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The Med Cell:

The Ankle

Dr Stefan Eriksson

The ankle is the second region of the body to be covered by The Med Cell. As in the foot, the ankle region is of significance to the combat practitioner in terms of both inflicting and receiving injuries.  Like injuries to the foot, ankle injuries can effectively immobilize the injured party. During the American Civil War, ankle fractures were treated with amputation. Orthopaedic medicine has progressed a long way in the intervening 150 years. Nevertheless the ankle is very commonly injured during a range of normal daily activities, including athletic pursuits. An athlete with a history of a previous ankle sprain has a five times increased risk of suffering a further ankle sprain. Ankle injuries are extremely common. In fact, in the United States it is estimated that approximately 25,000 ankle sprains occur every day. In one Australian study, ankle injuries accounted for 7% of martial arts injuries in 500 presentations to the ED (Victorian Minimum dataset).
 
This article will first examine basic anatomy, followed by injuries to the region and their diagnosis and treatment. Finally, application of the preceding information to close combat will be discussed.

ANATOMY OF THE ANKLE

The ankle, while consisting of fewer bones, joints and soft tissue structures than the foot, is actually difficult to define in terms of boundaries. This means that injuries to the ankle often overlap with those of the foot and lower leg.

While learning the contents of the ankle can seem daunting, it becomes easier if we remember that there are only 3 articulating bones, and 3 groups of ligaments that make up the ankle joint.

Bones of the ankle

In terms of articulation, the ankle involves three bones:

• tibia
• fibula
• talus (see x-ray 1)

It is a complex hinge joint, and is of the synovial type, which means that damage to one component of the joint can lead to marked swelling from synovial fluid leakage.

The calcaneus is also included in discussion of the ankle region as it provides ligamentous attachments.

Each bone is now examined in more detail. (readers are advised to inspect the previous Med Cell article which deals with the bones of the foot for more in-depth coverage of the talus and calcaneus.

Tibia

The tibia is the larger of the two bones that make up the lower leg. The tibia lies medial to the smaller fibula, and can be felt through the very thin covering of soft tissue. Take a look at x-rays 1&2 and note:

• the tibia widens at the lower end of its shaft
• anteromedially, there is a prominence called the medial malleolus, which is a very important landmark we will refer to throughout the article
• laterally there is a small triangular area with a small groove for the fibula.
• the distal articular or joint surface (known as the plafond, meaning domed ceiling) is concave. Note the anterior and posterior lips which extend more distally.

X-ray 1 AP view: X-ray of the left ankle. The purple line on the right indicates the ankle mortise within which the talus sits neatly. 

X-ray 2 Lateral view: x-ray of the left ankle showing the anterior and posterior lips of the tibial plafond. The plafond or articular surface is outlined in yellow.

Fibula

The fibula is a slender bone that runs down the lateral part of the lower leg. Again, referring to x-ray 1 observe:

• The lower end is triangular shaped
• This bulbous lower end forms the medial malleolus

Talus

The talus was discussed in the foot article, but it is worth briefly looking at the anatomy of this bone. See x-ray 1

• It consists of head, neck and body
• Broader anterior portion
• Articular surfaces for the medial and lateral malleoli, and for the navicular and calcaneus.

Together, the distal ends of the tibia and fibula form the ankle mortise, within which the talus sits.

Ankle Ligaments

To simplify the complicated ligamentous arrangement of the ankle joint, it is easiest to divide the ligaments into 3 complexes: 1 Medial Ligamentous Complex, 2 Lateral Ligamentous complex and 3 Syndesmosis.

1. Medial Ligamentous Complex (MCL Complex) :

• composed of deltoid ligament
• deltoid ligament in 2 layers, superficial and deep
• deep part is a narrow band extending from the medial malleolus to the side of the talus.
• superficial part is triangular, composed of three bands that link the medial malleolus with the talus and navicular bones
• see illustration 1 below

Illustration 1: Medial Collateral Ligament complex showing the superficial layer of the deltoid ligament.

