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What is a high ankle sprain?
A high ankle sprain is an injury to the distal tibiofibular syndesmosis. The syndesmosis includes structures such as the anterior-inferior tibiofibular ligament (AITFL), posterior-inferior tibiofibular ligament (PITFL), interosseous ligament (IOL), inferior transverse ligament, and interosseous membrane (IOM). These are highlighted in the figure below.
Figure 1: the distal tibiofibular syndesmosis
These injuries are typically associated with high-speed collisions or injuries where the foot is forcefully externally rotated while in a dorsiflexed positon. Other ankle ligaments may be injured concurrently, and it can occur with or without associated fractures.
Why is it important to recognize this injury?
High ankle sprains should be differentiated from the more common collateral ligament ankle sprains, because management and prognosis are different. In the absence of associated fractures, these injuries may be easily missed on imaging and exam, and can be associated with prolonged recovery and chronic pain.
How do you diagnose a high ankle sprain?
History: suspect high ankle sprain if the mechanism is one of forced external rotation of a dorsiflexed foot, or a collision. Pain is usually diffuse, and worse with walking up hills, pivoting, or doing single leg heel raise.
- Start with a general ankle exam to rule out other concurrent injuries. This may include an examination of the collateral ligaments, as well as determining the need for imaging with the Ottawa Ankle Rule (http://www.theottawarules.ca/ankle_rules)
- The following maneuvers are specific to syndesmotic injuries:
- Crossed leg test (https://youtu.be/Qb-euOa57TE): in sitting position, ask patient to cross their affected leg over the other leg with the distal third of fibular resting on the opposite knee. Apply down-ward pressure over the medial knee of the painful leg. Positive test is reproduction of pain in the ankle.
- Fibular translation test (https://youtu.be/W3SHqKqkK14): stabilize tibia with one hand, then grasp fibular with other and attempt to translate it anterior or posterior. A painful soft end point with greater than 2 to 3 mm of translation, or increased translation compared to contralateral side is a positive examination.
- Tibiofibular squeeze test (https://youtu.be/ANgWSz0UoDg): Squeeze the fibular and tibia together using the palms. Pain at syndesmosis is a positive exam.
- Dorsiflexion external rotation stress test (https://youtu.be/s53uzyUv0bc): Dorsiflex the foot while applying an external rotation force. Pain is a positive test.
- Stabilization tape test: patient is asked to do dynamic movements including walking, heel and toe walking, single legged heel raise, and standing pivot. Then the ankle is tightly taped in a circumferential fashion just above the ankle joint, and patient is asked to repeat the movements. Positive test is reduction of pain with taping.
- Direct palpation – tenderness along the anterolateral joint line and proximal compared to typical sprain. Tenderness on palpation may extend proximally along the fibula.
Imaging: Standard lower extremity weight-bearing x-rays (AP and mortise views) may show increased tibiofibular clear space (normal < 6mm), decreased tibiofibular overlap (normal > 6mm on AP view, > 1 mm on mortise view), and increased medial clear space (normal < 4mm). See Figure 2 for reference. Optional stress views (external rotation stress or gravity stress views) may help assess for ankle stability.
Figure 2: Radiographic features of a normal ankle. Image from Orthobullet and altered to include labels (https://www.orthobullets.com/foot-and-ankle/7029/high-ankle-sprain-and-syndesmosis-injury)
CT/MRI are more sensitive and specific but are often not required to make the diagnosis – they should be considered for operative planning or if high suspicion and plain radiographs are normal.
Without gross instability, high ankle sprains should be treated non-operatively. In contrast to the more common lateral ankle sprains, syndesmotic injuries should be immobilized initially, and patient made non-weight bearing. The immobilization and non-weightbearing phase may be up to 2-3 weeks (or shorter if milder injuries), followed by protected weightbearing in a CAM boot and physiotherapy rehabilitation. High ankle sprains may take over a month to heal.
Surgical indications include unstable ankle on stress views, presence of associated fractures, and failure of conservative therapy.
High ankle fractures are syndesmotic injuries that can occur with or without a concurrent fracture and should be suspected when the mechanism is forced external rotation of a dorsiflexed foot or collision. It should be differentiated from a collateral ankle ligament sprain because management and prognosis are different. These injuries should be initially treated with a period of immobility and non-weightbearing, and slowly progress to functional rehabilitation.
