Peroneal Tendonitis - DOC

Peroneal Tendonitis

Peroneus brevis and peroneus longus anatomy illustrated by San Francisco and Houston ankle expert

All About Peroneal Tendon Problems  A tendon is a structure that is the body’s equivalent of a cable. But instead of steel wire, thin collagen strands bundle together and connect muscle to bone. The peroneal tendons are frequently injured in runners and triathletes. They are also commonly injured during an ankle sprain. The result is pain in the outside of the ankle or foot. 


What is the Peroneal Tendon?  There are two peroneal muscles, in the outside (lateral aspect) of your leg. Their tendons course down around the ankle to connect the muscle to the foot. The peroneus longus is longer (as the name suggests) and starts up near the knee.  The peroneus brevis tendon is shorter, starting about halfway between the ankle and the knee.  

Although these two tendons have similar names and are spaced close together, they have very different functions. The peroneus longus helps stabilize the first metatarsal bone against the ground so you can push off when you walk or run. If the peroneus longus becomes weak or doesn’t work properly, the midfoot becomes unstable and a bunion can develop.  

The peroneus brevis attaches to the base of the fifth metatarsal bone. It helps to serve as your landing gear when the foot hits the ground as you walk or run. It is also the only muscle that can effectively stop your ankle from rolling over during an ankle sprain. If this muscle and tendon doesn’t work, ankle instability can result.   

Peroneus brevis and peroneus longus anatomy illustrated by San Francisco and Houston ankle expert   

What is Peroneal Tendonitis?  Peroneal tendinitis is inflammation within either of these two tendons. Peroneal tendinitis can occur anywhere along the tendon, all the way from where the tendon begins at the muscle to where it attaches to the bone in the foot. However, most often the peroneal tendinitis occurs somewhere around the outside of the ankle or foot.  Mostly this is because the tendons change direction in these areas. If overused or strained, the tendon may become inflamed and painful in this area. 

The good news is that peroneal tendinitis is usually short-lived.  It may start from some minor ankle sprain. Simply stepping in a pothole when jogging or tripping over a root when running on a trail can do it. But if given time to heal, the tendon will often repair itself and the pain will go way.  

However, sometimes when a minor peroneal injury starts, the person continues to exercise in spite of the ankle pain. Runners, cyclists, triathletes, soccer players, and basketball players are all notorious for continuing to workout while hoping the ankle pain will magically disappear. Then the normal inflammation (that’s supposed heal the tendon) turns into chronic inflammation. With chronic inflammation, the persistent inflammatory cells actually cause damage within the tendon. The tendon starts to degenerate and become weaker. This degeneration of the peroneal tendon is referred to by doctors as “peroneal tendonosis.” 

What is Peroneal Tendonosis?  Peroneal tendonosis is really an autoimmune disease of the collagen fibers that makes up the tendon. It is caused by chronic irritation of the tendon. As it progresses, the fibers start to become disorganized.  They become more prone to microscopic tears.  Over time, the tearing of the peroneal tendon can progress and make it even weaker.  It then becomes prone to splitting much the way you peel apart string cheese. It can even rupture or completely tear. If you notice pain behind the outside ankle bone, or outside of the foot, this could be peroneal tendonosis. It is very important that you seek treatment to avoid permanent tendon damage. 

You Might Have Peroneal Tendonitis/Tendonosis if you have any of the following symptoms: 

Peroneal Pain: if you have soreness, stiffness, aches, or tenderness in the peroneal tendon area, it could be tendonitis. In its early stages, you may only notice this pain when you walk or run. You might only notice some soreness in the foot and/or ankle when you get out of bed, first thing in the morning.  Many people ignore this because the pain seems to disappear as the day goes on. The pain and stiffness may decrease after you have been walking for a while.  However, runners will often notice that it hurts more and the pain returns during long runs, hill repeats and speed workouts. 

Peroneal Tenderness: if you press anywhere along the course of the peroneal tendons and you feel tenderness or pain, this should be alarming. You should never have any tenderness when you press along the peroneal tendons anywhere. If you notice tenderness in either of the peroneal tendons, you should see a foot and ankle expert immediately. 

