Medial Saphenous Nerve Neuroma: The Often-Missed Cause of Burning Inner-Knee Pain

Pain along the inside of the knee is commonly blamed on the meniscus, arthritis, tendons, ligaments, or the knee joint itself. But when the pain feels burning, electric, unusually sensitive to touch, or seems centered around an old surgical scar, another possibility deserves attention: a medial saphenous nerve neuroma.

The saphenous nerve is a sensory nerve that supplies feeling to parts of the inner knee, lower leg, and ankle. Around the knee, one of its most important branches is the infrapatellar branch of the saphenous nerve, a small nerve that crosses the front and inner portion of the knee. Because of its superficial location and variable course, this nerve can be injured during knee surgery, through direct trauma, or by scar tissue developing around it. ^[1,2]

Most saphenous nerve injuries do not produce a painful neuroma. Some cause temporary numbness or altered sensation that gradually improves. In a smaller number of patients, however, an injured or divided nerve attempts to regenerate unsuccessfully. The nerve fibers can develop into a disorganized, hypersensitive bundle known as a traumatic neuroma.

The result can be surprisingly severe pain from a very small nerve.

For someone who has persistent pain after an otherwise successful knee operation, recognizing this possibility can make the difference between repeatedly treating the knee joint and identifying the actual source of pain.

A neuroma is not usually a tumor in the conventional sense. A traumatic neuroma develops when a peripheral nerve is damaged, cut, stretched, or trapped and the regenerating nerve fibers are unable to reconnect normally with their intended tissues.

Instead, the nerve fibers may grow irregularly into surrounding scar tissue. This can create a highly sensitive area that generates pain when touched, stretched, compressed, or sometimes even without obvious stimulation.

A medial saphenous nerve neuroma refers to a painful neuroma involving the saphenous nerve or one of its branches along the medial, or inner, side of the knee or leg.

Around the knee, the infrapatellar branch of the saphenous nerve is particularly important because it travels through superficial tissues where surgical incisions and portals are frequently placed. Damage to this nerve has been documented after total knee replacement, anterior cruciate ligament reconstruction, knee arthroscopy, meniscus surgery, and other operations around the knee. ^[2-5]

The terms saphenous nerve neuralgia, infrapatellar saphenous neuralgia, saphenous neuropathy, and infrapatellar nerve neuroma may therefore appear when discussing similar forms of nerve-related medial knee pain.

They are related conditions, but they are not necessarily identical. A patient can have an irritated or entrapped saphenous nerve without having a true neuroma.

Understanding the anatomy helps explain why this nerve can be injured so easily.

The saphenous nerve originates from the femoral nerve and is primarily derived from the third and fourth lumbar nerve roots. Unlike many larger peripheral nerves, the saphenous nerve is essentially sensory. It does not normally control the major muscles responsible for moving the knee or ankle. ^[1]

The nerve travels down the thigh through a passage known as the adductor canal. As it reaches the region of the knee, it gives rise to important sensory branches.

One branch continues down the medial side of the leg toward the ankle. Another, the infrapatellar branch of the saphenous nerve, travels toward the front and inner portion of the knee.

This infrapatellar branch provides sensation over portions of the:

• Inner knee
• Front of the knee below the kneecap
• Upper inner portion of the shin
• Tissues around the lower kneecap and proximal tibia

Its exact path varies considerably from person to person. That anatomical variability is one reason surgeons cannot always predict exactly where the nerve will cross a planned incision. ^[2]

A 2026 anatomical and ultrasound review further emphasized the clinical importance of understanding the variable course of the infrapatellar branch when evaluating chronic knee pain and performing image-guided procedures. ^[3]

Previous knee surgery is one of the most important causes of injury to the infrapatellar branch of the saphenous nerve.

The nerve may be directly cut by an incision, stretched, compressed, caught in sutures, affected by surgical retraction, or subsequently trapped within postoperative scar tissue.

Operations associated with saphenous nerve injury include:

• Total knee replacement
• Anterior cruciate ligament reconstruction
• Meniscus surgery
• Knee arthroscopy
• Patellar tendon procedures
• Hamstring tendon graft harvesting
• Open knee surgery
• Repeated revision knee procedures

Injury to the infrapatellar branch during total knee replacement is well recognized because the nerve commonly crosses the area of the surgical approach. ^[4]

Importantly, nerve injury does not mean that every patient will develop chronic pain. Many patients experience only numbness or altered sensation around the incision. A painful neuroma develops only in a subset of injured nerves.