2. Lateral Ligamentous Complex (LCL Complex):

• made up of 3 portions
• anterior talofibular ligament (ATFL). This is the weakest of the LCL complex ligaments and is the most frequently injured ankle ligament.
• posterior talofibular ligament (PTFL)
• calcaneofibular ligament (CFL)
• see illustration 2 below

Illustration 2: Lateral Ligament complex. PTFL, Posterior Talofibular Ligament; CFL, Calcaneofibular Ligament; ATFL, Anterior Talofibular Ligament. The AITFL (Anterior Inferior Talofibular Ligament) is not part of the lateral ligament complex.

3. Syndesmosis (also known as the interosseous complex):

• most important ankle joint ligament complex as it contributes most to the structural integrity of the ankle
• comprises 4 portions
• anterior inferior tibiofibular ligament (AITFL)
• posterior inferior tibiofibular ligament (PITFL)
• inferior transverse tibiofibular ligament
• interosseous ligament, a thickening of the tibiofibular interosseous membrane
• see illustration 3.

Illustration 3: Syndesmosis. IOM, Interosseus Membrane; IOL, Interosseus Ligament; AITFL, Anterior Inferior Tibiofibular Ligament; PITFL, Posterior Inferior Tibiofibular Ligament.

Tendons Crossing the Ankle Joint

Although there are no direct tendinous attachments to the portions of bones that make up the ankle, all tendons inserting onto bones of the foot must by necessity cross the ankle. This has obvious implications in that disruption to the structures comprising the ankle joint may rupture tendons passing over it.

Achilles tendon (tendo calcaneus)

• Named after the Greek legend Achilles. Myth has it that he was the mightiest of the Greeks who fought in the Trojan War. When Achilles was an infant, his mother held him by the heel and dipped him into the river Styx. Everything that touched the water became invulnerable except the heel, which remained dry and unprotected. This was Achilles downfall, as he was eventually struck in the heel by an arrow and died of the wound.
• Largest tendon in the body
• Strongest tendon in the human body and can withstand forces of more than 1000 pounds. Subject to a persons entire bodyweight with each step, and depending on length of stride, speed, terrain and additional loads carried, can be subject to more than 12 times bodyweight with each step.
• Connects the gastrocnemius and soleus (calf) muscle to the calcaneus (heel) bone
• Thin tendon sheath, making it prone to rupture
• Very little subcutaneous tissue between Achilles tendon and overlying skin
• Limited blood supply, especially 2 – 6 cm above the insertion onto the calcaneus
• Tendon begins where gastrocnemius and soleus end, roughly 15cm proximal to the insertion onto calcaneus
• Acts to plantarflex the foot
• See illustration 4 below 

Illustration 4. Achilles tendon. Blue arrow on the left shows upward movement of the tendon, causing plantarflexion of the foot (arrow on the right)

Other Tendons

A multitude of other tendons pass around the ankle. They can be grouped according to their position, medial, lateral, anterior or posterior. Each group of tendons passes under a fibrous band called a retinaculum. The retinaculum acts as a kind of pulley and anchors the tendons.

The tendons on the medial and lateral sides pass posterior to the respective malleoli. The individual tendons will not be examined here. However, it is worth remembering that as a general rule, tendons that cross anteriorly act to dorsiflex the foot, those passing laterally evert, the medial tendons act to invert, and the Achilles tendon which is posterior obviously plantarflexes the foot. From here, it is relatively easy to deduce what injuries will be sustained when each of the regions is disrupted, which will be discussed later.

Nerves

Nerves can easily become damaged in ankle sprains or fractures and result in loss of muscle function, so it is important to understand some basic anatomy

Three important nerves cross the ankle joint to supply muscles of the foot

1. two branches of the common peroneal nerve

• superficial peroneal nerve which supplies muscles that evert the foot
• deep peroneal nerve which supplies muscles which dorsiflex the foot

2. tibial nerve, which supplies muscles which plantarflex and invert he foot

Other Structures

One structure worth mentioning is the saphenous vein

• 1-2 cm anterior to the medial malleolus
• valuable for fluid administration via cutdown even when the patient is shocked
• important for venous drainage of the foot

Finally, arterial blood supply to the foot and ankle is prone to injury when the ankle itself is injured. Two major arteries supply the foot, the posterior tibial artery and the dorsalis pedis artery.

