Can radiologists and orthopaedic surgeons distinguish between traumatic and degenerative rotator cuff tears on MRI?

MRI plays an important role in the evaluation of rotator cuff tears. Our study aimed to determine if specific MRI criteria can be used to distinguish between acute traumatic and pre-existing degenerative lesions.

The study included 40 MRIs or MR-arthrograms with rotator cuff tears. Twenty tears were traumatic and 20 were non-traumatic. Two radiologists specialized in musculoskeletal imaging, an experienced shoulder surgeon and a registrar trained in shoulder surgery assessed on each MRI the presence or absence of the following 11 parameters: tendon oedema, oedema in the muscles of the rotator cuff and the deltoid, edema and cysts in the greater tuberosity, tendon stump at the insertion site, tangent sign, tendon kinking, cobra sign, superior and posterior decentering of the humeral head. All investigators were blinded to the age and sex of the patients, the cause of the tendon lesion, the duration of the symptoms and the proportions of traumatic and non-traumatic tears. They were also asked for their assessment regarding the cause of each patient's tear, traumatic or degenerative.

All features could be observed with varying percentages in both groups. It was therefore impossible to assign a specific MRI to one group or the other, even with a combination of two or three features. One observer categorized 25 of 40 cases correctly (62.5%), two observers assigned 22 cases (55%), and one observer 19 cases (47.5%) correctly.

In individual cases, a partial or full-thickness lesion of the supraspinatus tendon or a postero-superior rotator cuff tear without advanced fatty infiltration cannot be correctly assigned to an acute traumatic or a preexisting lesion based on MRI.