Summary

Also at long-term follow-up, a higher Critical Shoulder Angle and Acromion Index significantly increased the retear risk after arthroscopic supraspinatus tendon repair.

Abstract

Aim

To evaluate the long-term effect of the critical shoulder angle (CSA) and acromion index (AI) on the postoperative healing rate after arthroscopic supraspinatus tendon repair.

Background

The negative effect of a high CSA and AI on the short-term healing rate after arthroscopic repair of the supraspinatus tendons is already known. No studies with a long-term follow-up are yet published.

Methods

Patients with a symptomatic, single-tendon, full-thickness supraspinatus tear in whom non-operative management had failed were treated with an arthroscopic repair. Preoperative radiographs were used to measure CSA and AI. Eight years postoperatively MRI-studies were performed and evaluated on repair integrity. Patient Reported Outcome Measurements (PROMs) were collected pre- and postoperative.

Results

Thirty-one patients were evaluated 8 years postoperatively. The mean age at time of the surgery was 61 ± 9 years. MRI evaluation showed that 20 (65%) patients had an intact repair and 11 (35%) had a full-thickness retear. No significant differences were found between the intact and retear groups regarding to age (P = 0.605), initial tear size (P = 0.485), retraction grade (P = 0.439) and all PROMs.
The mean CSA for the intact group (33° ± 1°) was significantly lower than the CSA in the retear group (38° ± 1°; P = 0.004). The odds ratio of having a retear is 5.50 if the CSA = 35° (P = 0.059). The mean AI for the intact group (0.72± 0.11) was significantly lower than the AI in the retear group (0.81 ± 0.08 ; P = 0.021). If the AI was = 0.75, the odds ratio of having a retear was 6.19 (P = 0.045).

Conclusion

Also at long-term follow-up, a higher CSA and AI significantly increased the retear risk after arthroscopic supraspinatus tendon repair. A CSA =35° leads to an 5,5-fold increased risk of retear. An AI =0.75 leads to a 6-fold increase in risk of retear after arthroscopic supraspinatus tendon repair.