Translation, Cross-Cultural Adaptation, and Validation of the Italian Version of the Shoulder Instability-Return to Sport After Injury (SI-RSI) Scale.

OBJECTIVE To culturally adapt and validate the Italian version of the Shoulder Instability-Return to Sport after Injury (SI-RSI-I) scale. METHODS The SI-RSI-I was developed by adapting the Anterior Cruciate Ligament-Return to Sport Index-Italian version and replacing the term "knee" with "shoulder." Subsequently, it underwent validation following COSMIN recommendations. The study involved athletic participants who experienced SI. They completed the SI-RSI-I together with other measurement instruments: Western Ontario Shoulder Instability Index, Kerlan-Jobe Orthopedic Clinic Score, EuroQol-5D-5L, and Numeric Pain Rating Scale. The following psychometric properties were investigated: structural validity, internal consistency, test-retest reliability, measurement error, and construct validity. RESULTS The study included 101 participants (age mean [SD] 28.5 [7.4] y; 83 males, 18 females). The SI-RSI-I showed a single-factor structure, excellent internal consistency (α = .935), and excellent test-retest reliability (ICC = .926; 95% CI, .853-.964). The standard error of measurement was 6.1 points, and the minimal detectable change was 17.0 points. Furthermore, SI-RSI-I demonstrated moderate to strong correlations with all reference scales, confirming 8 out of 9 (88.0%) hypotheses, thus establishing satisfactory construct validity. CONCLUSION The SI-RSI-I has demonstrated robust internal consistency, reliability, validity, and feasibility as a valuable scale for assessing psychological readiness to return to sport in Italian athletes with SI.