Foot drop can change the way you walk almost immediately. Patients often describe catching their toes on the ground, having to lift the knee unusually high, or feeling that the foot will not do what they want it to do. When we evaluate peroneal nerve palsy, the most important question is not simply why the foot is weak. We need to determine where the nerve is being affected and whether the nerve is being compressed, stretched, injured, or interrupted. The common peroneal nerve is particularly vulnerable as it passes around the fibular head near the outside of the knee. Finding the source early can make a meaningful difference in treatment decisions and recovery.
Anatomy
The common peroneal nerve is one of the major branches of the sciatic nerve. It travels along the outside of the knee and wraps around the fibular head before dividing into the superficial and deep peroneal nerves.
The deep peroneal nerve supplies muscles that lift the foot and extend the toes. The superficial peroneal nerve supplies muscles that turn the foot outward, or evert it.
Because the common peroneal nerve sits relatively close to the skin around the fibular head, it is more vulnerable to external pressure than some other nerves. Pressure in this area can interfere with the nerve’s ability to send signals to the muscles of the lower leg and foot.
Why Peroneal Nerve Palsy Develops
Compression is one of the more common mechanisms. Prolonged leg crossing, sustained squatting, pressure against the outside of the knee, or a tight cast or brace can place pressure on the nerve.
Trauma around the knee can also injure it. Fractures or dislocations involving the fibula or knee may stretch, compress, or directly damage the nerve.
Peroneal nerve problems can also occur after certain surgical procedures around the knee or hip. Less commonly, a mass such as a ganglion cyst or bone growth can compress the nerve.
Rapid weight loss can remove some of the soft-tissue padding around the fibular head, making the nerve more susceptible to pressure.
Systemic conditions that affect nerves can also influence symptoms and recovery. Diabetes, for example, can make nerves more vulnerable to injury.
Symptoms
The most recognizable symptom is foot drop, meaning difficulty lifting the front of the foot.
Patients may notice:
- The toes catching on the ground while walking
- A need to lift the knee higher to clear the foot
- Weakness when lifting the foot upward
- Difficulty extending the toes
- Weakness when turning the foot outward
- Numbness or tingling along the outer lower leg or top of the foot
- Altered sensation between the first and second toes when the deep peroneal nerve is involved
- Pain or tenderness around the outside of the knee in some cases
The symptoms depend on where the nerve is affected. A problem involving the common peroneal nerve can produce a broader pattern of weakness and sensory changes than an isolated deep peroneal nerve problem.
What We Look for at the First Visit
We begin by watching the patient walk. A high-stepping gait can be an important clue because the patient is compensating for the inability to adequately lift the foot.
We then test individual muscle groups rather than simply labeling the problem as foot drop. We assess dorsiflexion, toe extension, and eversion and compare the findings with the opposite side.
Sensation is also carefully mapped. The location of numbness or tingling can help us determine which portion of the nerve is involved.
We examine the area around the fibular head for tenderness or a positive Tinel’s sign, which can sometimes indicate irritation of the nerve.
The examination also helps us determine whether the problem may actually be coming from somewhere else, such as the lower back.
Testing Helps Locate the Problem
Electromyography and nerve conduction studies can help determine whether the nerve is functioning normally and can provide information about the location and severity of the injury.
Imaging is selected based on what we find clinically. X-rays can identify fractures, deformity, or other bony abnormalities around the knee.
MRI can be useful when we are looking for a mass, cyst, structural abnormality, or other cause of nerve compression. Ultrasound can also provide a dynamic view of the nerve and may help identify focal compression or a cyst in an appropriate setting.
The purpose of testing is not simply to confirm that the patient has foot drop. We want to identify why the foot has become weak and whether the nerve still has the potential to recover.
Problems That Can Look Similar
Foot drop does not automatically mean that the peroneal nerve is injured at the fibular head.
A lumbar nerve-root problem can produce weakness that resembles peroneal nerve palsy. Other neurologic conditions can also affect the ability to lift the foot.