Peroneal Deformity: any abnormal appearance of the tendon should be of concern.  The peroneal tendons are normally firm, thin and perfectly smooth. If you feel any lump, bump, knot or nodule anywhere along the tendons, this is not normal. Peroneal tendonosis is the most common reason for these types of abnormal changes in the tendon. However, there are other problems that can cause these deformities such as a ganglion cyst or other tendon tumors. 

Peroneal Subluxation: any popping or clicking in the outside of the ankle can be worrisome. If the peroneal tendons are flipping back and forth over the outside of the fibula (ankle bone) they can become weak and torn. You may only hear this sound occasionally when walking, running, or cycling. It is important to have it checked out by a sports medicine foot and ankle specialist, even if it isn’t sore.   

What Causes Peroneal Tendonitis? Most of the time, peroneal tendinitis is caused by ankle sprains or over-use. If you start to roll your ankle and the peroneus brevis fires to hold the ankle steady, it can get small splits or tears within the tendon. It is also relatively common in people who stress their ankles with cutting sports such as basketball, soccer and tennis. These folks are simply more likely to strain the tendons as they play.  

Distance runners, cyclists and triathletes often develop this problem because of the repetitive nature of their sports. If you have a foot type (such as a high-arch or supinated foot) that puts abnormal stress and strain on the tendon, it can get irritated, inflamed and injured from the thousands of strides during a marathon. Thousands of pedal strokes on long bicycle rides can have the same effect. Even though cycling is low-impact compared to running, riding a bike with an inflamed tendon can still prevent tendon healing and lead to a chronic problem.   

While peroneal tendonitis is mostly caused by a specific injury or activity, there are other factors that can put you at risk of peroneal tendon injury. Some medications can weaken the tendon and increase the risk of peroneal tendon injury and ruptures (complete tear).  If you are taking steroids (prednisone) or flouroquinalone antibiotics (Cipro, Levaquin, etc.) you should not exercise unless you have talked to your doctor. The FDA has posted “Black Box” warnings about these antibiotics and the associated risk of tendon ruptures. 

A torn peroneal tendon is serious, mainly because it is unlikely to heal on its own. Any suspected torn tendon can cause permanent damage. It needs to be evaluated by a foot and ankle surgeon, preferably one who treats runners and athletes. In some cases surgery might be needed to repair the splits in the tendon.   

Diagnosis of Peroneal Tendonitis  If you think you might have peroneal tendonitis, your foot physician will begin by taking a complete history to get an idea of how if might have started. A physical exam will be performed. X-rays are taken to determine the shape of fibula, joint alignment in the rearfoot, and to look for avulsion fractures or subtle retinacular fractures that might be related.  The exam, history and x-rays might be sufficient for your foot surgeon to get an idea of the treatment that will be needed. In some cases, you may also need an ultrasound or MRI to look closer at peroneal tendons.  While fractures show up well on xray, torn tendon, inflammation and tendon degeneration show up much better on ultrasound and MRI. These test results can usually be explained on the first visit. You then will have a full understanding of how the problem started, what you can do to treat it, and what you can do to prevent it from getting any worse. You will also know how to make your peroneal pain go away.        

How is Peroneal Tendonitis Treated?  Treatment of Peroneal Tendonitis: 

Non-surgical Treatments Surgery for peroneal tendonitis should always be the last resort. We believe that biologic treatments that preserve normal tendon anatomy are very helpful, particularly for runners, athletes, and active professionals with buy schedules. All non-surgical approaches attempt to calm down the inflammation and prevent any degeneration of the tendon. Some non-surgical treatments include: 

Oral Anti-inflammatory Medications. NSAID’s (non-steroidal anti-inflammatory medications) such as Motrin, Aleve, and Steroids (like prednisone) may help control the pain and stop the inflammation in the tendons.

Topical Anti-inflammatory Medications. NSAID’s in cream or lotion form may be applied directly to the painful area. With these, there is no concern for stomach upset or other problems often associated with oral medication.  

