Simultaneous measurement of plantar pressure and shear forces in diabetic individuals.

Plantar foot ulceration is a diabetic complication whose underlying causative factors are still not fully understood. The goal of the current work was to simultaneously record plantar pressure and shear and examine the interrelationship of these forces; specifically, if peak shear and pressure occurred at the same site/time and whether adjacent shear forces had a greater tendency to be directed towards or away from each other. A custom built 16 transducer array was used to record forefoot shear and pressure during gait initiation in a cohort of 12 neuropathic diabetic individuals. The individuals were barefoot and the transducers were covered with a 5 mm thick layer of Minorplast. The greatest pressure occurred in the medial metatarsal heads (189 kPa) and the greatest shear in the lateral metatarsal heads (33 kPa). The interaction of the shear forces revealed that the plantar tissue was stretched to a greater magnitude than it was bunched (24 kPa vs 12 kPa, averaged over all regions). Normal distributions were determined for stretching and bunching in both the medial-lateral and anterior-posterior directions. When shear and pressure were considered in combination, half of the neuropathic individuals had peak shear and pressure occurring at the same site. These peak stresses did not occur at the same time (average difference of 0.186 s). The results of this study help to further characterize tissue stresses experienced on the plantar surface of the foot during gait initiation in neuropathic diabetic individuals.

[1]  Kari L. Keskinen,et al.  XVth congress of the international society of biomechanics : book of abstracts , 1995 .

[2]  Brian L. Davis,et al.  A Device for Simultaneous Measurement of Pressure and Shear Force Distribution on the Plantar Surface of the Foot , 1998 .

[3]  G. Reiber,et al.  Diabetic Foot Care: Financial Implications and Practice Guidelines , 1992, Diabetes Care.

[4]  M Lord,et al.  Method for in-shoe shear stress measurement. , 1992, Journal of biomedical engineering.

[5]  B L Davis,et al.  Foot ulceration: hypotheses concerning shear and vertical forces acting on adjacent regions of skin. , 1993, Medical hypotheses.

[6]  J Larsson,et al.  What is the most effective way to reduce incidence of amputation in the diabetic foot? , 2000, Diabetes/metabolism research and reviews.

[7]  I A Stokes,et al.  The neuropathic ulcer and loads on the foot in diabetic patients. , 1975, Acta orthopaedica Scandinavica.

[8]  C. I. Franks,et al.  Dynamic Foot Pressure and Other Studies as Diagnostic and Management Aids in Diabetic Neuropathy , 1983, Diabetes Care.

[9]  J. Pollard,et al.  Method of healing diabetic forefoot ulcers. , 1983 .

[10]  J. Shaw,et al.  An analysis of dynamic forces transmitted through the foot in diabetic neuropathy. , 1998, Diabetes care.

[11]  D. Sims,et al.  Plantar sensory threshold in the ulcerative foot. , 1986, Leprosy review.

[12]  L. By,et al.  Skin stress and blood flow in sitting paraplegic patients. , 1984, Archives of physical medicine and rehabilitation.

[13]  J W Tappin,et al.  Study of the relative timing of shear forces on the sole of the forefoot during walking. , 1991, Journal of biomedical engineering.

[14]  B. Bowerman.  Statistical Design and Analysis of Experiments, with Applications to Engineering and Science , 1989 .

[15]  C. Grunfeld,et al.  Aesthesiometry: quantification of cutaneous pressure sensation in diabetic peripheral neuropathy. , 1988, Journal of rehabilitation research and development.

[16]  F. Logerfo.  The high risk foot in diabetes mellitus , 1992 .

[17]  P. Cavanagh,et al.  The Effect of Callus Removal on Dynamic Plantar Foot Pressures in Diabetic Patients , 1992, Diabetic medicine : a journal of the British Diabetic Association.

[18]  Dinsdale Sm,et al.  Decubitus ulcers: role of pressure and friction in causation. , 1974, Archives of physical medicine and rehabilitation.

[19]  R M Cothren,et al.  Frequency content of normal and diabetic plantar pressure profiles: implications for the selection of transducer sizes. , 1996, Journal of biomechanics.

[20]  M. Dhanendran,et al.  Vertical forces acting on the feet of diabetic patients with neuropathic ulceration , 1981, The British journal of surgery.