Abstract Background The impact of the etiology of rotator cuff injury (RCI) on outcomes after rotator cuff repair remains unclear. This study aimed to evaluate the postoperative outcomes of patients with RCIs of different etiologies and identify the risk factors affecting prognosis. Methods This study included 73 patients with RCI who underwent arthroscopic rotator cuff repair. The patients were categorized into either a traumatic group or a non-traumatic group based on their history of trauma. Preoperative and postoperative assessments included shoulder range of motion, muscle strength, and physical examination findings specific to the shoulder for both groups. Clinical differences between arthroscopic repair of traumatic and non-traumatic RCIs were evaluated using univariate analysis. Logistic regression analysis determined independent risk factors for rotator cuff repair prognosis. Results Among the 73 patients, 31 were in the traumatic group and 42 in the non-traumatic group, with a minimum postoperative follow-up of 12 months and a mean follow-up of 13.8 months. The duration of the disease was significantly longer in the non-traumatic group compared with the traumatic group (P