ANKLE MECHANICS

The axis of the ankle joint runs in an oblique line, and can be visualized as passing from the tip of the medial malleolus then backwards and downwards to the lateral malleolus. In other words, take the tips of your index fingers and place one on the tip of the lateral malleolus and the other on the tip of the medial malleolus. An imaginary line connecting these two points roughly approximates the axis of the ankle. This is important because:

• normally the talus fits into the mortise precisely
• during normal range of motion this fit remains precise
• due to the oblique angle of the axis and the  fact it passes in an inferior and posterior direction, plantarflexion produces internal rotation, and dorsiflexion produces external rotation
• this helps predict what injuries result from different foot positions

In terms of ankle ligament mechanics, we can easily summarize the important points below:

• MCL covers a relatively small distance and acts to limit excessive external rotation of the talus in the mortise
• LCL is more complicated as the lateral side of the ankle travels over a greater arc of motion
• The syndesmosis strongly binds the fibula to the tibia, but allows a small amount of rotation of the tibia during normal gait.

ANKLE INJURIES

Ankle injuries take many forms, so it is easiest to divide ankle injuries according to what type of tissue is affected. The table below outlines the various ankle injuries, and this is followed by a more complete description of each type of injury.

 

Bony Fractures	supination-adduction
(Lauge-Hansen classification)	supination-external rotation
	pronation-external rotation
	pronation-abduction
	Fractures of adjacent bones
Ligament Injuries	Medial collateral injuries
	Lateral collateral complex injuries
	Syndesmosis injuries
Soft Tissue Injuries	Laceration
	Bruising and crushing injuries
Tendon Injuries	Rupture or dislocation
Nerve Injuries	Stretching or Laceration
Vascular Injuries	Venous or Arterial

BONY FRACTURES

Fractures of the ankle can be classified in two different ways. The first is based on the mechanism of injury and resultant ankle fracture pattern, known as the Lauge-Hansen classification. As this approximates the descriptions of injuries as applied to close combat, it will be used here. Readers wanting to research ankle fractures more thoroughly than presented here should be aware that a second system is used by orthopaedic surgeons. It is called the Danis-Weber classification and is based on radiographic findings.
The Lauge-Hansen classification is useful for our intended purpose as stated above. The system consists of 4 configurations. The first part of the name describes the position of the foot at the moment of injury (supination or pronation), and the second part indicates the force applied through the talus to cause the observed injury, or in other words, the motion of the foot with respect to the leg (external rotation, abduction or adduction). In addition, each configuration has a number of stages describing sequential injuries as the force is applied. The 4 patterns are:

1. Supination-Adduction
2. Supination-External Rotation
3. Pronation-Abduction
4. Pronation-External Rotation

Let’s look at each in turn.

Supination-Adduction

• Most common mechanism of injury to the ankle.
• 10 – 20 % of malleolar fractures.
• There are two stages to this injury pattern. Refer to image 1

Image 1. Refer to text. Curved blue arrow indicates adducting force applied to supinated foot. Numbers indicate sequence of injuries when supinated foot is forcibly adducted.

1. Initially the foot is fixed in a supinated or inverted position, and then an adducting force is exerted on the talus. As the lateral side of the ankle is thus under tension, it leads to injury to the LCL. This can in turn completely tear and pull off (avulse) a portion of the distal fibula. This is usually a transverse fracture. See x-ray 3

x-ray 3:  Arrows point to a transverse fracture through the distal right fibula as a result of inversion injury.

2. Next, as the talus continues to adduct, it impacts on the medial malleolus and shears bone off the distal tibia. This is usually a vertical or oblique fracture.

Often these injuries can occur simply as a result of unintended weight bearing on the lateral border of the foot.

Supination-External Rotation

• 50 – 75 % of malleolar fractures
• Typical “rolling the ankle” injury
• The foot is in a supinated position and then an external rotatory force is applied. For example, the foot is fixed in supination, and the body falls to the opposite side. As the tibia internally rotates, the talus shears the fibula. See image 2.

