Subscapularis volume analysis as a radiological criterion for evaluating success after arthroscopic repair of supraspinatus tears

Abstract

Aim: The aim of this study was to compare the volumes of the supraspinatus and subscapularis muscles measured on preoperative magnetic resonance imaging (MRI) with the volumes obtained at the end of the postoperative 1st year, and to examine whether the change in the intact subscapularis muscle volumes is an indicator of well-being. Materials and Methods: The study included twenty-one patients who underwent double-row arthroscopic repair for full-thickness isolated supraspinatus rotator cuff tear and who were followed-up in our hospital between 2016 and 2019. All patients underwent clinical and radiological MRI examinations of the shoulder before arthroscopic repair and at the final follow-up 1 year after surgical repair. Fatty degeneration of the supraspinatus muscles was graded according to the Goutallier classification. Functional results were evaluated with the Constant shoulder score. For muscle volume measurements, sagittal oblique PD-weighted images were used. The supraspinatus (SPS) and subscapularis (SS) muscle areas were measured in the Y-shape formed by the coracoid process, spina scapula, and scapula body in the suprascapular groove. Results: The mean age was 57.33 +/- 8.27 (range, 42 to 69) years. Among the patients, 57.1% (n = 12) were female and 42.9% (n = 9) were male. The mean follow-up time was 22.57 +/- 7.87 (range, 12 to 36) months. The degrees of fatty degeneration according to the Goutallier classification were as follows: 7 patients (33%) had grade 1 atrophy, 10 patients (47.6%) had grade 2 atrophy and 4 patients (19%) had grade 3 atrophy. The Constant score increased from 48.38 +/- 5.57 to 81.14 +/- 6.11 (p<0.001). On the final MRI examination, the supraspinatus muscle volume increased from a mean value of 462.48 +/- 135.68 to a mean value of 480.81 +/- 140.83 (p=0,004). The mean subscapularis muscle volume increased from 1374.29 +/- 248.21 to 1415.71 +/- 250.56 (p<0.001). A positive correlation was found between the postoperative subscapularis volume and postoperative supraspinatus volume values of the patients (p = 0.004; r = 0.601). Discussion: The postoperative volume values of all patients increased in the follow-up after isolated supraspinatus tears. In the patients with grade 1 and 2 fatty degeneration, the volume increase in the supraspinatus and subscapularis muscles after repair was significant and correlated with each other. We think that the use of subscapularis muscle volume in radiological assessment of well-being following the repair of the rotator cuff may be a criterion for evaluation of success.