Plantar Pressures and Trophic Ulceration. an Evaluation of Footwear.

Trophic ulceration is a most serious hazard to the man with anaesthetic feet who leads an active life. The only way to heal an ulcer is to rest it. If the patient walks on the ulcer it deepens and osteomyelitis ensues ; the scarring and distortion make further ulceration inevitable until walking finally becomes impossible. The entire history of a plantar trophic ulcer is dominated by mechanical factors. lt starts from trauma or excessive local pressure and is maintained by repeated minor injuries ; it heals readily without special treatment if rested completely, and its recurrence can be prevented by careful regulation of stresses on the scar. There are, of course, changes in denervated tissues which alter their response to injury and modify their mechanism of repair. These intrinsic changes are imperfectly understood and difficult to change, but they are insufficient to cause or maintain a plantar ulcer in the absence of external mechanical factors. In many parts of the world today thousands of leprosy patients are having trophic ulcers of the feet treated for months and years by various forms of local applications and dressings at a high cost in time and money. To obtain this treatment patients have to walk to and from their homes on bandaged feet, continuing the mechanical stresses which are largely responsible for the ulceration. At the trophic ulcer clinics ofthe Christian Medical College and Hospital, Vellore, limitation of ward space has made it necessary to treat hundreds of patients by methods which allow ambulation. The results were poor indeed until immobilisation in plaster (Khan 1939) became the standard treatment. The regularity and speed with which these trophic ulcers heal in a walking plaster is most impressive and support the concept that the ulceration is related mainly to mechanical factors. From the practical point of view it suggests firstly that ulceration can be prevented, and secondly that recurrence of ulceration can be avoided by the wearing of shoes which provide conditions similar to those in a plaster. These possibilities prompted our study of pressures on feet during walking in plasters and in various types of footwear. To appreciate the relationship between pressure and plantar ulceration it is necessary first to analyse the forces acting on the sole of the foot. For this it is helpful to divide any such force into two components-one parallel and the other perpendicular to the surface of the skin.