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OBJECTIVE To investigate changes in the foot muscle energy reserves in diabetic non-neuropathic and neuropathic patients. RESEARCH DESIGN AND METHODS We measured the phosphocreatinine (PCr)/inorganic phosphate (Pi) ratio, total (31)P concentration, and the lipid/water ratio in the muscles in the metatarsal head region using MRI spectroscopy in healthy control subjects and non-neuropathic and neuropathic diabetic patients. RESULTS The PCr/Pi ratio was higher in the control subjects (3.23 +/- 0.43) followed by the non-neuropathic group (2.61 +/- 0.36), whereas it was lowest in the neuropathic group (0.60 +/- 1.02) (P < 0.0001). There were no differences in total (31)P concentration and lipid/water ratio between the control and non-neuropathic groups, but both measurements were different in the neuropathic group (P < 0.0001). CONCLUSIONS Resting foot muscle energy reserves are affected before the development of peripheral diabetic neuropathy and are associated with the endothelial dysfunction and inflammation.

Objective: To characterize structural changes and the metabolic profile of foot muscles and correlate them with diabetic neuropathy measurements using phosphorus-31 ((31)P) rapid acquisition with relaxation enhancement (RARE) magnetic resonance imaging (MRI)., Research Design and Methods: We studied 12 control subjects, 9 non-neuropathic diabetic patients, and 12 neuropathic diabetic patients using (31)P RARE and proton ((1)H) MRI at 3 Tesla. The ratio of the total cross-sectional area of the foot to that of the muscle tissue was calculated from transaxial (1)H and (31)P images. The average (31)P concentration across the metatarsal head region was measured from the (31)P images., Results: The muscle area-to-total area ratio differed among all three groups (means +/- SD): 0.55 +/- 0.04 vs. 0.44 +/- 0.05 vs. 0.06 +/- 0.06 for control, non-neuropathic, and neuropathic subjects, respectively (P < 0.0001). The average (31)P concentration also differed among all groups: 27.7 +/- 3.8 vs. 21.7 +/- 4.8 vs. 7.9 +/- 8.8 mmol/l for control, non-neuropathic, and neuropathic subjects (P < 0.0001). The muscle area-to-total area ratio strongly correlated with clinical measurements: Neuropathy Disability Score, r = -0.83, P < 0.0001; vibration perception threshold, r = -0.79, P < 0.0001; and Semmes-Weinstein monofilaments, r = -0.87, P < 0.0001., Conclusions: Small muscle atrophy is present in diabetes before clinical peripheral neuropathy can be detected using standard clinical techniques. The (31)P RARE MRI method evaluates the severity of muscle atrophy, even in the early stages when neuropathy is absent. This technique may prove to be a useful diagnostic tool in identifying early-stage diabetic foot problems.

