Do the biomechanical properties of the ankle–foot complex influence postural control for people with Type 2 diabetes?
Introduction
Type 2 diabetes (DM), a lifelong health problem with a growing prevalence, is accompanied by various complications including diabetic peripheral neuropathy (DPN) (World Health Organization, 2002). Symptoms of DPN may include sensory deficits in light touch and proprioception; and motor deficits in terms of reduced strength in the ankle muscles (Deshpande et al., 2008). The sensory and motor deficits may subsequently result in balance disorders and an increased risk of falling, which may lead to injuries and hospitalization in this group of patients (Menz et al., 2004, Wallace et al., 2002).
Thickening of tendinous and ligamentous structures of hands and feet has long been observed in people with DM, and their plantar pressure during walking has been noted to be significantly higher than people without DM (Ledoux and Blevins, 2007, Pataky et al., 2005). D'Ambrogi et al. (2005) reported a significant increase in the thickness of plantar fascia for people with DM regardless of the presence of DPN.
The ankle–foot complex, consisting of the ankle joint, foot segment, and muscles, plays an important role in the biomechanics of postural control. An increased Young's modulus in the plantar soft tissues may alter the biomechanics in the ankle–foot complex for people with DM, leading to an increased risk of developing foot ulcers or possibly diminishing postural control. Among the individuals with diabetic neuropathy, the plantar soft tissues over the foot were significantly stiffer as compared to those of the age-matched healthy control (Sun et al., 2011). The pathological stiffening of the soft tissue of the ankle–foot complex may interfere with the sensory feedback and flexibility of the foot in stance, which may have a subsequent impact on postural control in standing. However, there is a lack of research on whether the changes in the biomechanical properties of the ankle–foot complex are associated with postural control for people with DPN.
The objectives of the present study were to compare the Young's modulus and unloaded thickness of soft tissues of the ankle–foot complex and the postural control in standing of individuals with (i) DM but no DPN; (ii) DPN; and (iii) age-matched healthy control subjects. Also, the correlations between the Young's modulus and thickness with postural control of these individuals were examined.
Section snippets
Subjects
Subjects ranging in age from 40 to 80 who had a confirmed diagnosis of Type 2 DM were recruited from two local out-patient diabetes clinics. Using the Semmes Weinstein monofilament (SWM) test (Rolyan* Monofilaments, Smith & Nephew, Inc., Germantown, USA), a sensory test was performed to classify the participants into two groups: (i) subjects with DM but no DPN (DM-non-DPN) (n = 23) (Duration of diabetes: 10.4 (SD 9.0) years), and (ii) subjects with DPN (DPN) (n = 9) (Duration of diabetes: 10.7 (SD
Results
Demographic data for the subjects are summarized in Table 1. No significant between-group differences were found, except in body weight, body mass index, and fasting plasma glucose (P < 0.05).
Thickness of soft tissue at the Achilles tendon
We found that the soft tissue at the Achilles tendon in people with DM was significantly thicker than that in the control and DPN groups. Also, there was a trend of increased thickness of the plantar soft tissue in all individuals with DM as compared to the control subjects. Thickening of the tendinous and ligamentous structures of the hands and plantar surface of feet has long been observed in people with DM (D'Ambrogi et al., 2003, Duffin et al., 2002). But this is the first study that
Conclusions
Individuals with DM, particularly those with neuropathy, manifested an increase in the Young's modulus of their plantar soft tissues, but not in the Achilles tendon. Changes in the biomechanical properties of the ankle–foot complex were correlated with the postural control in people with DM.
Conflict of interest
None of the authors have any financial and personal relationships with other people or organizations that could inappropriately influence (bias) this work.
Acknowledgements
This project was funded by the General Research Fund of the Research Grants Council of Hong Kong (PolyU 5128/08E). The funding source had no role in the study design, data collection, analysis and interpretation of data, writing or in the decision to submit this manuscript.
References (32)
- et al.
