Blog 2: Ankle Sprains: Why Most Athletes Never Recover
Part 2: Chronic Ankle Instability: Why It Keeps Happening and What Is Really Going On
Welcome back to Ankle Sprains and Chronic Instability. In Part 1 we covered what actually happens during a lateral ankle sprain, why the injury involves more than just the ligaments, and why up to 40 percent of sprains progress to chronic instability when rehabilitation is inadequate. Part 2 goes deeper into chronic instability itself. What is actually happening in the ankle that makes it keep giving way?
What Chronic Ankle Instability Actually Is
Chronic ankle instability is defined clinically as a condition characterized by recurrent episodes of the ankle giving way, persistent feelings of instability, and repeated lateral ankle sprains occurring more than twelve months after the initial injury. It is not just a weak ankle. It is a complex interaction between mechanical changes to the joint structures and neurological changes to how the nervous system controls and protects the ankle.
Researchers divide chronic instability into two components:
Mechanical instability: objective laxity in the lateral ligament complex resulting from inadequate healing of the initial sprain. When ligament fibres heal with scar tissue rather than properly organized collagen, the mechanical restraint they provide to inversion is reduced. The ankle has more range of motion than it should in directions the ligaments are supposed to prevent.
Functional instability: neuromuscular and proprioceptive deficits that impair the ankle's ability to protect itself even when the mechanical integrity of the ligaments is relatively intact. Many athletes with chronic instability have ligaments that have healed adequately but continue to experience giving way episodes because the nervous system's ability to anticipate and respond to inversion forces is significantly impaired.
In clinical practice, most athletes with chronic instability have elements of both. The mechanical laxity creates an ankle that is more vulnerable to inversion forces, and the proprioceptive deficit means the neuromuscular response that should catch and correct that inversion arrives too late to prevent it.
The Proprioceptive Deficit: The Missing Piece in Most Rehabilitation
Proprioception is the body's ability to sense the position and movement of a joint without visual input. In a healthy ankle, mechanoreceptors in the ligaments, joint capsule, and surrounding muscles continuously provide the nervous system with information about ankle position. When the ankle begins to invert, this information triggers a rapid neuromuscular response in the peroneal muscles that resists the inversion and protects the lateral structures.
In a sprained ankle, the mechanoreceptors in the damaged ligaments are injured alongside the ligament fibres themselves. The information they provide to the nervous system is reduced, delayed, or disrupted. Research consistently shows that athletes with a history of lateral ankle sprains have measurably slower peroneal reaction times than those without, meaning the protective muscle response that should prevent an inversion injury arrives too late to stop it.
This is the mechanism behind the feeling that the ankle just gives way without warning. It is not weakness in the traditional sense. It is a delayed reflex arc that cannot protect the ankle from forces that arrive faster than the nervous system can respond.
Restoring proprioception is the most important and most consistently neglected component of ankle sprain rehabilitation. Without it, the ankle remains vulnerable regardless of how strong the surrounding muscles are.
What Happens to the Rest of the Body
Chronic ankle instability does not stay in the ankle. The body adapts to the unreliable ankle in ways that create problems upstream:
• Altered gait mechanics: athletes with chronic instability often develop subtle changes to their walking and running patterns to protect the ankle. These compensatory patterns increase load on the knee, hip, and lower back in ways that contribute to injury risk in those structures over time.
• Peroneal inhibition: the peroneals, which are the primary dynamic stabilizers of the lateral ankle, often become inhibited and underactive in athletes with chronic instability. The repeated sprain episodes create a cycle of injury and guarding that reduces peroneal activation and further compromises the ankle's protective capacity.
• Hip abductor weakness: research has shown that athletes with chronic ankle instability frequently have weaker hip abductors and altered hip mechanics compared to those without. The hip abductors play a role in controlling lower limb alignment during single leg loading, and when they are weak the entire lower limb chain is less stable.
• Psychological impact: athletes with chronic instability report reduced confidence in the ankle during sport, avoidance of cutting and pivoting movements, and in some cases reduction in overall sporting participation. The psychological dimension of chronic ankle instability is real and clinically significant.
When to Investigate Further
Most lateral ankle sprains and chronic instability presentations are managed conservatively with excellent outcomes. However, there are presentations that warrant imaging and further investigation:
• Pain that is significantly disproportionate to the mechanism of injury, or that does not begin to improve within 72 hours, should be assessed for bony injury. The Ottawa Ankle Rules are a validated clinical tool for determining when X-ray is indicated.
• Persistent deep ankle pain that does not resolve with rehabilitation despite adequate time may indicate an osteochondral lesion of the talus, which requires MRI to identify and may require specialist management.
• Any instability that is not responding to an adequate course of rehabilitation, particularly when there is evidence of significant mechanical laxity, may warrant orthopaedic consultation to discuss whether surgical reconstruction of the lateral ligaments is appropriate.
Up Next: Rehabilitation Done Right
You understand what chronic instability is and why the standard approach of rest and return does not fix it. Part 3 of Ankle Sprains and Chronic Instability covers what a proper rehabilitation programme looks like, the specific stages of recovery, and what needs to happen before an ankle is truly ready to return to sport. See you there.
______
Chronic ankle instability is very fixable with the right rehabilitation approach. If your ankle has been giving way repeatedly or you have never fully trusted it since a previous sprain, reach out to book an assessment with Dr. Keirstyn at Endurance Therapeutics and let us look at the full picture.
📍 Endurance Therapeutics | Oakville, Ontario
📞 905-288-7161