Fatty replacement of rotator cuff in brain-injured patients is associated with hemiplegic arm function, but not with tendon tear: A multicenter study.
BACKGROUND
The association between fatty replacement of rotator cuff and hemiplegic upper extremity function has not been defined yet. Moreover, the relationships among rotator cuff tears, shoulder pain, spasticity, and fatty replacement were not clearly studied.


OBJECTIVE
We investigated the association of fatty replacement of the supraspinatus and infraspinatus muscles with tendon tear in stroke or brain-injured patients.


METHODS
A total of 72 hemiplegic patients were enrolled in 3 hospitals, and ultrasonography of both shoulders was performed once. Fatty replacement of the supraspinatus and infraspinatus was graded by the visibility of outer contours, pennate pattern, central tendon, and echogenicity.


RESULTS
Fatty replacement was observed in 22 (30.6%) out of the 72 patients (in 18 supraspinatus muscles and 12 infraspinatus). Inter-rater agreement (kappa value) between the 2 physiatrists was 0.530 for the supraspinatus, and 0.411 for the infraspinatus. The Fugl-Meyer assessment score, Brunnstrom stage, and modified Barthel index were significantly lower in patients with fatty replacement of the supraspinatus or infraspinatus (group 1) than in those without (group 2). The motor power of both shoulders, the pain-free range of motion, spasticity, and hemiplegic shoulder pain were comparable between the two groups. The tear rate of the supraspinatus, infraspinatus, or subscapularis tendon at the hemiplegic side was higher than that at the contralesional side in each group, although there was no significant difference between group 1 and group 2.


CONCLUSIONS
Disuse leading to muscle atrophy rather than rotator cuff tear might be the cause of fatty replacement of these muscles, which may be associated with decreased function of the hemiplegic upper extremities.
Department of Biomedical Engineering, Seoul National University College of Medicine, Seoul, Republic of Korea.|Department of Rehabilitation Medicine, Chungnam National University Hospital, Daejeon, Republic of Korea.
Jaewon
J
Beom
Department of Rehabilitation Medicine, Seoul National University College of Medicine, Seoul National University Hospital, Seoul, Republic of Korea.
Hye Jin
HJ
Jang
Department of Rehabilitation Medicine, Seoul National University College of Medicine, Seoul National University Hospital, Seoul, Republic of Korea.|Department of Rehabilitation Medicine, Gangwon Do Rehabilitation Hospital, Chuncheon-si, Gangwon-do, Republic of Korea.
Tai Ryoon
TR
Han
Department of Rehabilitation Medicine, Seoul National University College of Medicine, Seoul National University Hospital, Seoul, Republic of Korea.
Byung-Mo
BM
Oh
Department of Rehabilitation Medicine, Seoul National University College of Medicine, Seoul National University Bundang Hospital, Seongnam, Republic of Korea.
Nam-Jong
NJ
Paik
Department of Rehabilitation Medicine, Seoul National University College of Medicine, Seoul National University Bundang Hospital, Seongnam, Republic of Korea.
Eun Joo
EJ
Yang
Department of Rehabilitation Medicine, Seoul National University College of Medicine, Seoul MetropolitanGovernment Seoul National University Boramae Medical Center, Seoul, Republic of Korea.
Shi-Uk
SU
Lee
D000328:Adult; D001930:Brain Injuries / Q000150:complications / Q000473:pathology*; D005260:Female; D006429:Hemiplegia / Q000473:pathology*; D006801:Humans; D008297:Male; D008875:Middle Aged; D016059:Range of Motion, Articular; D017006:Rotator Cuff / Q000000981:diagnostic imaging*; D014463:Ultrasonography
Atrophy; brain injuries; hemiplegia; rotator cuff; ultrasonography