The tibiofibular syndesmosis joint plays a primary role in providing the stability and congruency to the mortise of the talocural joint under axial loads. Immediate recognition and prompt management of syndesmotic injuries should minimise complications and improve the prognosis and return to sport timeframes.
Injuries to the syndesmotic tibiofibular joint are less likely to occur than lateral ankle sprains. Beumer et al., (2004) estimates that the incidence of acute syndesmotic injury varies from 1-11% of all ankle injuries. Sports that involve high intensity twisting and cutting maneuvers or those with limited mobility, such as wearing a boot in skiing or ice hockey, have the highest incidence of this injury. Delayed or poor initial management of a syndesmosis injury will increase the likelihood of the athlete developing secondary complications. These complications can include heterotrophic ossification, joint synovitis, anterior impingement, osteoarthritis, oesteochondral lesions and chronic ankle pain.
The syndesmosis complex forms the distal articulation between the tibia and fibula. The articulation is anchored by a number of ligaments that are crucial to the normal function of the joint. These ligaments include the interosseous membrane (IOM), the anterior inferior tibiofibular ligaments (AITFL), the posterior inferior tibiofibular ligaments (PITFL), the interosseous ligament and the transverse tibiofibular ligaments (TTFL). This ligamentous structure provides a very strong and stable ankle mortise. Subsequently injury to this complex is often caused by high load and force.
The most commonly reported mechanism of a syndesmosis injury involves a forced external rotation of the foot on the tibia. This may occur when the athlete rapidly pivots internally off a foot that is planted in external rotation. Less common mechanisms reported in theliterature involve hyper-dorsiflexion of the ankle, which occurs when an individual falls forward over the planted foot; inversion of the ankle with a planar-flexed foot and internal rotation of the foot and ankle complex (Williams, N., Allen, J., 2010).
The classic sign of a syndesmotic injury is tenderness on palpation over the anterior and posterior tibiofibular ligaments. As the severity of the injury increases, tenderness may increase proximally over the insertion of IOM That is 2-3cm proximal to the ankle joint.
Nussbaum et al., (2004) developed a return to competition formula to guide prognosis of syndesmosis injuries with the exclusion of fracture or frank diastasis. This formula is based on distance from tip of medial malleolus to the most proximal point of tenderness on the anterior portion of the IOM.
Time to return to play = 5 + (0.93 x Tenderness length in cm)) -/+ 3.72 days
SURGERY Vs. CONSERVATIVE
Syndesmotic surgical repair is generally indicated for a fibular fracture at least two centimeters above the ankle joint in the presence of a deltoid ligament disruption or with complete diastasis (Mulligan 2010). Conservative management is indicated for stable sprains where by there is no to minimal radiographic widening of the mortise upon external rotation stress.
Conservative management programs generally involve early rigid immobilization and pain relief strategies. The severity of injury and degree of instability is used to dictate early immobilisation and weight bearing status. Grade I sprains that are considered stable will likely require immobilsation in a moon boot for 3 -14 days depending on injury severity. The average return to sports will be between 4-8 weeks. Surgical reduction should be considered for grade II injuries, where stress views on radiographs demonstrate diastasis..Porter (2009) states grade II injuries, which are occultly unstable, may be overlooked and treated too conservatively (non-surgically), leading to latent complications.. For stable grade II sprains, a more conservative approach may be considered. This will typically involve weight bearingimmobilsation in a moon boot for 4-6 weeks. Syndesmosis injuries with frank diastasis or fracture are considered grade III injuries and should be treated with surgical reduction. Internal fixation with trans-syndesmotic screws is the most common surgical intervention for tibiofibular stabilization.
The primary aim of rehabilitation is to restore the function of the ankle joint with respect to the kinematics, range of motion and dynamic control to provide a safe return to sport.
Dorsiflexion should be introduced with caution in the rehabilitation program as excessive dorsiflexion can cause further separation of the syndesmosis and lead to impaired tissue healing.. Porter et al (2014) state 95-100% of the pre injury range of motion must be regained before athletes initiate strength exercises. Furthermore they comment on the importance of regaining range of motion within the first six weeks as only a slight change will occur thereafter.
Strength is based around restoring the eccentric control of the pronator forces by the tibialis posterior and the eccentric control of dorsiflexion to protect against weight bearing dorsiflexion stress on the syndesmosis.
Proprioceptive balance retraining is imperative throughout the rehabilitation ideally implemented with training of gluteus medias and maximus (Bullocak- Saxton 1994) for proximal control.
Orthotic intervention may be required to minimise over pronation, which can stress the medial deltoid and tibiofibular ligaments.
The ability to perform a repetitive, painless hop test is a common indicator that the athlete is ready to transition to the final phase of rehabilitation. Running will commence once the athlete has restoredpre-injury range of motion, strength and endurance compared to the uninjured side. This will then progress to gradually introducing the athlete back into athletic movements that are specific to their sport such cutting, bounding & plyometric training.
A through return to sport testing should be conducted with 80-90% symmetry with single leg jumps tests and the star excursion balance test, comfort with push off and cutting maneuvers, and a normal foot and ankle disability index (FADI).
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