Paper # 136: Analysis of Evidence-Based Medicine for Shoulder Instability

Abstract

This review summarizes the process of proper development and testing of the scoring systems, discusses the role that they should play in the use of clinical research with respect to shoulder instability, and explains the dichotomy of postoperative recurrence and high shoulder scores. Clinical research has become a major influencing factor in the determination of treatment choice in our society. Outcome data has been requested by third party payors, patients, and administrators alike. Currently, there are numerous scoring systems that have been used to evaluate the efficacy for treatment of shoulder instability. Some of these are based upon the specific condition of shoulder instability; however, other systems are broadly based to incorporate a spectrum of shoulder conditions. The scoring systems which address instability include the Rowe/Modified Rowe, the American Shoulder and Elbow Surgery (ASES), the Shoulder Rating Questionnaire (SRQ), the Melbourne Instability Shoulder Score (MISS), the Disabilities of the Arm, Shoulder and Hand (DASH) score, the Western Ontario Shoulder Instability Index (WOSI), the Oxford Instability Score (OIS), the Constant-Murley (CM), the Athletic Shoulder Outcome Rating Scale (ASORS), the University of California Los Angeles (UCLA), and the Simple Shoulder Test (SST). This review summarizes the process of proper development and testing of the scoring systems, discusses the role that they should play in the use of clinical research with respect to shoulder instability, and explains the dichotomy of postoperative recurrence and high shoulder scores. The scoring systems were evaluated for proper development, reliability, validity, and responsiveness for a homogeneous subset of patients with known instability. Reliability was determined by both the intraclass correlation coefficient (ICC) and Internal Consistency. Responsiveness was shown by both the Standardized Response Mean and the Effect Size. Validity was evaluated taking into account construct, criterion and content validity. Only 3 of the 11 scoring systems, the MISS, the DASH, and the WOSI, appear to have used an adequately described developmental process. The SRQ, MISS, WOSI, OIS, and SST were shown to be reliable for patients with instability. The SRQ, MISS, WOSI, OIS, and ASES have all been shown to be largely responsive. The SRQ, MISS, OIS, and SST all appear to have moderate validity. The ASES and the WOSI both have significant support to conclude high validity for patients with instability. However, the ASES does not appear to optimally determine outcome measurement and was found to be less responsive in patients with instability compared with other pathologies. There are only two scoring systems, the WOSI and the MISS, which should be used as the universally accepted shoulder scoring systems for shoulder instability. The SRQ and OIS were found to be less responsive for patients with instability compared to patients with other shoulder dysfunctions. Other scoring systems lack interrater reliability, validity and/or responsiveness for patients in the instability population. The ASES scoring system should be used for patients with upper extremity problems other than those with shoulder instability, as this instrument has been proven to be valid, reliable and responsive. Standardizing the scoring system used in clinical studies performed for the treatment of shoulder instability will lead to more consistent results as well as results that may be able to be compared between studies.