RESUMEN
INTRODUCTION: The aim of this study was to estimate the incidence of stiffness during the first 6 months after rotator cuff repair and to evaluate postoperative stiffness with respect to its risk factors and its influence on the outcome at 6 months postoperatively. METHODS: In a prospective cohort of 117 patients (69 women, 48 men; average age 59) from our institutional rotator cuff registry, who underwent either arthroscopic (n = 77) or open (n = 40) rotator cuff repair, we measured shoulder range of motion (ROM) at 3 and 6 months post-surgery. We evaluated the incidence of stiffness and analyzed functional outcomes, comparing various preoperative and intraoperative factors in patients with stiffness to those without at the 6-month mark. RESULTS: Shoulder stiffness was observed in 31% of patients (36/117) at 3 months postoperatively, decreasing to 20% (23/117) at 6 months. No significant link was found between stiffness at 6 months and demographic factors, preoperative stiffness, tear characteristics, or the type of repair. Notably, patients undergoing arthroscopic repair exhibited a 4.3-fold higher risk (OR 4.3; 95% CI 1.2-15.6, p = 0.02) of developing stiffness at 6 months compared to those with mini-open repair. Despite these differences in stiffness rates, no significant variation was seen in the American Shoulder and Elbow Surgeons (ASES) score, Single Assessment Numeric Evaluation (SANE) score, or Visual Analog Scale (VAS) scores at 6 months between the groups. CONCLUSION: The incidence of postoperative shoulder stiffness following rotator cuff repair was substantial at 31% at 3 months, reducing to 20% by 6 months. Mini-open repair was associated with a lower 6-month stiffness incidence than arthroscopic repair, likely due to variations in rehabilitation protocols. However, the presence of stiffness at 6 months post-surgery did not significantly affect functional outcomes or pain levels.