Peroneal tendon problems may cause pain and weakness around the outside of the ankle but do not produce the same neurologic pattern. Problems involving other peripheral nerves can produce different areas of sensory loss and weakness.
The distinction matters because treating the nerve at the knee will not correct a problem that actually originates in the spine or elsewhere along the nerve’s pathway.
Protecting the Foot While the Nerve Recovers
When the nerve is compressed but not permanently damaged, removing the source of pressure may allow function to gradually return.
We may recommend avoiding prolonged leg crossing, deep squatting, or direct pressure over the fibular head. Any tight cast, brace, or other external source of compression needs to be evaluated.
An ankle-foot orthosis, or AFO, can hold the foot in a safer position while the nerve recovers. This can reduce toe catching and help prevent falls.
Physical therapy can focus on maintaining available ankle motion, strengthening muscles that still have adequate function, and retraining the walking pattern. Therapy does not make a severed nerve regenerate, but it can help preserve function while recovery occurs.
When Surgery Becomes Reasonable
Surgery depends on the cause of the nerve dysfunction.
If there is a clear structure compressing the nerve, such as a cyst or other mass, removing the source of compression may be appropriate. A nerve that remains compressed despite appropriate nonsurgical treatment may also require decompression.
When the nerve has been severely injured or disrupted, treatment may involve more complex nerve procedures depending on the location and extent of the injury.
For longstanding foot drop in which useful nerve recovery is no longer expected, a tendon transfer may be considered. Instead of relying on a poorly functioning nerve, we use a functioning tendon and redirect it so that it can help lift the foot.
This is a different goal from nerve decompression. Decompression attempts to give the nerve an opportunity to recover. Tendon transfer provides another mechanical way to restore useful foot elevation when nerve recovery is inadequate.
Recovery Depends on the Cause
Recovery from peroneal nerve palsy is highly dependent on the type and severity of nerve injury.
A temporary compression injury may improve after the pressure is removed. More significant nerve injuries can take substantially longer to recover and may leave persistent weakness or sensory changes.
After decompression or another surgical procedure, rehabilitation focuses on protecting the surgical site while gradually restoring motion, strength, balance, and gait.
Nerves recover differently from muscles and tendons. Improvement may be gradual, and the absence of immediate strength after surgery does not necessarily mean that treatment has failed.
What We Watch for During Recovery
We monitor whether strength, sensation, and walking ability are improving. We also watch for persistent foot positioning problems, falls, muscle weakness, or compensatory problems elsewhere in the leg.
If the expected recovery does not occur, we reconsider the diagnosis and determine whether there is continued compression, more extensive nerve damage, or another source of weakness.
A brace may remain useful even when some nerve recovery occurs if the foot is still not strong enough for safe walking.
What a Good Outcome Means
A good outcome means being able to walk safely and use the foot with as little compensation as possible.
For some patients, that means the nerve recovers enough to restore normal dorsiflexion and sensation. For others, particularly after a severe or longstanding nerve injury, the goal may be reliable foot clearance with an AFO or restoration of active dorsiflexion through a tendon transfer.
The appearance of the foot matters less than whether it functions safely. We want patients to walk without repeatedly catching the toes, losing balance, or having to dramatically alter their gait.
When We Recommend Prompt Evaluation
New foot drop should not simply be watched indefinitely.
We recommend evaluation when there is new weakness lifting the foot or toes, persistent numbness or tingling along the lower leg or foot, or difficulty walking that develops after an injury, surgery, prolonged compression, or another neurologic event.
Sudden foot drop accompanied by significant new neurologic symptoms, severe weakness, or other concerning symptoms requires prompt medical assessment.
The earlier we identify an ongoing source of nerve compression or a significant nerve injury, the more options we may have for protecting the foot and addressing the underlying problem.
The content on this page has been authored, edited, or approved by the doctors below, and was last reviewed for accuracy on September 15, 2026.
