Brad Dresher and Brian Donley
DEFINITION
Peroneal tendon tears are a disruption of the fibers, most commonly of the peroneal brevis tendon.
Acute tears rarely may be the result of an ankle fracture or severe sprain.
The most common type of tear, an attrition tear, is the result of multiple subluxations or peroneal tendinitis.
ANATOMY
The peroneus longus and peroneus brevis tendons both originate in the lateral compartment of the leg.
The peroneus brevis inserts into the base of the fifth metatarsal and the longus into the proximal plantar first metatarsal and the first cuneiform.
Both muscles are innervated by the superficial peroneal nerve.
The peroneus longus courses posterior to the peroneus brevis tendon as they pass through the common peroneal synovial sheath proximal to the lateral malleolus.
The superior peroneal retinaculum prevents subluxation of the peroneal tendons, forming a 1- to 2-cm fibrous sling from the posterolateral aspect of the distal fibula to the anterior Achilles sheath and lateral wall of the calcaneus.
The inferior peroneal retinaculum covers the tendons 2 to 3 cm distal to the lateral malleolus.
The peroneal tubercle of the calcaneus separates the peroneus longus and brevis into separate sheaths.
PATHOGENESIS
Traumatic rupture may occur with ankle fractures or severe sprains3 but is rare.
Partial longitudinal tears are commonly associated with peroneal tenosynovitis.
Peroneus longus tears often are seen with a painful os peroneum, an enlarged peroneal tubercle, or pathology at the cuboid or calcaneus.
Instability of peroneal tendons at the level of the superior peroneal retinaculum may be a cause of tendinitis leading to tears.
Brevis tendon tears can be caused by compression between the lateral ridge of the malleolus and the peroneus longus tendon.3
Brevis tears are commonly at the level of the distal lateral malleolus.
NATURAL HISTORY
Injury to the peroneal tendons is a frequently overlooked cause of persistent lateral ankle pain.
There have been two mechanisms described by Munk and Davis6 leading to a tear of the peroneus brevis tendon.
Subluxation of the peroneus brevis tendon may occur as a result of chronic ankle instability, and the tearing of the superior peroneal retinaculum. The tendon may split as it subluxes over the sharp posterolateral edge of the fibula.6
The second mechanism described is tearing of the brevis tendon caused by compression between the posterior fibula and the peroneus longus tendon.1
Peroneus longus tears, unlike peroneus brevis tears, are commonly seen at the level of the peroneal tubercle.
PATIENT HISTORY AND PHYSICAL FINDINGS
The evaluation of a patient with suspected peroneal pathology should start with a thorough history from the patient. Pain, swelling, and warmth may be caused by an acute injury or prolonged repetitive activity.
The patient should be asked to pinpoint the area of pain to the examiner.
Peroneus brevis tendon tears cause pain and persistent swelling along the peroneal tendon sheath and commonly behind the fibula.4
Peroneus longus tendon tears present with pain in the cuboid groove, in the plantar aspect of the foot, or at the level of the peroneal tubercle.8
Patients should be asked about other existing conditions. Rheumatoid arthritis, psoriasis, hyperparathyroidism, diabetic neuropathy, calcaneal fractures, and local injections have been associated with an increased risk of peroneal tendon tears.8
A history of subluxation or dislocation (FIG 1) can also give rise to peroneal tendon pathology.
Physical examination of the peroneal tendons should include:
Assessment for posterolateral hindfoot swelling. Swelling indicates pathology; swelling about the lateral or posterolateral side of the ankle could represent tendinitis, tenosynovitis, repetitive subluxation, or tear.
Inspection for hindfoot alignment. Any varus position from neutral is a positive finding. Varus position is associated with an increased rate of peroneal tendon disorders.5
FIG 1 • Dislocation of peroneal tendons.
Palpation along the course of the peroneal tendons should be performed to identify areas of tenderness. Any tenderness along tendons is a positive finding. Tenderness along the peroneal tendons may represent tendinitis, tenosynovitis, or tear.
Strength: ankle and foot eversion strength against resistance. Weakness in eversion is probably pathology, but near-normal eversion strength may not rule out peroneal pathology due to recruitment of other muscle groups. Strength may be decreased due to pain or tendon rupture.
