Influence of a lower leg brace on traction force in healthy and ruptured achilles tendons

Abstract

Background: we investigated how ruptured Achilles tendons are loaded in a brace. There is an ongoing discussion whether patients should be recommended to bear weight on the injured limb. However, little is known about the effects of bracing on tensional loading of the healing Achilles tendon: it is uncertain if load-bearing actually stresses the Achilles tendon inside a brace. Methods: we measured plantar flexion moment inside the brace, in order to estimate tensional loading of the tendon, by use of an insole with pressure transducers. Results: after wearing the brace for 1 hour, young healthy individuals reduced their maximum flexion moment during gait by half. Patients with Achilles tendon rupture showed no measurable flexion moment during gait with the brace, 4 or 7 weeks after injury. Only when specifically instructed, they could produce a considerable plantar flexion moment. We noted that gait speed with the brace at 4 weeks correlated with a heel-raise functional test at 1 year: the higher the spontaneous gait speed, the less the functional difference between the injured and the uninjured leg (r2=0.68; p=0.002). Conclusion: the correlation with gait speed suggests that the patients’ general physical aptness has an impact on the end result.