What is a key concept in tendon healing after repair?

• A. Healing is rapid and complete within days
• B. Healing is slow; initial collagen formation occurs over weeks, with remodeling over months; full strength takes several months
• C. Tendon healing occurs only with grafts
• D. Tendon cannot regain original strength

Answer: (B)

Tendon healing after repair works on a gradual, staged timeline where strength builds slowly over weeks to months. Right after repair, the tissue is relatively weak. In the early period, inflammation triggers a proliferative phase where fibroblasts lay down collagen, mainly type III, forming scar tissue that bridges the repair but is disorganized and offers limited strength. Over the ensuing weeks to months, remodeling realigns the collagen fibers along the direction of pull, and the tissue gradually shifts from type III to stronger type I with increased cross-linking. This process explains why initial healing occurs over weeks and remodeling continues for months, with full mechanical strength typically taking several months. Proper immobilization followed by progressive loading helps guide this process and prevent gap formation, and grafts are not required for basic tendon healing—the native tissue can heal with the right biological and mechanical conditions, though the timeline is inherently slow.