Controlled digital motion by electrical stimulation of the flexor muscle in chickens

A method for producing motion in the deep flexor tendon by electrical stimulation of its muscle was devised and applied in 38 chickens whose legs were immobilized after tendon repair. Six days prior to tendon surgery, stainless steel electrode wires were implanted in the muscle belly. Stimulation was carried out from day 18 to day 35 after tendon surgery. Stimulation consisted of trains of pulses (50 pulses per second for 0.5 seconds) repeated every 2 seconds with the output voltage adjusted to produce only slight flexion of the distal phalanges of the toes. The stimulation was well tolerated by the chickens and produced the desired tendon motion. Muscle fiber changes were minimal and appeared to be related to the trauma of electrode implantation.