Although diabetes and peripheral neuropathy are perhaps the most important risk factors for neuropathic osteoarthropathy, we hypothesized that peak plantar pressures may also be higher in patients who have this condition. We are unaware of any reports in the medical literature that have specifically addressed this hypothesis. We obtained data from the medical records of 164 diabetic patients who had been managed in a multidisciplinary tertiary-care diabetic foot-specialty clinic. We then divided the patients into four groups: those who had acute Charcot arthropathy, those who had neuropathic ulceration, those who had neuropathy without ulceration, and those who had neither neuropathy nor ulceration. The peak plantar pressures were significantly higher in the patients who had acute Charcot arthropathy and those who had a neuropathic ulcer (p < 0.001 for both) compared with the pressures in those who had no history of arthropathy and those who had neuropathy without ulceration. With the numbers available, we could not detect a significant difference in the peak pressure between the affected and the unaffected foot in the patients who had Charcot arthropathy (mean [and standard deviation], 100+/-8.5 compared with 101+/-9.6 newtons per square centimeter; p > 0.05). However, the mean peak pressure was significantly higher on the ulcerated side than on the contralateral side in the patients who had a neuropathic ulcer (90+/-18.8 compared with 86+/-20.7 newtons per square centimeter; p < 0.02). Although the midfoot was the site of maximum involvement in all patients who had Charcot arthropathy, the peak plantar pressure was on the forefoot, suggesting that the forefoot may function as a lever, forcing collapse in the midfoot.