Sports and Exercise Medicine
Syndesmosis Injuries
Diagnosis, Management and Rehab
Syndesmosis injury, also known as “high ankle sprain”, is not common in general but athletes are more prone to it. 0.5% of syndesmosis injuries are not accompanied by fractures while 13% are accompanied by fractures.
The mechanism of syndesmosis injury is external rotation and eversion injury. External rotation forces the talus laterally which pushes the fibula away from the tibia. This leads to increased forces within the tibio-talar joint stressing ligamentous complexes, congruing of ankle joints and subluxation of the fibula.
Diagnosis
Missed injuries as they will cause ongoing pain and accelerated OA
If the syndesmosis injury is treated promptly, it is possible to accomplish excellent functional outcomes
Along with a syndesmosis injury, the following injuries can be observed:
- Osteochondral defect (up to 25%)
- Peroneal injury (up to 25%)
- Fracture
- Weber B/C occult fractures (base 5th metatarsal, anterior calcaneal process, lateral talar process)
It is also important to watch for:
Deltoid ligament injury – deep and superficial fibres, avulsion fracture
Anatomy
Several ligaments form the syndesmosis: the AITFL (anterior-inferior tibiofibular ligament), PITFL (posterior-inferior tibiofibular ligament) which is the strongest point, interosseous membrane, interosseous ligament (distal part of the interosseous membrane), and the inferior transverse ligament. The structure of the syndesmosis can be seen in the following figure.
It is important to make sure the syndesmosis is healthy as it maintains integrity between the tibia and fibula. It also resists axial, rotational and translation forces.
Presentation
Patients typically present with the following symptoms to indicate a syndesmosis injury:
- Anterolateral ankle pain
- Medial ankle pain if the deltoid ligament is involved
- Swelling – globally throughout the ankle
- Pain when bearing weight
Through examination, this is what you might find:
o Tender syndesmosis and along interosseous membrane – the higher the tenderness, the worse the prognosis.
o External rotation with dorsiflexion in prone position and bent knee – unable to maintain knee in mid-line
o Pain on squeeze testing – when squeezing together the tibia and fibula at the midshaft level, referred pain at the syndesmosis is experienced.
o Pain on heel raise, inability to heel raise.
Scans
When doing an x-ray, you need to do a weight-bearing “mortise” view to visualise the opening of the syndesmosis and you may need comparison views.
An MRI is considered the gold standard as you will easily be able to visualise the AITFL and PITFL making it highly sensitive and specific.
Results of an MRI can be observed in the following figure and table:
The management of syndesmosis injury depends on the injury grade identified through the Modified West Point Classification as follows:
o Grade I: Sprain AITFL, no instability or diastasis
o Grade II: Spain AITFL / IOL, mild instability / no frank diastasis
§ IIA: Normal deltoid, negative squeeze test
§ IIB: Injured deltoid, positive squeeze test.
o Grade III: Complete tear, frank instability and diastasis
Management of Grades I–IIA is non-operative while operative intervention is necessary for Grades IIB–III.
For Grades I–IIA, progressive rehabilitation is done and patients can be expected to return to sports after around six weeks.
As for Grades IIB–III, an arthroscopic assessment with or without stabilisation is done and patients are expected to return to sports after around nine weeks.
Surgical Techniques
When it comes to surgical techniques, an arthroscopic assessment is done, and if the syndesmosis is unstable, stabilisation through screw/suture-button. A syndesmotic ligaments repair or deltoid repair may be required as well.
If the injury is chronic, meaning it has lasted more than 3 months, we might opt for ligament reconstruction (tendon autograft). In case of an established syndesmotic OA, syndesmotic arthrodesis is done.
Rehabilitation
And finally, these are the rehabilitation protocols the patient goes through:
· surgical stabilisation - period of immobilisation and restricted weight-bearing
· progressing to restoration of range of movement, strength and proprioception
· eventually sports-specific drills become the focus prior to return to competition.
· Conservative management
· significant syndesmosis injuries can also be successful
· carefully selected following MDT discussions
· number of factors including function, imaging, sport and often ‘time of season’ and age of player
While the details of rehabilitation protocols can differ, the outline framework below gives an insight into the goals of each stage.
Authors
- Dr Kal Parmar
- Mr Francesc Malagelada
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Sources
- 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