Relationship between pre-operative central sensitization and post-operative outcome after arthroscopic rotator cuff repair-longitudinal outcomes over 2 post-operative years.

Background: Whether pre-operative central sensitization (CS) affects post-operative outcomes after arthroscopic rotator cuff repair (ARCR) remains unclear. This study aimed to evaluate the potential association between pre-operative CS and post-operative pain and function for 2 years in patients who underwent ARCR for small-to-medium rotator cuff tears. Methods: Sixty patients with small-to-medium full-thickness rotator cuff tears who underwent ARCR and were followed up for 24 months post-operatively were enrolled. The presence or absence of CS was evaluated using the Japanese version of the Central Sensitization Inventory (short form). Patients were divided into 2 groups according to the presence or absence of CS, with scores ≥10 defined as CS. Baseline demographic and radiologic factors (eg, smoking status, diabetes mellitus, occupation, tear size, and fatty infiltration) were recorded and compared between groups. Post-operative outcomes, including pain (numerical rating scale), shoulder range of motion, muscle strength, and clinical scores (Constant, American Shoulder and Elbow Surgeons), were assessed at 3, 6, 12, 18, and 24 months. Rotator cuff integrity was evaluated by magnetic resonance imaging (MRI) at 3, 6, 12, and 24 months post-operatively. Results: CS was present in 45% of patients. There were no significant differences in baseline demographic, clinical, or radiologic factors, as well as in pre-operative shoulder joint range of motion, strength, or pain between the groups with and without CS. Patients with CS exhibited significantly less improvement in pain on motion, abduction strength, and clinical scores at multiple time points up to 18 months; by 24 months, however, these differences had diminished. Conclusion: Pre-operative CS may be associated with delayed improvement in post-operative motion-related pain and clinical scores after ARCR, although its long-term impact appears limited. Clinicians should consider pre-operative CS among factors that may affect post-operative functional recovery, particularly in the first 18 months, with no apparent difference by 24 months.