Influence of Diabetic Distal Symmetric Polyneuropathy on the Performance of the Musculoskeletal System of Lower Leg and Foot

Abstract

Introduction: Complications on the lower extremities are a major cause of morbidity, disability, emotional and physical suffering in people with diabetes. Diabetic neuropathy (DN) is the most frequent complication of both types of diabetes. Lack of performance of the musculoskeletal system of lower leg and foot can results in high focal plantar pressures with increased ulceration risk in patients with neuropathy.

Aim: To determine the impact of the severity of distal symmetric polyneuropathy (DSPN) on the foot and ankle muscle strength and the range of motion (ROM) at ankle joint (AJ), subtalar joint (SJ) and first metatarsophalangeal joint (I MTP).

Methods: A cross-sectional study was conducted among 100 diabetic patients. The level of DSPN was assessed using the Neuropathy Disability Score. Function of ten foot and ankle muscles has been evaluated by manual muscle testing. Muscle strength was scored by semiquantitative grading system used in the Michigan Diabetic Neuropathy Score. ROM at the AJ, SJ and I MTP was measured with goniometer.

Results: The average patients age was 61.91±10.74 and diabetes duration 12.25±8.60 years. DSPN was present in 45% of patients. The average strength of foot and ankle muscles expressed by muscle score was 11.56±5.08. The average ROM at AJ was 47.85°, at SJ 35.10° and at I MTP 72.70°. Correlations between the severity of the DSPN and muscle function, ROM at AJ, SJ and I MTP were statistically significant. ROM at SJ and I MTP declines significantly with progression of neuropathy but not significant at AJ.

Conclusion: The severity of DSPN is significantly associated with foot and ankle muscle weakness and ROM at the SJ and the I MTP, but not significantly with the ROM at the AJ.

Keywords: Diabetes Mellitus; complications; muscles.

Figure 1.. Pearson’s correlation between the severity of the DSPN and muscle function, ROM at AJ, SJ and I MTP joint. Pearson coefficient is statistically significant in all relationships that were observed, except for relations between ROM at AJ and SJ. *p<0,05. DSPN–distal symmetrical polyneuropathy, AJ – ankle joint, SJ – subtatalar joint, I MTP – first metatarsophalangeal joint, ROM–range of motion

Figure 2.. Foot and ankle muscle strength in groups of patients with different stages of diabetic neuropathy. Strength of ankle and foot muscle significantly declines with progression of neuropathy; p<0,05. ** post-hoc Tukey test p<0,05

Figure 3.. Range of motion at ankle joint in groups of patients with different stages of diabetic neuropathy. Range of motion at ankle joint in groups of patients with different stages of neuropathy declines with progression of neuropathy, but not significantly; p>0,05.

Figure 4.. Range of motion at subtalar joint in groups of patients with different stages of diabetic neuropathyRange of motion at subtalar joint in groups of patients with different stages of neuropathy significantly declines with progression of neuropathy; p<0,05. ** post-hoc Tukey test p<0,05

Figure 5.. Range of motion at first metatarsophalangeal joint in the groups of patients with different stages of diabetic neuropathy. Range of motion at first metatarsophalangeal joint in the groups of patients with different stages of diabetic neuropathy significantly declines with progression of neuropathy; p<0,05. ** post-hoc Tukey test p<0,05