The infrapatellar branch of the saphenous nerve is also vulnerable during anterior cruciate ligament reconstruction, particularly when hamstring tendons are harvested.

Prospective research has demonstrated that sensory disturbance around the knee can occur following anterior cruciate ligament reconstruction, although symptoms often improve with time. ^[5]

Persistent burning pain or hypersensitivity, especially when localized near the surgical incision or graft-harvesting site, may warrant evaluation for a more significant nerve injury.

Arthroscopy is often described as minimally invasive, but the small portals used to introduce surgical instruments still pass through skin and superficial tissues containing sensory nerves.

Because the infrapatellar branch has an unpredictable course, even a relatively small arthroscopic incision may occasionally injure it.

A recent prospective study evaluating arthroscopic portal incisions documented infrapatellar saphenous nerve injury in a proportion of patients following knee arthroscopy. ^[6]

Again, most sensory changes do not progress into a painful neuroma, but persistent focal neuropathic pain deserves further investigation.

Surgery is not the only cause.

A direct blow, laceration, penetrating injury, fall, or severe soft-tissue injury involving the medial knee can damage the saphenous nerve.

If nerve fibers become disrupted and regenerate abnormally, a post-traumatic neuroma can develop.

Sometimes the nerve itself has not been completely divided.

Instead, healing tissues may surround or tether the nerve.

Postoperative fibrosis can prevent the nerve from gliding normally when the knee bends and straightens. Repeated pulling or compression of the nerve can produce pain that resembles a neuroma.

Ultrasound studies have demonstrated both neuroma formation and postsurgical nerve entrapment in patients with chronic anteromedial knee pain. ^[7]

Each operation creates additional scar tissue and places superficial nerves at risk.

For this reason, patients who have undergone several procedures around the same knee may have a greater likelihood of scar-related nerve irritation or neuroma formation.

Nerve pain often feels different from mechanical knee pain.

Patients may describe the pain as:

• Burning
• Stinging
• Shooting
• Electric
• Sharp
• Pins and needles
• Hot or searing
• Painful tingling
• Sudden shocks when the area is touched

The pain may be concentrated in a very small spot or spread along the sensory territory of the nerve.

One of the classic complaints is burning pain along the inner knee, particularly around or just below the kneecap.

Rather than feeling deep inside the joint, the pain may seem unusually superficial, almost as though it is located directly underneath the skin.

A patient may notice one particularly painful point along an old incision.

Pressing this location can trigger sharp pain that travels away from the scar.

This type of focal sensitivity should raise suspicion for an injured superficial sensory nerve.

Neuropathic pain can produce allodynia, meaning something that normally should not hurt becomes painful.

For example, discomfort may be triggered by:

• Pants rubbing against the knee
• Bedsheets touching the skin
• Kneeling
• Crossing the legs
• Light pressure over a scar
• A knee brace
• Touching or shaving the area

This extreme sensitivity is different from the deeper aching usually associated with osteoarthritis.

Patients may experience numbness next to an area of burning pain.

Although that sounds contradictory, it is common with peripheral nerve injuries. Some nerve fibers may no longer transmit sensation normally while other damaged fibers generate excessive pain signals.

Tapping or pressing over an injured nerve may produce an electric sensation traveling along the nerve.

Doctors refer to this clinical finding as a Tinel sign.

A positive Tinel sign over the course of the infrapatellar branch of the saphenous nerve has been used as part of the clinical evaluation for suspected neuroma and saphenous neuropathy. ^[4,7]

Some patients notice increased pain when bending or straightening the knee.

This can occur if scar tissue is tethering the nerve or if movement places tension on the affected nerve.

In severe cases, the patient may begin avoiding movement because of pain, contributing to stiffness and reduced function.

Yes, although the nerve itself does not control knee movement.

Pain may cause a person to protect the knee and avoid normal motion. Over time, reduced movement can contribute to stiffness.

Cases have been reported in which an infrapatellar saphenous nerve neuroma after total knee replacement was associated with considerable pain and restricted range of motion. ^[4]

The important point is that knee stiffness does not automatically mean something is mechanically wrong inside the joint.

A painful superficial nerve may sometimes contribute to the patient’s reluctance or inability to move the knee normally.

The symptoms overlap with many much more common knee problems.