Influence of sensory input on plantar pressure distribution
Clin. Biomech.
(1995) - et al.
Effect of Achilles tendon loading on plantar fascia tension in the standing foot
Clin. Biomech.
(2006) Plantar soft tissue loading under the medial metatarsals in the standing diabetic foot
Med. Eng. Phys.
(2003)- et al.
Relationship between skin resistance level and static balance in type II diabetic subjects
Diabetes Res. Clin. Pract.
(2008) - et al.
Comparison of the mechanical properties of the heel pad between young and elderly adults
Arch. Phys. Med. Rehabil.
(1998) - et al.
Plantar tissue stiffness in patients with diabetes mellitus and peripheral neuropathy
Arch. Phys. Med. Rehabil.
(2002) - et al.
The effect of aging on the biomechanical properties of plantar soft tissues
Clin. Biomech.
(2010) - et al.
The compressive material properties of the plantar soft tissue
J. Biomech.
(2007) - et al.
Walking stability and sensorimotor function in older people with diabetic peripheral neuropathy
Arch. Phys. Med. Rehabil.
(2004) - et al.
A biomechanical model of the foot
J. Biomech.
(1986)
Changes in the thickness and stiffness of plantar soft tissues in people with diabetic peripheral neuropathy
Arch. Phys. Med. Rehabil.
Biomechanical assessment of plantar foot tissue in diabetic patients using an ultrasound indentation system
Ultrasound Med. Biol.
International consensus and practical guidelines on the management and the prevention of the diabetic foot. International Working Group on the Diabetic Foot
Diabetes Metab. Res. Rev.
Choosing a practical screening instrument to identify patients at risk for diabetic foot ulceration
Arch. Intern. Med.
Enzymic and non-enzymic cross-linking mechanisms in relation to turnover of collagen: relevance to aging and exercise
Scand. J. Med. Sci. Sports
Contribution of plantar fascia to the increased forefoot pressures in diabetic patients
Diabetes Care
Cited by (20)
Clinical complications of tendon tissue mechanics due to collagen cross-linking in diabetes
2021, The Science, Etiology and Mechanobiology of Diabetes and its ComplicationsEffects of maturation and advanced glycation on tensile mechanics of collagen fibrils from rat tail and Achilles tendons
2018, Acta BiomaterialiaCitation Excerpt :Enzymatic and AGE cross-links both contribute to the chemical stability of collagen [17,18], and tissues tend to get mechanically stronger with maturation, and weaker with inhibition of enzymatic cross-links [19,20]. Induction of AGEs in vitro has also been associated with increased stiffness and strength [21,22], although in vivo findings are inconsistent [23–26]. Glycation is thought to be detrimental to tissue function with brittleness and reduced strain capacity [27], but there is little such evidence at the tissue level [22].
Real-time sonoelastography and ultrasound evaluation of the Achilles tendon in patients with diabetes with or without foot ulcers: A cross sectional study
2015, Journal of Diabetes and its ComplicationsCitation Excerpt :Because of the similarity between our study group with current ulcers and the group of patients with diabetes with previous neuropathic ulcers involved in Giocomozzi et al.'s study, the results may not be accidental. It has been hypothesized that the non-enzymatic glycation of the collagenous component due to the hyperglycemia contributes to this thickening (Palastanga, Field, & Soames, 1989; Sarrafian, 1993), as well as the increase in the mechanical load on the foot resulting from the higher body mass commonly noted in people with DM (Cheing et al., 2013; Duffin, Lam, Kidd, Chan, & Donaghue, 2002). In our study, BMI of the groups were similar.
Morphological Changes and Pathological Findings in the Achilles Tendons of Diabetic Patients: A Meta-Analysis of Comparative Clinical Studies
2023, Muscles, Ligaments and Tendons JournalAcute short term effects of endurance and resistance training on balance control in patients with diabetic peripheral neuropathy
2023, International Journal of Neuroscience