A 65-year-old woman, who recently relocated after retiring, comes to the office to establish medical care. The patient has a history of hypertension, type 2 diabetes mellitus, hyperlipidemia, and osteoarthritis. She does not monitor blood pressure at home and reports "fair" glycemic control with oral antidiabetic medications. The patient does not use tobacco, alcohol, or illicit drugs, and formerly worked as a salesperson in a department store. Blood pressure is 138/76 mm Hg and pulse is 82/min. BMI is 34 kg/m2. Cardiopulmonary and abdominal examinations are unremarkable. Foot examination reveals her 3rd and 4th toes appear "claw shaped," with dorsiflexion of the proximal phalanges at the metatarsophalangeal joints and plantar flexion of the proximal and distal interphalangeal joints. Which of the following is the most likely cause of this patient's lower extremity findings?
Show Explanatory Sources
This patient has a claw toe deformity, characterized by dorsiflexion at the metatarsophalangeal joints and plantar flexion at the proximal and distal interphalangeal joints. Claw toe and hammer toe (similar to claw toe, but with dorsiflexion at the distal interphalangeal joints) deformities are common in elderly patients and reflect an imbalance in strength and flexibility between the flexor and extensor muscle groups. These deformities are often due to a simple mechanical problem, such as chronically ill-fitting shoes, but in a patient with longstanding diabetes they may suggest underlying diabetic peripheral neuropathy.
The etiology of foot deformities in patients with diabetic neuropathy involves multiple factors, including atrophy of intrinsic foot muscles due to degeneration of motor axons, decreased pain sensation and proprioception, and concurrent orthopedic and vascular disorders. Long-term complications of diabetic neuropathy include callusing, ulceration, joint subluxation, and Charcot arthropathy (bone and soft tissue destruction and deformity).
(Choice B) Symptomatic osteoarthritis of the foot usually involves the midfoot and the first metatarsophalangeal joint. Involvement of the lesser toes is much less common.
(Choice C) Interdigital (Morton) neuroma is mechanically induced neuropathic degeneration of the interdigital nerves. It presents with numbness or pain at the distal forefoot between the 3rd and 4th toes. It does not cause significant deformity, and gross inspection of the foot is typically normal.
(Choice D) Plantar fasciitis is characterized by collagenous degeneration at the insertion of the plantar fascia on the calcaneus. It presents with heel pain that is worst when standing on hard surfaces, especially with the first steps of the day.
(Choice E) Spinal stenosis is an abnormal narrowing of the spinal canal. Compression of the associated nerve roots results in lower extremity pain, numbness/paresthesia, and weakness that are worse with extension of the spine (eg, walking upright).
Educational objective:
Claw toe and hammer toe deformities reflect an imbalance in strength and flexibility between the flexor and extensor muscle groups. In a patient with longstanding diabetes, these deformities may suggest underlying diabetic peripheral neuropathy. Other complications of diabetic neuropathy include callusing, ulceration, joint subluxation, and Charcot arthropathy.