An exercise programme for patients with diabetic complications: a study on feasibility and preliminary effectiveness.

AIMS: To investigate the feasibility and preliminary effectiveness of an exercise programme for patients with diabetic complications. METHODS: In this pre-post design study, 22 patients from a diabetic foot outpatient clinic participated in a 12-week individualized exercise programme, consisting of aerobic and resistance exercise, with specific safety precautions. Feasibility was assessed on the basis of programme adherence, adverse events, achievement of the target training intensity and patient satisfaction. Preliminary effectiveness was evaluated with pre-post-changes in blood glucose regulation (HbA(1c) ), muscle strength (isometric peak torque) and perceived limitations in functioning (Patient Specific Function Scale with visual analogue scale). RESULTS: Twenty patients completed the exercise programme with a high mean attendance (85%). No training-related severe adverse events occurred. The target training intensity was achieved by 70% of the participants. Patient satisfaction was high. HbA(1c) decreased from 8.2% before to 7.8% after the programme (P=0.005), muscle strength increased from 136.4 to 150.4 Nm (P = 0.046) and perceived limitations in functioning decreased from 7.2 to 5.8 mm (P=0.003). CONCLUSIONS: The prescribed exercise programme had a potentially positive effect on blood glucose regulation, muscle strength and perceived limitations in functioning in patients with diabetic complications.

A review of the biomechanics of the diabetic foot.

In general, diabetic foot ulcers result from abnormal mechanical loading of the foot, such as repetitive moderate pressure applied to the plantar aspect of the foot while walking. Diabetic peripheral neuropathy causes changes in foot structure, affecting foot function and subsequently leading to increased plantar foot pressure, which is a predictive risk factor for the development of diabetic foot ulceration. Prevention of diabetic foot ulceration is possible by early identification of the insensitive foot, therefore a foot "at risk," and by protecting the foot from abnormal biomechanical loading. Abnormal foot pressures can be reduced using several different approaches, including callus debridement, prescription of special footwear, injection of liquid silicone, Achilles tendon lengthening, and so forth. Off-loading of the diabetic wound is a key factor in successful wound healing, as it is associated with reduced inflammatory and accelerated repair processes. Pressure relief can be achieved using various off-loading modalities including accommodative dressing, walking splints, ankle-foot orthosis, total contact cast, and removable and irremovable cast walkers.

Corneal confocal microscopy: a non-invasive surrogate of nerve fibre damage and repair in diabetic patients.

AIMS/HYPOTHESIS: The accurate detection, characterization and quantification of human diabetic neuropathy are important to define at risk patients, anticipate deterioration, and assess new therapies. Corneal confocal microscopy is a reiterative, rapid, non-invasive in vivo clinical examination technique capable of imaging corneal nerve fibres. The aim of this study was to define the ability of this technique to quantify the extent of degeneration and regeneration of corneal nerve fibres in diabetic patients with increasing neuropathic severity. METHODS: We scanned the cornea and collected images of Bowman's layer (containing a rich nerve plexus) from 18 diabetic patients and 18 age-matched control subjects. RESULTS: Corneal nerve fibre density (F(3)=9.6, p<0.0001), length (F(3)=23.8, p<0.0001), and branch density (F(3)=13.9, p<0.0001) were reduced in diabetic patients compared with control subjects, with a tendency for greater reduction in these measures with increasing severity of neuropathy. CONCLUSION/INTERPRETATION: Corneal confocal microscopy is a rapid, non-invasive in vivo clinical examination technique which accurately defines the extent of corneal nerve damage and repair and acts as a surrogate measure of somatic neuropathy in diabetic patients. It could represent an advance to define the severity of neuropathy and expedite assessment of therapeutic efficacy in clinical trials of human diabetic neuropathy.

A comparison of the Neuropen against standard quantitative sensory-threshold measures for assessing peripheral nerve function.