Image 2. Refer to text. Curved blue arrow indicates external rotation force applied to supinated foot. Numbers indicate sequence of  injuries when supinated foot is forcibly externally rotated.

4 sequential injuries:

1. First the AITFL tears
2. Next, as force is continually applied, the fibula is sheared by the talus and a short oblique fracture results (see x-ray 4)
3. Rupture of the PITFL or fracture of the posterior malleolus occurs (not shown in image 2), until finally,
4. The medial malleolus is either avulsed and appears as a transverse fracture, or the deltoid ligament ruptures in preference. (see x-ray 5)

x-ray 4:  Oblique fracture through right distal fibula after supination-external rotation.

x-ray 5: x-ray of right ankle after supination-external rotation. Blue arrow indicates short oblique fracture of distal fibula which progressed to transverse fracture of the medial malleolus after further external rotation (indicated by red arrow)

Image 3: Right medial and lateral malleolar fractures as a result of supination-external rotation in an AFL player who described "rolling" his ankle. Note the marked swelling, especially over the lateral malleolus.

Pronation-Abduction

• 5 – 20 % of malleolar fractures
• The foot is pronated or everted and an abducting force is applied to the talus or foot. This means that the medial portion of the ankle comes under increasing tension as the force is applied, and on the opposite lateral side the ankle becomes compressed. See image 3.

Image 4: Curved blue arrow indicates abducting force applied to pronated foot. Numbers indicate sequence of injuries.

There are 3 sequential injuries:

1. First, as the medial portion of the ankle comes under tension, the deltoid ligament either ruptures, or avulses a transverse fragment of the medial malleolus. (see x-ray 6)
2. Next, as the force continues to be applied, the talus abducts and exerts stress on the ligaments of the syndesmosis, and the AITFL and possibly the PITFL ruptures.
3. Lastly, as continued force is applied, the fibula fractures. As this lateral portion of the ankle is compressed, the fracture is often comminuted.

x-ray 6 AP view: Fracture of the left medial malleolus, avulsed after pronation-abduction.
The image below shows medial malleolar swelling and bruising from a medial malleolus fracture:

Image 5: Soft tissue swelling overlying right medial malleolus fracture

Pronation-External Rotation

• 5 – 15 % of malleolar fractures
• The foot is pronated or everted, and an external rotation force acts through the foot. See image 5.
  Although there are 4 sequential injuries, the first two are essentially the same as those in pronation-abduction.
• The 3rd injury is also a fibular fracture, though it is of a different pattern (higher) than that in pronation-abduction
• The last structures to be affected are the posterior malleolus and the PITFL

Image 6. Refer to text. Curved blue arrow indicates direction of external rotation force applied to pronated foot. Numbers indicate sequence of injuries when the pronated foot is forcibly externally rotated.

Note that when this force is applied, it can also result in a fracture of the proximal fibula, just below the level of the knee.

Diagnosis

In 1992 the University of Ottawa in Canada developed a simple set of rules to exclude ankle fractures in patients presenting to emergency departments. The purpose was to speed up diagnosis and reduce the number of unnecessary x-rays. Most emergency medicine practitioners worldwide have adopted these rules. Why are they being included here? Because these rules have been shown to have 100 % accuracy in excluding fractures, and by applying these rules you can reliably exclude a fracture in a person who has acutely injured their ankle (Bachman et al). So what are the rules?

If a person injures their ankle, a fracture must be excluded if there is pain in the malleolar region AND one of the following two criteria is met:

1. There is bone tenderness on palpation of the posterior edge of the distal 6cm or tip of the medial or lateral malleolus (see picture), or
2. The person was unable to weight bear on the affected side BOTH immediately after the injury, and for 4 steps in the emergency room. Limping on the affected side counts as weight bearing.

If neither of these criteria is met, THERE IS NO ANKLE FRACTURE, though serious ligament damage may have occurred. Always remember to exclude fractures in the foot.