Neurovascular assessment: sensory examination along the sural nerve distribution. Pain along the sural nerve distribution is assessed to rule out sural nerve neuritis.
Peroneal tunnel compression test. The foot is dorsiflexed and everted while manual pressure is applied along the retrofibular region. A positive finding (pain) indicates possible tendinitis, tenosynovitis, or tear.
Plantarflexion of the first ray. With the foot in neutral, active plantarflexion of the first ray is tested. Loss of plantarflexion of the first ray compared to the unaffected side is a positive sign. Loss or limitation of plantarflexion of the first ray is consistent with dysfunction of the peroneus longus tendon.
Testing for peroneal tendon dislocation or subluxation involves active rotation of the ankle, with subluxation or dislocation on palpation and visualization noted. Dislocation or subluxation gives rise to tendinitis or tears.
IMAGING AND OTHER DIAGNOSTIC STUDIES
Plain radiographs and weight-bearing views of the ankle and foot are obtained. An axillary heel view will allow evaluation of the peroneal tubercle and the retromalleolar groove. Radiographs are important in ruling out fractures, arthrosis, tumors, and impingement.
MRI is the study of choice when evaluating the peroneal tendons. Heterogeneity or discontinuity of the tendon, a fluidfilled tendon sheath, marrow edema along the lateral calcaneal wall, and a hypertrophied peroneal tubercle are all indications of peroneal tendon tears (FIG 2).
Often the MRI underestimates the extent of pathology with regard to tears of the peroneus longus tendon.8
Peroneal tenography allows indirect visualization of the tendons by injecting contrast into the sheaths. Tenography may be useful to test for external compression, dislocation, and complete rupture.
FIG 2 • MRI findings.
Ultrasound is noninvasive and does not expose the patient to radiation. Complete ruptures are seen as discontinuities in the tendon and partial tears are represented by focal lucencies. However, ultrasound has limited usefulness in imaging disorders of the peroneal tendons and is very dependent on the quality of the ultrasonographer.
CT scanning may be a useful tool in the assessment of peroneal tendons. Soft tissue imaging allows tendons to be differentiated from adjacent structures. Rupture, impingement, dislocation, and tenosynovitis may demonstrated.3
DIFFERENTIAL DIAGNOSIS
Sural nerve neuritis
Calcaneus fractures
Os peroneum fracture
Lateral malleolar avulsion fractures
Lateral ankle impingement
Hypertrophic peroneal tubercle
Bony spurring at the posterior lateral fibular groove of the calcaneus
Prominent exostoses
Hindfoot arthrosis
Tumor
NONOPERATIVE MANAGEMENT
Nonoperative management consists of nonsteroidal antiinflammatory medication, rest, activity modification, a lateral heel wedge, rarely use of an ankle–foot orthosis, and in difficult cases immobilization in a short-leg cast or walking boot for 6 weeks.
Use of corticosteroid injections have been reported, but tendon splitting and rupture should be considered as possible complications of injection.3
SURGICAL MANAGEMENT
Redfern and Myerson7 describe an algorithm for surgical treatment, evaluating functional tendons, mobility of the remaining peroneal musculature, ankle stability, and position of the heel.
After an MRI and clinical examination indicate a tear or rupture and the patient has failed to respond to conservative treatment, surgery is indicated.
The procedure is finalized when intraoperative examination is performed.
Upon gross examination three types of tears or ruptures are evaluated:
Type I: Both tendons are grossly intact.
Type II: One tendon is torn, the other usable.
Type III: Both tendons are torn and unusable.
Preoperative Planning
All imaging studies are reviewed.
MRI has been reported to both underestimate and overestimate the degree of tendon pathology.7
Operative planning should rest on the clinical evaluation, failure of conservative treatment, and occasionally injection of local anesthetic into the tendon sheath.7
Deformity of the hindfoot or laxity of the ankle ligaments that could cause recurrent tendon tears should be noted preoperatively and addressed in a single procedure with any peroneal tendon pathology.
Positioning
The patient is positioned supine with a bump under the ipsilateral hip.
A well-padded tourniquet is placed on the ipsilateral thigh.
Blankets are used under the operative ankle to elevate the operative extremity.
The contralateral leg is secured to the table with tape.
Approach
Following the course of the peroneal tendons, a slightly curved 10-cm incision is made posterior to the lateral malleolus and carried distally along the course of the tendons.
