In people who recurrently sprain their ankle, it is not uncommon to hear a clicking coming from the outside of their ankle. This phenomenon is commonly known as “snapping” ankle or slipping peroneal tendon. As the name suggests for this ankle injury, the clicking sound arises from the peroneal tendons slipping in and out of the groove behind the bone sticking out on the outside of the ankle. Medically, it’s known as peroneal subluxation.
The peroneal muscles are made of 2 muscles and lie on the outside of the ankle. They assist in pointing the foot downwards and outwards. These two muscles run through a groove behind the lateral malleolus and are kept within the groove by a sheath. This complex is then re-enforced by a ligament-like structure known as a retinaculum, preventing the tendon from slipping out of the groove.
Why do I get this problem?
When you roll your ankle outwards, it may put the peroneal tendons on a forceful stretch. This forceful stretch may cause tears in the retinaculum. Frequent sprains would thus increase the strain on the retinaculum, which ultimately might cause the retinaculum to tear. This tear in the retinaculum compromises the integrity of complex, allowing the tendon to slip in and out of the groove.
However, in some cases, there is a structural defect that causes the slipping. There are some people born with a shallow groove and thus gives rise to the slipping
Diagnosis and Management of Snapping Ankles
Diagnosing a peroneal subluxation is normally overlooked as this problem is commonly superseded with other more acute pain of an ankle sprain, like swelling arising from an Anterior Talofibular Ligament (ATFL) strain. Diagnosing this problem requires a close examination of the ankle. An experienced Sports Physician, Orthopedic Surgeon or Sports Physiotherapist would normally assess the ankle in all ranges to check whether the tendon would slip out.
Another common test would be a resisted up pointing and out turning of the ankle. This could cause the tendon to thicken and slip out of the groove and can be felt at the back of the lateral malleolus. Pain, tenderness and swelling may also be seen over the tendon behind the retinaculum.
The first choice of management for a peroneal subluxation is a referral to physiotherapy for rehabilitation. In acute stages, the aim is to prevent further aggravation to the strain on the retinaculum and a cast might be used for the first 4-6 weeks. During that period, gentle stretching of the tendon and range of movement is advised to prevent stiffening of the ankle. Ultrasound and cryotherapy may also be used to help manage the pain and swelling if present. Following the protective phase, proprioceptive training and eccentric strengthening exercises of the peroneal tendons are essential in the prevention of a recurrence.
However, 50% of acute subluxation tends to recur in active athletes. This would normally result in either surgery or a retirement from the sport. There are 3 common surgical techniques:
- Retinaculum Repair
- Groove Reconstruction
- Construction of a bony block
Following surgery, physiotherapy will be essential to get you back to sports.
An immobilization period varying from 3-6 weeks will follow after surgery. Upon removal of the cast, achieving a full range of movement of your ankle will be the main goal of rehabilitation in the first 4 weeks. Pain controlling modalities like ultrasound and TENS may be used if pain is present.
Building up the strength and proprioception of the ankle with exercises like calf raises and single leg stand (eyes open/ eyes closed) would normally start about the same time. Progressing proprioceptive training from standing on a stable ground to a rocker board, followed by a wobble board is a normal progression before proceeding to agility drills. Only when one achieves full range of movement, good strength and ability to complete sports-specific agility drills will one be allowed to return to sports.