Elsevier

Gait & Posture

Volume 37, Issue 4, April 2013, Pages 603-610
Gait & Posture

The role of foot morphology on foot function in diabetic subjects with or without neuropathy

https://doi.org/10.1016/j.gaitpost.2012.09.024Get rights and content

Abstract

The aim of this study was to investigate the role of foot morphology, related with respect to diabetes and peripheral neuropathy in altering foot kinematics and plantar pressure during gait. Healthy and diabetic subjects with or without neuropathy with different foot types were analyzed. Three dimensional multisegment foot kinematics and plantar pressures were assessed on 120 feet: 40 feet (24 cavus, 20 with valgus heel and 11 with hallux valgus) in the control group, 80 feet in the diabetic (25 cavus 13 with valgus heel and 13 with hallux valgus) and the neuropathic groups (28 cavus, 24 with valgus heel and 18 with hallux valgus). Subjects were classified according to their foot morphology allowing further comparisons among the subgroups with the same foot morphology. When comparing neuropathic subjects with cavus foot, valgus heel with controls with the same foot morphology, important differences were noticed: increased dorsiflexion and peak plantar pressure on the forefoot (P < 0.05), decreased contact surface on the hindfoot (P < 0.03).

While results indicated the important role of foot morphology in altering both kinematics and plantar pressure in diabetic subjects, diabetes appeared to further contribute in altering foot biomechanics. Surprisingly, all the diabetic subjects with normal foot arch or with valgus hallux were no more likely to display significant differences in biomechanics parameters than controls. This data could be considered a valuable support for future research on diabetic foot function, and in planning preventive interventions.

Highlights

► Simultaneous three-dimensional kinematics and pressure analysis of three foot's subsegments: hindfoot, midfoot, forefoot. ► Comparison between controls, diabetics non neuropathic and neuropathic subjects’ foot biomechanics. ► Foot morphology contribution to altered biomechanics. ► Data were collected during gait on 60 subjects: 20 controls and 40 diabetics. ► Statistically significant alterations on neuropathic and diabetic subjects with different foot morphology and heel/hallux alignment.

Introduction

Diabetic and neuropathic subjects (DPN) are at increased risk for ulcer development at sites exposed to repetitive, high plantar loading [1], [2]. Several studies have been conducted in the last decade to investigate diabetic foot biomechanics alterations especially in term of foot kinematics and plantar pressure (PP) during gait [1], [3], [4], [5], [6], [7], [8]. Previous PP studies demonstrated an important correlation between the sites displaying higher PP and the presence of callosities of DPN subjects [8], [9]. Stresses were found to be relatively higher and located closer to the skin surface where skin breakdown was most likely to occur [10]. Others demonstrated an association between higher peak PP and morphological foot alteration in DPN [8], [11]. Ledoux et al. investigated diabetic subjects considering the structural differences between types of foot and demonstrated close relationships between foot morphological alterations and plantar ulcerations [12], [13], [14].

Several kinematics studies have compared DPN to control subjects (CS) [5], [6]. Although these studies provided insight into the potential influence of diabetes on kinematics during gait, the majority of them considered the foot as a rigid segment and evaluated its motion with respect to the tibia. Only two recent studies [4], [5] applied a three-dimensional (3D) multisegment foot kinematic model to evaluate DPN foot kinematics during gait, and observed significant alterations especially in DPN's forefoot triplanar angles [4], [5]. It has also been shown that limited joint mobility may contribute to increased foot subsegments loading by limiting foot flexibility and restraining the forward progression of body weight during the stance phase of gait [3]. However data substantiating the causes and consequences of foot morphology on limited mobility and excessive PP in DPN is limited.

The purpose of this study was to explore the relationship between foot deformities, 3D multisegment foot kinematics and PP during gait in diabetes and DPN. This was pursued by assessing in vivo 3D multisegment foot kinematics [5] and PP of both CS and diabetes subjects with and without neuropathy.

Results of this study can be used as a support to design foot orthotic devices [15], [16]. Recent literature [15], [16] emphasized the importance of considering both foot biomechanics and morphology when planning various foot orthotics devices in order to efficiently reduce plantar ulcer formation and avoid amputation in diabetic subjects.

Section snippets

Subjects

Subjects were recruited among the patients attending the outpatient Clinic at the Department of Metabolic Disease of the University of Padova (Italy). Inclusion criteria were: type 1 and 2 diabetic subjects with walking ability, no history of ulcers or neurological disorders (apart from neuropathy), orthopedic problems, lower limb surgery, cardiovascular disease. CS were recruited among hospital personnel and chosen to be age-, BMI- and gender-matched with the diabetic subjects. On the basis of

Results

The clinical, demographic characteristics, time and space parameters of the studied subjects were reported in Table 1, and show that all patients were in fair metabolic control. The DPN had a higher prevalence of both micro- and macrovascular complications. Results of the biomechanic analysis are shown in Table 2, Fig. 1, Fig. 2, Appendix. In Table 2 results of the comparison among the CS, the NoDPN and the DPN without taking into account foot morphology (GB approach) have been reported and

Discussion

We applied a four-segment 3D foot kinematic model together with a three-segment foot PP model in order to examine the role of foot morphology on function in DPN and NoDPN. This was performed not only taking into account the pathology but also the type of foot, heel and hallux alignment.

In order to avoid inter-operator errors in classifying foot morphology, a single orthopedic surgeon with extensive experience undertook this [12], [13], [14], [19], [27]. This has been shown to improve its

Conflict of interest statement

The authors have no conflict of interest to disclose.

Acknowledgements

The authors thank the Imago Ortesi (Piacenza) for providing the plantar pressure systems. We also acknowledge the contribution of Giulia Donà and Federico Foletto for their help in collecting the data in the initial stages of this research.

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