The neuropathic joint: a neurovascular bone disorder

Area of Science:

• Orthopedics
• Neurology
• Pathology

Background:

• The pathogenesis of neuropathic joints remains controversial, with two primary theories: neurotraumatic and neurovascular.
• The neurotraumatic theory posits that repeated mechanical trauma to an insensitive joint causes damage.
• The neurovascular theory suggests a neurally mediated vascular reflex leading to hyperemia and bone resorption.

Observation:

• Clinical, radiographic, and pathologic observations indicate a dual role for both theories in neuropathic joint development.
• Sympathetic nervous system dysfunction is initially observed to trigger persistent hyperemia.
• This hyperemia leads to significant osteoclast-mediated bone resorption.

Findings:

• Both neurotraumatic and neurovascular mechanisms contribute to neuropathic joint pathogenesis.
• The process begins with sympathetic dysregulation causing hyperemia and bone resorption.
• Secondary pathologic fractures and repair occur only if the insensitive joint is subjected to continued weight-bearing.

Implications:

• Understanding the dual pathogenesis is crucial for effective treatment strategies for neuropathic joints.
• Targeting both vascular and mechanical factors may be necessary for managing this condition.
• Further research can elucidate the precise interplay between neural control, vascular changes, and mechanical stress.