Three-dimensional quantitative measurements of atrophy and fat infiltration in sub-regions of the supraspinatus muscle show heterogeneous distributions: a cadaveric study

• Published in: Archives of orthopaedic and trauma surgery Vol. 142; no. 7; pp. 1395 - 1403
• Main Authors: Trevino III, Jose H., Yuri, Takuma, Hatta, Taku, Kiyoshige, Yoshiro, Jacobs, Philip M., Giambini, Hugo
• Format: Journal Article
• Language: English
• Published: Berlin/Heidelberg Springer Berlin Heidelberg 01.07.2022; Springer Nature B.V
• Subjects: Atrophy; Bone surgery; Health sciences; Magnetic resonance imaging; Medicine; Medicine & Public Health; Orthopaedic Surgery; Orthopedics; Rotator cuff; Shoulder; Surgical outcomes; Atrophy; Rotator cuff tear; Fat infiltration; Occupation ratio; Goutallier classification; Muscle sub-region
• ISSN: 1434-3916; 0936-8051; 1434-3916
• DOI: 10.1007/s00402-021-03765-8

Introduction Rotator cuff tears are common in the older population. Atrophy and fat infiltration develop un-evenly in torn supraspinatus (SSP) muscles leading to pre- and post-surgical complications. The purpose of the current study was twofold: first, to implement a volumetric and quantitative magnetic resonance imaging (MRI) approach to quantify the degree of muscle atrophy and fat infiltration within the SSP muscle and its four sub-regions (AS, PS, AD, and PD); second to compare 3-D MRI outcomes to the standard 2-D assessment and investigate their relationship with tear size. Materials and methods Fifteen cadaveric shoulders were obtained and MRI performed. Quantitative 3-D outcomes included SSP muscle volume, fossa volume, fat-free muscle volume, and fat fraction for the whole SSP muscle and its four sub-regions. 2-D and qualitative measurements included tear size, 2-D fat infiltration using the Goutallier classification, tangent sign, and occupation ratio. Results Linear regression outcomes with tear size were not significant for both cross-sectional area ( r  = − 0.494, p  = 0.061) and occupation ratio ( r  = − 0.011, p  = 0.969). Tear size negatively correlated with fat-free muscle volume for both AS and PS sub-regions (AS: r  = − 0.78, p  < 0.001; PS: r  = − 0.68, p  = 0.005, respectively) while showing no significant correlation with fat fraction outcomes. AD and PD sub-regions positively correlated with tear size and fat fraction outcomes (AD: r  = 0.70, p  = 0.017; PD: r  = 0.52, p  = 0.045, respectively), while no significant correlation was observed between tear size and fat-free muscle volumes. Conclusion Quantitative 3-D volumetric assessment of muscle degeneration resulted in better outcomes compared to the standard 2-D evaluation. The superficial supraspinatus muscle sub-regions primarily presented muscle atrophy, while the deep sub-regions were mainly affected by fat infiltration. 3-D assessments could be used pre-surgically to determine the best course of treatment and to estimate the muscles’ regenerative capacity and function.