tendinosis

Tendinosis is a chronic degeneration of a tendon’s collagenous structure with little or no inflammatory cell involvement. It represents a form of tendinopathy that results from a failed healing response to repetitive microtrauma and long-standing overuse.

Pathophysiology involves disorganized collagen fibers, increased type III collagen, and accumulation of ground substance and proteoglycans. Tenocytes may show abnormal activity, and neovascularization can occur, contributing to pain and dysfunction.

Clinically, tendinosis presents as persistent focal tendon pain and tenderness that worsens with loading. Morning stiffness is typically mild or absent, and swelling is not prominent. Weakness and reduced functional performance may accompany the pain.

Diagnosis is based on history and examination, with imaging used to document degeneration. Ultrasound often shows tendon thickening and hypoechoic or heterogeneous areas; Doppler can reveal neovascularity. MRI may demonstrate degenerative changes and edema within the tendon. Laboratory tests are not diagnostic and are used mainly to exclude inflammatory or systemic conditions.

Treatment emphasizes load management and tendon-directed rehabilitation. First-line strategies include activity modification, gradual progression of loading, and structured eccentric strengthening programs. Physical therapy can aid in correcting movement patterns and restoring tendon function. Short-term analgesia such as acetaminophen or NSAIDs may be used for pain, but NSAIDs do not cure the condition. Corticosteroid injections are generally discouraged because they can weaken the tendon and increase rupture risk. Other interventions with variable evidence include platelet-rich plasma, extracorporeal shockwave therapy, and, after failed conservative care, surgical debridement or repair.

Prognosis varies by tendon and duration of symptoms, but many patients improve with proper rehabilitation and load management. Recurrence is common if training loads are not adjusted. Common sites include the lateral elbow, patellar tendon, Achilles tendon, rotator cuff tendons, and gluteal tendons.