Category Archives: MSK

Ankle Injuries

 Ankle injuries account for a massive amount of ED work.  Many patients present following accidents at home or while playing sport.  Often all the patient actually wants is some reassurance; this is often easier to give if you know a little about the ankle.

Ankle Sprain accounts for up 5% of ED visits in the UK, which is approximately 5600 attendances a day.  Once someone has sprained their ankle once, they often go onto have residual symptoms of instability and ‘resprain’.  We often think of it as a relatively benign injury, but it’s common, it often necessitates a period of rest to recover, and this has a wider economic impact.  The US army estimated in 1994 that it lost $1 billion in lost duty time due to ankle sprain alone.

Anatomy

ankle3The ankle is a hinge synovial joint.  The tibia and fibula articlulate with the talus.  The end of the tibia and fibula along with the posterior tibifibular ligament form a mortise, that the top of the talus (trochlea) fits into.

The talus articulates on the sides, and on it’s superior surface.

The talus is widest at its anterior edge.  This means that when your foot is down flat the widest part of the talus is inside the mortis, pushing against the fibula and tibia.  This is inherently very stable.  When you are plantar flexed the narrowest part of the talus is inside the mortis, the fibula and the tibia cannot grip both sides of the talus which means it is more likely to move suddenly and cause injury.  The majority of ankle sprains occur as a result of unexpected inversion of a plantarflexed foot.

 

Ligaments

Lateral ligaments (the weaker set, outer aspect of ankle)

ankle1Anterior Talofibular ligament – (weak) anteriomedial band from lateral malleolus to neck of the talus.  This one is the weakest, and is the ligament that tears most often in ankle sprains.

TEST – anterior draw test: grab the heel, stabilise the calf, and see if you can pull the foot toward you.  You should feel an end point, if there is some give (or lots of pain, the ATFL is probably gone).

Posterior Talofibular ligament – (strong) horizontal band malleolar fossa to lateral tubercle of talus

Calcaneofibular ligament – posterioinferiorly from the tip of the lateral malleolus to the lateral surface of the calcaneus

TEST – stabilise the lower limb and invert the foot under stress.  There should be an end point, if there isn’t the ligament is probably broken.  This is painful! Most of the time patients stop us doing this test, so its utility is marginial.

From our point of view these three ligaments are the most common to tear or break.  The distinction to a certain degree is academic in the context of an acute injury.

 

Medial Ligaments (the stronger) AKA Deltoid ligament.

This is a fan (or triangular) ligament that begins at the medial malleolus and attach to the talus, calcaneus and navicular, forming

  • Tibionavicular ligament
  • Anterior and Posterior tibiotalar ligament
  • Tibiocalcaneal ligament.

The deltoid ligament is pretty strong.  A tears much less readily than the lateral ligamentous complex.

 

Example Case

“Jake” a 36 year old Sunday league footballer presents with left ankle pain and swelling following a “bad tackle”.

History is as important in minor injuries as it is in medical problems, when taking a history from someone with an injury it is important to try and visualise exactly what their limb was doing at the time of the injury.  The direction of force, impact site, and immediate symptoms all give useful clues.

Jakes say he was about to shoot, when a defender came in with a slide tackle from his left hand side and struck his left ankle.  He was trying to kick the ball with his right foot.  Jake hit the floor immediately, “he knew he had done something” but managed to take the penalty that was awarded to him (me missed).

Examination of ankle injuries should be from the knee down.  Look for tenderness over

  • Proximal fibula
  • Lateral Malleolus and ligaments – with anterior draw test, and forced inversion test
  • Medial Malleolus and ligaments
  • Navicular
  • Calcaneum
  • Achilles Tendon
  • Base of 5th Metatarsal

When to Xray?

Ankle rules diagram from mdcalc.com (looks a lot like the BMJ one).  Borrowed.
Ankle rules diagram from mdcalc.com (looks a lot like the BMJ one). Borrowed.

Use the ottowa ankle and foot rules:  derived to increase the specificity of ankle xray.

It is important to examine the ankle fully, as well as assessing if they are “ottowa positive or negative”.  You should have a lower threshold for Xray in the following patient groups

  • Young children <6
  • Pregnant women (ligamentous laxity)
  • Intoxicated individuals
  • Elderly patients

So in Jake’s case, our decision to Xray will depend on our examination findings, however the likelihood of him having a serious fracture is unlikely as he took the penalty he was awarded.

So we Xray Jake’s ankle, and there is no fracture.  So if Jake has a ‘simple ankle sprain’ what advice can we give in terms of rehab?

 

Acute phase 1st week

RICE, No sport, Gentle mobilisation, script for analgesia, If in a manual (non-sitting job) sign off for 5 days.  I don’t routinely give crutches.

I also always suggest physiotherapy after the first week especially if they are a in any way serious about sport.

Rehab phase 2nd week to 5th week.

Start returning to sport.  Phased return.  Use of ankle brace/tubigrip when exercising to decrease risk of re-injury.

Prevention phase – week 6 plus

I suggest wobble boards (improve proprioception), and during exercise using tape or a brace (depending on their personal preference).

Troubleshooting

If you get yourself into the situation with a patient when you are convinced it’s a sprain but they won’t walk you can try the following strategies

  • Double and triple check the film.  Are you missing a small avulsion or a mid foot fracture?
  • Have you given them enough analgesia?  Load ‘em up!
  • Try them with crutches
  • LAST RESORT – back slab and OOPD follow up + crutches.  Sometimes if the sprain is severe this is all that you can do in the acute setting.