Rotator cuff (RC) injuries are characterized by tendon rupture, muscle atrophy, retraction, and fatty infiltration, which increase injury severity and jeopardize adequate tendon repair. Epigenetic drugs, such as histone deacetylase inhibitors (HDACis), possess the capacity to redefine the molecular signature of cells, and they may have the potential to inhibit the transformation of the fibro-adipogenic progenitors (FAPs) within the skeletal muscle into adipocyte-like cells, concurrently enhancing the myogenic potential of the satellite cells. HDACis were added to FAPs and satellite cell cultures isolated from mice. The HDACi vorinostat was additionally administered into a RC injury animal model. Histological analysis was carried out on the isolated supra- and infraspinatus muscles to assess vorinostat anti-muscle degeneration potential.Aims
Methods
Rotator cuff muscle atrophy and fatty infiltration affect the clinical outcomes of rotator cuff tear patients. However, there is no effective treatment for fatty infiltration at this time. High-intensity interval training (HIIT) helps to activate beige adipose tissue. The goal of this study was to test the role of HIIT in improving muscle quality in a rotator cuff tear model via the β3 adrenergic receptor (β3AR). Three-month-old C57BL/6 J mice underwent a unilateral rotator cuff injury procedure. Mice were forced to run on a treadmill with the HIIT programme during the first to sixth weeks or seventh to 12th weeks after tendon tear surgery. To study the role of β3AR, SR59230A, a selective β3AR antagonist, was administered to mice ten minutes before each exercise through intraperitoneal injection. Supraspinatus muscle, interscapular brown fat, and inguinal subcutaneous white fat were harvested at the end of the 12th week after tendon tear and analyzed biomechanically, histologically, and biochemically.Aims
Methods
Scapulothoracic fusion (STF) for painful winging
of the scapula in neuromuscular disorders can provide effective pain
relief and functional improvement, but there is little information
comparing outcomes between patients with dystrophic and non-dystrophic
conditions. We performed a retrospective review of 42 STFs in 34
patients with dystrophic and non-dystrophic conditions using a multifilament
trans-scapular, subcostal cable technique supported by a dorsal
one-third semi-tubular plate. There were 16 males and 18 females
with a mean age of 30 years (15 to 75) and a mean follow-up of 5.0
years (2.0 to 10.6). The mean Oxford shoulder score improved from
20 (4 to 39) to 31 (4 to 48). Patients with non-dystrophic conditions
had lower overall functional scores but achieved greater improvements
following STF. The mean active forward elevation increased from
59° (20° to 90°) to 97° (30° to 150°), and abduction from 51° (10°
to 90°) to 83° (30° to 130°) with a greater range of movement achieved
in the dystrophic group. Revision fusion for nonunion was undertaken
in five patients at a mean time of 17 months (7 to 31) and two required
revision for fracture. There were three pneumothoraces, two rib
fractures, three pleural effusions and six nonunions. The main risk
factors for nonunion were smoking, age and previous shoulder girdle surgery. STF is a salvage procedure that can provide good patient satisfaction
in 82% of patients with both dystrophic and non-dystrophic pathologies,
but there was a relatively high failure rate (26%) when poor outcomes
were analysed. Overall function was better in patients with dystrophic
conditions which correlated with better range of movement; however,
patients with non-dystrophic conditions achieved greater functional
improvement.
We compared the quantitative electromyographic activity of the elbow flexors during four exercises (forced inspiration, forced expiration, trunk flexion and attempted elbow flexion), following intercostal nerve transfer to the musculocutaneous nerve in 32 patients who had sustained root avulsion brachial plexus injuries. Quantitative electromyographic evaluation of the mean and maximum amplitude was repeated three times for each exercise. We found that mean and maximum elbow flexor activity was highest during trunk flexion, followed by attempted elbow flexion, forced inspiration and finally forced expiration. The difference between each group was significant (p <
0.001), with the exception of the difference between trunk flexion and attempted elbow flexion. Consequently, we recommend trunk flexion exercises to aid rehabilitation following intercostal nerve transfer.