Purpose The purpose of this study was to examine the impact of distal clavicle resection (DCR) on subjective and objective outcome measures in patients with acromioclavicular (AC) joint osteoarthritis (OA) and rotator cuff tear. Methods Prospectively collected data of consecutive patients with arthroscopic evidence of OA of the ACJ with complete data at 2 years were used for the data analysis. Patients with moderate-to-severe OA of the AC joint underwent a DCR in conjunction with rotator cuff repair, while patients with mild OA of the ACJ underwent surgery related to concomitant rotator cuff tear without a DCR. Results Data of 184 (72 females, 112 males, mean age: 62) patients with rotator cuff tear and varying degrees of OA of the AC joint were used for the analysis. Of 184 patients, 144 (78 %) had a resection of distal clavicle (resection group) and 40 (22 %) did not have a resection (no-resection group). Both groups showed a statistically significant (p Conclusion When untreated surgically, even mild arthroscopic findings of AC joint OA may lead to a poorer outcome after rotator cuff repair. Further characterisation of patients in whom mild arthroscopic findings of OA of AC joint are clinically significant and warrant resection is needed. Level of evidence Retrospective outcome study, Level II.