In orthopaedics and rehabilitation, the assessment of health-related quality of life (HRQL) is an important outcome to consider when assessing the effectiveness of various interventions [1, 2]. Validated patient-reported questionnaires are commonly used to obtain the patients’ necessary perception of the limitations that are associated with various musculoskeletal conditions. A number of joint and disease-specific HRQL measures now exist for many of the main conditions of the shoulder, including rotator cuff tears and recurrent instability [1, 3]. Some measures were developed using rigorous and accepted methodology [4, 5], while others were developed based on clinical validity and utility [4, 6, 7].

Many of these instruments have been assessed for their reliability and validity and to a lesser degree, their responsiveness, or ability to assess change over time and have been found to be adequate [8�C10]. However, it has been hypothesized that the less rigorously developed questionnaires may not be as responsive or as discriminative, when compared with newer, condition-specific questionnaires [1, 4, 6, 11].Questionnaire selection may play an important role in determining the extent of recovery or disability as well as detecting differential recovery among patients, particularly when only modest differences in outcome may be expected (e.g., comparison of different surgical interventions). Thus, it is important that appropriate HRQL assessment tools are chosen in order to detect clinically important changes (1) over repeated postoperative time periods (responsiveness) and/or (2) among different patient subgroups (discriminant validity).

Patients with chronic posttraumatic shoulder instability commonly experience significant impairment during work, sports, or while performing activities of daily living (ADL). Often times, their limitations are great enough to warrant surgical intervention [12, 13]. The short-and long-term success of these techniques has been widely demonstrated within the literature, with the incidence of postoperative recurrent dislocation being less than 10% and of recurrent postoperative instability (i.e., recurrent dislocation or subjective sense of subluxation being less than 20%) [13]. Given that this population experiences significant functional AV-951 gains following surgery, we felt that this condition was an appropriate one to compare how selected shoulder questionnaires perform in (1) responsiveness and (2) discrimination among preselected subsets of patients.