Paper 29: Incidental Teres Minor Atrophy in Patients Undergoing Arthroscopic Rotator Cuff Repair of the Supraspinatus Occurs Frequently and is Associated with Worse Postoperative Outcomes Without Higher Failure Rates
Authors: Steuer Fritz , Okundaye Osatohamwen , McMahon Sophia , Fox Michael , Lesniak Bryson , Musahl Volker , Rodosky Mark , Lin Albert 
Published: August 2024

Objectives: Fatty infiltration and rotator cuff atrophy has been associated with poor clinical outcomes during rotator cuff repairs. Compared to supraspinatus and infraspinatus atrophy there has been minimal research on the effect of teres minor atrophy on surgical outcomes and failure rates in rotator cuff repairs. The purpose of this study was to assess the incidence and outcomes of arthroscopic rotator cuff repairs (ARCR) for partial and full thickness supraspinatus tears in patients with incidentally identified teres minor fatty infiltration. Methods: A consecutive series of 272 shoulders from 256 patients who underwent arthroscopic, double row transosseous equivalent repairs by 3 fellowship trained surgeons with minimum 1 years follow up for partial and full thickness tears of the supraspinatus tendon was reviewed. Revision repairs and concomitant subscapularis repairs were excluded. Preoperative MRI was reviewed to classify teres minor fatty infiltration using the modified Goutallier classification. Preoperative and postoperative range of motion, strength, visual analog scale (VAS), subjective shoulder value (SSV), Patient-Reported Outcomes Measurement Information System (PROMIS) mental/physical health, American Shoulder and Elbow Surgeons Shoulder Score (ASES), and Brophy shoulder activity scores were collected. Failure defined as a symptomatic retear identified on postoperative MRI or need for revision surgery was also collected. Paired t-tests, Chi-squared, and Fisher’s exact tests were utilized for continuous and binary variables, respectively. Statistical significance was at p < 0.05. Results: A total of 106 patients met the inclusion criteria with 47 partial thickness tears and 59 full thickness tears. The average age of 67 and average follow-up of 30 months (range 10-92) were included. Tear size (16.37 vs 13.62, p = 0.30), and Goutallier classification of supraspinatus (0.51 vs 0.62, p =0.41), and infraspinatus (0.42 vs 0.47, p = 0.81) did not differ between the two groups. Incidental teres minor fat infiltration was present in 53% of cases with an overall frequency in Goutallier stage as follows: 47% - Grade 0, 38% - Grade 1, 14% - Grade 2, 1% - Grade 3, and 0% - Grade 4. For partial tears, postoperative PROMIS mental and physical scores were significantly better in those without teres minor fatty infiltration versus in those without (16.7 vs 14.3, p=0.01; 15.5 vs 13.5, p=0.02), while ROM, strength, and PROs were not statistically significant. For full tears, those without fat infiltration had statistically significantly better PROs on PROMIS physical (16.25 vs 14.07, p=0.01), ASES (83 vs 63, p=0.02), Brophy (8.3 vs 5.2, p=0.02), and SSV scores (94 vs 83, p=0.046). No other differences in ROM, strength, and other PROs were identified. No differences were identified for retear and revision rates among patients regardless of fatty infiltration (partial: retear, 7.7% vs 9.5%, p = 0.59; revision, 7.7% vs 9.5%, p = 0.59; revision, 12.5% vs 5.7%, p = 0.18). Conclusions: Our study demonstrates that incidentally noted teres minor fatty infiltration occurs in over 50% of patients undergoing arthroscopic rotator cuff repair for full thickness supraspinatus tears and is associated with worse postoperative outcome scores without higher failure rates. Compared to full thickness tears, teres minor atrophy in partial thickness tears showed a lesser effect on outcome scores with only significantly worse post operative PROMIS mental and physical scores. Identification of these patients preoperatively with strategies to optimize may be necessary to improve outcomes.