Radiographs and MRIs of Ti and T2 weighted images in the coronal oblique and axial plane of the shoulders were performed on 26 patients (28 shoulders) with degenerative rotator cuff tears and several gradations of arthropathic changes.
The average age of the patients at examination was 67 years (range,35 to 87).
The arthropathic changes of the shoulder were classified into 5 groups by the x-ray findings as follows. Group A (3 shoulders)-superiorly migrated humeral head and narrowed joint space, B (5)-only superior migration, C (3)-only joint space narrowing, D (6)-subacromial spurs without superior migration, and E (11)-no changes. The presence, location and size of the cysts and the spurs in the humeral head of each group were evaluated, and the relationship between the cysts and the other arthropathic changes was investigated. The size of the cyst was judged as a large one with 15% or more of a maximum humeral head diameter and a small one with less.
Cysts were observed in 10 shoulders (35.7%) and located in 4 positions of the anatomical neck: center, posterior, posteroinferior of the greater tubercle, and anteromedial of the lesser tubercle. Only one cyst in groups A and B with an elevated humeral head,2 anterior large cysts and many spurs in group C with severe arthropathic changes of the glenohumeral joint,7 cysts and a few spurs in group D and E were observed. In group E only two spurs were observed in two cases which had large cysts at the center of the greater tubercle.
The formation of cysts was suspected to be early bone changes prior to the spurs and narrowing of the joint space. The location and enlargement of the cysts may be associated with the progression of arthropathic changes in the glenohumeral joint.
