Several population-based studies have indicated that the incidence of the Charcot deformity ranges from 0.10 percent to 2.9 percent.1-3 In a controlled study of 680 patients with diabetes, 0.15 percent developed Charcot foot deformity.4 In an observational study, Fibrin and colleagues reported an incidence of 0.03 percent in 3,000 patients with diabetes.5 The incidence is undoubtedly greater because many cases are not reported and there are few long-term studies that monitor the occurrence, development and frequency of the Charcot deformity in the diabetic population.
With the dramatic increase in people developing diabetes, there will be an increase in Charcot neuroarthropathy. The most significant predisposing factor in the development of the Charcot deformity is neuropathy. Between 9 to 32 percent of patients with diabetes have decreased sensation of there lower extremities.6 Researchers have also determined that pronounced neuropathy was the constant factor in the Charcot foot rather than the length of time that the patient had diabetes or how well the patient’s diabetes was controlled.7
Charcot patients usually do not report a history of trauma. Most indicate that their foot just became red and swollen, and the shape of their foot seemed to change. Some patients report pain but many have no significant discomfort.
One theory as to the Charcot pathogenesis is that any form of trauma may initiate the process. This can be acute, sub-acute or repetitive. Just walking with a loss of the protective threshold can start the process. Weightbearing results in microfractures initially but with continued walking, the fractures become more severe and fragmentation occurs with eventual collapse and deformity of the foot.
Over a period of weeks and months, the reparative process creates callus formation that radiographically resembles a hypertrophic nonunion. This process is known as the neurotramautic theory. The neurovascular concept suggests that a state of hyperemia exists from an overactive vasomotor autonomic neuropathy. Increased blood flow to the lower extremity increases local bone metabolism. This in turn stimulates osteoclastic activity, resulting in resorption of bone. The developing osteopenia weakens the bone, predisposing it to failure.8-10 Pinsur feels that the pathogenesis of Charcot neuropathy may actually involve a combination of both processes.11
When peripheral neuropathy results in a loss of sensation and a loss of motor function, this creates an imbalance of the intrinsic musculature of the foot. As the Achilles tendon continues to contract, this creates excessive stress through the midfoot, which results in collapse of the arch and development of a rocker bottom deformity.
1. Rajbhandari SM, Jenkins RC, Davies C, et al. Charcot neuroarthropathy in diabetes mellitus. Diabetologia 2002;45(8):1085-96.
2. Sanders LF: Charcot neuroarthrophy of the foot. In: Bowker J, Pfeifer M (eds): The Diabetic Foot, 6th edition. Mosby, St. Louis, 2001, p. 439-66.
3. Cofield RH, Motrisin M, Beabout JW. Diabetic neuroarthropathy in the foot: patient characteristics and patterns of radiographic changes. Foot Ankle Int. 1983;4(1):15-22.
4. Sinha S, Munichoodappa CS, Kozak G. Neuro-arthropathy (Charcot joints) in diabetes mellitus (clinical study of 101 cases). Medicine 1971;51(3):191-210.
5. Fabrin J, Larsen K, Holstein P. Long-term follow-up in diabetic Charcot feet with spontaneous onset. Diabetes Care 2000;23(6):796-800.
6. Pakarinen T, Laine HJ, Honokonen SE, et al. Charcot arthropathy of the diabetic foot. Current concepts and review of 36 cases. Scand J Surg 2002; 91(2):195-201.
7. Foltz K, Fallat L, Schwartz, S. Usefulness of a brief assessment battery for early detection of Charcot foot deformity in patients with diabetes. J Foot Ankle Surg 2004; 43(2): 87-92.
8. Herbst SA, Jones KB, Saltzman CL. Pattern of diabetic neuropathic arthropathy associated with the peripheral bone mineral density. J. Bone Joint Surg. 2004:86(3):378-383.
9. Young M, Breddy JL, Vevers A, et al. The prediction of diabetic peripheral neuropathy using vibration perception thresholds: a prospective study. Diabetes Care. 1994:17(6):557-560.
10. Young MJ, Marshall A, Adams, JE, et al. Osteopenia, neurological dysfunction, and the development of Charcot neuroarthropathy. Diabetes Care 1995;18(1): 34-38.
11. Pinzur MS. Current concepts review: Charcot arthropathy of the foot and ankle. Foot Ankle Int. 2007:28(8):952-959.