Analysis of Evidence-Based Medicine for Shoulder Instability

Abstract 

Clinical research has become a major influencing factor in the determination of treatment choice in our society. Outcome data have been requested by third-party payers, patients, and administrators alike. Currently, there are over 10 different scoring systems that have been used to evaluate the efficacy of treatment for shoulder instability. Some of these scoring systems are based on the specific condition of shoulder instability; however, other systems are broadly based to incorporate a spectrum of shoulder conditions. This review summarizes the process of proper development and testing of the scoring systems, discusses their role in clinical research with respect to shoulder instability, and explains the dichotomy of postoperative recurrence of instability and high shoulder scores. The Shoulder Rating Questionnaire (SRQ), Melbourne Instability Shoulder Score (MISS), Western Ontario Shoulder Instability Index (WOSI), Oxford Instability Score (OIS), and Simple Shoulder Test were shown to be reliable for patients with instability. The SRQ, MISS, WOSI, OIS, and American Shoulder and Elbow Surgeons score have all been shown to be largely responsive. There are 2 shoulder scoring systems, the WOSI and the MISS, that we recommend be used to evaluate shoulder instability. The SRQ and OIS were found to be less responsive for patients with instability compared with patients with other shoulder dysfunctions. Other scoring systems lack inter-rater reliability, validity, and/or responsiveness for patients in the instability population. The optimal scoring system for patients with upper extremity problems other than those with shoulder instability has yet to be determined; however, the American Shoulder and Elbow Surgeons score may be considered, because this instrument has been proven to be valid, reliable, and responsive.

Key Words: Shoulder, Scoring systems, Outcome measurements, Validity, Melbourne Instability Shoulder Score (MISS), Western Ontario Shoulder Instability Index (WOSI)