Type III Sugaya Classification after Rotator Cuff Repair: Preoperative Risk Factors and Progression to Retear

The Sugaya classification is a widely used classification system to assess rotator cuff tendon integrity after repair. However, Sugaya type III has received less attention in the literature compared to types I/II or IV/V. Existing data on preoperative risk factors and long-term outcomes are limited, and for Sugaya type III, there remains inconsistency regarding whether it should be classified as a healed or retorn tendon. The purpose of this study was to evaluate preoperative risk factors for the development of Sugaya type III and its longitudinal outcomes after rotator cuff repair. We hypothesized that it would be associated with preoperative tear severity and have a higher risk of developing a retear compared to Sugaya types I/II.

This retrospective study consisted of 124 consecutive patients who underwent arthroscopic rotator cuff repairs involving the supraspinatus/infraspinatus and/or subscapularis tendon. Repair integrity was examined by magnetic resonance imaging (MRI) according to the Sugaya classification at 6 months postoperatively and ultrasound (US) imaging at the final follow-up. We compared preoperative demographic data, clinical scores, and US results for Sugaya types I/II and type III.

The mean follow-up period was 28 months (range, 12-73 months). Based on MRIs at 6 months postoperatively, there were 76 (61%) Sugaya type I/II, 33 (27%) type III, and 15 (12%) type IV/V. On the final US evaluation, 5 patients with type I, II, or III had a newly developed retear, including 1 of 76 Sugaya type I/II patients (1.3%) and 4 of 33 Sugaya type III patients (12.1%). This difference in the late development of a retear between the early Sugaya type I/II and type III groups was statistically significant (p = 0.014). Our multivariate analysis showed that fatty infiltration of the infraspinatus was the only independent preoperative risk factor for the development of Sugaya type III (p = 0.005). The American Shoulder and Elbow Surgeons (ASES) score at the final follow-up was significantly lower in the retorn group than in the healed group (93.0 ± 7.6 and 96.4 ± 4.7, respectively; p = 0.036).

Postoperative Sugaya type III repair status is associated with preoperative inferior muscle quality of the infraspinatus and can progress to a retear with a higher risk than Sugaya type I/II.