Repetitive mechanical stress and denervation in plantar ulcer pathogenesis in rats

To test the hypotheses that physiologic limits of repetitive mechanical stress can stimulate the formation of ulcers on the plantar surface of the foot, and that denervation predisposes to such ulcer formation, 90 rats were subjected to neurectomy or tenotomy and the response of each animal's hind foot to 10,000 daily repetitions of mechanical stress in a walking simulator was determined. Plantar ulceration occurred in the neurectomized animals within 7 to 10 days of commencing the simulated walking procedures. Histologic examination of all the stimulated footpads showed traumatic damage in both neurectomized and tenotomized animals. It was concluded that normal levels of repetitive mechanical stress can cause plantar ulceration and that such ulceration occurs more readily in the denervated foot.