Tendon Tendinosis Development and Characteristics

Primary Mechanism: Degenerative Overuse

Tendon tendinosis occurs through a degenerative process caused by repetitive mechanical loading that overwhelms the tendon's ability to repair itself, resulting in collagen disorientation and fiber separation—not through inflammation as commonly misunderstood, according to the American Academy of Family Physicians 1
The fundamental pathophysiology involves repetitive microtrauma from cumulative mechanical stress that exceeds the tendon's reparative capacity, as reported by the American Academy of Family Physicians 1, 2
Structural breakdown results in degeneration of the normally highly arranged collagen fiber structure, with visible collagen disorientation and fiber separation on histology, as noted by the American Academy of Family Physicians 1, 3

Tendons are relatively hypovascular proximal to their insertion points, which predisposes them to hypoxic degeneration, according to the American Academy of Family Physicians 2

The critical error is mislabeling tendinosis as "tendonitis", as stated by the American Academy of Family Physicians and Praxis Medical Insights 1, 4
This misdiagnosis leads to overreliance on anti-inflammatory medications that provide only short-term pain relief, as reported by Praxis Medical Insights 4
Failure to address the underlying degenerative process, as noted by Praxis Medical Insights 4

Degenerative changes were found in the vast majority of over 1000 spontaneously ruptured tendons analyzed, with specific inflammatory or systemic diseases accounting for less than 2% of cases, as reported by the American Academy of Family Physicians 3
Histology shows collagen disorientation and fiber separation, consistent with tendinosis rather than inflammatory infiltrates, according to the American Academy of Family Physicians and Praxis Medical Insights 3, 4

The natural history of tendon tendinosis follows a predictable course, characterized by an insidious onset of load-related localized pain coinciding with increased or new activity, as reported by the American Academy of Family Physicians and Praxis Medical Insights 1, 2, 4
Early-stage pain during activity may subside after warm-up, but progresses to pain at rest in later stages, according to the American Academy of Family Physicians 3