Sport medicine

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Many people engaged in recreational and professional sporting activity suffer from foot pain at one time or another.  However, foot pain can be secondary to many situations – some related to sports and other are not.  A famous cause of toe pain, for example, is podagra secondary to gout.  This post will not discuss gout…  Sports related foot pain is also diverse and can actually be secondary to several causes.  This post will discuss pain in the plantar (bottom) aspect of the foot.

Foot sesamoid bone fracture

Sesamoid bones are bones that form within tendons.  Two such sesamoid bones are present around the sheath of the flexor hallucis longus in the plantar aspect of the big toe.  These are the medial and lateral sesamoid bones.  With repeated stress (that can be induced by many types of sports) these bones can break.

Sesamoid stress fracture often has an insidious start.  It is exacerbated by activity.  Clinical features of sesamoid bone stress fractures include local tenderness over the plantar aspect of the big toe, swelling and pain on movement (up and down of the toe).

Imaging studies to diagnose toe sesamoid bone fracture include computed tomography, MRI and bone scan.  If there is frank fracture plain radiograph might show it:

The medial sesamoid is more commonly affected

Treatment for sesamoid bone fractures can be conservative or surgical.  However, these bones tend not to heal and therefore, surgical attachment is often necessary.

Morton’s neuroma

Morton’s neuroma is not a cause of foot pain per se, but rather a cause of a specific painful area in the bottom of the foot (plantar aspect).  Morton’s neuroma is actually located between the 3rd and 4th toes.

The pain is caused because of irritation of the nerves that pass through that area.  The characteristics of the foot pain in Morton’s neuroma are of burning, shooting pain (“neuropathic” pain).  A common cause of Morton’s neuroma is therefore wearing shoes that are too tight.

Morton’s neuroma can be diagnosed by pressing over the 3rd inter phalangeal space.  The pressure is applied from above, not from the plantar aspect.

Treatment of Morton’s neuroma is often conservative (changing shoes, rest) and surgery is only performed when all other measures fail.  Surgery involves excising the inciting nerve.

Plantar faciitis

Plantar faciitis, a cause of foot pain near the heel, is discussed here.

The limbs are divided into compartments by fibrous fascia.  Each compartment has a relatively constant volume.  A rise in the pressure in these compartments can cause tissue damage and this is called compartment syndrome.  By the way, the term ‘compartment syndrome’ usually refers to the limbs, however there are other locations of rising pressure such as the abdomen after surgery or trauma.

Mechanism of compartment syndrome

Compartment syndrome is all about the pressure a compartment and its contents can take.  As volume increases in a compartment, its ability to receive it decreases and at some point the veins draining the compartment will be pressed and pressure rises abruptly.  As the pressure rises, it exceeds the capillary pressure and tissue perfusion with nutrients is impaired.  This in turn causes muscle damage and swelling, further increasing pressure.  Nerves are also damaged due to lack of nutrient supply and direct pressure.

Symptoms of compartment syndrome

The classical pentade of symptoms of compartment syndrome are known as the 5 P’s:

• Pain – the pain in compartment syndrome is severe, un-proportional to objective findings and not relieved by analgesia.  Passive stretching increases pain.
• Paresthesia
• Pallor
• Pulseless
• Paralysis

Another important sign of compartment syndrome is swelling of the affected limb.  This can be demonstrated by comparison to the unaffected limb.

The diagnosis of compartment syndrome is made by combining the  history with the clinical findings and with pressure measurement in the compartment.  A pressure over 30 mmHg (normally the pressure is less than 10 mmHg)  or a difference of over 30 mmHg between the compartment pressure and diastolic pressure makes the diagnosis more likely.

Causes of compartment syndrome

Acute compartment syndrome is caused by abrupt rise in pressure in the limb compartment.  Various injury mechanisms can serve as the cause for this rise in pressure.  Examples include long bone fracture, muscle contusion, limb ischemia, major vessel injury, electrocution and burns.  Physical exertion in a non-trained individual is rarely known to cause acute compartment syndrome.

