Background: Less invasive procedures have recently been introduced to facilitate an earlier return to sports or work activities after rotator cuff repair. Few reports, however, have verified whether such procedures are really less invasive than conventional open repair. The purpose of this study was to compare the postoperative thickness of the deltoid muscle in patients treated with either conventional or mini-open rotator cuff repair.

Methods: Conventional open repair was performed from 1994 through 1997 in forty-three patients with rotator cuff tears. The mini-open deltoid-splitting approach was introduced in 1997, and the cases of thirty-five patients who underwent that procedure were reviewed. The two groups were compared with respect to the thickness of the anterior fibers of the deltoid muscle measured on the transverse magnetic resonance images, the degree of active forward flexion, and the times required for return to work and sports activities.

Results: The thickness of the anterior deltoid fibers did not change significantly after surgery in the mini-open repair group, whereas it was significantly decreased in the open repair group at six months as well as at twelve months postoperatively (p < 0.05). At three months postoperatively, the mean University of California at Los Angeles score for active forward flexion in the patients treated with the mini-open repair (4.9 points) was significantly greater than that in the patients in the conventional open repair group (4.6 points) (p < 0.05). In addition, the mean time-period required for return to work in the mini-open repair group (2.4 months) was significantly shorter than that required in the control group (3.4 months) (p < 0.05).

Conclusions: The mini-open repair appeared to cause less postoperative atrophy of the deltoid muscle than did the conventional open rotator cuff repair, and patients treated with the mini-open repair recovered more quickly.

Level of Evidence: Therapeutic study, Level III-2 (retrospective cohort study). See Instructions to Authors for a complete description of levels of evidence.