SLR - August 2019 - Alina Kogan
Altered Achilles Tendon Function During Walking in People with Diabetic Neuropathy: Implications for Metabolic Energy Saving
Reference: Petrovic M, Maganaris CN, Deschamps K, Verschueren SM, Bowling FL, Boulton AJM, Reeves ND. Altered Achilles Tendon Function During Walking in People with Diabetic Neuropathy: Implications for Metabolic Energy Saving. J Appl Physiol (1985). 2018 May 1;124(5):1333-1340.
Scientific Literature Review
Reviewed By: Alina Kogan, DPM
Residency Program: NYU Langone Hospital – Brooklyn, NY
Podiatric Relevance: The Achilles tendon has the ability to store and release energy during walking, thus decreasing metabolic expenditure. In diabetics, specifically diabetics with diabetic peripheral neuropathy, the Achilles tendon tends to be stiffer thus causing an increased metabolic cost of walking. This study was designed to investigate the effects of diabetes and diabetic peripheral neuropathy on the Achilles tendon during walking.
Methods: This is a level III prospective controlled study for diabetic patients with or without diabetic peripheral neuropathy with Achilles tendon stiffness and increased metabolic cost of walking. This study involved a total of 56 patients, 13 with diabetes and moderate to severe peripheral neuropathy (DPN), 20 with diabetes and no neuropathy (DM), and 23 without diabetes and neuropathy (control group). Outcomes of the study were evaluated using the modified neuropathy disability score (mNDS), vibration perception threshold (VPT), gait analysis, dynamometry measurements for measuring of maximal plantarflexion strength, Achilles tendon force calculation and MRI scanning, and stiffness and hysteresis during walking.
Results: Participants with diabetic peripheral neuropathy displayed significantly higher VPT (control 6.1, DM 8.2, and DPN 27.4) and mNDS (control 1, DM 2, DPN 7) compared with the control group. Peak ankle plantarflexion was significantly lower in diabetics with peripheral neuropathy and diabetics than the control group (P<0.01) for self-selected speed of walking and 1.0m/s walking speeds. Diabetics and diabetics with peripheral neuropathy had higher Achilles tendon stiffness (Control 210, DM 231, DPN 240) and higher tendon hysteresis (control 18, DM 21, and DPN 24 percent). There was also decreased tendon elongation during walking in diabetics and diabetics with peripheral neuropathy as compared to the control (control 1.81 cm at self-selected speed and 1.67 cm at 1.0 m/s, DM 1.66 cm at self-selected speed and 1.51 cm at 1.0 m/s, DPN 1.54 cm at self-selected speed and 1.47 at 1.0 m/s).
Conclusions: The authors of this study concluded that there is reduced Achilles tendon elongation during the loading phase of walking and reduced tendon recoil during the propulsive phase in people with diabetes and especially in diabetics with peripheral neuropathy. Diabetics and diabetics with peripheral neuropathy had higher stiffness and hysteresis of the Achilles tendon as compared to the control group. These findings indicate that there is a reduced elastic energy contribution from the Achilles tendon in walking in diabetics and diabetics with peripheral neuropathy causing an increase in metabolic cost of walking. Due to reduced storage and release of elastic energy from the Achilles tendon in diabetics and diabetics with peripheral neuropathy, a greater contribution is required from plantarflexory muscles. Future higher-level studies are needed to evaluate the complications associated with reduced Achilles tendon elongation and increased cost of walking via the greater contribution of plantarflexory muscles in diabetics and diabetics with peripheral neuropathy.