Part 6: Detection and Prevention of Foot Problems in Type 2 Diabetes

Background - Footwear to Reduce Ulceration and AmputationA pivotal or initiating event commonly precedes the development of a foot ulcer orleads to an amputation (Pecoraro et al, 1990). This may be an acute traumatic event,such as stepping on a tack, or the result of abnormal pressure on the foot, such aswearing new or ill fitting shoes or socks. Pressure ulcers, also called stress ulcers ormal perforans, frequently result from repetitive low-pressure stress of walking on anunprotected neuropathic foot, resulting in repeated friction over prominences such asa plantar callus. In addition they may result from ingrown toenails or fromimmobilisation in a bed or chair. This initiating event superimposed on an at risk foot(eg insensate or with vascular insufficiency) is often the critical factor which mayultimately lead to amputation (Mayfield et al, 1996).Apelqvist et al (1990) studied 314 consecutive people with diabetes and a foot ulcerand identified an acute traumatic precipitating event in 18%, ill fitting shoes or socksin 39%, mal perforans in 12%, paronychia in 6%, decubitus pressure in 5%, and noobvious precipitating event in 16%. In another study shoe trauma preceded ulcerationin 47% of 386 ulcers in 239 people (Edmonds et al, 1986).Mayfield et al (1996) in a retrospective study of 61 diabetic Pima Indians withdiabetes who underwent an amputation identified trauma as the pivotal event in 44%(shoe trauma 8% of total) and new onset ulcer without trauma, many of which wereprobably mal perforans, in 39%.Elevated plantar pressure is causally related to the occurrence of foot ulcers in peoplewith diabetes with neuropathy (Veves et al, 1992). As well as exposing the foot toinjury, barefoot walking is associated with higher foot pressures than wearing shoes.In addition the type of footwear also has a significant influence on plantar pressures(Lavery et al, 1997; Kastenbauer et al, 1998).Tovey (1984) has detailed the desirable characteristics of appropriate diabeticfootwear aiming to reduce shock and shear, and accommodate, stabilise and supportdeformities.• width to accommodate the first metatarsophalangeal joint• length should allow about 1cm between the end of the shoe and the longesttoe• depth to allow sufficient room in the toe area and instep• laces to adjust for oedema and deformities• snug fit of heel without undue motion• wide low heels to improve stabilityWearing of inappropriate footwear is common in people with diabetes. Reiber et al(2002b) studied footwear in people with diabetes and a history of foot ulcer. A total of400 people (mean age 62 years) with diabetes and a history of healed full-thicknessfoot lesion, no foot deformities requiring a custom shoe, and ability to walk one blockand climb one flight of stairs daily were included in this cross-sectional study. 58% ofsubjects were insensate to the 10g monofilament. In general, women spent an averageof 51% of their time in dangerous shoes defined as those with shallow or narrow toebox, no laces, open toes or heels, and a heel height placing extra pressure on the ball74