Blunt dissection is taken to the peroneal sheath, while protecting the sural nerve (FIG 3).
FIG 3 • Sural nerve position during approach.
TECHNIQUES
TYPE I: BOTH TENDONS GROSSLY INTACT
Perform the standard approach.
Open the peroneal sheath in line with the tendons.
Perform an intraoperative examination of the peroneal tendons to evaluate the amount of degeneration or tears (TECH FIG 1A).
Perform a synovectomy, followed by removal of any degenerated tendon (TECH FIG 1B).
If the remaining usable tendon is 50% or more of the original diameter, then a repair is indicated.
Use a running 3-0 absorbable Vicryl suture to tubularize the tendon and return it to a smooth surface (TECH FIG 1C).
Obtain hemostasis.
Repair the sheath using 2-0 suture, followed by subcutaneous closure, and use nonabsorbable suture for the skin.
TECH FIG 1 • A. Thickened peroneus longus, normal-appearing brevis. B. Débridement of peroneus longus. C. Repair of tendon.
TYPE II: ONE TENDON TORN AND THE OTHER USABLE
Perform the standard approach.
Open the peroneal sheath in line with the tendons.
Perform an intraoperative examination of the peroneal tendons to evaluate the amount of degeneration or tears.
If one tendon is found to be more than 50% unusable, then a tenodesis is indicated.
Perform the tenodesis side to side to the usable tendon proximal.7
The sheath should remain open.
Obtain hemostasis.
Subcutaneous closure and use nonabsorbable suture for the skin.
TYPE III: BOTH TENDONS TORN OR UNUSABLE
Perform the standard approach.
Open the peroneal sheath in line with the tendons.
Perform an intraoperative examination of the peroneal tendons to evaluate the amount of degeneration or tears.
In type III, both peroneal tendons are more than 50% degenerated or torn.
Examine for excursion of the proximal muscle.
If no excursion is present due to scarring and fibrosis, a tendon transfer is indicated.
If excursion is present and the tissue bed is scarred, then a staged allograft with silicone rod is considered.
If excursion is present and the tissue bed is free from scarring, then an onstage allograft or tendon transfer is considered.7
POSTOPERATIVE CARE
A posterior splint is applied in the operating room.
At 1 week the splint is changed to a partial weight-bearing cast.
At 3 weeks a wound check with suture removal is done, followed by a walking boot for 3 more weeks.
At 6 weeks a prefabricated ankle brace is applied and active range-of-motion exercises are started.
Physical therapy for calf strength is initiated at 6 weeks.
Return to activities is considered at 3 months, with an orthotic containing lateral posting.
OUTCOMES
A study by Redfern and Myerson7 assessed 29 feet with peroneus longus and brevis tears.
31% had normal peroneal strength postoperatively, and 59% had moderate peroneal strength.
9% had postoperative complications.
50% continued to experience some painful symptoms postoperatively; in all but three patients, pain was mild.
COMPLICATIONS
Wound infection
Sural nerve neuritis
Complex regional pain syndrome
Adhesive tendinitis
Failed repair
REFERENCES
1. Bassett FH III, Speer KP. Longitudinal rupture of the peroneal tendons. Am J Sports Med 1993;21:354–357.
2. Bonnin M, Tavernier T, Bouysset M. Split lesions of the peroneus brevis tendon in chronic ankle laxity. Am J Sports Med 1997;25: 699–703.
3. Clarke H, Kitaoka HB, Ehman RL. Peroneal tendon injuries. Foot Ankle Int 1998;19:280–288.
4. Krause J, Brodsky J. Peroneus brevis tendon tears: pathophysiology, surgical reconstruction and clinical results. Foot Ankle Int 1998; 19:271–279.
5. Manoli A II. The subtle cavus foot, “the underpronator,” a review. Foot Ankle Int 2005;26:256–263.
6. Munk R, Davis P. Longitudinal rupture of the peroneus brevis tendon. J Trauma 1976;16:803–806.
7. Redfern D, Myerson M. The management of concomitant tears of the peroneus longus and brevis tendons. Foot Ankle Int 2004; 25:695–707.
8. Selmani E, Gjata V, Gjika E. Current concepts review: peroneal tendon disorders. Foot Ankle International 2006;27:221–228.