Foot Drop

Differential Diagnosis

Top to Bottom:

1. Brain:
   • CVA (Cerebrovascular Accident).
   • Space-occupying lesion.
2. Spine:
   • Spinal dysraphism.
   • L4/5 far lateral or L5/S1 posterolateral disc lesion.
3. Hip:
   • Post Total Hip Replacement (THR) iatrogenic injury.
   • Trauma.
4. Knee:
   • Post Total Knee Replacement (TKR) iatrogenic injury.
   • Compression neuropathy under Biceps femoris fascia.
   • Trauma (fracture, knee dislocation).
   • Mass (popliteal cyst, tumor).
   • Direct nerve injury (penetrating injury).
5. Other Causes:
   • Neural tumor (e.g., neurofibroma).
   • Mass lesions.
   • Neurological conditions (e.g., Polio, Spina Bifida).
   • Achilles tendon rupture.

Examination

Look

• Gait:
  • Loss of 1st rocker.
  • Compensatory pelvic tilt, lateral bend, or leg circumduction.
  • Compensatory hip and knee flexion for foot clearance during swing.
  • Toes make initial contact instead of the heel.
  • Heel lands with a characteristic slap.
• Muscle Appearance:
  • Wasting of anterior and peroneal compartment muscles.
  • Fasciculations in affected muscles.
• Scars and Masses:
  • Inspect hip, knee, leg, and spine for scars or masses.
• Deformities:
  • Identify any deformities.
  • Compare with the other leg.

Feel

• Sensory Assessment:
  • Test dermatomes and peripheral nerves.
• Tinel’s Sign:
  • Perform from proximal to distal.
• Popliteal Fossa:
  • Palpate for masses.
• Achilles Tendon:
  • Assess for abnormalities.

Move

• Neurological Function:
  • Assess myotomes and peripheral nerve motor power:
    • Tibialis Anterior (TA).
    • Tibialis Posterior (TP).
    • Gastrocnemius-Soleus (GS).
    • Peroneal muscles.
• Differentiation Tests:
  • Distinguish between L5 root involvement and peripheral nerve injury by testing Gluteus Medius (GM).
• Spinal Irritation Tests:
  • Straight Leg Raise (SLR).
  • Cross-over test.
• Upper Motor Neuron (UMN) Signs:
  • Babinski sign.
  • Clonus.

Finishing Steps

• Obtain a detailed history.
• Conduct a vascular examination to rule out vascular causes.