What to Do About Peroneus Longus Pain Near Knee

If you’re a runner, you need to know as much as you can about the anatomy of your legs so you can properly identify the source of any pain or discomfort as soon as it occurs. Doctor’s appointments can take weeks and just no running for all that time, or running on a hurt leg, can be bad.

So, today I cover one of the most important muscles in the leg and the issues that you may have with the peroneus longus pain near knee.


What is the Peroneus Longus?


Most of you probably haven’t heard the term ‘peroneus longus,’ but you’re probably familiar with the muscles it refers to anyways. It’s the large muscle which starts at the head of your fibula (also known as the calf bone) and runs down most of it, connecting to it.

Near the end of the bone, it becomes a tendon and runs around the lateral malleolus of your ankle (the bony protrusion on the outer side of it). After that it continues down the foot, attaching to your medial cuneiform and your first metatarsal bone.

This is an extremely vital leg muscle, and it provides you with stability in conjunction with the peroneal retinaculum and they steady your leg upon your foot. It works with the brevis muscles to plantarflex the foot and antagonizes muscles which are the dorsiflexors of the foot - the peroneus tertius and tibialis anterior. Without this muscle, standing on one leg would not be possible, for example.


As with any muscle that’s so vital, it is prone to a lot of strain and tends to take the brunt of the impact when you’re using your leg, such as when running. It’s especially vital and suffers the most strain when you’re running on rough or uneven surfaces, for example. Due to that, injuries of the peroneus longus are not uncommon in runners, and are the most frequent reason for peroneus longus pain near knee.

But, what exactly causes them and how will you know if your peroneus longus is injured? Well, that’s what I will talk about next.

The Reasons Why Peroneus Longus Pain Near Knee Appears

Pain in your peroneus longus can occur for a wide variety of reasons, but it is usually due to simple overuse. However, how do you recognize that your peroneus longus is what’s hurting in the first place?

Well, the most common type of condition affecting this vital muscle is peroneal tendonitis, though it is also a rare condition overall. It is most easily recognized by the swelling on the lateral side of the ankle accompanied by pain and redness or bruising. However, many other conditions can cause those same symptoms – there are other symptoms unique to peroneal tendonitis.

The pain tends to occur along the length of the tendon or on the outside of your foot. It can also run along the outside edge of your fifth metatarsal bone. You’ll find that running will be painful and trying to dorsiflex your foot will also cause discomfort and pain.

However, you won’t suffer much pain while you’re standing or lightly pressing the swollen area. If there is significant tenderness in the area, you might be suffering from a different condition, like a metatarsal fracture for example. If you suspect you might have a different condition, visit your doctor.

Upper Back Pain After Running

There are other conditions which might cause pain in your peroneus longus, especially at the other end, near the knee. One of the most common ones is peroneal nerve entrapment, which occurs when a peripheral nerve is trapped in a tunnel by compression, stretching, impact or another form of trauma.

This most commonly occurs at the fibular neck, near the knee and the common symptoms are - decreased blood flow due to pressure on the nerve; ectopic stimuli (loss of conduction or unintended conduction of nerve signals); numbness; paresthesias (tingling or pins and needles feeling); pain near the knee; muscle weakness and more.


If left untreated, this usually temporary injury can become permanent and lead to further symptoms. Fluid will collect in the space that your nerve is occupying, and your nerve will swell which will make the symptoms more severe. You might start to feel burning sensations, which is a sign of permanent injury. The pain will become stronger, and it will worsen with activity, but it can be present even when resting.

In case you feel any of these symptoms you should go to your doctor as soon as possible and get checked out. Don’t try to run through the pain.

What are the Risk Factors?

What is the main cause of these conditions? Well, for the most part, it is overuse. When you’re running too much and on rough surfaces, you will put a lot of strain on your legs, and you might cause the compression of the nerve or the swelling of the tendon.

One risk factor particular to peroneal tendonitis is a high arch in your foot. This is because a high arch causes increased pressure on the peroneal tendons, making them more predisposed to injury. Higher intensity interval workouts and faster running also put larger pressure on the leg muscles and put you at more risk.

As for peroneal nerve entrapment, your genetics can put you at a higher risk – people with congenitally smaller nerve tunnels will naturally get this condition more frequently. Aging and bone degeneration can also put you at a higher risk. Tendons and muscles that are swollen from overuse, like the peroneus longus, will crown out the nerve and might cause it to get compressed.

Better running habits and more rest will help in either case. When you feel pain, you shouldn’t try to force yourself through it.

The Correct Treatment Options

For peroneal tendonitis, the recommended treatment consists of taking anti-inflammatory drugs as prescribed and massaging the affected area to reduce painIcing the affected area can also help, but it is not recommended since it can further hurt the muscle if applied incorrectly. In some cases, surgery might be necessary. 

Certain stretching and strengthening exercises can help return you to the full range of motion after the swelling subsides and will help prevent further injuries. Seated calf raises or standing calf raises with bent knees can be particularly effective at strengthening your peroneus longus. Three sets of thirty seconds for each, three times per day, should suffice. The right ankle supports might also be beneficial.

For peroneal nerve entrapment, the treatment is different, and it is usually not done at home. Nerve decompression surgery might be necessary, and it is effective in around 70 percent of cases. However, the symptoms may persist, and that’s probably because of permanent nerve damage – sadly, not a lot can be done about that.

Returning to Running

You can return to running after either of these conditions, but the road ahead might be long and arduous. Depending on how bad the condition was, you might be back to running in a matter of months or more than a year in some cases.

It all depends on your rehab program and how bad the injury was, which is up to your doctor but also up to you and how strictly you adhere to the instructions.

When returning to running after either of these injuries you might experience some pain, but as long as it does not get progressively worse it is not a cause for concern – it’s normal. If you do get continuous and progressively worse pain, talk to your doctor about it.


So, that’s the condensed version of everything you might need to know about your peroneus longus and the peroneus longus pain near knee associated with it. I can only hope this short guide was helpful to you and that you will be able to avoid any severe injuries. Good luck running and I’ll see you next time.

Bella Williams

Hi! I'm Bella. I love running. I write this blog to share everyone about running.

Click Here to Leave a Comment Below 1 comments
Christopher Batman - March 21, 2018

Thank you so much for the great article, it was fluent and to the point. Cheers.


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