Someone with medial knee pain may initially be evaluated for:

• Medial meniscus injury
• Knee osteoarthritis
• Medial collateral ligament injury
• Pes anserine bursitis
• Tendon disorders
• Patellofemoral pain
• Scar tissue
• Implant problems following knee replacement
• Lumbar nerve irritation
• Complex regional pain syndrome

After total knee replacement, physicians must also consider potentially serious problems such as infection, implant loosening, instability, malalignment, fracture, or other mechanical complications before attributing persistent pain to a superficial nerve. ^[4,7]

The saphenous nerve is small, and standard knee X-rays cannot show a tiny nerve neuroma.

Routine magnetic resonance imaging may also focus mainly on bones, cartilage, ligaments, and the joint itself unless nerve pathology is specifically being considered.

This is one reason the diagnosis can be delayed.

There is no single test that diagnoses every case.

The strongest diagnosis usually comes from combining the medical history, physical examination, pain distribution, imaging when appropriate, and the response to a diagnostic nerve block.

The doctor will typically ask:

• Did the symptoms begin after surgery or trauma?
• Where exactly is the pain?
• Is it burning, shooting, or electrical?
• Is the skin unusually sensitive?
• Is there numbness or tingling?
• Does touching the surgical scar reproduce the pain?
• Does the pain travel when a particular spot is pressed?

The timing of symptoms can provide an important clue.

Persistent medial knee pain that begins after surgery and remains despite satisfactory healing of the knee joint deserves evaluation for a possible nerve-related cause.

The examiner may carefully map the painful and numb areas of skin.

A focal tender point over the expected course of the saphenous nerve or infrapatellar branch is particularly important.

The physician may gently tap the area to look for a Tinel sign. Reproduction of electric or radiating pain supports involvement of the nerve but is not enough by itself to establish the diagnosis.

One of the most useful diagnostic techniques is an injection of local anesthetic around the suspected nerve.

If temporarily numbing the nerve produces substantial relief of the characteristic pain, it provides evidence that the nerve is contributing to the symptoms.

Studies of postoperative infrapatellar saphenous neuralgia have found that patients with suggestive clinical findings and a positive response to a diagnostic nerve block were more likely to respond to nerve-directed treatment. ^[7]

A diagnostic block is not infallible, however. Injection accuracy, anatomical variation, scar tissue, and overlapping sources of knee pain can influence the response.

Ultrasound has become particularly useful because peripheral nerves can be examined dynamically and compared with surrounding tissues.

A skilled clinician may use ultrasound to look for:

• Enlargement of the nerve
• A focal neuroma
• Scar tissue surrounding the nerve
• Abnormal nerve architecture
• Entrapment
• The relationship between the nerve and a surgical scar

High-resolution ultrasound studies have demonstrated that the infrapatellar branch can be identified despite considerable anatomical variation. ^[2,7]

Ultrasound also allows the physician to guide a diagnostic or therapeutic injection directly around the suspected nerve.

Magnetic resonance imaging may sometimes help identify a neuroma or exclude other structural causes of knee pain.

However, small superficial nerves can be difficult to visualize, so a normal magnetic resonance imaging scan does not necessarily eliminate a saphenous nerve disorder.

Specialized sensory nerve conduction testing can sometimes assess the infrapatellar branch of the saphenous nerve. Techniques for evaluating conduction in this small sensory nerve have been described. ^[8]

However, diagnosis often remains primarily clinical and ultrasound-based because of the small size and variable anatomy of the nerve.

Treatment depends on whether the problem involves irritation, entrapment, a true neuroma, or another type of nerve injury.

Not everyone requires surgery.

Reducing activities that repeatedly compress the painful nerve may help control symptoms.

Depending on the location of the neuroma, this may mean temporarily avoiding:

• Kneeling
• Direct pressure on the scar
• Tight knee sleeves
• Positions that stretch the affected tissues
• Repetitive movements that consistently reproduce nerve pain

The goal is generally not permanent avoidance of activity. Rather, activity modification may help reduce repeated irritation while the diagnosis and longer-term treatment plan are established.

Some patients benefit from carefully supervised desensitization techniques.

These involve gradually exposing the hypersensitive skin to different textures or gentle pressure so that the nervous system becomes less reactive to normal stimulation.

Physical therapy may also address knee stiffness, weakness, altered gait, and movement patterns that developed because the patient was protecting the painful area.

