抄録
(Materials and methods) Thirty-five shoulder MRI images of 19 RA patients were evaluated. From the MRI images, the thickness of the rotator cuff(supraspinatus: SSP, infraspinatus: ISP, and subscapularis: SBS)was measured, and the cuff tears, the pannus formation and the joint destruction were also observed. The MRI images of 15 normal shoulders were examined as the control.
(Results) A rotator cuff tear was recognized in 4 of the 35 shoulder MRI images. These shoulders were then eliminated from further studies. According to the bone destruction and the pannus formation, the RA shoulders were classified into three groups. A shoulder without a pannus formation or bone destruction was classified as group A(n=5), that with a pannus formation but without any bone destruction was classified as group B(n=16), and that with a pannus formation and a bone destruction was classified as group C(n=10). In group A, the mean thickness of the SSP was 5.29±0.47mm, that of the ISP was 3.08±0.59mm, and that of the SBS was 4.49±0.39mm. No tendons of group A were significantly thinner than the normal tendons. In group B, the mean thickness of the SSP was 3.30±1.28mm, that of the ISP was 3.14±0.80mm, and that of the SBS was 4.55±0.69mm. The SSP tendons of group B were significantly thinner than the normal SSP tendon. In group C, the mean thickness of the SSP was 2.05±0.79mm, that of the ISP was 2.08±0.84mm, and that of the SBS was 3.06±1.29mm. All the tendons of group C were thinner than the normal tendons.
(Summary)The characteristic rotator cuff changes of an RA shoulder were the thinning of rotator cuffs. The thinning of the cuff was mainly seen in the SSP in the early pannus formation stage (Group B), but spread all over the cuff in the joint destruction stage(Group C).
