients with universally applied gold standard.