Sports and Exercise Medicine
Syndesmosis Injuries
Diagnosis, Management and Rehab
An athlete presents to the ER with anterolateral ankle pain, swelling of the ankle and inability to bear weight, after falling during a football game; these symptoms should raise the alarm of a syndesmosis injury.
A syndesmosis injury happens through external rotation and eversion. External rotation forces the talus literally which pushes the fibula away from the tibia increasing forces within the tibiotalar joint, stressing the ligamentous complexes which stretch the syndesmotic ligament or even causes a tear.
Diagnosis
Being an athlete means being at higher risk of falling and retaining injuries. A football, rugby or hockey player is prone to fractures and sprains due to the high physical demand of practice and competition.
The questions running through the doctor’s head in these moments are: is it a sprain? Is it a fracture? Is it a ligament tear? Can the patient move? How long will it take them to recover?
An ankle injury commonly overlooked is the syndesmotic injury or the high ankle sprain. This type of sprain is not common as it accounts for around 24.6% of ankle injuries[1]. It is often mistaken for a lateral sprain as the symptoms of both injuries are similar[2]. Misdiagnosis leads to delay of treatment, increasing the risk of chronic pain, early arthritis and instability. When it is properly detected and treated, complete recovery can be expected. With an incidence of up to 18% of the ankle sprains and an even higher incidence for athletes[3], a better understanding of syndesmotic injuries is necessary.
Physical examination includes documenting areas of focal tenderness:
The syndesmosis and interosseous membrane where the level of tenderness is directly proportional to the prognosis. In addition, provocative manoeuvres are done (i.e., the external rotation stress test) where the patient will be unable to maintain their knee in the mid-line. On the squeeze test (squeezing the tibia and fibula at the midshaft level), pain at the syndesmosis is experienced as well as pain on heel raise or inability to raise the heel.
Anatomy
Understanding the anatomy of syndesmosis makes it easier to know what to expect in imaging. The syndesmosis is made up of several ligaments: AITFL (anterior-inferior tibiofibular ligament), PITFL (posterior-inferior tibiofibular ligament), interosseous membrane, interosseous ligament and the inferior transverse ligament.
The structure of the syndesmosis is clear in Figure 1. A healthy syndesmosis maintains the integrity between the tibia and fibula in addition to resisting axial, rotational and translation forces.
Scans
Understanding the anatomy of syndesmosis makes it easier to know what to expect in imaging. The syndesmosis is made up of several ligaments: AITFL (anterior-inferior tibiofibular ligament), PITFL (posterior-inferior tibiofibular ligament), interosseous membrane, interosseous ligament and the inferior transverse ligament. The structure of the syndesmosis is clear in Figure 1. A healthy syndesmosis maintains the integrity between the tibia and fibula in addition to resisting axial, rotational and translation forces.
The golden standard for syndesmosis injury is an MRI scan where it is easy to visualize the AITFL and PITFL making it highly sensitive and specific. A weight-bearing “mortise” view must be done in x-ray to visualize the opening of the syndesmosis and even then comparison views might be needed.
Results of an MRI can be observed in Figure 2 and Table 2:
Managing a syndesmosis injury requires understanding the grade of the injury as per the Modified West Point Classification where the injury is classified based on the severity into grade I, grade IIA, grade IIB and grade III.
In grade I, the AITFL is sprained without instability or diastasis. Grade II also indicates a sprained AITFL as well as mild instability and no diastasis. In case of a normal deltoid and positive squeeze test, the case is classified as IIA, whereas an injured deltoid and a positive squeeze test indicate grade IIB. As for grade III, a complete tear and frank instability and diastasis are present.
Grade I and grade IIA are usually treated non-operatively; the patient only goes through progressive rehabilitation and is expected to return to sports after around six weeks.
However, grade IIB and grade III require an arthroscopic assessment. Through the assessment, if the syndesmosis is unstable, stabilization through screw/suture-button is done. A syndesmotic ligament repair or deltoid repair may also be needed and the patient is expected to return to sport after around nine weeks.
Surgical Techniques and Rehabilitation
In a chronic syndesmosis injury that has lasted for more than three months, a ligament reconstruction may be the treatment of choice and in case of established syndesmotic OA, syndesmotic arthrodesis is done.
The rehabilitation process has multiple stages. First, the patient goes through “surgical stabilisation” which is a period of immobilisation and restricted weight-bearing and then they progress to restoration of range of movement, strength and proprioception. In order to be capable of going back to competition, focusing on sports-specific drills is inevitable.
Through conservative management, significant syndesmosis injuries can also be treated successfully by discussing the plan carefully in a multidisciplinary team considering certain factors such as function, imaging, sport, time of season and age of the player.
Authors
- Dr Kal Parmar
- Mr Francesc Malagelada
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Sources
[1] https://www.podiatrytoday.com/treating-high-ankle-sprains-football-players
[2] https://www.foothealthfacts.org/article/sprained-ankles-can-be-complicated-and-misdiagnose#:~:text=The%20less%20common%20type%E2%80%94a,in%20the%20lower%20ankle%20area.
[3] https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4128849/
* https://synapse.koreamed.org/ViewImage.php?Type=F&aid=109274&id=F1&afn=120_JKFAS_22_4_145&fn=jkfas-22-145-g001_0120JKFAS
* https://www.aspetar.com/journal/upload/PDF/2014127152113.pdf