What is tendinosis and how is it treated in adults with a history of repetitive strain or overuse?

What is Tendinosis?

Tendinosis is a degenerative breakdown of your tendon's internal structure caused by repetitive wear and tear—not inflammation—where the normally organized collagen fibers become disorganized and separated, leading to chronic pain with activity. 1, 2

The Critical Misunderstanding

• The most important thing to understand is that tendinosis is NOT "tendonitis"—there is no inflammation involved. 1, 3, 2
• This is a degenerative condition where the tendon's collagen fibers (the rope-like structures that give tendons their strength) become disorganized and start to break down. 1, 2
• When doctors examined over 1,000 ruptured tendons under a microscope, they found degenerative changes in the vast majority, with inflammatory or systemic diseases accounting for less than 2% of cases. 2, 4
• The confusion between tendinosis and tendonitis matters because it leads people to rely too heavily on anti-inflammatory medications (like ibuprofen) that only provide temporary pain relief without fixing the underlying problem. 3, 2

How It Develops

• Tendinosis happens when you repeatedly stress a tendon beyond its ability to repair itself—think of it like a rope that frays from constant use. 2
• The repetitive microtrauma from cumulative mechanical stress overwhelms your tendon cells' capacity to fix the damage. 2
• Your tendons have relatively poor blood supply in certain areas, which makes them more vulnerable to this type of breakdown because they can't get enough oxygen and nutrients to heal properly. 1, 2
• This explains why tendinosis commonly affects specific areas: rotator cuff (shoulder), elbow (tennis/golfer's elbow), patellar tendon (knee), and Achilles tendon (heel). 1

What It Feels Like

• The pain typically starts gradually and is directly related to activity—it hurts when you use the affected tendon. 3, 2
• Early on, the pain may appear during activity but improve after you "warm up," but as it progresses, you'll have pain even at rest. 2
• The pain is usually described as "sharp" or "stabbing" and is very localized to one specific spot. 3
• You'll notice the pain gets worse when you increase your activity level or start a new repetitive movement pattern. 3, 2

How It's Treated

• About 80% of people fully recover within 3-6 months with conservative treatment. 1
• The cornerstone of treatment is relative rest (not complete immobilization), icing, and eccentric strengthening exercises—these are exercises where you slowly lengthen the muscle-tendon unit under load. 1
• Pain medications like NSAIDs can help with acute pain relief but won't fix the underlying degenerative process, so they should be used sparingly and not as the primary treatment. 1
• Corticosteroid injections can relieve pain but should be used cautiously because they don't address the degeneration and may have side effects. 1
• Surgery is reserved for the roughly 25% of patients who don't improve after 3-6 months of proper conservative treatment. 1

Common Pitfalls to Avoid

• Don't expect anti-inflammatory medications alone to cure tendinosis—they mask symptoms but don't heal the degenerative changes. 3, 2
• Don't confuse initial pain relief with actual healing—the tendon structure needs time and proper loading to reorganize its collagen fibers. 2
• Don't assume complete rest is best—controlled, progressive loading through eccentric exercises is crucial for recovery. 1