Chronic Ankle Instability: When Repeated Sprains Lead to Ligament Surgery

Almost everyone has rolled an ankle. For most people it swells, aches for a few weeks and then fades from memory. For others it never quite settles. The ankle turns on uneven pavement, on a curb, on a trail, sometimes on flat ground, and each sprain seems to come more easily than the last. That pattern is what surgeons call chronic ankle instability.

This guide explains why some sprains turn into a chronic problem, what rehab should look like before surgery is considered, how ligament repair and reconstruction work, and what to ask before committing to an operation. It is general information. Only an orthopedic or foot and ankle surgeon who has examined you can tell you whether surgery fits your situation.

The ligaments behind most sprains

The common sprain is an inversion injury, where the foot rolls inward and the outside of the ankle takes the strain. According to the American Academy of Orthopaedic Surgeons, around 90% of ankle sprains involve this kind of injury to two ligaments on the outer ankle: the anterior talofibular ligament (ATFL) and the calcaneofibular ligament (CFL) (AAOS OrthoInfo, accessed 2026). A less common sprain affects the deltoid ligament on the inside of the ankle.

Sprain grades at a glance

Grade	Ligament damage	Looseness on exam
1	Stretching and microscopic tearing	No instability
2	Partial tear	Slight looseness compared with the other ankle
3	Complete tear	Marked instability

Source: AAOS OrthoInfo. Even a complete grade 3 tear can heal without surgery if it is immobilized and properly rehabilitated, according to AAOS. That is the first clue that most ankle surgery for instability is about failed healing, not the initial injury.

How a sprain becomes a chronic problem

AAOS identifies incomplete rehabilitation as the most common cause of chronic instability after a sprain. People feel better, skip the balance work and go back to sport before the ankle has relearned how to protect itself.

Part of what is lost is proprioception, the joint's sense of its own position. When that sense is off, the muscles react a fraction too late, the ankle rolls again, and each new sprain can stretch the ligaments further. Over time, repeated injury can lead to chronic pain and damage to cartilage and bone.

A study of an arthroscopic repair technique defined chronic lateral ankle instability as recurrent sprains or a sense of giving way that persists for at least 12 months after a significant injury, and cited earlier work finding that roughly 20 to 30% of athletes with a previous sprain report lingering pain and instability (Liu et al., 2023).

Warning signs worth a specialist visit

• The ankle gives way repeatedly, especially on uneven ground.
• Pain lasts beyond 4 to 6 weeks after a sprain, which AAOS notes may indicate a chronic problem.
• Persistent swelling or a sense of looseness.
• Catching or locking, which can suggest a loose fragment or cartilage injury.
• You avoid sports or walking on trails because you no longer trust the ankle.

AAOS notes that MRI may be considered if symptoms continue beyond 6 to 8 weeks despite conservative care. Imaging helps show ligament damage and associated problems, such as cartilage or tendon injuries, that might be treated at the same time as the ligament.

Rehab done properly

Because incomplete rehab is such a common cause, a structured program is the standard first step. AAOS describes three phases:

1. Protection and swelling control, with a brief period of immobilization if needed. For grade 3 sprains this may mean a cast or cast-brace for 10 to 14 days.
2. Restoring function: range of motion, strengthening and, crucially, balance training. Immobilization ends during this phase to prevent stiffness.
3. Graded return to activity, building toward the specific demands of your sport or job.

AAOS describes the whole program as taking as little as 2 weeks for minor sprains and up to 6 to 12 weeks for more severe injuries. If you have never done a supervised balance program, that is often the first thing a surgeon will ask you to try.

When surgery becomes reasonable

Surgery for ankle sprains is rare, AAOS says. It is reserved for people who still have instability and pain after months of rehabilitation and nonsurgical treatment. Surgery may also be considered when a severe sprain comes with other injuries, such as cartilage damage or a tendon rupture, or for a high ankle sprain with instability of the syndesmosis, the ligament complex that binds the two lower leg bones together.

The surgical options

AAOS describes three main approaches. Many operations combine them.

