Impact of symptom bilaterality and hand dominance on patient-reported disability outcomes.

Objectives: It is not clear if using patients with bilateral symptoms would impact the level of disability reported in orthopaedic research. The purposes of this study were to (1) examine the prevalence of bilateral shoulder symptoms (significant pain, stiffness or weakness affecting function) in patients with rotator cuff impingement syndrome, rotator cuff tear and osteoarthritis of the glenohumeral joint, (2) explore risk factors associated with bilateral shoulder symptoms, and (3) examine the impact of symptom bilaterality and hand dominance on pre- and post-operative patient-oriented disability outcomes.

Methods: This study involved secondary analysis of prospectively collected data of patients who had undergone shoulder surgery and had returned for their 1-year follow-up. Two outcome measures were collected prior to surgery and at 1-year following surgery: the American Shoulder and Elbow Surgeons and the Constant-Murley Score.

Results: Data of 772 patients, 376 (49%) females, 396 males (51%); 288 (impingement syndrome), 332 (rotator cuff tear), and 152 (osteoarthritis) were included in the analysis. There was a statistically significant difference in the prevalence of bilateral symptoms being 44%, 28%, and 22% in the osteoarthritis, impingement syndrome, and rotator cuff tear groups, respectively (p < 0.0001). The prevalence of dominant side involvement was 71%, 67%, and 53% in the rotator cuff tear, impingement syndrome, and osteoarthritis groups (p < 0.0001). Older age and female sex were risk factors for development of bilateral symptoms only in patients with rotator cuff tear. Neither symptom bilaterality nor dominant arm involvement had a negative impact on patient-oriented disability outcome measures prior to or after surgery (p > 0.05).

Conclusion: This study shows that patients with osteoarthritis of the glenohumeral joint have the highest prevalence of bilateral shoulder complaints. The older age and the female sex increased the risk of having bilateral symptoms in patients with rotator cuff tear. Having bilateral shoulder symptoms or dominant side involvement was not associated with higher level of disability prior or after surgery.