foot drop

Etiology

• peripheral nerve injury
• stroke
• neuropathy
  • peroneal neuropathy caused by compression at the fibular head is the most common compressive neuropathy in the lower extremity
    • foot drop is its most notable symptom
    • 90% are unilateral
  • peroneal nerve palsy after total knee arthroplasty (0.3-4% of cases) or proximal tibial osteotomy (3-13% of cases)
  • postoperative causes of peroneal nerve palsy include hematomas & constrictive dressings
• dorsiflexor injuries
• compartment syndrome
• drug toxicity
• diabetes mellitus
  • Charcot foot
• vitamin B12 deficiency
• thiamine deficiency
• uremia

Pathology

• weakness in muscles of dorsiflexion
  • tibialis anterior
  • extensor hallucis longus (EHL)
  • extensor digitorum longus
• spasticity of muscles of plantar flexion
  • gastrocnemius

Clinical manifestations

• steppage gait*

* video of steppage gait in patient with bilateral foot drop

Laboratory

• glucose in serum/plasma
• urea nitrogen in serum/plasma
• creatinine in serum/plasma
• hemoglobin A1c in erythrocytes
• erythrocyte sedimentation rate (ESR)
• C-reactive protein in serum/plasma
• serum protein electrophoresis/immunofixation electrophoresis
• vitamin B12 in serum/plasma

Radiology

• X-ray of the tibia, fibula, & ankle
• ultrasound if bleeding is suspected in a patient with a hip or knee prosthesis
• magnetic resonance neurography
• electromyography
• MRI of brain if stroke is suspected

Management

• correct underlying pathology
• avoid leg crossing if due to peroneal neuropathy
• surgery
• orthotics
• nerve stimulation
• erythropoietin* in 3 doses of 5000 U/kg over 1 week after nerve injury

* erythropoietin has neuroprotective &, possibly, neurotrophic properties

More general terms

• gait ataxia

Additional terms

• high-step gait; steppage gait