Because neuroma pain originates from a nerve, conventional anti-inflammatory medications may not always provide adequate relief.

Depending on the patient’s overall medical condition, a physician may consider medications commonly used for neuropathic pain.

Medication decisions should be individualized because these drugs can have important side effects and interactions.

A local anesthetic injection may serve both diagnostic and therapeutic purposes.

Some procedures combine local anesthetic with corticosteroid when inflammation or scar-associated neuritis is suspected.

A clinical series involving patients with persistent medial knee pain after total knee replacement found that ultrasound-guided treatment directed at the infrapatellar saphenous nerve produced meaningful improvement in a number of patients. ^[9]

The duration of relief varies.

Selected patients with confirmed nerve-mediated pain may be considered for radiofrequency-based procedures.

These techniques target the pain-generating sensory nerve while attempting to reduce transmission of painful signals.

Radiofrequency procedures are generally considered only after the suspected nerve has been carefully identified and other causes of pain have been evaluated.

Cryoablation uses controlled cold temperatures to temporarily disrupt conduction through a sensory nerve.

The infrapatellar branch of the saphenous nerve has increasingly been studied as a target for image-guided pain procedures, including cryoablation. ^[3]

Because anatomy varies considerably, accurate nerve localization can be important.

Peripheral nerve stimulation is an emerging option for selected patients with persistent saphenous neuralgia.

A small case series examining peripheral nerve stimulation for saphenous neuralgia reported symptom improvement in many treated patients, although complications occurred and larger comparative studies are needed before its precise role is established. ^[10]

This approach is usually considered when more conservative treatments have failed and the pain has been clearly linked to a peripheral nerve.

If the nerve remains intact but is trapped within scar tissue, surgery may sometimes be performed to release the nerve.

This procedure is known as neurolysis.

The objective is to remove constricting scar tissue and allow the nerve to lie more freely within surrounding tissues.

Whether neurolysis or nerve excision is preferable depends on the type and location of injury.

When a clearly identified neuroma causes persistent disabling pain despite nonoperative treatment, surgical removal may be considered.

Studies involving patients with painful postoperative or traumatic neuromas of the infrapatellar branch have reported substantial pain improvement following carefully selected surgical treatment. ^[11,12]

One series evaluating patients with painful infrapatellar saphenous neuroma after total knee replacement reported marked reduction in pain following neuroma excision after other causes of painful knee replacement had been excluded. ^[11]

Another longer-term study of postsurgical and post-traumatic infrapatellar saphenous nerve neuromas found that surgical treatment provided clinically meaningful improvement for many patients, although not everyone became completely pain-free. ^[12]

That is an important expectation to understand: neuroma surgery can be very effective in appropriately selected patients, but it is not a guaranteed cure.

For complex or recurrent neuromas, surgeons increasingly use techniques designed to give the divided nerve somewhere purposeful to grow.

One such technique is targeted muscle reinnervation.

Instead of simply cutting a painful nerve and leaving the nerve ending in soft tissue, the surgeon connects the sensory nerve ending to a nearby motor nerve branch.

The technique was initially developed in amputees but has subsequently been explored for painful peripheral nerve neuromas, including saphenous nerve neuromas. ^[13]

It is generally reserved for selected complex cases and is not required for routine infrapatellar nerve irritation.

Success depends heavily on making the correct diagnosis.

This cannot be overstated.

If pain is coming from instability of a knee replacement, a recurrent meniscus tear, infection, lumbar radiculopathy, or another problem, treating the saphenous nerve is unlikely to solve it.

Conversely, when symptoms follow the anatomical distribution of the nerve, examination identifies a focal painful point, ultrasound shows neuroma or entrapment, and a diagnostic nerve block provides significant temporary relief, confidence in a nerve-mediated diagnosis becomes considerably stronger. ^[7]

Published surgical series show encouraging results in properly selected patients, but most studies involve relatively small groups of patients. Larger controlled studies are still needed to determine which treatments provide the best long-term outcomes.

A mild nerve injury may improve over time.

Postoperative numbness and tingling can gradually decrease as irritated nerves recover and the nervous system adapts.

A mature painful neuroma, however, is structurally different. Once disorganized nerve regeneration has become established, the neuroma itself may not simply disappear.

Symptoms can nevertheless fluctuate, and some patients can manage them without surgery.

That is why treatment usually begins by determining exactly what type of nerve injury is present rather than assuming every painful area requires neuroma removal.

