Lateral Ankle Sprain series, Part 1: An Introduction to Anatomy of the Ankle

It might seem odd to jump from the shoulder/overhead athlete in one topic series to lateral ankle sprains at the other end of the body in the very next, but I promise there is a connection – there always is. Many overhead athletes rely on the hip opposite their dominant side for power generation and stability – L hip (stance hip) for R handed pitchers, L hip adduction in R handed javelin throwers etc… Therefore, if the opposite hip is important, then so too is the opposite ankle. After all, the contralateral hip relies on the ankle to remain upright. 

Lateral ankle sprains are among the most common in sports injury. The ankle joint is comprised of three separate articular surfaces: the talocrural, subtalar, and distal tibiofibular joints. The talocrural joint is the articulation between the dome of the talus and the distal ends of the tibia and fibula, while the subtalar joint comprises of the anterior and posterior articulations of the talus and calcaneus, and distal ends of the tibia and fibula join together to form the final piece of the ankle in a syndesmotic joint.

The talocrural joint sits on an oblique axis and is the hinge joint that is responsible for dorsiflexion. This joint is crucial during weight bearing, as it allows any torque in the lower leg (internal/external rotation) to be transmitted to the foot (supination/pronation). The subtalar joint, an articulation between the calcaneus and talus is responsible for rear foot eversion/inversion and also participates in this force transfer. The subtalar joint is made up of two separate joint cavities and therefore, 2 separate joints, the anterior subtalar joint (talocalaneonavicular) and the posterior subtalar joint. The sinus tarsi and canalis tarsi separate the anterior and posterior components. Due to the location of the sinus tarsi, it is vulnerable to overuse injuries and ankle sprains, resulting in sinus tarsi syndrome – impingement of fatty tissue.

The distal tibiofibular joint makes up the last piece of the ankle joint. The tibia and fibula have two articulations, one distally and one proximally, and are connected along their shafts by a syndesmosis. Due to two points of contact between the tibia and fibula, as therapists, we need to address both in an ankle sprain. In normal dorsiflexion ROM, the fibula should glide superiorly and a little posteriorly. Most commonly, the distal tibiofibular joint can be anterolaterally shifted in chronic ankle injuries, reducing overall ROM in dorsiflexion – this is also due to reduced ligamentous stability from the anterior talofibular ligament (ATFL). Therefore, assessment of symmetry bilaterally of the fibula position following a lateral ankle sprain is paramount.

The main ligaments involved in stabilizing the ankle include the ATFL, posterior talofibular ligament (PTFL), calcaneofibular ligament (CFL) – all responsible for lateral stability – and the deltoid ligament – for medial stabilbity. The former three are more commonly injured due to their role in lateral stability and the prevalence of lateral ankle sprains, however the deltoid ligament can be pinched during grade 3 lateral ankle sprains.

Aside from rehabilitating the site of pain and addressing joint mobility/strength/proprioception deficits locally, it is vital to search up the chain for impairments – namely, the glutes/hip (including adductors) and anywhere along the lateral – including the peroneals and TFL – and functional lines. We are all familiar with the functional relationship between the glutes-lumbosacral fascia-lats (aka. Hip to contralateral shoulder relationship), however that is only on the posterior side, but there exists a similar relationship anteriorly. This relationship links the adductors and the contralateral lateral sheath of the rectus abdominis and pectoralis major.

When treating an athlete with an ankle sprain it is important to note not only the site of pain but to also address the core and hips higher up in the chain. This is due to the alterations in motor recruitment during gait following an ankle injury – antalgic gait often leads to mild Trendelenburg gait pattern and reduced activation of hip stabilizers in single limb stance secondary to pain. In the previous topic series, I’ve discussed how important it is for overhead athletes, and the demands of their sport, to have functional glute and core strength – it generally is a good idea to assess in any athlete. In one study it was also shown that any individual with a history of ankle sprains have reduced glute function. In the following segments I will address some manual interventions including taping and neuromuscular interventions, and return to sport testing.

References:

Hertel, J. Functional anatomy, pathomechanics, and pathophysiology of lateral ankle sprains. Journal of Athletic training. 2002;37(4):364–375

Kobayashi, T. Fibular Malalignment in individuals with Chronic Ankle Instability. JOSPT. 2014; 44(11): 872-878

 

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