Pilon Fractures

There is one more fracture that warrants mention in this article. This is termed a pilon fracture, after the French word for pestle (as in mortar and pestle), referring to the shape of the distal tibial metaphysis.

• up to 10 % of tibial fractures
• can be low energy e.g. skiing, or high energy e.g. motor vehicle accident or fall from a height
• axial force drives talus into the tibial plafond and fractures the articular surface, while rotational forces shears the bone and causes fragmentation.
• position of the foot at time of impact determines the fracture pattern. See illustration 5.

Illustration 5: Pilon fractures are dependent on foot position at time of impact. 1 Plantarflexed, 2 Neutral position, 3 Dorsiflexed. Adapted from Browner et al.

As can be seen from the illustration, if the foot is plantarflexed (1), the axial force will result in fracture of a posterior portion of the tibia; a dorsiflexed foot (3) will, on axial loading, result in an anterior fragment of the tibia being displaced; in the neutral position (2), both anterior and posterior portions of the tibia are fractured and displaced.

An example of a pilon fracture is shown in x-ray 7 below. This occurred in a young male who jumped 3 metres off a balcony and landed on his feet in the neutral position.

x-ray7: Arrows indicate fractures on both medial and lateral portions of the distal fibula.

Pilon fractures are a surgical emergency and many have poor outcomes.

‘Floating Ankle’

One special type of fracture worth briefly mentioning is that which occasionally occurs in military personnel. The ‘floating ankle’ is caused by violent trauma or blasts e.g. antipersonnel landmines. Modern combat boots often protect the foot and prevent immediate amputation, but at the boot top the distal tibia is susceptible to fracture.

Ankle Dislocations

• almost never occur in isolation
• usually part of complex malleolar fractures
• dislocation of the tibiotalar joint
• requires urgent reduction to preserve the foot

X-rays 8 and 9 demonstrate dislocation of the ankle joint with associated fracture of the fibula. These occurred in an 18 year old male who jumped a fence in bare feet and slipped on the wet grass (x-ray 8), and a 17 year old female who several days later also slipped on wet grass in bare feet (x-ray 9). What is the take home message here?

x-ray 8: Note how the tibia has completely dislocated forward of the talus thus disrupting the mortise

x-ray 9: Right ankle dislocation. Note again the displacement of the tibia off the talus, and the fibular fracture.

Below are two images of a dislocated ankle in someone who slipped on rocks at the beach. In the first image, note the whitish area at the medial malleolus due to lack of blood supply – a true emergency.

Image 7: Ankle dislocation, medial view

Image 8 Ankle dislocation, anterior view

ANKLE LIGAMENT INJURIES

An acute traumatic injury to a ligament is termed a sprain. Remember that a ligament is a dense tissue band that connects two bones at their articulating ends (see med cell intro). The term sprain only implies that a ligament has been damaged, so sprains are divided into 3 groups according to the severity of the ligament damage:

• A first degree sprain results in the microscopic partial tearing of a few ligament fibres, but there is no joint instability as a consequence.
• A second degree sprain is more severe, involving complete disruption of some ligament fibres, but there is little or no joint instability
• A third degree sprain is the most severe, and is the complete tear or rupture of the ligament. The joint is unstable and there is almost complete loss of function.

A sprain results when the ankle moves in a direction that the ligament is unable to tolerate. Generally the ankle will be swollen and tender, though the degree of swelling is not related to the severity of injury.

Why are ankle sprains important?

• They are the most common injury resulting from recreational sports of ANY body part
• Some studies report complete ligament rupture in up to 75 % of cases
• As mentioned, a previously injured ankle significantly increases the risk of subsequent injury to that ankle. Often this can be due to mechanical instability (the ligaments become more lax or loose), or functional instability (person has impaired sense of foot position due to nerve damage).

Let’s look at the 3 groups of ankle ligaments in turn.

Medial Collateral (Deltoid) Ligament Rupture

As discussed in the section on fractures, the deltoid ligament is ruptured as a result of eversion – the foot is planted and the leg is externally rotated. It almost never occurs in isolation, being associated with medial malleolar fractures and fractures of the distal fibula.