Objective: We have previously demonstrated that high plantar pressures can predict foot ulceration in diabetic patients. The aim of the present study was to evaluate both the relationship between forefoot and rearfoot plantar pressure in diabetic patients with different degrees of peripheral neuropathy and their role in ulcer development., Research Design and Methods: Diabetic patients of a 30-month prospective study were classified according to the neuropathy disability score: scores of 0, 1-5, 6-16, and 17-28 are defined as absent (n = 20), mild (n = 66), moderate (n = 95), and severe (n = 57) neuropathy, respectively. The F-Scan mat system was used to measure dynamic plantar pressures. The peak pressures under the forefoot and the rearfoot were selectively measured for each foot, and the forefoot-to-rearfoot ratio (F/R ratio) was calculated., Results: Foot ulcers developed in 73 (19%) feet. The peak pressures were increased in the forefoot of the severe and moderate neuropathic groups compared with the mild neuropathic and non-neuropathic groups (6.2 +/- 4.5 and 3.8 +/- 2.7 vs. 3.0 +/- 2.1 and 3.3 +/- 2.1 kg/cm(2) [mean +/- SD], respectively; P < 0.0001). The rearfoot pressures were also higher in the severe and moderate neuropathic groups compared with the mild neuropathic and non-neuropathic groups (3.2 +/- 2.0 and 3.2 +/- 1.9 vs. 2.5 +/- 1.3 and 2.3 +/- 1.0, respectively; P < 0.0001). The F/R ratio was increased only in the severe group compared with the moderate and mild neuropathic and non-neuropathic groups (2.3 +/- 2.4 vs. 1.5 +/- 1.2, 1.3 +/- 0.9, and 1.6 +/- 1.0, respectively; P < 0.0001). In a logistic regression analysis, both forefoot pressure (odds ratio 1.19 [95% CI 1.11-1.28], P < 0.0001) and the F/R ratio (1.37 [1.16-1.61], P < 0.0001) were related to risk of foot ulceration, whereas rearfoot pressure was not., Conclusions: Both the rearfoot and forefoot pressures are increased in the diabetic neuropathic foot, whereas the F/R ratio is increased only in severe diabetic neuropathy, indicating an imbalance in pressure distribution with increasing degrees of neuropathy. This may lend further evidence toward the concept that equinus develops in the latest stages of peripheral neuropathy and may play an important role in the etiology of diabetic foot ulceration.

The aim of the present study was to examine if diabetes in the absence of neuropathy affects the exercising capacity of IDDM patients, and whether regular, intense training has a beneficial effect on endothelial function. Five groups of subjects were studied: 23 healthy control subjects who exercised regularly (age 33 +/- 6 years), 23 nonneuropathic type 1 diabetic patients who exercised regularly (age 33 +/- 6 years, IDDM duration 11 +/- 8 years), 7 neuropathic type 1 diabetic patients who exercised regularly (age 36 +/- 7 years, IDDM duration 22 +/- 8 years), 18 healthy subjects who did not exercise regularly (age 34 +/- 7 years), and 5 nonneuropathic type 1 diabetic patients who did not exercise regularly (age 31 +/- 4 years, IDDM duration 20 +/- 3 years). All groups were matched for age, sex, and body weight. No differences existed in the energy expenditure per week in physical activity among the three exercising groups or between the two nonexercising groups. The maximal oxygen uptake was similar between control and diabetic nonneuropathic exercisers, and among diabetic neuropathic exercisers, control nonexercisers, and diabetic nonexercisers; however, a significant difference existed between the first two and the last three groups (P < 0.0001). A stepwise increase was found in the resting heart rate among the groups, ranging from the lowest in control exercisers to the highest in diabetic nonexercisers, but the maximal heart rate was lower only in diabetic neuropathic exercisers compared with all other groups (P < 0.05). Assessments of endothelial function in both macro- and microcirculation were performed in 12 control exercisers, 10 diabetic nonneuropathic exercisers, 5 diabetic neuropathic exercisers, 17 control nonexercisers, and 4 diabetic nonexercisers. When all diabetic patients were considered as one group and all control subjects as another, the microcirculation endothelial function in the diabetic group was reduced compared with the control subjects (91 +/- 49 vs. 122 +/- 41% flux increase over baseline; P < 0.05). In contrast, no differences existed among the three diabetic groups or between the two control groups. Similarly, in macrocirculation, a reduced response during reactive hyperemia was observed in the diabetic patients compared with control subjects (7.0 +/- 4.5 vs. 11.2 +/- 6.6% diameter increase; P < 0.05), whereas again no difference existed among the three diabetic groups or between the two control groups. These data suggest that diabetes per se does not affect aerobic exercise capacity (VO2max) in physically active individuals, but is reduced in the presence of neuropathy. In addition, regular exercise training involving the lower extremities does not improve the endothelial function in the micro- and macrocirculation of the nonexercised upper extremity in type 1 diabetic patients.

