Our aim was to describe the atypical pattern of increased fatty
degeneration in the infraspinatus muscle compared with the supraspinatus
in patients with a massive rotator cuff tear. We also wished to
describe the nerve conduction and electromyography findings in these
patients. A cohort of patients undergoing surgery for a massive rotator
cuff tear was identified and their clinical records obtained. Their
MRI images were reviewed to ascertain the degree of retraction of
the torn infraspinatus and supraspinatus muscles, and the degree
of fatty degeneration in both muscles was recorded. Nerve conduction studies
were also performed in those patients who showed more degeneration
in the infraspinatus than in the supraspinatus.Aims
Patients and Methods
The April 2014 Shoulder &
Elbow Roundup. 360 . looks at: arthroscopic capsular release successful after six months; MCIC in cuff surgery; analgesia following arthroscopic cuff repair; platelet-rich fibrin; and cuff tear and
The June 2014 Shoulder &
Elbow Roundup360 looks at: suprascapular nerve and rotator cuff pathology; anchors in Bankart repair: it’s not what you’ve got, but how you use it; not all shoulder PROMs are equal; reverse shoulder arthroplasty OK in trauma; not all in the mind: frozen shoulder personality debunked; open and arthroscopic repair equivalent in shoulder instability; natural history of olecranon fractures not so bleak?; and resurfacing of the shoulder: a Danish perspective.
Although many clinical and experimental investigations have shed
light on muscle atrophy and intramuscular accumulation of fat after
rotator cuff disruption, none have reported on their onset in the
absence of muscle retraction. In 30 rabbits, we detached one supraspinatus (SSP) tendon and
repaired it immediately, thus preventing muscle retraction. The
animals were killed in groups of 10 at one, two and six weeks. Both
shoulders of 15 non-operated rabbits served as controls. We measured
the weight and volume of SSP muscles and quantified the cross-sectional
area of intramuscular fat (i-fat) histologically.Objectives
Methods
This study examined the role of vitamin D as a factor accounting for fatty degeneration and muscle function in the rotator cuff. There were 366 patients with disorders of the shoulder. A total of 228 patients had a full-thickness tear (group 1) and 138 patients had no tear (group 2). All underwent magnetic resonance arthrography and an isokinetic muscle performance test. The serum concentrations of vitamin D (25(OH)D3) were measured. In general, a lower serum level of vitamin D was related to higher fatty degeneration in the muscles of the cuff. Spearman’s correlation coefficients were 0.173 (p = 0.001), −0.181 (p = 0.001), and −0.117 (p = 0.026) for supraspinatus, infraspinatus and subscapularis, respectively. In group 1, multivariate linear regression analysis revealed that the serum level of vitamin D was an independent variable for fatty degeneration of the supraspinatus and infraspinatus. The serum vitamin D level has a significant negative correlation with the fatty degeneration of the cuff muscle and a positive correlation with isokinetic muscle torque.
