Peroneal tendonitis is inflammation of the peroneal tendons. The tendons are part of the peroneus brevis and peroneus longus muscles that help to stabilize the foot when walking, and control the eversion, or movement to the outside, of the foot. They run down the lateral (outer) length of the fibula (one of the lower leg bones), through a groove behind the lateral malleolus (outer anklebone), and along the outer edge of the foot to attach to bones in the foot. Contraction of the peroneal muscles causes the tendons to glide within the groove, causing the foot to either point down or out to the side.
These tendons are exposed to repetitive stress and are vulnerable to damage. Small tears, usually along the line of the tendon, can gradually accumulate and eventually cause symptoms. The normal response of the body to injury is inflammation and swelling as healing nutrients are brought in the blood to the damaged area. This inflammatory response causes pain and, in the case of peroneal tendonitis, may cause a patient to limp when walking, or, if severe enough, prevent participation in normal sporting activities.
Although a particular accident such as an ankle sprain may be the cause of peroneal tendonitis, more usually it develops over time with repeated stresses placed upon the tendons. It can develop during recovery from an ankle sprain when the peroneal muscles have to work harder to support an unstable ankle joint. The natural shape of the foot may be a predisposing factor: for example, a high arch commonly places disproportionate stress on the tendons. The natural aging process can also be a factor as it leads to brittle tendons that are more susceptible to damage.
Typical symptoms of peroneal tendonitis may include:
- Ache above or below the outer anklebone, which may be during or after exercise, at night, upon getting up in the morning, or, if the condition is severe, constant
- Prominent peroneal tendons when standing
- Noticeable limp when walking
- Possible swelling visible behind the outer anklebone
- Warmth in the affected area
- Tenderness behind the outer anklebone when pressed
- Numbness or burning sensation on the outside of the foot
- Decreased ability to evert the foot (move the foot outwards)
Your doctor will ask you about your medical history, including any previous injuries to your ankle, leg or hip. You will be asked about your general health, level of activity and any sports that you may participate in. Your current condition will be discussed and your doctor will ask about any injury that caused the initial pain. Your symptoms will be noted and considered.
Your foot, ankle and lower leg will be physically examined. You may be asked to walk so that the doctor can evaluate your gait and the natural positioning of your feet. Your ankle will be manipulated to assess the strength and stability of the joint, and it will be palpated (touched) to determine areas of tenderness.
X-rays will probably be taken to rule out bone fractures, and an MRI (magnetic resonance imaging) scan may be performed to view the ligaments and other soft tissues of the ankle and to determine the presence and extent of any peroneal tendon tears, along with any other soft tissue injuries.
Treatment depends on the severity of the injury. Inflammation without peroneal tendon tears will usually subside with nonsurgical methods. Such treatment includes:
In some instances surgery is necessary to trim any damaged tendon, repair any tears or improve the track behind the fibula that the peroneal tendons run along. Other surgical procedures might include repairing the thick tissue over the tendons that normally holds them in the groove. The peroneal tubercle, a lump of bone on the outside of the heel, may need removal if it is enlarged and irritating the peroneal tendons. Likewise, any bony spur on the back of the fibula that is causing inflammation can be trimmed. Rarely, the heel is surgically repositioned to redistribute force more equally over the rear part of the foot. Occasionally, if a peroneal tear involves more than 50% of the tendon, the tendon is stitched to the other tendon for stability. In general, a careful assessment is made of the stability and alignment of the ankle, and surgical procedures performed to relieve pressure on the peroneal tendons.
- Relieving pressure on the tendons to prevent further injury and allow healing to begin. A brace such as an ankle lacer or a short-leg walking boot can be worn for two to four weeks to immobilize the ankle.
- Ice, crushed in a bag and with a towel protecting the skin, can be applied to the inflamed area for as long as is comfortable, several times a day. This will help to reduce inflammation and relieve pain.
- Over the counter pain medication can be taken, such as acetaminophen (Tylenol) or NSAIDs (non-steroidal anti-inflammatory drugs).
- Refraining from activities that put pressure on the tendons, for a few weeks, will allow healing to take place.
- Wearing orthotics, if you have a high arch, will adjust the position of your foot so as to relieve pressure on the peroneal tendons. The most useful orthotic for this condition has a recessed area under the head of the first long bone in the foot.
- Physical therapy, to treat the acute phase of the injury and then to strengthen muscles, improve balance, and increase range of motion, may include such measures as ice, heat, and ultrasound.
- Cortisone injections provide relief in cases where symptoms will not abate, but due to the risk of rupturing a tendon, these injections are seldom given.
Following surgery you would wear a short-leg cast for up to six weeks and then a walking boot for another month.
Whether or not you have had surgery, physical therapy will play a large part in rehabilitating the ankle. A return to your normal activities, especially sports, must be undertaken slowly and carefully so as not to inflame the vulnerable tendons. Full recovery can take several months.