Less Common Arthropathies

Neuropathic arthropathy, also known as a Charcot joint, is a destructive arthritis characterized by fracture, subluxation, and dislocation of the articular structures in the setting of neurologic damage to the involved joint or limb.

Both central (upper motor neuron) and peripheral (lower motor neuron) lesions may lead to the development of neuropathic arthropathy.

Diabetic neuropathy is now the most common cause of neuropathic arthropathy. Neuropathic arthropathy occurs in 7.5% of diabetic patients.

The pathologic features of Charcot arthropathy include cartilage destruction, bone eburnation, osteophytosis, and loose body formation.

Two major theories have been proposed to explain the development of neuropathic arthropathy: the neurovascular theory and the neurotraumatic theory.

Neuropathic arthropathy typically presents as an acute or subacute monoarthritis with swelling, erythema, and variable amounts of pain in the affected joint.

Two consistent clinical features of neuropathic arthropathy are the presence of a significant sensory deficit and a degree of pain that is less than would be expected considering the amount of joint destruction evident on radiographs.

The differential diagnosis of neuropathic arthropathy includes osteomyelitis and other deep tissue infections, fracture, gout, calcium pyrophosphate dihydrate deposition disease, Milwaukee shoulder/knee syndrome, osteonecrosis, and osteoarthritis.

■ Plain radiographs are extremely helpful in making the diagnosis of neuropathic arthropathy. ■ Categorizing the disease into three clinical stages— acute, subacute, and remodeling—is a useful way to organize approaches to therapy.