Investigation of standing balance in patients with diabetic neuropathy at different stages of foot complications.

BACKGROUND: Diabetic peripheral neuropathy is known to cause postural instability. This study investigated standing balance in patients with diabetic neuropathy with secondary foot complications: foot ulceration, partial foot amputation and trans-tibial amputation, which are expected to pose further challenge to balance control. METHODS: In this cross-sectional study, 23 patients with diabetic neuropathy alone (controls) were compared with 23 patients with diabetic foot ulceration, 16 patients with partial foot amputation and 22 patients with trans-tibial amputation. Posturography was used to determine the centre of pressure excursion during quiet standing. Differences between the 4 groups were tested using ANOVA and post-hoc comparisons. FINDINGS: The 4 groups varied in neuropathy score (P=0.001) and demonstrated significant decline in balance from neuropathy alone to foot ulceration, to partial foot amputation and trans-tibial amputation based on total excursion of centre of pressure (P<0.001) and centre of pressure excursion in antero-posterior direction (P<0.001). The excursion of centre of pressure in medio-lateral direction varied between 4 groups (P<0.05) however, there was no significant trend. The distance between ankles increased significantly from neuropathy to trans-tibial amputee group (P=0.001). Post-hoc comparison with controls revealed that each of three study groups demonstrated decreased balance (diabetic neuropathy vs. foot ulceration, P=0.001, diabetic neuropathy vs. partial foot amputation, P=0.002 and diabetic neuropathy vs. trans-tibial amputation, P=0.009). INTERPRETATION: Balance deterioration among patient groups from diabetic neuropathy alone to trans-tibial amputation appears to result from bio-mechanical impairment caused by progression of foot complications in addition to postural instability caused by diabetic neuropathy.

Walking performance in people with diabetic neuropathy: benefits and threats.

AIMS/HYPOTHESIS: Walking is recommended as an adjunct therapy to diet and medication in diabetic patients, with the aim of improving physical fitness, glycaemic control and body weight reduction. Therefore we evaluated walking activity on the basis of capacity, performance and potential risk of plantar injury in the diabetic population before it can be prescribed safely. SUBJECTS, MATERIALS AND METHODS: Twenty-three subjects with diabetic neuropathy (DMPN) were compared with 23 patients with current diabetic foot ulcers, 16 patients with partial foot amputations and 22 patients with trans-tibial amputations. The capacity for walking was measured using a total heart beat index (THBI). Gait velocity and average daily strides were measured to assess the performance of walking, and its impact on weight-bearing was studied using maximum peak pressure. RESULTS: THBI increased (p<0.01) and gait velocity and daily stride count fell (p<0.001 for both) with progression of foot complications. The maximum peak pressures over the affected foot of patients with diabetic foot ulcers (p<0.05) and partial foot amputations (p<0.01) were higher than in the group with DMPN. On the contralateral side, the diabetic foot ulcer group showed higher maximum peak pressure over the total foot (p<0.05), and patients with partial foot amputations (p<0.01) and trans-tibial amputations (p<0.05) showed higher maximum peak pressure over the heel. CONCLUSIONS/INTERPRETATION: Walking capacity and performance decrease with progression of foot complications. Although walking is recommended to improve fitness, it cannot be prescribed in isolation, considering the increased risk of plantar injury. For essential walking we therefore recommend the use of protective footwear. Walking exercise should be supplemented by partial or non-weight-bearing exercises to improve physical fitness in diabetic populations.

Community walking activity in neurological disorders with leg weakness.

BACKGROUND: The aims of this study were to determine walking mobility in the community in individuals with lower limb weakness and to establish the extent to which some clinic based measures predict such activity. METHODS: Five groups (n = 12-18) of independently ambulant patients with lower limb weakness due to neurological conditions and a matched healthy control group were recruited. Measures of isometric knee extension/flexion muscle strength, time to stand up (sit-to-stand, STS), gait speed, and daily step counts (recorded over 7 days) were obtained. The Rivermead Mobility Index (RMI) provided a measure of functional ability. Between group differences and associations were explored. Backward stepwise regression analysis was used to identify variables influencing daily step count in individuals with neurological impairment. RESULTS: Patients were significantly weaker (mean (SD) quadriceps strength 69+/-34% v 102+/-37% predicted), slower to stand up (2.9+/-1.3 v 2.0+/-0.6 s), and had slower self selected gait speed (0.74+/-0.3 v 1.2+/-0.2 m/s) than controls. Mean daily step count was also lower (3090+/-1902 v 6374+/-1819) than in controls. In neurology patients step count was correlated with RMI score (r(s) = 0.49, p<0.01) and STS (r = -0.19, p<0.05). However, self selected gait speed was the only significant predictor in the regression analysis (p<0.01) of daily mean step count. CONCLUSIONS: Measures of muscle strength, timed STS, and RMI do not appear to closely reflect community walking activity in these patient groups. Self selected gait speed was partially predictive. Measurement of community walking activity may add a new dimension to evaluating the impact of interventions in neurological disorders.

Risk of plantar ulceration in diabetic patients with single-leg amputation.

BACKGROUND: There is a disconcerting rate of bilateral limb loss in patients with diabetes. Therefore, this study aimed to explore plantar loading of the surviving foot following unilateral trans-tibial amputation within a wider context of daily walking activity to investigate the precise risk to the surviving limb. METHODS: Twenty-one subjects with diabetic neuropathy and trans-tibial amputation were matched for weight; height; age and gender with 21 control subjects with diabetic neuropathy without history of plantar ulceration. Gait parameters, in-shoe plantar pressure distribution and daily walking (using the step activity monitor) were recorded. Student's t-tests were used to compare groups (alpha-level: 0.05). FINDINGS: The trans-tibial amputations group walked almost 30% slower compared to controls (P < 0.01), with reduced cadence (P < 0.01), and shorter strides (P < 0.01). Despite walking slower, the surviving foot showed higher mean peak plantar pressures in the trans-tibial amputations group over the heel (P < 0.001) however there was no significant difference over the I-II and lateral III-IV-V metatarso-phalangeal regions. Pressure time integral was higher over the heel (P < 0.00), I-II (P < 0.01) and III-IV-V metatarso-phalangeal (P < 0.05) in the trans-tibial amputations group. The amputee group walked less steps per day (P < 0.01). INTERPRETATION: Adaptations in gait and level of walking activity affect plantar pressure distribution and ultimately the risk of ulceration to the surviving foot. Therefore rehabilitation measures should consider implications for plantar loading and the potential risk of ulceration to the surviving foot.