Establishing A Conservative Treatment Algorithm For Peroneal Tendon Tears

Disorders of the peroneal tendons are an underappreciated cause of lateral hindfoot and ankle pain.^1-7 In fact, in a study of a variety of healthcare providers, Dombek and colleagues found only 60 percent of peroneal tendon injuries had a proper diagnosis at the initial office visit.¹

Among these disorders, peroneal tendon tears can often be chronically debilitating for the active individual. These tendons function as the primary evertors of the foot and provide dynamic stabilization of the lateral ankle.^2,8 When a tear develops within a tendon, chronic swelling, pain and a feeling of instability of the ankle may occur.^3,4,9-11 Although much less likely, deformity of the hindfoot also reportedly sets in over time if weakness of the peroneal tendons goes unchecked.⁸ Early recognition is important as it may increase the effectiveness of conservative treatment while potentially reducing downtime from activity.

We do not clearly understand the etiology behind the development of peroneal tendon tears but researchers believe they result from a combination of mechanical and anatomic factors.^1,8 Authors have documented acute lateral ankle sprains as common precipitating events but have also described other potential mechanisms, including chronic ankle ligamentous laxity and peroneal subluxation.^1,3,4,12

When an inversion stress occurs at the foot, the lateral soft tissue structures can stretch, tear or rupture depending on how much force the foot experiences. If the superior peroneal retinaculum becomes compromised, the peroneal tendons may sublux and repetitively wear against the posterolateral ridge of the fibula, leading to a tear of the tendons.^{1,3,5,6,8-10,12} Tears could also potentially develop from stenosis within the retrofibular groove from a low-lying muscle belly, peroneus quartus, proliferative tenosynovitis or another space-occupying mass, thus compressing and wearing the tendons against the posterior aspect of the distal fibula.^1,3-5,9,12 In particular, researchers believe the peroneal brevis tendon is more commonly involved due to its compromising position between the peroneus longus and distal fibula.^5,10-13

Other anatomic variants that may contribute to peroneal tendon tears include a convex fibular groove, hypertrophic peroneal tubercle, posterior lateral fibula spurring or a cavovarus foot type.^1,4-7,10

The true incidence of peroneal tendon tears is also unknown but authors think it is more common than actually reported.^6,8,10,13 Sobal and colleagues demonstrated an 11.3 to 37 percent presence of attritional wearing of the peroneal brevis tendon in cadaveric specimens in two studies.^11,13 Miura and coworkers also reported a similar 37.5 percent presence of peroneal brevis tendon split lesions within their sample of 112 cadaveric ankles within the Japanese population.¹⁰ Regardless of the true incidence of peroneal tendon tears, researchers generally agree that treatment should focus on the symptomatic lesion, which in theory arises less often clinically.^3,8

Essential Diagnostic Insights

On the clinical exam, tenderness and swelling along the course of the peroneal tendons (usually in the retrofibular space) are the most consistent findings when a partial tear of a tendon is involved.^1,4-6,8 In particular, manually compressing the retrofibular space with resistance to active dorsiflexion and eversion of the foot can often elicit pain.⁵ One should also assess the potential for subluxation of the tendons and instability of the ankle joint during the clinical exam. Consider X-rays initially, especially if one suspects an os peroneum or other contributing osseous pathology.^4,7

While magnetic resonance imaging (MRI) is the gold standard for visualization of the tendons and surrounding soft tissues, use caution in interpreting the results as researchers have reported a poor association between MRI and intraoperative findings.^1,2,4,6-8

Diagnostic ultrasound can also be highly sensitive and specific in observing tendon pathology depending on operator experience, and it is a useful modality to assess for dynamic subluxation of the tendons.^2,4,12

Keys To Conservative Treatment Of Peroneal Tendon Tears

Initial conservative treatment focuses on reducing inflammation while providing support to the tendons to allow them to heal. This occurs through the PRICE (protection, rest, ice, compression and elevation) method along with anti-inflammatory medications.^4,7,12 Consider protection in the form of orthoses with or without a lateral wedge, ankle bracing, or a boot or cast depending on the severity of symptoms. While formal physical therapy is a mainstay in the rehabilitation process, the tenosynovitis needs to calm down before therapy can commence to reduce the risk of flare-ups and worsening of the condition.⁴

Our initial approach to isolated peroneal pathology is through a careful clinical exam and a progressive treatment algorithm. Cases may range from mild symptoms that may benefit from nonsteroidal anti-inflammatory medications, orthoses and supportive shoes to severe symptoms that may require a below-the-knee walking boot and oral steroids. In the latter condition, it is our preference to place the patient on a 16-day tapered course of prednisone, tapering down 5 mg from 40 mg every two days. The patient then returns after two to three weeks. At this point, physical therapy may begin if the inflammation has calmed down enough. If the patient wore a boot, the therapy team may also assist in gradually transitioning the patient back into a supportive shoe with or without a lace-up ankle brace.

