Is preoperative elevated glycated hemoglobin (HbA1c) a risk factor for postoperative shoulder stiffness after posterior-superior rotator cuff repair?

Background: Postoperative shoulder stiffness (POSS) affects a large number of patients undergoing rotator cuff repair (RCR). Diabetes may increase the risk of POSS. Preoperative glycated hemoglobin (HbA1c) is a convenient measure of glucose control in this group. The aim of the present study was to determine a relationship between preoperative HbA1c and POSS in patients undergoing postero-superior RCR. Methods: Two hundred fifty patients with full-thickness postero-superior rotator cuffs who underwent RCR were followed for 6 months. Pre- and post-operative external rotation with arm by the side at 3 and 6 months were measured. Patient demographics, tear characteristics, preoperative HbA1c level, and surgical details were recorded. Patients with subscapularis tears, concomitant instability, partial thickness tears, arthritis, and irreparable rotator cuff tears were excluded. Univariate and multivariate logistic regression were used to determine the association between patient characteristics and POSS at 6 months. Results: At the end of 6 months, 16% (41/250) of patients had POSS. Multivariate analysis demonstrated an elevated preoperative HbA1c level was a statistically significant predictor of POSS at 6 months (odds ratio 7.04, P < .01) after posterior superior RCR. Lower preoperative external rotation (P = .02) and female sex (P < .01) were also risk factors associated with POSS. Age, hand dominance, worker's compensation claim status, etiology, and size of the tear, surgical technique, and additional treatments were not statistically significant predictors. Conclusion: Elevated preoperative HbA1c level is associated with POSS after RCR. Measuring HbA1c preoperatively may assist clinicians to identify patients at risk of POSS. HbA1c is a modifiable parameter that could then be optimized preoperatively in order to improve outcomes.