Foot Drop

DEFINITION:
  • Inability to raise the front part of foot due to weakness or paralysis of tibialis anterior muscle that lift the foot
  • Foot drop occur due to peroneal nerve injury
  • Can happen to one foot or both feet
ETIOLOGY:
  • L4-L5 disc herniation the herniated disc compressing the L5 nerve root
  • Lumbosacral Plexus injury due to pelvic fracture
  • Sciatic nerve injury hip dislocation
  • Injury to the knee dislocation
  • Common peroneal nerve injury
  • Neurodegenerative disorder of the brain multiple sclerosis, stroke, cerebral palsy
  • Motor neuron disorder polio and amyotrophic lateral sclerosis
  • Injury to the nerve roots spinal stenosis
  • Peripheral nerve disorder acquire peripheral neuropathy induced by lead
  • Damage to the peroneal nerve muscular dystrophy
  • Established compartment syndrome foot drop is late finding,irreversible muscle and nerve ischemia occur in patient if fasciotomy is not performed
SYMPTOMS:
  • Inability to lift the front part of the foot
  • Abnormal gait which drag the front of foot on the ground during walking (steppage gait)
  • Foot drop with weakness of the anterior tibial, posterior tibial, and peroneal muscles with Sensory loss is demonstrated over the anterior shin and dorsal foot suggest a radiculopathy at L5 
  • An exaggerated, swinging hip motion
  • Tingling, numbness & slight pain in the foot
  • Difficulty performing certain activities that require the use of the front of the foot
  • Muscle atrophy in the leg
  • Limp foot
CLINICAL FEATURES:
  • Type 1 foot drop:
  1. High lesion : total foot drop
  2. Unable to do dorsiflexion and inversion of foot
  3. Able to do eversion
  4. Front of leg is wasted
  5. Sensation lost over dorsal web space of the leg
  • Type 2 foot drop:
  1. Low lesion : incomplete of foot drop
  2. Unable to do eversion
  3. Able to do dorsiflexion and inversion of the foot
  4. Wasting of outer half of leg
  5. Sensation lost over outer leg and foot
  • Gait of Foot Drop
  1. Gait of foot drop gait is high stepping gait
  2. The patients lift the knee high and slaps the foot to the ground on advancing to the involved side
DIAGNOSIS:
  • Occur during routine examination where patient find it’s difficult to walk on their heel
  • Plain X-ray
  • Magnetic Resonance Imaging (MRI)
  • Electromyography (EMG) and nerve conduction study
  • SD curve
  • Tinel sign
TREATMENT:
  • Conservative treatment : shows high incidence of recovery
  • Splintage – splint knee in 20° of flexion and ankle in 90° for night time
  • In day time, walking is allowed by using ‘foot-drop appliance’
  • Varieties of foot drop appliances:

  1. dynamic-spring shoe
  2. static- back stop shoe
  • Ankle foot orthotics (AFO)
  1. support the foot with light-weight leg braces and shoe inserts
  • Exercises
  1. strengthen the muscle, help to maintain range of motion (ROM) and improve gait
  • Electrical Functional Stimulations 
  1. electrically stimulate the peroneal nerve during footfall
  • Surgery – done if conservative management fails
  • Repairs or decompresses a damaged nerve that fuses the foot and ankle joint or transfers tendons from stronger leg muscles
  • Choices of surgery
  1. tendon transfers – for mobile foot drop
  2. tendo-archilles lengthening - in fixed equinus
  3. subtalar stabilizer procedur – for fixed varus
  4. triple arthrodes – for fixed varus at the subtalar joint
  5. In case of intervertebral disk prolapse at L4 – L5 level involving L5 root surgical intervention is indicated
Exam Question of
  • Classic sign of lead induced peripheral neurotoxicity is Foot drop
  • A previously healthy 45 yrs old laborer suddenly develops acute lower back pain with right-leg pain and weakness of dorsiflexion of the right great toe showing foot drop is indicated for early surgical intervention
  • Foot drop is features of common peroneal nerve injury
  • Foot drop with weakness of the anterior tibial, posterior tibial, and peroneal muscles with Sensory loss demonstrated over the anterior shin and dorsal foot suggest a radiculopathy at L5
  • Foot drop occurs due to the involvement of Sciatic nerve, Direct injury to the dorsiflexors, Common peroneal nerve palsy
Don't Forget to Solve all the previous Year Question asked on Foot Drop