Lateral Collateral Ligament Injuries

Inversion injuries are the most common mechanism, accounting for nearly 4 out of 5 ankle sprains. The ligaments comprising the LCL are usually damaged in a front to back direction. The ligament that is most commonly damaged is the anterior talofibular ligament (ATFL).

A forcible supination can occur with the foot in dorsiflexion or plantarflexion.

• So in supination with dorsiflexion, in addition to the ATFL, the fibulocalcaneal ligament can also be torn.
• In the supinated and plantarflexed foot, in addition to the ATFL, the anterior capsule can also be torn.
• In the supinated foot with an external rotation force applied, the tibiofibular syndesmosis may also be involved.

Treatment

Treatment generally is non-surgical, and in the early stages the RICE protocol should be followed (as with any sprain):

• R = Rest
• I = Immobilisation (a cast may be required)
• C = Compression
• E = Elevation

In addition, anti-inflammatory medication, if not contraindicated, should be administered

Syndesmotic ligament injuries

• Often called a ‘high ankle sprain’ due to the relative position of the ligaments compared with other ankle ligaments.
• occur in up to 10 % of ankle sprains
• can also occur with other ligament sprains and fractures.
• Occur during excessive abduction or adduction of the foot or extreme dorsiflexion or a combination of both dorsiflexion and rotation.
• To visualize this injury, imagine the foot is fixed on the ground, with the body falling forward while the person attempts to turn to the side.
• can result in chronic instability
• can be difficult to diagnose

Achilles tendon injuries

These can be divided in to 2 groups of injuries

1. Overuse injuries. These comprise peritendinitis, tendinosis, and partial tears.

• most common overuse syndrome seen in sports medicine clinics
• approximately 1 in 10 runners will get an Achilles tendon injury
•  result from repeated microtrauma when the tendon is continually exposed to load bearing forces e.g. running
• average age of patient about 30 years
• predisposing factors include change in training intensity, moving from a soft to hard training surface and inappropriate footwear
• initially localized pain on exertion as a result of swelling, but this eventually progresses to pain at rest and eventually partial rupture of the tendon
• rest is advocated in most cases, along with anti-inflammatory medicine and attention to predisposing factors. However, in some cases, surgery may be required.

2. Achilles tendon rupture

• A total of 865 members of the U.S. military underwent repair of Achilles tendon ruptures at U.S. military hospitals during calendar years 1994, 1995, and 1996. (Davis, J)
• cause is spontaneous rupture of the Achilles tendon in  most cases, though direct trauma e.g. a bludgeon weapon or blade, can result in rupture.
• most common in 30 – 50 year age group, with men more commonly affected than women.
• “weekend warriors”, not warmed up, tight muscles etc.
• more commonly the left Achilles tendon, most likely due to the fact that right hand dominant people push off with their left foot
• 3 ways in which the Achilles can rupture are:

1. Pushing off on the weight bearing foot while extending the flexed knee e.g. out of the blocks in a sprint, or jumping.
2. Suddenly and unexpectedly dorsiflexing the foot, which would happen when stepping into a hole
3. Violent dorsiflexion of the foot when it is plantarflexed, such as in falling from a height. (Arner and Lindholm)

• usually person feels sudden pain in the heel, and may mistakenly think they have been shot or kicked in the heel.
• will have weakness when plantarflexing

Testing for Achilles tendon rupture (Thompson test)

This is included here as it is a common injury. Have the person kneel or lie face down on a bed with the foot over the edge. Now squeeze mid-calf below the thickest part of the muscle and observe to see whether the foot passively plantarflexes. If there is minimal movement then the tendon is ruptured. See image 8. 

Image 9: Thompson test. Squeezing the calf as shown will plantarflex the foot (black dotted line) if the tendon is intact. There will be no movement with Achilles tendon rupture.

Treatment

This is controversial. Some surgeons will treat simply with a below knee cast. However, re-rupture rates are high. Others will operate to surgically repair the tendon rupture. In any case, specialist treatment is required.