Hypoxia is considered to be one of the main aetiopathogenic factors of diabetic neuropathy. We have examined the effects of the reversal of hypoxia, achieved by revascularization, on peripheral nerve function in diabetic patients with or without clinical neuropathy. Fifty-six patients [mean age 62 (range 30-74) years, 44 (79%) males, 15 (27%) with insulin-dependent diabetes of 20 years (range 1-57) duration, and creatinine level 92.8 +/- 30.9 mumol/l (mean +/- SD)] were tested pre-operatively while 30 (54%) were reexamined at least 6 weeks post-operatively. At baseline the leg scheduled for operation showed worse measurements compared to the control leg when tested for Semmes-Weinstein monofilaments, peroneal motor conduction velocity (PMCV) (33.7 +/- 7.18 vs 35.7 +/- 6.09 m.s-1, p < 0.05) and transcutaneous oxygen tension (37.4 +/- 24.6 vs 52.0 +/- 21.5 mm Hg, p < 0.0001) while no differences were found in the vibration perception threshold and leg temperature. When baseline and post-operative measurements were later compared in the operated leg, no differences were noticed in the vibration perception threshold, PMCV and Semmes-Weinstein monofilaments but the transcutaneous oxygen tension increased significantly (32.7 +/- 27.1 vs 64.6 +/- 14.5 mm Hg, p < 0.001). No differences were noticed in any of the above parameters in the contralateral leg. No correlations were found between changes in transcutaneous oxygen tension and PMCV values measured at baseline and at the follow-up visit in either leg. Similar results were found when patients were stratified according to severity of neuropathy, ischaemia and the level of the bypass. We conclude that although there is greater impairment of nerve function in the more ischaemic leg, reversal of hypoxia does not result in any significant improvement of the nerve function measurements.

Specially designed Thor-Lo footwear has been shown to reduce the in-shoe foot pressures in diabetic patients at risk of foot ulceration when compared to their own footwear. Fifty at high risk patients 32 (64%) males, 17 (34%) type 1 diabetes) have been provided with this foot wear and have been followed up for 6 months. Mean age was 57.6 (range, 34-78) years, duration of diabetes 22.4 (range, 4-50) years, Neuropathy Symptom Score 3.36 +/- 2.96 (mean +/- S.D.), Neuropathy Disability Score 16.8 +/- 6.83, VPT 43.4 +/- 11.8 Volts while 43 (86%) could not feel a 5.07 or smaller Semmes-Weinstein monofilament. Forty-two (84%) patients were re-examined at an interim visit 3 months after baseline, while 37 (74%) completed the study. In-shoe peak forces and pressures were measured using the F-Scan system. No difference was found among the peak force among baseline (95.5 +/- 26 kg), interim (96.5 +/- 33) and final visit (97.7 +/- 25.2, P + NS). There was no difference in peak pressures at the baseline (3.98 +/- 1.42 kg.cm-2), second visit (4.13 +/- 2.30) and the final visit (4.25 +/- 1.51). Nine (18%) patients developed foot problems and one died during the study. We conclude that no changes in foot pressures were found over a period of 6 months of continuous usage of the specially designed footwear in a group of diabetic patients at risk of foot ulceration. Further prospective studies are required to evaluate the impact of specially designed footwear in reducing the rate of foot ulceration.

