Contribution of Plantar Fascia to the Increased Forefoot Pressures in Diabetic Patients

Abstract

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...

Plantar Fascia Thickness, a Measure of Tissue Glycation, Predicts the Development of Complications in Adolescents With Type 1 Diabetes

“…Previously we have not found an association between PFT and foot pressure (11); however, a likely explanation is that patients were only examined at baseline and at a relatively early time point in the disease. In adults with type 1 and type 2 diabetes, PFT was associated with increased foot pressure, suggesting that PFT contributes to the development of neuropathy (10). In contrast, an inverse association between PFT and pressure was found in neuropathic patients with diabetes (mean age 61 years) (20), but it may be that longstanding increased pressure in the diabetic foot led to secondary thinning of the plantar fascia.…”

“…These findings suggest that glycation and oxidation of collagen in soft tissues may be independent risk factors for microvascular complications. Previous studies assessing PFT in diabetes have been cross-sectional and predominantly examined foot biomechanics (10,20). This is the first longitudinal study to demonstrate that baseline PFT is an independent predictor of microvascular complications and thus is a novel measure of tissue glycation.…”

“…Limited joint mobility in the hands has been previously described as an index of tissue glycation, but its prevalence has fallen significantly in the past two decades (8). Ultrasound has recently been used to detect thickening of the plantar aponeurosis, a tissue rich in collagen and susceptible to nonenzymatic glycation, in adults with type 1 and type 2 diabetes (9,10). We have previously demonstrated that increased plantar fascia thickness (PFT) was present in one-third of adolescents with type 1 diabetes compared with nondiabetic control subjects, whereas limited passive extension of the interphalangeal joints of the hands was present in 13% (11).…”

Prevention of diabetic foot ulceration: new evidences for an old problem

“…However true ischemic ulcers are observed only in 15 % of cases. The remaining 35 % have both PAD and PN present at the same time: neuroischemic ulcers [2].Many factors may be responsible of the appearance of an ulcer in those patients: intrinsic factors related to the progressive appearance of limited joint mobility, soft tissue stiffness, early and persistent windlass mechanism [3] presence of structural foot deformities as hammer toes, hallux valgus or pes cavus. Metatarsal heads are prominent.…”

Atrophy of Foot Muscles

“…An inverse relationship has been found between the plantar fascia thickness and the dynamic foot pressure (11), and changes in the structure of the plantar fascia seem to influence the joint mobility of the first metatarsophalangeal joint (12). No ultrasonographic study has been performed to quantify the amount of striated muscles in the diabetic foot.…”