Exercise restraint when prescribing traditional physical therapy as strengthening and proprioception exercises often cause a repeat flare-up of symptoms. Our current therapy protocol includes ultrasound of the tendon area followed by instrument-assisted soft tissue mobilization (IASTM) techniques such as the Graston^® Technique (Graston Technique) and Astym^® (Astym). These techniques are often helpful for chronic tendinopathies as they are designed to produce a controlled, localized inflammatory response, stimulate fibroblast proliferation and improve mobilization by reducing scar tissue.^14-16 We generally schedule therapy sessions with both ultrasound treatment and IASTM techniques twice a week for three or four weeks. For those individuals who do not respond to this protocol, an MRI (if you haven’t already obtained one) may be prudent to assess the quality of the tendons and look for any other cause that may be contributing to the persistence of symptoms.

Intra-Sheath Steroid Injections: Can They Have An Impact For Resistant Peroneal Tears?

In the resistant case of peroneal tendon pain, longitudinal tears of the peroneus brevis, either in isolation or in combination with the peroneus longus tendon, are very common findings on MRI. The tendons still remain functional in this orientation but the associated inflammation to the surrounding tissues often makes continued use of the tendons difficult. We have found intra-sheath steroid injections to be a useful adjunctive treatment modality in this scenario.

It is our preference to perform these injections with fluoroscopic guidance to make sure we are truly delivering the medication to the area of pathology. Our usual mixture is 1 mL of 0.5% bupivacaine, 1 mL of 4 mg/mL dexamethasone sodium phosphate and 1 mL of fluoroscopic dye. Injecting medication into the tendon sheath often has a tendency to lead to proximal extravasation, even if one is directing the needle and pushing distally. To counter this, it is generally easier to start distal and work proximal.

To begin, determine the distal course of the peroneus brevis tendon by having the patient dorsiflex and evert the foot. The tendon insertion on the base of the fifth metatarsal is generally more dorsal on the foot than one would typically think. After determining the course, proceed to inject the needle proximal to the insertion and feel for the different layers of tissue while advancing the needle. Once the needle is in the sheath, deliver some of the medication into the area with fluoroscopic visualization. The dye should stay within the sheath. After confirming placement, continue to push the medication while making sure it covers the area of pathology. Often, this requires that the dye advance around the lateral malleolus of the ankle. If it does not, as sometimes can be the case with stenosing tenosynovitis, one may need to select additional injection points along the tendon sheath.

Two to four injections spaced several weeks apart are often needed to get the area to completely calm down but the patient should see noticeable improvement with each one. Physical therapy may then resume to assist in advancement back to activity.

When Patients Need Surgery For Peroneal Tears

If the patient’s symptoms prove resistant to conservative measures, surgical intervention may be warranted to reestablish some degree of functionality and stability to the hindfoot and ankle. This may range from simple debridement with direct repair of the degenerative tendon to the complex reconstruction, and is often based upon the viability of the tendons and degree of underlying causative factors.

Krause and Brodsky, and Redfern and Myerson have all developed algorithms based on intraoperative findings to assist in the surgical decision-making process.^6,8 Several studies have suggested that surgical intervention is often required when a longitudinal split tear of a tendon is involved.^2,6

Our conservative protocols have proven to be fairly effective in our practice, greatly reducing the number of individuals who ultimately require surgery. Admittedly, some patients fare better than others. In our experience, those whose primary sport involves running generally do not have as much successful long-term results with conservative management as those returning to other forms of physical activity.

In Conclusion

Always be suspicious of peroneal tendinopathy in the presence of lateral hindfoot and ankle pain. Our progressive treatment protocol includes providing protection and support to the tendons, anti-inflammatory modalities including potential intra-sheath steroid injections, and the advancement of physical therapy. With proper utilization of the aforementioned conservative modalities, we can increase the patient’s ability to return to normal physical activity fairly quickly and potentially avoid the necessity of surgery.

Dr. Pentek is a Sports Medicine Podiatry Fellow at Virginia Mason Medical Center in Seattle.

Dr. Reeves is an attending physician at the Virginia Mason Podiatric Sports Medicine Fellowship at the Virginia Mason Medical Center in Seattle. He is also an Associate Professor at the California College of Podiatric Medicine at Samuel Merritt University. He is a Fellow of the American Academy of Podiatric Sports Medicine.

Dr. Heit is the Fellowship Director of the Sports Medicine Fellowship at Virginia Mason Medical Center in Seattle.

References

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