Peroneal Tendon Subluxation: The "Ankle Sprain" That Isn't

Key Takeaways

• Peroneal tendon subluxation occurs when the superior peroneal retinaculum tears, letting the peroneus longus and brevis tendons slip out of the fibular groove behind the outer ankle bone.
• Up to 88% of peroneal tendon subluxation cases are initially misdiagnosed as a routine lateral ankle sprain, according to case-series data in the orthopaedic literature.
• The hallmark symptom is a snapping or popping sensation over the back-outer ankle during cutting, pivoting, or skating motions, distinct from the aching, diffuse pain of a sprain.
• A newly described modified Das De procedure (Subawa & Febyan, Arthroscopy Techniques, August 2026) reconstructs the retinaculum with local tissue instead of altering bone, aiming for a faster, lower-morbidity return to sport.
• Athletes treated surgically for chronic peroneal instability typically return to full sport participation within 3 to 6 months with a structured rehabilitation protocol.

The Hook

In August 2026, surgeons Subawa and Febyan published a technical note in Arthroscopy Techniques describing a modified surgical fix for a foot and ankle problem that gets missed more often than almost any other lateral ankle injury: peroneal tendon subluxation, also called peroneal tendon dislocation. Their paper, 'Modified Das De Procedure in Peroneus Longus Tendon Dislocation,' lays out a soft-tissue technique to stabilize the peroneal tendons without cutting bone, and it underscores a point I make in clinic almost every week. When an athlete rolls the outside of the ankle and feels or hears a 'snap' or 'pop' along the outer ankle bone, the default assumption is almost always a simple ankle sprain. Often, it is not. It is the peroneal tendons slipping out of the groove behind the fibula, and if it is treated like a sprain, it keeps happening.

Short answer:

Peroneal tendon subluxation is when the two peroneal tendons behind the outer ankle bone (fibula) slip out of their normal groove because the retinaculum holding them in place tears or stretches. It causes a snapping or popping sensation with recurrent 'giving way,' is frequently misdiagnosed as an ankle sprain, and is confirmed with a dynamic ultrasound or MRI. Persistent or recurrent cases are treated surgically with retinacular repair or groove-deepening, often allowing athletes to return to sport in 3–6 months.

The Science

What causes peroneal tendon subluxation? It happens when the superior peroneal retinaculum (SPR), a thin fibrous band anchoring the peroneus longus and peroneus brevis tendons inside the retromalleolar groove behind the fibula, tears or stretches under a sudden, forced dorsiflexion-and-eversion load, most often in skiing, basketball, soccer, ice skating, and gymnastics. Once the SPR fails, the tendons are free to sublux (partially slip) or fully dislocate over the fibula with every push-off, cutting, or pivoting motion.

Roughly 82% of people have a shallow or convex retromalleolar groove rather than the deep, concave groove that normally locks the tendons in place, per cadaveric and imaging studies, a structural variant that predisposes some athletes after a single traumatic event, and explains why the injury clusters in cutting/pivoting sports and rigid-boot sports like skating and skiing.

Diagnosis is tricky because the tendons often spontaneously reduce between episodes, so a static exam or a standard MRI taken with the foot still can look deceptively normal. Level IV case-series and systematic-review evidence (Foot & Ankle International; Knee Surgery, Sports Traumatology, Arthroscopy) supports dynamic ultrasound — imaging the groove while the examiner resists active eversion — as the most sensitive way to catch the tendons subluxing on demand. The tell-tale clinical clue is a palpable or audible snap directly over the fibula, not the diffuse ligament tenderness typical of an inversion sprain.

The Solution at P.O.W.

How is peroneal tendon subluxation treated at Prisk Orthopaedics and Wellness? Treatment starts non-operatively for a true first-time, acute subluxation and escalates to surgery for recurrent instability, the pattern we see in most athletes by the time they reach our office. Acutely, I typically recommend 4 to 6 weeks in a below-knee cast or rigid boot with the foot held in slight plantarflexion and inversion to protect the healing retinaculum, followed by peroneal-specific strengthening and proprioceptive retraining.

Once an athlete has recurrent subluxation or frank dislocation, common, since a torn retinaculum rarely heals well enough on its own to withstand cutting sports, surgery becomes the more predictable path back. As the foot and ankle sports medicine surgeon at P.O.W., I tailor the surgical plan to each case: superior peroneal retinaculum repair or reconstruction (techniques like the modified Das De procedure in this month's literature use local fascia and tendon-sheath tissue rather than bone), retromalleolar groove deepening for a shallow groove, or both together when needed. Any associated fibular rim fracture or lateral ligament tear is addressed in the same setting. Post-operatively, athletes progress through a staged P.O.W. rehab program,  protected weight-bearing, then peroneal strengthening, then sport-specific cutting drills,  with most cleared for full sport between 3 and 6 months.

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