AIMS: To investigate the efficacy of the Neuropen, a new clinical device that assesses both pain and pressure perception, to evaluate peripheral nerve function in diabetic patients compared with standard clinical testing methods. METHODS: Peripheral nerve function was assessed in 124 diabetic patients attending a multidisciplinary diabetes clinic, using (i) the modified Neuropathy Disability Score (NDS), derived from assessment of vibration, pinprick (pain), temperature sensation plus ankle reflexes, and (ii) vibration perception threshold (VPT) measured at the hallux. Patients were stratified into various neuropathic groups according to their NDS score. In addition, nerve function was assessed using the Neuropen, a device combining a 10-g monofilament and a weighted Neurotip. Inability to feel sensation on either or both feet for each test of the Neuropen (i.e. the monofilament or the Neurotip) was defined as an abnormal response. RESULTS: The sensitivity of the Neuropen to detect neuropathy compared with the NDS (score > or = 6/10) was high using either an abnormal monofilament response (87.8%), an abnormal Neurotip response (91.8%) or a combination of the two (82.0%). Neuropen specificity improved, however, when the combination of abnormal monofilament and abnormal Neurotip responses was used (68%), rather than the individual tests (57% and 41%, respectively). CONCLUSIONS: The Neuropen is a sensitive device for assessing nerve function and may provide an inexpensive alternative screening method to identify patients with moderate to severe neuropathy.

Plantar tissue thickness is related to peak plantar pressure in the high-risk diabetic foot.

OBJECTIVE: To investigate the relationship among plantar foot pressure, plantar subcutaneous tissue thickness, severity of neuropathy (vibration perception threshold [VPT]), callus, and BMI in a large group of neuropathic diabetic patients at risk of foot ulceration. RESEARCH DESIGN AND METHODS: A total of 157 diabetic neuropathic patients (VPT >25 V) without either peripheral vascular or ulcer history were studied. Plantar foot pressure and plantar tissue thickness were measured at each metatarsal head (MTH) using an optical pedobarograph and an ultrasound scanning platform, respectively. RESULTS: A significant association was observed between peak plantar pressure and plantar tissue thickness at all MTHs (-0.26 < r < -0.61, P < 0.0001), with the least pronounced association at the first MTH. In addition, the pressure time integral was significantly associated with plantar tissue thickness (-0.24 < r < -0.57, P < 0.0001). BMI was significantly related to plantar tissue thickness (0.18 < r < 0.45, P < 0.05), but not to peak forefoot pressures. Subjects with callus had significantly reduced plantar tissue thickness at all MTHs except the first MTH and increased peak pressures at all MTHs (P < 0.001). CONCLUSIONS: This study confirms a strong inverse relationship between plantar tissue thickness and dynamic foot pressure measurements. Long-term follow-up of this patient population will confirm whether reduced plantar tissue thickness predicts the development of diabetic foot ulcers.

Off-loading the diabetic foot wound: a randomized clinical trial.

OBJECTIVE: To compare the effectiveness of total-contact casts (TCCs), removable cast walkers (RCWs), and half-shoes to heal neuropathic foot ulcerations in individuals with diabetes. RESEARCH DESIGN AND METHODS: In this prospective clinical trial, 63 patients with superficial noninfected, nonischemic diabetic plantar foot ulcers were randomized to one of three off-loading modalities: TCC, half-shoe, or RCW. Outcomes were assessed at wound healing or at 12 weeks, whichever came first. Primary outcome measures included proportion of complete wound healing at 12 weeks and activity (defined as steps per day). RESULTS: The proportions of healing for patients treated with TCC, RCW, and half-shoe were 89.5, 65.0, and 58.3%, respectively. A significantly higher proportion of patients were healed by 12 weeks in the TCC group when compared with the two other modalities (89.5 vs. 61.4%, P = 0.026, odds ratio 5.4, 95% CI 1.1-26.1). There was also a significant difference in survival distribution (time to healing) between patients treated with a TCC and both an RCW (P = 0.033) and half-shoe (P = 0.012). Patients were significantly less active in the TCC (600.1 +/- 320.0 daily steps) compared with the half-shoe (1,461.8 +/- 1,452.3 daily steps, P = 0.04). There was no significant difference in the average number of steps between the TCC and the RCW (767.6 +/- 563.3 daily steps, P = 0.67) or the RCW and the half-shoe (P = 0.15). CONCLUSIONS: The TCC seems to heal a higher proportion of wounds in a shorter amount of time than two other widely used off-loading modalities, the RCW and the half-shoe.

Efficacy of injected liquid silicone in the diabetic foot to reduce risk factors for ulceration: a randomized double-blind placebo-controlled trial.

