Why do I keep spraining my ankle?

The ankle joint is stabilized by both static and dynamic structures. Stabilizing structures can be damaged by a significant sprain or recurrent ones including lateral ankle ligaments, ankle syndesmosis, peroneal tendons, and bony structures. up to 30% of ankle sprains can lead to chronic symptoms especially if they are not properly treated or a reinjury occurs prior to complete healing. The more frequent sprains happen, the more unstable and damaged the ankle becomes. The most common cause of mechanical instability is the deficiency of lateral ankle ligaments.

What is the difference between functional and mechanical instability?

Functional instability is a condition with instability symptoms at the ankle without a detectable laxity of the ankle joint. This is commonly related to poor muscle coordination or imbalance. Mechanical instability is a much more common condition but the detection of subtle instability can be challenging. In my experience, a careful physical examination using an anterolateral drawer test and a talar tilt test is the most practical method. MRI scans can often demonstrate damaged ligaments and associated injuries within and around the ankle joint.

What is the treatment for an unstable ankle?

Treatments vary depending on the chronicity and severity of symptoms but usually include brief immobilization, physical therapy, ankle bracing, and taping. It is not uncommon that the unstable ankle may have associated injuries such as cartilage damage, bone spurs, loose bodies, and inflamed joint lining tissue. Patients that fail 3-6 months of non-operative treatments or have severe pain from associated injuries may benefit from surgical treatment.

What is the role of surgical treatment?

Surgical treatments for ankle instability aim to decrease pain, improve proprioceptive feedbacks, improve alignment, and restore ligamentous stability. Arthroscopy is an essential initial step of surgery to help treat intraarticular lesions, confirm the diagnosis, and detect associated conditions (Pictures below). The ruptured ligament should be anatomically repaired with or without augmentation using synthetic tape or a tendon graft. It is important that associated conditions such as peroneal tendon damage, malalignment, and generalized ligamentous laxity are taken into account and possibly treated in the same setting for best outcomes.

What is the recovery after a surgical repair of ankle instability?

Recovery depends on the details of surgical repair, quality of soft tissue, adjunct procedures, and patient’s overall mobility. Typically, the patient is allowed to bear full weight on the affected ankle right away using a walking boot. Patients should use crutches or a walker for enhanced stability. For prolonged ambulation, a knee scooter may be considered. Ankle motion should start on the next day after surgery to prevent stiffness, especially in dorsiflexion. Patients can usually wean off from the boot by 6 weeks and gradually return to sports using a lace-up ankle brace.

What are the benefits and risks for a repair of an unstable ankle?

Benefits: restored stability, prevention of future reinjury, treatment of associated painful conditions

Risks: nerve irritation, wound infection, deep vein thrombosis, painful scar, reinjury

Author: Phinit Phisitkul, MD