The appearance of the teres minor muscle in rotator cuff tears

Abstract

BackgroundIn large and massive rotator cuff repair or total shoulder arthroplasty with severe atrophy of rotator cuff muscle, the appearance of the teres minor was reported to be a prognostic factor postoperatively. The purpose of this study was to examine the appearance of teres minor on MRI in patients with the various types of rotator cuff tears.Materials and methodsThis MRI study consists of 198 subjects (112 shoulders in males, 87 shoulders in females, average age of 61.9 years). We classified the198 shoulders into the 7 groups of rotator cuff tears using conventional planes of MRI. Using the Image J software, we measured the area of ISP, TM, external rotation (ER) muscles area on the most lateral side on which the scapular spine was in contact with the scapular body on the oblique sagittal image of MRI. The size and quality of teres minor were compared in each group. The size of teres minor to the infraspinatus was assessed. One factor ANOVA was used for statistical analysis; p less than 0.05 was considered to indicate a statistically significant result.ResultsThe normal group was confirmed to apply to the normal distribution, so TM / ER less than 0.105 was defined as atrophic, and TM / ER greater than 0.304 as hypertrophic. TM / ER in the SSP+ISP group were statistically higher than those of other groups. A negative correlation was found between the size of infraspinatus and teres minor.ConclusionsThe progression of atrophy of infraspinatus induced the hypertrophy of teres minor, especially in posterosuperior tears. BackgroundIn large and massive rotator cuff repair or total shoulder arthroplasty with severe atrophy of rotator cuff muscle, the appearance of the teres minor was reported to be a prognostic factor postoperatively. The purpose of this study was to examine the appearance of teres minor on MRI in patients with the various types of rotator cuff tears. In large and massive rotator cuff repair or total shoulder arthroplasty with severe atrophy of rotator cuff muscle, the appearance of the teres minor was reported to be a prognostic factor postoperatively. The purpose of this study was to examine the appearance of teres minor on MRI in patients with the various types of rotator cuff tears. Materials and methodsThis MRI study consists of 198 subjects (112 shoulders in males, 87 shoulders in females, average age of 61.9 years). We classified the198 shoulders into the 7 groups of rotator cuff tears using conventional planes of MRI. Using the Image J software, we measured the area of ISP, TM, external rotation (ER) muscles area on the most lateral side on which the scapular spine was in contact with the scapular body on the oblique sagittal image of MRI. The size and quality of teres minor were compared in each group. The size of teres minor to the infraspinatus was assessed. One factor ANOVA was used for statistical analysis; p less than 0.05 was considered to indicate a statistically significant result. This MRI study consists of 198 subjects (112 shoulders in males, 87 shoulders in females, average age of 61.9 years). We classified the198 shoulders into the 7 groups of rotator cuff tears using conventional planes of MRI. Using the Image J software, we measured the area of ISP, TM, external rotation (ER) muscles area on the most lateral side on which the scapular spine was in contact with the scapular body on the oblique sagittal image of MRI. The size and quality of teres minor were compared in each group. The size of teres minor to the infraspinatus was assessed. One factor ANOVA was used for statistical analysis; p less than 0.05 was considered to indicate a statistically significant result. ResultsThe normal group was confirmed to apply to the normal distribution, so TM / ER less than 0.105 was defined as atrophic, and TM / ER greater than 0.304 as hypertrophic. TM / ER in the SSP+ISP group were statistically higher than those of other groups. A negative correlation was found between the size of infraspinatus and teres minor. The normal group was confirmed to apply to the normal distribution, so TM / ER less than 0.105 was defined as atrophic, and TM / ER greater than 0.304 as hypertrophic. TM / ER in the SSP+ISP group were statistically higher than those of other groups. A negative correlation was found between the size of infraspinatus and teres minor. ConclusionsThe progression of atrophy of infraspinatus induced the hypertrophy of teres minor, especially in posterosuperior tears. The progression of atrophy of infraspinatus induced the hypertrophy of teres minor, especially in posterosuperior tears.