Less Can Be as Effective as More: Two WOSI Items Capture Clinical Outcomes After Surgical Stabilization for Shoulder Instability.

BACKGROUND: WOSI is one of the most popular and detailed questionnaires in both rating of the current patient status as well as measuring patients' recovery after treatment of shoulder instability. It includes questions about both psychological and somatic aspects of the patient's functioning. Our aim was to test whether the psychological items of the WOSI questionnaire, regarding beliefs and emotions, can be an indicator of recovery.

METHODS: WOSI items with the highest psychological load (PSYCHE-WOSI) were identified through expert rating and assessed using the intraclass correlation coefficient and hierarchical cluster analysis (Ward's method, tree diagram). Data from 78 patients (mean follow-up, 4.3 months) after surgical stabilization for shoulder instability, including WOSI, UCLA, Constant, ASES, and SST scores, were used to assess their utility as recovery indicators. Correlation, regression, and canonical correlation analyses were performed to identify PSYCHE-WOSI items most strongly associated with pain, function, range of motion, and overall PROMs.

RESULTS: The PSYCHE-WOSI factor comprised items 13, 15, 16, 17, 19, 20, and 21. Items 15 and 17 showed the strongest associations with function, range of motion, and overall PROMs, whereas items 16 and 21 were most strongly associated with pain outcomes.

CONCLUSION: A distinct psychological factor can be identified within WOSI. PSYCHE-WOSI items are strongly associated with PROMs and may provide a simple, rapid, and cost-effective tool for assessing recovery, supporting a more holistic, patient-centered approach to postoperative rehabilitation.

LEVEL OF EVIDENCE: Basic Science Study, Validation of Outcome Instrument.