Approach	What it does
Arthroscopy	A camera-guided look inside the joint to remove loose fragments of bone, cartilage or ligament; may also be used to place stitches that repair ligaments through small incisions
Open repair	The torn or stretched ligament is stitched under direct view
Reconstruction	The damaged ligament is replaced with a tissue graft, usually taken from a nearby tendon or ligament

The Broström-type repair

The most familiar repair for lateral instability carries the name Broström. The 2023 study above describes it as an anatomic repair of the ATFL, first proposed in 1966 and later modified by other surgeons. It can be done open or arthroscopically. In a group of 39 patients treated with an arthroscopic version and followed for an average of 22 months, the authors reported improved pain and function scores, and 33 of the 39 returned to their pre-injury level of activity (Liu et al., 2023). That is a single small series with one technique, so treat it as an illustration of the procedure, not a prediction for you.

When a graft is needed

If the native ligament tissue is too poor to repair, or a previous repair has failed, surgeons may reconstruct the ligament with a graft. Ask where the graft would come from and how that affects your recovery.

Recovery after ligament surgery

AAOS notes that a cast or protective boot is typically used for a period of immobilization, and warns that putting weight on the ankle or moving it too early can tear the repair or graft. Rehab then works on strength, motion and balance, and may take weeks to months depending on the injury and the operation.

Plan for these practical needs:

• Crutches or a knee scooter, and a home set up for limited weight bearing.
• Time off work if your job involves standing or walking.
• Driving restrictions, which are stricter if the right ankle is the operated side.
• A physical therapist lined up for the balance and strength phase, which is what protects the repair long term.
• Clear criteria for returning to sport, agreed with your surgeon.

Repair or reconstruction: how the choice is usually made

Patients often ask whether one operation is "better." In practice, the choice follows the tissue. If the existing ligament is stretched but still usable, a repair that tightens and reattaches it is generally the first option. If the tissue is badly damaged, very thin, or a previous repair has failed, a graft may be needed to rebuild it. Factors such as body weight, the demands of your sport or job, and general ligament looseness can also influence what a surgeon recommends.

The decision is sometimes finalized only during surgery, once the surgeon can see the tissue. Ask in advance what would lead them to switch from a repair to a reconstruction, and how that would change your recovery and cost.

Possible complications

Every operation carries the general risks of infection, wound problems and blood clots. Around the ankle, small sensory nerves run close to the surgical area. In the 2023 series, two of 39 patients had irritation of the superficial peroneal nerve, which persisted in one. Ask your surgeon how they protect nearby nerves and what symptoms to report.

If you are planning surgery away from home

An ankle operation affects your ability to walk through airports, carry luggage and sit with the leg down for hours. Long flights deserve real thought after ankle surgery: the CDC's traveler guidance points out that an operation and a flight each add to clot risk on their own, and that combining them compounds it (CDC Yellow Book, 2026 edition). Ask your surgeon when it is safe for you to fly and whether you need clot prevention.

• Send MRI images and a written history of your sprains and rehab before booking.
• Request wheelchair assistance at airports.
• Confirm who will check the wound and when you move out of the cast or boot.
• Bring the surgeon's written rehab protocol home to your physical therapist.

Questions to ask your surgeon

• Is my problem mechanical looseness, poor balance control, or both?
• Have I had enough supervised balance rehab to rule out a nonsurgical fix?
• Does my MRI show cartilage or tendon damage that should be treated at the same time?
• Would you repair my ligament or reconstruct it with a graft?
• How long will I be in a cast or boot, and when can I bear weight?

Frequently asked questions

Can a completely torn ankle ligament heal without surgery?

Often, yes. AAOS notes that even a complete grade 3 tear can heal without surgical repair if it is immobilized and rehabilitated properly. Surgery is usually reserved for instability that persists after months of rehab.

Why does my ankle keep rolling even though the sprain healed?

AAOS identifies incomplete rehabilitation as the most common cause of chronic instability. Loss of proprioception, the ankle's sense of its own position, can make the muscles react too late, leading to repeat sprains. A structured balance and strength program is usually the first step.

What is the Broström procedure?

It is a repair of the anterior talofibular ligament on the outside of the ankle, first described in 1966 and modified since. It tightens and reattaches the stretched or torn ligament and can be done through an open incision or arthroscopically.

Will I need a cast after ankle ligament surgery?

AAOS notes that a cast or protective boot is typically used for a period after surgery, because early weight bearing or movement can tear the repair. How long depends on your surgeon's protocol and the procedure.

When should I get an MRI for a sprained ankle?

AAOS says MRI may be considered when symptoms continue beyond 6 to 8 weeks despite conservative treatment. It can show ligament damage and related injuries such as cartilage or tendon problems.