Yuhao Shi, MD
Sports and Exercise Medicine Fellow, University of Ottawa
Advisor: Dr. Taryn Taylor, BKIN, MSc, MD, CCFP (SEM), Dip Sport Med
1. Wake, J. & Martin, K. D. Syndesmosis Injury From Diagnosis to Repair: Physical Examination, Diagnosis, and Arthroscopic-assisted Reduction. J. Am. Acad. Orthop. Surg. 28, 517–527 (2020).
2. High Ankle Sprain & Syndesmosis Injury – Foot & Ankle – Orthobullets. https://www.orthobullets.com/foot-and-ankle/7029/high-ankle-sprain-and-syndesmosis-injury.
Article: Brison RJ, Day AG, Pelland L, et al. Effect of early supervised physiotherapy on recovery from acute ankle sprain: randomised controlled trial. BMJ 2016;355:i5650
Lateral ankle sprains are one of, if not the most common musculoskeletal injuries and account for approximately 14% of sports injuries. Resulting from inversion of the ankle after quick changes in direction or awkward landings, most ankle sprains are grade 1 (mechanically stable) or grade 2 (some joint laxity) ligament sprains of the anterior talo-fibular ligament (ATFL). These can be graded by performing the anterior drawer test and comparing side to side, with the optimal time to test at day 5 post injury. If there is any pain in the malleolar zone, bone tenderness at the posterior edge or tip of either malleolus, or inability to bear weight for four steps immediately after the trauma and in the ED, then radiographs are indicated as per the Ottawa ankle rules.
Like everything MSK related, physical therapy is recommended for the rehabilitation process, however the evidence for supervised physiotherapy (PT) is limited in terms of breadth and quality. Principles of PT in ankle sprains include early weightbearing as tolerated, range of motion exercises (drawing out the alphabet with the foot), strengthening of lateral stabilizers (peroneals) using resistance bands, and proprioceptive training (standing on one leg/BOSU ball/mini trampoline/wobble board). It takes 8-12 weeks for complete neuromuscular retraining so bracing or taping for at least this period of time is recommended.
Recently, an article was published out of Kingston which is the largest randomised controlled trial (RCT) to have evaluated the therapeutic benefits of supervised physiotherapy in the treatment of acute ankle sprains. In this study, patients who presented to the ED in Kingston were randomized to either the usual care or physiotherapy arms. The usual care arm included medical assessment and a one-page written summary of instruction for basic management of the injury at home, including ankle protection, rest, ice, compression, elevation, use of analgesics as necessary, graduated weight bearing activities, and information about expected recovery. Participants assigned to the physiotherapy arm were provided with usual care (as above) plus a regimen of supervised physiotherapy. They received a maximum of 7 treatment sessions of 30 minutes in length (maximum 210-minute dose) and treatment was augmented by standardised home exercise programs. Ankle function reported by patients, re-injury, clinical measures, and laboratory based assessments of ankle strength were recorded at one, three, and six months.
Groups were similar at baseline and showed that ~40% of sprains were sport-related and ~60% had previous sprains, highlighting the recurrent nature of these injuries. Except for seeing a benefit for physiotherapy at three months in the subgroup of patients aged <30yo, there were no significant differences between groups. These results are in contrast to a recent meta-analysis which indicated rehabilitative exercises were associated with significant improvements in self reported function and reduced risk of recurrent injury, which was lowest with a cumulative dose of >900min of therapeutic exercise. Compliance of with appointments and home exercises in the Kingston study was recorded but unfortunately not included in the results, which hinders our ability to judge the dose of exercise received.
In summary, this trial can be interpreted in a couple of ways. First, it suggests that supervised physiotherapy may not reliably improve clinical outcomes post low-grade ankle sprain within 6 months, and therefore maybe we don’t need to push supervised PT as much in the general population given that it also comes with significant financial cost. Secondly, it could also suggest that a dose of greater than 210 min of therapeutic exercise may be required to see improved clinical outcomes, so if you’re going to do PT, you might need to err on the side of being more aggressive with the volume of rehab. And considering that less than half of participants had excellent outcomes by 6 months, further investigation to reduce morbidity would be prudent.
- Brukner & Khan’s Clinical Sports Medicine, 4th ed. Peter Brukner, Karim Khan Sydney: McGraw-Hill Australia; 2012.
- Doherty C, Bleakley C, Delahunt E, Holden S. Treatment and prevention of acute and recurrent ankle sprain: an overview of systematic reviews with meta-analysis. Br J Sports Med 2016 doi:10.1136/bjsports-2016-096178
Ryan Shields, MD, MSc, CCFP
PGY-3 Sport and Exercise Medicine
Advisor: Dr. Taryn Taylor, BKin, MSc, MD, CCFP (SEM), Dip SPort & Exercise Medicine