Design and Testing of the Degree of Shoulder Involvement in Sports (DOSIS) Scale

Abstract

Background: For athletes affected by shoulder problems, the most important expectation is to resume sporting activities. The ability to return to sport is related to several parameters, including the type and level of sport played. By focusing on these parameters, the Degree of Shoulder Involvement in Sports (DOSIS) scale allows for a better assessment of the involvement of the shoulder in sports. Purpose: To design the DOSIS scale and test its psychometric features. Study Design: Cohort study; Level of evidence, 3. Methods: The DOSIS scale was developed as a patient self-administered scale by the Sport Committee of SIGASCOT (Società Italiana del Ginocchio Artroscopia Sport Cartilagine Tecnologie Ortopediche) to score sports activity based on 3 parameters: (1) type of sport, (2) frequency with which the sport is played, and (3) level at which the sport is played. In a subsequent phase, the psychometric features of the DOSIS scale were measured in a cohort of 85 patients who were affected by recurrent anterior shoulder instability and who underwent an open Bristow-Latarjet procedure or an arthroscopic Bankart repair. The content validity, criterion validity, construct validity, responsiveness, and test-retest reliability were measured and compared with the psychometric features of the Tegner activity scale. Results: Neither the DOSIS nor the Tegner activity scale showed floor or ceiling effects, but the DOSIS scale had a different distribution of scores, with a tendency toward a higher percentage of patients with high scores. The test-retest reliability analysis of the DOSIS scale revealed excellent intraobserver reliability (intraclass correlation coefficient = 0.96). Regarding the construct validity, 3 of the 4 hypotheses that we tested were significant. The DOSIS scale showed good criterion validity when compared with the Tegner activity scale (ρ = 0.3, P = .003), and the effect size between the preoperative and postoperative DOSIS scale was 1.1. Conclusion: The DOSIS scale showed acceptable psychometric features and seems to be a valid instrument for shoulder assessment in athletes.