No abstract

Increased thickness of Achilles tendon and plantar fascia, more evident in the presence of neuropathy, may contribute to an overall increase of tensile force and to the occurrence of an early Windlass mechanism, maintained throughout the whole gait cycle. This might play a significant role in the overall alteration of the biomechanics of the foot-ankle complex.

OBJECTIVES -Secondary to peripheral neuropathy, plantar hyperpressure is a proven risk factor for foot ulceration. But limited joint mobility (LJM) and soft tissue abnormalities may also contribute. The aim of this study was to evaluate the relationships among thickness of plantar fascia, mobility of the metatarso-phalangeal joint, and forces expressed under the metatarsal heads.RESEARCH DESIGN AND METHODS -We evaluated 61 diabetic patients: 27 without neuropathy (D group), 19 with neuropathy (DN group), and 15 with previous neuropathic foot ulceration (DNPU group). We also examined 21 control subjects (C). Ultrasound evaluation was performed with a high resolution 8-to 10-MHz linear array (Toshiba Tosbee SSA 240). The foot loading pattern was evaluated with a piezo-dynamometric platform. First metatarsophalangeal joint mobility was assessed with a mechanic goniometer.RESULTS -Diabetic patients presented increased thickness of plantar fascia (D 2.9 Ϯ 1.2 mm, DN 3.0 Ϯ 0.8 mm, DNPU 3.1 Ϯ 1.0 mm, and C 2.0 Ϯ 0.5.mm; P Ͻ 0.05), and significantly reduced motion range at the metatarso-phalangeal joint (D 54.0 Ϯ 29.4°, DN 54.9 Ϯ 17.2°, DNPU 46.8 Ϯ 20.7°, and C 100.0 Ϯ 10.0°; P Ͻ 0.05). The evaluation of foot-floor interaction under the metatarsal heads showed increased vertical forces in DN and DNPU and increased medio-lateral forces in DNPU. An inverse correlation was found between the thickness of plantar fascia and metatarso-phalangeal joint mobility (r ϭ Ϫ0.53). The thickness of plantar fascia was directly correlated with vertical forces under the metatarsal heads (r ϭ 0.52).CONCLUSIONS -In diabetic patients, soft tissue involvement may contribute to the increase of vertical forces under the metatarsal heads. Changes in the structure of plantar fascia may also influence the mobility of the first metatarso-phalangeal joint. Diabetes Care 26:1525-1529, 2003I n diabetic patients, peripheral neuropathy induces foot deformities and changes in the walking pattern that are responsible for the development of areas of high plantar pressure (1-3).Mechanical stress has been recognized to have a central pathogenic role in the onset of diabetic neuropathic ulcers (4). Among the factors that may contribute to increase mechanical stress, limited joint mobility (LJM) of the ankle joint is associated with increased peak forefoot pressures, and therefore with risk of ulceration (5,6). Atrophy and weakness of tibialis anterior and vastus lateralis muscles as well as atrophy of the intrinsic muscles have been recognized to induce important changes in the performance of the ankle movements and in the biomechanical properties of the diabetic neuropathic foot (3). Another well-known cause of increased forefoot pressure is the increased thickness of the Achilles tendon; the efficacy of its surgical lengthening on forefoot pressure release has been investigated and reported in literature, even if the results still show some discrepancies (7,8). Structural changes in the forefoot of diabetic neuropathic patients, in terms of bone and muscle...

Background: Long-term patients with diabetes and peripheral neuropathy show altered foot biomechanics and abnormal foot loading. This study aimed at assessing muscle performance and ankle mobility in such patients under controlled conditions.

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