Classic history and presentation: Patients with rotator cuff tendonitis commonly present with gradual onset of shoulder pain with repetitive overhead activity during heavy labor or sports, such as baseball, volleyball, tennis, and swimming (eg, throwing activities). Patients may describe difficulty with performing such overhead activities. Patients may also experience pain at night. The site of pain is usually on the anterior, lateral, or posterior aspect of the shoulder.
Prevalence: The overall prevalence of rotator cuff tendonitis is 1.2% in the general population and 2%-40% in the working population, depending on occupational demands.
- Age – Rotator cuff tendonitis is common in the elderly population. Age older than 50 years is associated with increased risk for rotator cuff tendonitis, likely secondary to the age-related degenerative changes in the tendons and age-related cumulative repetitive microtrauma.
- Sex / gender – Men are more commonly affected than women.
Pathophysiology: The pathophysiology of chronic rotator cuff tendonitis is thought to be multifactorial, with a combination of extrinsic and intrinsic factors. The extrinsic mechanism refers to damage to the tendon from compressive forces of surrounding structures, including the acromion and the coracoacromial ligament. The intrinsic mechanism refers to injury within the tendon from tensile overload, intrinsic degeneration (eg, aging, microvascular supply), or other insult.