ACHILLES TENDON STRAIN: RESEARCH FINDINGS WITH CLINICAL IMPLICATIONS

摘要

Tendons are susceptible to injury, either due to major overload or repeated sublinical injury. Individual fibres can withstand 2-5% strain before undergoing plastic deformation & permanent elongation. Tendons as a whole can withstand up to 20-50% strain, while still demonstrating a linear response and return to normal length. Under normal usage, tendons are strained only to 25-33% of maximum strength. Tendons are slow to heal, with no appreciable increase in strength within the first 3 weeks. Strength slowly increases from 3-6 weeks, with slow gains thereafter. Overstressing a tendon repair before adequate healing can result in gap formation and/or repair failure. Tendons undergoing a gap greater than 3mm during the repair process heal at a slower rate, with lower ultimate tensile resistance at 6 weeks compared to tendons healing with no gap.