PURPOSE: To evaluate the effectiveness of arthroscopic debridement (DB), partial 
(PR), and complete repair (CR) for massive rotator cuff tears (mRCT) in terms of 
functional and subjective parameters, and repair integrity.
METHODS: For this single-centre study, 68 consecutive shoulders with mRCT 
involving at least three tendons and treated with arthroscopic DB (n = 23), PR 
(n = 22), and CR (n = 23) were included. All patients (52-81 years) were 
prospectively assessed before and at a mean of 45 months after surgery using 
functional and subjective parameters. Preoperative tendon rupture pattern and 
post-operative repair integrity were assessed by MRI. A coding system describing 
accurately rotator cuff rupture, treatment, and integrity was established.
RESULTS: All treatment groups improved significantly from pre- to post-operative 
(P < 0.01), while preoperative parameters, except fatty degeneration, were not 
significantly different. However, post-operative comparisons revealed similar 
scores with DB (constant score, CS 65.8 ± 14.7, qDASH 24.1 ± 20.6) and PR (CS 
67.5 ± 9.9, P = n.s.; qDASH 20.5 ± 14.4, P = n.s.), while CR were significantly 
better (CS 80.3 ± 8.9; qDASH 7.0 ± 8.7; P ≤ 0.001). Force couple restoration of 
PR did not significantly influence outcome. Re-tear rates with CR (29 %) were 
lower compared to PR (53 %). Intact CR compared to intact PR showed better CS 
(83.4 ± 7.3 vs. 68.5 ± 10.6, P = 0.009) and qDASH (5.4 ± 8.3 vs. 21.2 ± 9.5, 
P = 0.006). The vast majority of patients were satisfied with their arthroscopic 
procedure (DB 87 %; PR 86 %; CR 91 %).
CONCLUSION: Arthroscopic DB, PR, and CR were effective in treating mRCT 
involving at least three tendons. Reparability of mRCT was influenced by fatty 
degeneration of the muscles. However, CR showed the most favourable short-term 
improvements.
LEVEL OF EVIDENCE: IV.