Foot Drop & Peroneal Neuropathy Testing in Sydney
Same-day nerve conduction studies to localise the lesion and predict recovery — Dr Ron Granot, FRACP, Bondi Junction
Book Your Test NowWhat is Foot Drop?
Foot drop is weakness of the muscles that lift the foot upward (dorsiflexion). The toes catch on the ground with each step, producing a distinctive high-stepping ("steppage") gait. The most common cause is injury to the common peroneal nerve as it wraps around the fibular head at the side of the knee — a vulnerable, superficial location easily compressed.
Common Causes
Habitual leg crossing
Prolonged pressure on the fibular head from crossed legs — particularly in people who have lost weight (reducing the protective fat pad).
Recent weight loss
Even modest weight loss reduces the cushioning around the peroneal nerve at the knee. A surprisingly common cause that often goes unrecognised.
Prolonged squat or kneel
Gardening, tile-laying, prolonged squatting (e.g. childbirth). The nerve is stretched and compressed in deep flexion of the knee.
Knee surgery or trauma
Total knee replacement, high tibial osteotomy, fibular head fracture, or post-traumatic scarring. Onset usually evident within days of the event.
Casting or splinting
Tight plaster cast or splint compressing the lateral knee. Should be released immediately if foot drop develops.
L5 radiculopathy
Compression of the L5 nerve root in the lower back can produce foot drop that mimics peroneal palsy. NCS distinguishes these.
Localising the Lesion
The pattern of weakness, sensory loss and reflex changes helps narrow down where the problem is — but only nerve conduction studies and EMG can give a definitive answer.
| Site | Distinguishing clinical features | NCS/EMG signature |
|---|---|---|
| Peroneal nerve at fibular head | Weak dorsiflexion + eversion. Numbness over outer shin and top of foot. Spared inversion (tibialis posterior). Normal ankle jerk. | Conduction block / slowing across the fibular head. EMG denervation limited to peroneal-innervated muscles. |
| L5 radiculopathy | Weak dorsiflexion + foot inversion + hip abduction. Back pain often present. Reflexes usually preserved. | NCS normal across fibular head. EMG denervation in L5-innervated muscles including tibialis posterior, gluteus medius, paraspinal muscles. |
| Sciatic neuropathy | Weakness in both peroneal and tibial distributions (peroneal usually more affected). Sensory loss extends to sole of foot. | Reduced peroneal AND tibial responses without conduction block at fibular head. |
| Motor neurone disease | Painless, progressive. May have fasciculations, upper motor neurone signs, or weakness in other regions. | Widespread denervation on EMG involving multiple regions and roots. |
See also: Sciatica & Lumbar Radiculopathy · Tarsal Tunnel Syndrome
What to Expect at Your Test
Brief clinical assessment
Dr Granot reviews your symptoms, the onset story (sudden vs gradual, any triggering event), and examines you — strength, sensation, reflexes and gait.
Nerve conduction studies
Peroneal motor recordings with stimulation at the ankle, below and above the fibular head — to detect conduction block or slowing across the knee. Tibial and sural studies to check for sciatic involvement or generalised neuropathy.
Needle EMG
Sampling of selected muscles to confirm and locate the lesion: tibialis anterior, extensor hallucis longus, peroneus longus, tibialis posterior (above-knee, L5-supplied), and where indicated gluteus medius and paraspinal muscles.
Diagnosis & prognosis
Findings discussed with you immediately. NCS at presentation predicts whether recovery is likely to be fast (intact nerve continuity) or prolonged (axonal injury). Formal report to your referring doctor the same day.
Treatment & Recovery
Most cases of peroneal palsy from compression at the fibular head recover spontaneously over weeks to months once the cause is removed. Management focuses on protecting the nerve and preventing falls during recovery.
Remove the cause
Stop leg crossing, avoid prolonged kneeling, remove or loosen tight casts. Lifestyle change is often the entire treatment.
Ankle-foot orthosis
A lightweight AFO holds the foot up during gait. Dramatically reduces falls and allows normal walking while the nerve recovers.
Physiotherapy
Stretching to prevent contracture, strengthening of supporting muscles, gait retraining. Started early, helps preserve function.
Imaging or surgery
MRI or ultrasound if a compressive lesion (ganglion, tumour) is suspected. Surgical decompression is occasionally needed for persistent compression that fails conservative measures.
Frequently Asked Questions
Get a Diagnosis & Recovery Plan for Your Foot Drop
Same-day results • Expert neurologist • Predicts recovery prognosis
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