Consider discussing a possible saphenous nerve problem with a physician if you have:

• Persistent burning pain on the inner side of the knee
• Electric or shooting pain around a surgical incision
• Extreme sensitivity to light touch
• Pain while kneeling because pressure is placed over a scar
• Numbness immediately beside a painful area
• A small spot that sends an electric shock through the knee when pressed
• Continuing medial knee pain after knee surgery despite otherwise satisfactory healing
• Pain that has not responded as expected to treatments directed at the joint itself

These symptoms do not prove that a neuroma is present, but they can justify a more focused peripheral nerve evaluation.

Depending on the situation, evaluation may involve an:

• Orthopedic surgeon
• Peripheral nerve surgeon
• Pain management physician
• Sports medicine specialist
• Physical medicine and rehabilitation physician
• Neurologist
• Musculoskeletal radiologist experienced in peripheral nerve ultrasound

Patients who have already undergone knee replacement should generally have important mechanical and infectious causes of postoperative pain excluded before the symptoms are attributed solely to a superficial nerve.

Can saphenous nerve damage cause pain on the inside of the knee?
Yes. The saphenous nerve and particularly its infrapatellar branch provide sensory innervation around the medial and anteromedial knee. Injury, entrapment, inflammation, or neuroma formation can therefore produce inner-knee pain. ^[1,2]

Can a neuroma develop after total knee replacement?
Yes. Injury to the infrapatellar branch of the saphenous nerve is well recognized during total knee replacement. In some patients, the injured nerve can develop into a painful neuroma. ^[4,11]

Is numbness around a knee replacement scar a neuroma?
Not necessarily.
Areas of numbness are relatively common after knee surgery because small sensory nerve branches may be cut during an incision.
A neuroma is more likely to cause focal tenderness, burning pain, hypersensitivity, tingling, or an electric sensation when the involved area is touched.

Can an infrapatellar saphenous nerve neuroma cause pain years after surgery?
It can.
Some patients develop persistent symptoms relatively soon after surgery, whereas others may not receive the correct diagnosis until much later.
Scar tissue, repeated local irritation, or increasing sensitivity of the damaged nerve may contribute to ongoing symptoms.

Does a normal knee magnetic resonance imaging scan rule out a saphenous nerve neuroma?
No.
Small superficial sensory nerves are not necessarily well evaluated on routine knee imaging. High-resolution ultrasound and a carefully performed clinical examination may provide additional information when peripheral nerve pain is suspected.

Can an injection confirm saphenous nerve pain?
A diagnostic injection with local anesthetic can be very helpful.
Substantial temporary improvement after accurately blocking the suspected nerve supports the idea that the nerve is contributing to the pain. ^[7]
It should still be interpreted together with the patient’s symptoms, physical examination, and imaging findings.

Does saphenous nerve damage cause muscle weakness?
The saphenous nerve is principally a sensory nerve, so an isolated injury does not normally cause significant muscle paralysis.
A patient may nevertheless feel that the leg is weak because pain makes it difficult to walk normally, climb stairs, kneel, or fully use the knee.
True neurological weakness may indicate involvement of another nerve or another medical problem and warrants further evaluation.

A medial saphenous nerve neuroma is an uncommon but important cause of persistent inner-knee pain, particularly after knee surgery or direct trauma.

The condition can be easy to overlook because conventional knee problems such as arthritis, meniscus disorders, tendon irritation, scar tissue, and complications following knee replacement are much more familiar causes of pain.

Certain symptoms provide clues that the nerve may be involved: burning or electrical pain, hypersensitivity to touch, numbness next to a painful area, pain centered around a surgical scar, and reproduction of symptoms by tapping over the nerve.

Diagnosis may involve a careful neurological examination, a Tinel sign, high-resolution ultrasound and, particularly, a diagnostic local anesthetic nerve block.

Treatment ranges from activity modification, desensitization and medication to image-guided injections, radiofrequency procedures, cryoablation, peripheral nerve stimulation, surgical neurolysis, or neuroma excision. More advanced nerve reconstruction techniques may be considered for recurrent or unusually complex cases.

Most importantly, persistent pain after knee surgery should not automatically be assumed to originate from the joint.

When the knee itself appears structurally sound but burning, hypersensitive medial knee pain continues, the saphenous nerve—and especially its infrapatellar branch—may deserve a closer look.

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