Summary
Rotator cuff morphometry on MRI - an observational study in Indian population
Abstract
Aim
To estimate normative dimensions of rotator cuff muscles on MRI to better understand the anatomy with reference to Indian population.
Background
Rotator cuff muscles include Supraspinatus, Infraspinatus, Teres minor, subscapularis. Supraspinatus tears are seen across all age groups. Predominantly of traumatic etiology in the younger and degenerative in the older. Following a tear of the tendon, it is prone for retraction. The amount of retraction is a key feature in deciding the surgical technique to be followed. Therefore a normative value of the distance of the musculotendinous junction of the muscle and its point of insertion will provide a reference for comparison. Estimation of similar parameters for the subscapularis also aides in comparative assessment.
Materials And Methods
MRI of 50 individuals with normal rotator cuff findings were assessed and the length of the supraspinatus tendon was measured on T2 weighted coronal section. The width of supraspinatus and the infraspinatus tendon were measured on the sagittal section in the most observable slice before the point of insertion. Length of the Subscapularis tendon was measured on axial section. Footprint dimensions were measured for both the muscles. All the measurements were done by a single senior musculoskeletal radiologist.
Inclusion criteria: Individuals with skeletal maturity, both male and female, with a normal rotator cuff morphology, who had taken MRI for other pathologies of the shoulder, example Bankart lesion, were included for the study.
Exclusion criteria: Individuals with pathologies of the rotator cuff, such as tendinitis, partial tear, complete tear, were excluded from the study.
Results
50 individuals were assessed in the study, 42 male and 8 female. The average age of the study population was 30.2 years. The average distance between the musculotendinous junction of the supraspinatus and its point of insertion was found to be 2.82 cm. The average footprint of the supraspinatus was found to be 1.29 cm. The combined width of supraspinatus and infraspinatus on the sagittal section was found to be 4.84 cm. The average subscapularis tendon length and footprint were found to be 2.99 cm and 1.44 cm respectively.
Conclusion
These values of the study population belonging to a specific geographical area provides the normative data for analysis. Hence understanding tear morphology and individualizing repair techniques will become relevant with reference to the concerned demographics.