Other tendon injuries around the ankle are relatively rare. Rupture of the posterior tibial tendon results in loss of the normal arch of the foot. Readers wanting to look further can do an internet search on peroneal tendon injuries, and posterior tibial tendon ruptures

Nerve Injuries

Nerve injuries are common in ankle sprains and fractures. Remembering their anatomy, both branches of the peroneal nerve and the tibial nerve can become stretched on excessive movement of the ankle, or a hematoma can develop in the nerve sheath.

In one study, more than 80 % of patients with grade 3 ankle sprain (inversion injury) had peroneal nerve injury, while more than 80 % had tibial nerve injury. (Nitz AJ, et al)

Injury decreases joint range of motion and can significantly prolong recovery time

Soft Tissue Injuries

Soft tissue injuries of the ankle are straightforward in terms of mechanism and outcome. Injuries can result from external forces;

• Blunt force e.g. being hit with a baseball bat, or being kicked
• Lacerations e.g. glass, knives etc.
• Crushing or de-gloving injuries
• Projectiles e.g. bullet wounds

Obviously, the site of impact will determine the injury, which can range from a slight graze to hematoma or even open wounds in blunt force trauma. Lacerations will cause division of skin in varying degrees of thickness, with blood loss, and concomitant nerve, ligament and tendon damage if severe.

Treatment should be aimed at preventing blood loss and further injury

Injuries can also result from intrinsic forces;

• bony fragments damaging blood vessels, nerves, muscle and ligaments leading to hematoma formation and swelling
• Ligament sprain causing hematoma and soft tissue swelling e.g. LCL rupture causing swelling over the lateral malleolus.

CLOSE COMBAT APPLICATIONS

So far the anatomy of the ankle region and the types of injury that can result when certain forces are applied to the ankle in various positions has been examined. From here it is a straightforward exercise to predict what will happen in close combat.

Firstly, imagine the foot fixed in a particular position e.g. neutral or slightly pronated. The foot may be fixed through various mechanisms, including leg bars, being caught in equipment e.g. Bergen rucksack, wedged by features in the terrain e.g. small crevice in the ground or under a tree root, and so on. Alternatively, a person lying prone will have their foot fixed in plantarflexion, risking syndesmotic ligament damage.

The next step is to consider from which direction the force is going to be applied from. Consider in the above example, where the foot is fixed in a neutral position on the ground, a force applied to the lateral aspect of the lower leg. It is easy to deduce that the injuries will run along the continuum of those discussed in pronation-abduction. Similarly, that same foot with a force applied from the inside of the lower leg, as in a leg bar takedown, will result in injuries equal to those discussed in the supination-adduction section. A force applied from BOTH the front and side in a posteromedial direction i.e. a 45 degree angle towards the rear and midline, will result in injuries that can range from supination-adduction to supination-external rotation.

Lastly, determine the speed at which the force is applied. A rapid force usually results in more severe injuries due to relatively larger kinetic energy, and so the injuries are likely to extend to the latter stages of the sequences mentioned above. Remember that, in general, any application of force will result in the weakest elements of the area being injured first.

The next Med Cell article will explore the knee.

References

• Arner O, Lindholm A. Subcutaneous rupture of the Achilles tendon: A study of 92 cases. Acta Chir Scand 1959, Suppl. 239
• Browner: Skeletal Trauma; Basic Science, Management and reconstruction, 3rd ed, Saunders Press 2003
• Davis, J, Military Medicine, Dec 1999: Achilles tendon ruptures stratified by age, race, and cause of injury among active duty U.S. military members
• Nitz AJ, et al, Nerve injury and grades II and III ankle sprains, Am J Sports Med 1985 May-Jun; 13(3):177-82
• Injuries associated with the martial arts, from the Victorian Emergency  Minimum Dataset 2001
• Lucas M Bachmann, Esther Kolb, Michael T Koller, Johann Steurer, and Gerben ter Riet
  Accuracy of Ottawa ankle rules to exclude fractures of the ankle and mid-foot: systematic review
  BMJ, Feb 2003; 326: 417

 

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