PurposeThe aim is to determine the effect on healing and functionality of patients after 1 year of biceps augmentation of a rotator cuff repair (RCR) compared to RCR plus long head of the biceps (LHB) tenotomy. In addition, to analyse the main factors involved in the recovery after the surgery.MethodsA prospective, comparative, non‐randomized study (Level of Evidence III) was conducted. Patients with repairable rotator cuff tears were allocated to either the control group, with a double row transosseous equivalent RCR with LHB tenotomy, or the RCR+augmentation with LHB group. Patients were evaluated for radiological (MRI), clinical (cuff size, Patte and Goutallier scales) and functional variables (Constant and American Shoulder and Elbow Surgeons [ASES] scales) before the intervention. At 1‐year follow‐up cuff healing was confirmed through MRI and functional evaluation with Constant, ASES, simple shoulder test [SST] and Disabilities of the Arm, Shoulder and Hand scales.ResultsSeventy‐seven patients underwent control or RCR+augmentation with LHB, there were no preoperative differences between the groups. After 1 year of the surgery, re‐rupture occurred in 38.5% and 16% of the patients in control and RCR+augmentation with LHB groups, respectively (p = .026). Total functionality was higher (p < .05) in RCR+augmentation with LHB than in the control group: Constant, SST and ASES scales. Among the explored factors involved in healing, re‐rupture occurred in 100% of the cases with high fatty degeneration. Besides, higher initial functionality (Constant scale) and RCR+augmentation with LHB increased the odds of healing (odds ratio [OR] = 1.12 [1.04–1.21]; OR = 5 [1, 61], respectively), while higher cuff length had a detrimental effect (OR = 0.92 [0.85–0.99]).ConclusionRCR+augmentation with LHB achieves a higher healing percentage and a better functional evolution than RCR+LHB tenotomy, 1 year after cuff repair. Fatty degeneration, cuff length and initial functionality are the main factors involved in cuff healing.Level of EvidenceLevel III randomized controlled trial.