Limited joint mobility is common in diabetes and is related to high foot pressures and foot ulceration. We have examined the differences in joint mobility and foot pressures in four groups matched for age, sex, and duration of diabetes: 31 white diabetic, 33 white non-diabetic, 24 black diabetic, and 22 non-diabetic black subjects. Joint mobility was assessed using a goniometer at the fifth metacarpal, first metatarsal, and subtalar joints. In-shoe and without shoes foot pressures were measured using an F-Scan system. Neuropathy was evaluated using clinical symptoms (Neuropathy Symptom Score), signs (Neuropathy Disability Score), and Vibration Perception Threshold. There was no difference between white and black diabetic patients in Neuropathy Symptom Score, Neuropathy Disability Score, and Vibration Perception Threshold. Subtalar joint mobility was significantly reduced in white diabetic patients (22 +/- 7 degrees) compared to white controls (26 +/- 4 degrees, black diabetic patients (25 +/- 5 degrees), and black controls (29 +/- 7 degrees), and increased in black controls compared to white controls and black diabetic patients (level of statistical significance p < 0.05). Without shoes foot pressures were higher in white diabetic patients (8.31 +/- 400 kg cm-2) compared to white controls (6.81 +/- 2.31 kg cma2), black diabetic patients (6.2 +/- 2.53 kg cm-2) and black controls (5.00 +/- 1.24 kg cm-2) and lower in black controls compared to white and black diabetic patients (p < 0.05 in all cases). We conclude that racial differences exist in joint mobility and foot pressures between black and white subjects.(ABSTRACT TRUNCATED AT 250 WORDS)

We have examined the variability in function measurements of three sensory foot nerves in neuropathic diabetic patients and have compared them to measurements from healthy non-diabetic subjects. Sixty-six healthy, non-diabetic subjects (30 (45%) males, mean age 56 years (range, 21-84 years)) and 61 age and sex matched diabetic patients (33 (54%) males, mean age 55 years (range, 34-78 years) Type 1 diabetes mellitus (DM), mean duration of DM 24 years (range, 2-48 years)) were tested. Current perception threshold (CPT) at 250 Hz was employed to test the sensory function of three nerves: superficial peroneal, sural and posterior tibial. The vibration perception threshold, (VPT) and the cutaneous perception threshold (CCPT) were also assessed at the great toe. According to the results of the neuropathy disability score (NDS), mild neuropathy was present in 8 (13%) patients, moderate in 33 (54%) and severe in 20 (33%). In both groups the CPT of the posterior tibial nerve was higher than the other two nerves (P < 0.0001) while no difference was found between the superficial peroneal and sural nerves (P = NS). CPT was different between the two feet at the superficial peroneal nerve in 39 (64%) diabetic patients and 34 (52%) controls (P = NS), at the sural nerve in 40 (65%) and 45 (68%) (P = NS), and at the posterior tibial in 36 (59%) and 33 (50%), respectively (P = NS). VPT was different by more than 10% at the great toes in 26 (43%) diabetic subjects and CCPT in 21 (34%). We conclude that although there is variation in sensory nerve function tests in diabetic patients this is similar to that noticed in healthy subjects. The great variability of all quantitative sensory testing indicates that more than one site should be tested.

Neuropathic ulcerations in diabetic patients are frequent causes of hospitalizations and morbidity. The plantar aspect of the first metatarsophalangeal joint is a common location for these ulcerations, because of the significant weightbearing forces generated through this joint and the presence of sensory and motor neuropathy. The authors describe 24 cases in which excision of the tibial sesamoid, fibular sesamoid, or both, was performed to resolve these lesions.

The records of 52 patients who underwent metatarsal osteotomies for the treatment of chronic neuropathic ulcerations between the years 1983 and 1985 were analyzed in a retrospective study. Long-term follow-up information was available for all but three patients. All patients were conservatively managed preoperatively and postoperatively with shoes, accommodative orthoses, and local care. A limb salvage rate of 94%, 46 of 49 patients, was achieved in this study. Although 13 patients developed transfer ulcerations, all but one were managed either with conservative care or a lesser podiatric procedure, and all remain healed to date.

Jacobs (1) reported use of the Clayton modification of the Hoffman procedure on 12 patients as the procedure of choice in select diabetics with abscess and ulceration. He described a dorsal transverse incision, amputation of all metatarsal heads, through-and-through drainage from a dorsal to plantar direction at the site of abscess formation, and use of a Jackson-Pratt drain dorso-laterally. The authors describe a modification of this procedure that has been performed for 6 years.