Assessing shoulder disability in orthopaedic specialist care: Introducing the Copenhagen Shoulder Abduction Rating (C-SAR)

Background: Differences in shoulder-disability among common shoulder-disorders in orthopaedic specialist care is unknown. Furthermore, rating of shoulder-disability using patient-reported outcomes is time-consuming, and a faster approach is needed. Objectives: First, compare shoulder-disability among common shoulder-disorders. Secondly, rate shoulder-disability according to the new and quick Copenhagen Shoulder Abduction Rating (C-SAR) and investigate criterion validity of C-SAR. Methods: Cross-sectional study including 325 consecutive patients with shoulder-disorders in orthopaedic specialist care. We assessed shoulder abduction range-of-motion and pain during testing (NRS:0-10), and shoulder-disability using Shoulder Pain and Disability Index (SPADI) subscales. Patients were sub-grouped using C-SAR, which is based on shoulder abduction range-of-motion and pain during testing: Severe (range-of-motion ≤90°), Medium (range-of-motion >90°, NRS:>5), Mild (range-of-motion >90°, NRS:≤5). Shoulder-disability was compared among diagnostic categories and C-SAR subgroups using ANCOVA-models. Results: Most patients were diagnosed with either subacromial impingement (n = 211) or full-thickness/complete rotator-cuff tear (n = 18), but adhesive capsulitis (n = 22) was the diagnostic category related to worst SPADI scores. Data for C-SAR subgrouping were available from 187/229 (82%) patients with rotator-cuff related disorders (subacromial impingement or rotator-cuff tears). C-SAR subgrouping was not feasible for patient with adhesive capsulitis or glenohumeral injury. Differences in shoulder-disability between Mild (n = 67) and Medium (n = 56) C-SAR subgroups were large for both SPADI-subscales (ES: 1.0, p < .0001). Only SPADI-function differed significantly between Severe (n = 64) and Medium C-SAR subgroups (ES: 0.4, p = .017). Conclusion: In orthopaedic specialist care, adhesive capsulitis relates to highest level of shoulder-disability, while C-SAR is a promising test to rate shoulder-disability for most patients, namely those with rotator-cuff related disorders.