Use of preoperative magnetic resonance imaging to predict rotator cuff tear pattern and method of repair (SS-78)

Abstract

Introduction: Crescent-shaped rotator cuff tears are relatively short and wide. The medial to lateral length of these tears is less than the anterior to posterior width. Crescent tears are typically mobile from medial to lateral and can usually be repaired by fixing the tendon end directly to the bone bed on the greater humeral tuberosity. Conversely, longitudinal (U-shaped and L-shaped) tears are relatively long and narrow. The medial to lateral length of these tears is greater than the anterior to posterior width. Longitudinal tears are typically mobile in an anterior/posterior direction and can usually be repaired by a side-to-side/margin convergence technique. But, if a contracted rotator cuff tear is too large, the tendon end cannot be pulled laterally directly to bone, the edges cannot be closed side-to-side, and other repair techniques such as interval slides or partial repairs are necessary. Rotator cuff tears are repaired according to tear pattern. How can preoperative MRI predict the tear pattern and the method of repair? Purpose: To determine MRI criteria for predicting rotator cuff tear pattern and method of repair. Methods: Sixty-six preoperative MRI scans were evaluated. The maximum medial to lateral length (L) of the tear was measured on T2 coronal cuts. The maximum anterior to posterior width (W) was measured on T2 sagittal cuts. The cases were divided into 3 groups: group 1, short-wide tears, L ≤ W, L < 2 cm; group 2, long-narrow tears, L > W, W < 2 cm; group 3, long-wide tears, L ≥ 2 cm, W ≥ 2 cm. Results: Of the 66 MRI scans, 55 were adequate for standardized measurement. Group 1, 16 cases: 15 were found at arthroscopy to be crescent tears repaired end to bone; 1 was repaired with interval slides. Group 2, 22 cases: all 22 were repaired side to side/margin convergence. Group 3, 17 cases: 4 were repaired side to side/margin convergence, 12 required interval slides, and 1 partial repair was performed. Conclusions: Tear pattern and method of repair can be predicted on high-quality MRI scan. L ≤ W and L < 2 cm predicts a crescent tear and end-to-bone repair (positive predictive value 93.8%). L > W and W < 2 cm predicts a longitudinal tear and side-to-side/margin convergence repair (positive predictive value 100%). L ≥ 2 cm and W ≥ 2 cm predicts that interval slides or partial repair may be necessary (positive predictive value 76.5%). The overall diagnostic model based on usable MRI scans significantly predicted arthroscopic outcome (P < .001 for χ-square test).