What Is Peroneal Tendon Subluxation?

Peroneal tendon subluxation occurs when one or both peroneal tendons (peroneus longus and brevis) slip out of their normal position behind the lateral malleolus, displacing anteriorly (forward). In the most dramatic cases, the tendons can be seen and felt snapping around the malleolus with ankle movement — a phenomenon called peroneal tendon dislocation.

The tendons are normally held in position by the superior peroneal retinaculum (SPR) — a fibrous band that acts as a restraining strap. Subluxation occurs when the SPR tears or becomes stretched, allowing the tendons to escape.

How It Happens

Acute peroneal subluxation most commonly occurs with sudden, forceful ankle dorsiflexion combined with reflexive peroneal muscle contraction — a defensive mechanism during a fall or landing. Skiers, soccer players, basketball players, and gymnasts are commonly affected. The injury is often misdiagnosed as a lateral ankle sprain at initial presentation, delaying appropriate management.

Chronic subluxation can develop gradually without a clear acute event, particularly in patients with a congenitally shallow fibular groove — the bony groove behind the lateral malleolus in which the tendons normally sit — that provides insufficient mechanical restraint.

Symptoms

The hallmark is painful snapping or clicking at the posterolateral ankle with activities requiring ankle dorsiflexion (running, hiking, descending stairs). Patients may be able to voluntarily reproduce the subluxation by dorsiflexing and everting the ankle. The posterolateral ankle may be tender and swollen. If subluxation is not recognized initially, patients often develop peroneal tendon tears from the repeated mechanical abrasion of the tendons against the fibular rim.

Non-Surgical Treatment

Acute peroneal subluxation (within 2–3 weeks of injury with an intact reduction) may be managed with 4–6 weeks of non-weight-bearing in a short leg cast, followed by structured rehabilitation. Conservative success rates are 50–75% for acute presentations. Chronic subluxation and cases where the tendons have already sustained tears have lower conservative success rates and typically require surgery.

Surgical Options

Superior Peroneal Retinaculum Repair

The primary surgical approach is anatomic repair and tightening of the torn or stretched SPR — reattaching it to the fibula with suture anchors and plicating (folding) any redundant tissue to restore appropriate tension. This is the most direct treatment of the underlying pathology and provides reliable results when the fibular groove is of adequate depth.

Fibular Groove Deepening

When the fibular groove is congenitally shallow or has been worn down, groove deepening (fibular groove retrohabilitation or deepening osteoplasty) is performed simultaneously. A portion of the fibular cortex behind the lateral malleolus is removed and the groove is deepened to provide a more secure mechanical pocket for the tendons. This reduces recurrence in patients with anatomically predisposing groove morphology.

Peroneal Tendon Repair

Concurrent longitudinal tears of the peroneus brevis (which occur from mechanical abrasion against the fibular rim during subluxation) are repaired simultaneously via direct suture repair and tubularization of the tendon.

Recovery

Recovery follows a structured progression: 4–6 weeks non-weight-bearing in a boot or cast, followed by progressive weight-bearing and physical therapy focusing on peroneal strengthening and proprioception. Return to running at 3–4 months and full sport at 4–6 months. Recurrence rates after surgical treatment are low (5–10%) when appropriate fixation is achieved and rehabilitation is completed.

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Dr. Tom Biernacki, DPM is a double board-certified podiatrist and foot & ankle surgeon at Balance Foot & Ankle Specialists in Southeast Michigan. With over a decade of clinical experience, he specializes in heel pain, bunions, diabetic foot care, sports injuries, and minimally invasive surgery. Dr. Biernacki is a member of the APMA and ACFAS, and his patient education content on MichiganFootDoctors.com and YouTube has reached over one million views.