- Chronic ankle instability is the persistent sense that the ankle "gives way," typically following one or more prior sprains.
- It is caused by stretched ligaments combined with impaired proprioception (balance control) that didn't fully recover from the initial injury.
- Treatment starts with a structured PT program focused on proprioception and peroneal strengthening — this resolves the majority of cases.
- Surgical ligament reconstruction (modified Broström procedure) is highly effective for cases that don't respond to PT.
- Recurrent sprains in a person with high-arched feet often need a longer reconstruction that also addresses foot mechanics.
What is chronic ankle instability?
Chronic ankle instability is the long-term consequence of one or more inadequately treated ankle sprains. The lateral ligaments — usually the ATFL and CFL — heal in a stretched position, and the proprioceptive system (the nerve feedback that tells your brain where your ankle is in space) doesn't fully reset. The result: the ankle rolls inward easily on uneven ground, on stairs, or during athletic activity, and the patient develops a chronic sense of mistrust in the joint.
It is most common in patients who have had multiple ankle sprains over the years, especially if those sprains were treated with rest alone rather than a structured rehabilitation program. High-arched foot types are particularly prone because the foot naturally tilts inward and predisposes to lateral sprains. Athletes in basketball, volleyball, soccer, and trail running are at higher risk.
At Northwest Extremity Specialists, our first move with chronic ankle instability is almost always a structured physical therapy program targeting proprioception, peroneal strengthening, and balance reflexes — this resolves the majority of cases. For ankles that have failed at least 6–8 weeks of dedicated PT, ligament reconstruction is highly effective. Modern modified Broström procedures restore ligament tightness and rebuild a stable ankle, with predictable return to sport.
See it in motion
Animations licensed from ViewMedica · Swarm Interactive
The lateral ligaments of the ankle (ATFL, CFL, PTFL) work together with the peroneal tendons (on the outside of the ankle) and the proprioceptive nerves to keep the ankle stable. When the ligaments are stretched from a prior sprain, the peroneal tendons must work harder to compensate. When they can't keep up — for example, on uneven terrain or fatigued at the end of a game — the ankle rolls and the cycle of instability repeats. Each subsequent sprain stretches the ligaments further.
What it feels like
Chronic ankle instability has a recognizable pattern of complaints:
- A repeated "giving way" of the ankle, especially on uneven ground
- A history of multiple ankle sprains on the same side
- Discomfort or aching in the ankle after activity
- Difficulty walking on uneven surfaces or hiking trails
- A sense of mistrust in the ankle — avoiding certain activities
- Swelling that comes and goes
- Lateral ankle tenderness
- Some patients also develop peroneal tendonitis from compensation
Why it develops
Chronic instability develops from the combination of mechanical and neuromuscular factors:
- One or more prior ankle sprains that did not fully rehabilitate
- Inadequate proprioceptive retraining after sprain recovery
- High-arched (cavus) foot type that predisposes to inversion
- Generalized ligamentous laxity (hypermobile joints)
- Loss of strength in the peroneal tendons
- Repeated participation in cutting or jumping sports without proper rehab between injuries
How we diagnose chronic ankle instability
A chronic instability exam includes a careful history (number and pattern of prior sprains), specific ligament stress tests (anterior drawer, talar tilt), proprioception assessment, and a foot-type evaluation to check for an underlying cavus deformity that may be contributing. Weight-bearing X-rays and sometimes stress X-rays are taken in our office. MRI may be used to evaluate cartilage damage, peroneal tendon involvement, or to plan surgery. Most patients leave the same day with a clear diagnosis and a structured rehabilitation plan.
Non-surgical care
The first-line treatment for chronic ankle instability is a structured PT program — not just generic strengthening, but a specific protocol focused on the proprioceptive and neuromuscular factors that drive instability:
- Formal physical therapy 1–2 times per week for 6–8 weeks
- Proprioceptive training (single-leg balance, BOSU work, wobble board)
- Peroneal tendon strengthening
- Functional sport-specific drills (cutting, jumping, landing mechanics)
- Lace-up ankle brace for activity, especially during rehabilitation
- Custom orthotics if a cavus foot type is contributing
- Lifestyle modifications during the rehab phase
- Home exercise program to maintain gains long-term
Surgical care
Surgical reconstruction is highly effective for patients whose ankle continues to give way despite at least 6–8 weeks of dedicated PT. The modified Broström procedure is the gold-standard operation, with excellent long-term results.
- Modified Broström procedure — repair and reinforcement of the stretched ATFL (and often CFL)
- Brostrom-Gould procedure — Broström with an additional retinacular reinforcement
- Anatomic ligament reconstruction with allograft or autograft tendon for revision or high-demand cases
- Combined procedures with peroneal tendon repair, cartilage treatment, or calcaneal osteotomy when indicated
After a modified Broström, patients are typically immobilized in a cast or boot for 2–4 weeks, then progress through a boot with gradual range of motion. Return to walking is around 6 weeks, return to running 3–4 months, and return to cutting sports 4–6 months. Outcomes are excellent — over 90% of patients return to pre-injury activity level with a stable ankle.
When to see a specialist
- A history of multiple ankle sprains on the same side
- A chronic sense that the ankle "gives way" or can't be trusted
- Avoiding activities you used to enjoy because of ankle instability
- Persistent ankle pain or swelling between sprains
- Recent acute sprain plus prior history of repeated sprains — early specialist involvement helps
Chronic ankle instability is initially evaluated by our sports medicine team — Dr. Todd Galle in Wilsonville and Dr. Manny Moy at Cedar Mill — or any of our board-certified podiatrists. Surgical reconstruction is performed by Dr. Ron Bowman or our surgical podiatry team (Dr. Horvath, Dr. Melillo) at our Tigard Locust office.