Neuromuscular Electrical Stimulation for Achilles Tendon Rupture Rehabilitation

Achilles Tendon Ruptures (ATR) are common and permanently affect the function of the lower leg. Regardless of treatment approach the majority of patients develop long term functional deficits, which include decreased plantar flexion strength, lower heel-rise height, and altered gait patterns. It is believed that tendon lengthening and calf muscle atrophy, which develop during the first few weeks of recovery, are major factors contributing to these functional deficits. The initial development of atrophy is likely caused by reduced loading and muscle activity of the affected leg. However, long-term atrophy may be related to tendon elongation. On the other hand, tendon elongation initially rises during the first few weeks of unloading and slowly reduces, but not completely, when loading is resumed. However, atrophied calf muscles may not provide sufficient loading for optimal tendon recovery. Therefore, there seems to be vicious spiral between tendon elongation and muscle atrophy.

The objective of this study is to develop a neuromuscular electrical stimulation (NMES) rehabilitation protocol for Achilles tendon ruptures. Our preliminary data has shown that force applied to the tendon can be modulated using electrical intensity and pad placement. Therefore, NMES can produce significant contraction in the calf muscles and induce controllable, low-magnitude, cyclic loading to the tendon; which cannot be achieved with voluntary muscle contractions. This approach can potentially overcome limitations of the current rehabilitation protocols.