Magnetic Resonance Imaging Grading System for Tears of the Latissimus Dorsi and Teres Major

Orthop J Sports Med. 2019 Mar 4;7(3):2325967119826548. doi: 10.1177/2325967119826548. eCollection 2019 Mar.


Background: Recent awareness of latissimus dorsi/teres major (LD/TM) injuries has led to an increase in diagnoses. No magnetic resonance imaging (MRI) classification system specific to the LD/TM exists, nor has tear severity been correlated with ability to return to sport (RTS).

Purpose/hypothesis: The purpose of this study was to report a novel MRI classification system for LD/TM tears as well as to correlate tear grade with performance and RTS. We hypothesized that the new MRI classification system would have high intra- and interobserver reliabilities and that players with higher grade tears would require operative management.

Study design: Cohort study (diagnosis); Level of evidence, 3.

Methods: All patients with LD/TM tears diagnosed by MRI who were under the care of 2 orthopaedic surgeons were included. On 2 occasions 60 days apart, MRIs were reviewed and graded by 2 authors using a new classification system. Intra- and interobserver reliabilities were calculated. Timing from injury to RTS was recorded, and performance upon RTS was analyzed.

Results: The proposed grading system had excellent intra- and interrater reliabilities (Cohen kappa >0.850). A total of 20 male patients (mean ± SD age, 26 ± 9.3 years) with LD/TM tears were included (80% were baseball pitchers). Of the 16 players treated operatively, 5 were initially treated nonoperatively by an outside physician but could not RTS (all professional baseball pitchers); 2 of these players had grade IIIA tears and 3 of the players had grade IVA tears. Regardless of initial treatment, ultimately 100% of the professional baseball players were able to RTS at a mean of 8.7 ± 3.3 months, although the initial nonoperative management failed for some of these players and they needed surgical intervention. No statistically significant differences were found between pre- versus postoperative performance in those professional players who were treated surgically.

Conclusion: The proposed MRI-based grading system for LD/TM tears had excellent reliability. This system may allow physicians to better advise patients and all involved health care providers. Consideration should be given to acutely treat grade III and IV tears with operative repair.

Keywords: Major League Baseball (MLB); latissimus dorsi; pitcher; return to play; shoulder; teres major.