A recent study published in the BMC Musculoskeletal Disorders assessed the effect of Botox injection into the supraspinatus muscle – one of the rotator cuff group muscles – after the surgical repair of the rotator cuff in a rat model. The study relied on the characteristics of botulinum toxin A (Botox) as a neurological toxin which causes a temporary muscular paralysis. Researchers performed surgical transection and repair of 82 supraspinatus tendons in rat models. After repair, each muscle was injected with Botox or saline for comparison purposes. Half of the shoulders were additionally treated with immobilization, and the other half were allowed free cage activity. The tendon healing quality was evaluated later on by histological examinations of the scarring zone and by biomechanical measurements of the repair site strength.
Researchers found that the tendon healing quality in the Botox injection group was better than that in the control groups and similar to the cast immobilization group; however, the combination of Botox injection and cast immobilization affected the surgical repair negatively. The avoidance of long-term immobilization in rats who underwent rotator cuff repair by injecting Botox into the muscles might be one of the potential benefits of this study; which leads to a minimal post-surgery stiffness and superior functional end results.