Ice. Ice can applied be applied right to the inflamed ankle area and help calm it down. Try applying ice to the affected area for 20 minutes per hour. Just make sure you don’t put ice directly against the skin. 

Exercises. Stretching exercises for the ankle prevent future sprains that started the problem. If you have Chronic Ankle Instability (or unstable ankles) this is critical to prevent it from coming back again. 

Pads. Placing gel pads over the tendon (at the outside of the ankle) may reduce irritation. 

Shoe modification. Avoid cycling shoes, hiking boots and ski boots that rub on the tender area. This may help stop the irritation, depending on the location of the tendonitis. 

Physical therapy. Physical therapy, such as ultrasound, massage and stretching can all reduce inflammation without surgery.

Orthotic devices. Custom arch supports known as foot orthotics control abnormal motion in the foot and stabilize the ankle to relieve stress on the peroneal tendons. Orthotics can decrease symptoms and help prevent it from happening again.  

Immobilization. In some cases, a walking cast boot or plaster/fiberglass cast is necessary to take pressure off the injured tendon, while allowing it to heal.

ESWT. Extra-corporeal Shock Wave Therapy uses high energy sound waves to break up diseased tissue in the peroneal tendon and stimulate your own body’s own natural healing processes to repair the diseased area. It is usually done in an outpatient surgery center.  There is no incision and no stitches with ESWT.  

PRP. Platelet Rich Plasma (PRP) is a therapeutic injection which uses your body’s own natural healing cells to repair the tendon. A small sample of blood is drawn from the patient and the healing factors found in the platelets are concentrated in a centrifuge. By injecting the concentrated solution right into the damaged peroneal tendon, a powerful healing can be stimulated.  This can be done in the office.  No hospital or surgery required.   

When Is Surgery Needed?  If and (only if) non-surgical attempts at tendinosis treatment fail, will it make sense to consider surgery. Having said that, we know that some types of splits, ruptures and tears in the peroneal tendons just won’t get better without surgery.  

Surgery for Peroneal tendonitis can include many different procedures. Some of these include removal of the diseased or degenerated portion of the tendon, ganglion or soft tissue tumor removal, sewing up the split in the tendon, reinforcing a weak tendon with a tendon graft, reshaping the groove in the fibula to prevent subluxation, and occasionally surgical repair of associated fractures. If the foot structure and chronic ankle instability is a primary cause of the tendonitis, surgery to repair the ligaments of the ankle (Lateral Ankle Stabilization Surgery) may be considered.  

Regardless of which exact surgery is planned, the goal is always to decrease pain and correct the problem. The idea is to get you back to your favorite activities. You will work with your foot and ankle surgeon will determine the exact surgical procedure that is most likely to correct the problem in your case. The two of you work as a team to develop a plan that will help assure success.   

How to Prevent Peroneal Tendon Problems  If you have had bouts of peroneal tendonitis, you may need to avoid running on certain surfaces. Uneven trails are notorious for stressing the peroneal tendons. Choose smooth trails or paved course to run on. Run on flat ground and avoid hill-repeats. Stay in the saddle as much as possible when cycling. Get a proper bike fit and to make sure your cleat position isn’t irritating the tendons.  If you play soccer, try to avoid fields that you know have hidden holes. If you have had many ankle sprains, you may need to wear an ankle brace. Make sure that your shoes don’t rub on the tender area. Rest the ankle at the first sign of soreness.  

If you have recurring peroneal tendon problems you might want to consider a little prophylactic cryotherapy after you work out. Just fill your bathtub with cold water and throw in a couple of trays of ice cubes.  Sitting in an ice bath is not for the faint of heart.  However, you can also kneel in the bathtub and get the same effects with much less discomfort.  Just ice your legs and knees in this way for about 10 to 15 minutes after your long runs and hard workouts.  

When to see a Foot Specialist for Peroneal Tendonitis  Any time you have clicking, popping, pain, tenderness or swelling along the outside of the foot or ankle, you should see an ankle expert. Get help immediately. Keep in mind that the micro-tears associated with chronic inflammation usually get progressively worse. It is best to stop the problem in its tracks, get it healed and then get back to your activities.