OBJECTIVE: To investigate the effectiveness of injecting liquid silicone in the diabetic foot to reduce risk factors for ulceration in a randomized double-blind placebo-controlled trial. RESEARCH DESIGN AND METHODS: A total of 28 diabetic neuropathic patients without peripheral vascular disease were randomized to active treatment with 6 injections of 0.2 ml liquid silicone in the plantar surface of the foot or to treatment with an equal volume of saline (placebo). No significant differences were evident regarding age or neuropathy status between the 2 groups. All injections were under the metatarsal heads at sites of calluses or high pressures. Barefoot plantar pressures (pedobarography) and plantar tissue thickness under the metatarsal heads (Planscan ultrasound device) were measured at baseline and at 3, 6, and 12 months after the first injection. Injection sites were photographed at all stages, and callus formation was scored as a change from baseline. Throughout the study, patients were treated by the same podiatrist for all podiatry treatment. RESULTS: Patients who received silicone treatment had significantly increased plantar tissue thickness at injection sites compared with the placebo group (1.8 vs. 0.1 mm) (P < 0.0001) and correspondingly significantly decreased plantar pressures (-232 vs. -25 kPa) (P < 0.05) at 3 months, with similar results at 6 and 12 months. A trend was noted toward a reduction of callus formation in the silicone-treated group compared with no change in the placebo group. CONCLUSIONS: The results confirm the efficacy of plantar silicone injections in reducing recognized risk factors associated with diabetic foot ulceration.

A comparative study of the Podotrack, a simple semiquantitative plantar pressure measuring device, and the optical pedobarograph in the assessment of pressures under the diabetic foot.

AIMS: To test the Podotrack, a simple inexpensive semiquantitative footprint mat, for potential use as a screening tool for high plantar pressures, against the optical pedobarograph (a computerized device). METHODS: The Podotrack was superimposed on the pedobarograph for simultaneous measurement of pressures from both systems. Three independent observers quantified the pressures of Podotrack footprints from healthy controls and diabetic patients, both before (n=164) and after (n=183) training. The sensitivity of the Podotrack to identify high pressure areas measured by the pedobarograph (> 12.3 kg/cm2) was 78.7%, 45.8% and 44.3% (observer A, B and C) before training, but improved to 96.2%, 92.4% and 91.1% after training (P<0.01). Specificity for all three observers was more than 90% before and after training. Inter-observer agreement improved significantly after training (P<0.001). CONCLUSION: After a simple training of the observers, the Podotrack identified approximately all high pressure areas, suggesting that the Podotrack could be a useful screening tool to identify areas at risk of ulceration in diabetic patients. We recommend a standard training package for new Podotrack users, to optimize identification of diabetic patients at risk of foot ulceration.

An analysis of dynamic forces transmitted through the foot in diabetic neuropathy.

OBJECTIVE: Biomechanical studies in diabetic neuropathy have clearly demonstrated abnormal foot pressures, but information on other aspects of gait is limited. This study aimed to investigate and describe the forces transmitted through the foot during walking in diabetic subjects with varying degrees of peripheral neuropathy and to determine if abnormalities in these forces might contribute to the risk of plantar ulceration. RESEARCH DESIGN AND METHODS: Subjects from the following groups were included: healthy control subjects (C); diabetic control subjects (D); subjects with diabetic neuropathy (DN); subjects with previous neuropathic ulceration (DNU); and subjects with Charcot neuro-arthropathy (CH). Gait analysis was performed as subjects walked over a Kistler force plate. Peak forces were measured (as percent body weight) in the vertical and horizontal planes. Comparisons were made between all of the groups and between each diabetic group and a healthy control group matched for walking speed. RESULTS: There were 181 subjects studied. In comparison with that of the speed-matched controls, the mean peak vertical force was higher in each of the diabetic groups, especially in the most neuropathic subjects (DNU, 113 vs. 110%, P < 0.01). This increase was entirely due to higher forces during heel contact (DNU, 111 vs. 106%, P < 0.001). The single peak force occurred during heel strike (rather than during foot push-off) in 23-38% of footsteps of healthy and diabetic control subjects but in 53-73% of footsteps of neuropathic subjects. There was also a trend for higher peak medial forces (CH, 6.2 vs. 5.5%, P < 0.05). CONCLUSIONS: Diabetic neuropathy is associated with a change in the time pattern of the forces transmitted through the foot and an increase in the vertical forces through the heel. The magnitude of the changes is small in absolute terms, but these changes may contribute to the risk of plantar foot ulceration.