The compartments of the limbs are as follows:   Lower leg – 4 compartments, thigh – 3 compartments, forearm – 2 compartments and upper arm – 3 compartments.

Lower leg compartment

The lower leg is divided into four compartments.  The compartments and their contents are as follows:

• Lateral lower leg compartment – Peroneus longus muscle, peroneus brevis muscle, superficial peroneal nerve.
• Anterior lower leg compartment – Tibialis anterior muscle, extensor hallucis longus muscle, extensor digitorum longus muscle, peroneus tertius muscle, anterior tibial artery and vein and the deep peroneal nerve.
• Superficial posterior lower leg compartment – Soleus muscle  gastrocnemius muscle (together they form the ‘Triceps surae‘), plantaris muscle, sural nerve.
• Deep posterior leg compartment – Flexor digitorum longus muscle, flexor hallucis longus muscle, popliteus muscle (located behind the knee and serves to unlock it), posterior tibial artery and vein and tibial nerve.

The tibialis posterior muscle is separate from these compartments and has its own sheath.

Treatment of compartment syndrome

The treatment of compartment syndrome includes cutting the compartment (or compartments) open.  This is known as fasciotomy.  The fasciotomy needs to be extensive and the wounds are usually not closed.  Sometimes fasciotomy is done as a preventive measure.

Chronic compartment syndrome

Chronic compartment syndrome in athletes is a syndrome in which pressure is increased in the limb compartments due to fascia thickening and muscle hypertrophy.

The typical symptom of chronic leg compartment syndrome is leg pain over the affected compartment that increases with exercise and resolves with 15-20 minutes of rest.

Diagnosis of chronic compartment syndrome is difficult.  It involves ruling out other differential diagnostic possibilities and direct pressure measurements during exercise.  The diagnostic pressures are:

• Resting pressure > 15 mmHg
• 1 minute post exercise > 30 mmHg
• 5 minutes post exercies >20 mmHg

Treatment includes avoiding the inciting exercise and fasciotomy if needed.  Results are reported to be good.

Approximately 5-10% of all spinal cord injury are sports related.  Spinal injury can be due to acute, one time trauma or to repetitive trauma.  Some spinal injuries are occult, and do not manifest immediately.  Essentially all the spinal elements are susceptible to injury including bones, cartilage, blood vessels, nerves, ligaments, tendons and muscles.

Acute cervical sprain

Acute cervical sprain is most often secondary to trauma.  The main symptom is neck pain.  There should be no motion limitation or neurological deficit.  It there is, the neck should be stabilized and the patient referred for further assessment.

Brachial plexus injury

Brachial plexus injury is also known as “Burner syndrome“.  The mechanism of brachial plexus injury is traction of  C5-6 due to depression of the shoulder while the head was turned to the other side.  Symptoms of brachial plexus injury include neurological deficit.  No pain should be present.  Brachial plexus injury can be prevented by strengthening the neck muscles and by using horse collars (in football).

Nerve root injury

Upper limb nerve root injuries are also called “stingers“.  The mechanism of nerve root injuries involves impact on an extended head (since forbidding impact with an extended neck the rate of sports related quadriplegia dropped significantly).  Symptoms include weakness and parasthesias in the affected limb.  There should be no pain on neck movement.  The most important differential diagnosis is fracture compressing a nerve.  This should be suspected when the symptoms persist.  Another important differential diagnosis are intervertebral disc injuries that can also compress nerves in a pincer mechanism.  The patient will exhibit limited neck motion.  In this case the neck needs to be immobilized and further assessment should be performed.  Another, more severe form, is vertebral disc sublaxation.  In cases of vertebral disc sublaxation the patient exhibits limited neck motionshould mandate neck immobilization.

Vertebral fracture

A neck injury that manifests as neck pain and motion limitation should be suspected to be vertebral fracture.  As pointed out, intervertebral disc injury and vertebral disc sublaxation will also manifest in a similar way.

Lateral neck X-rays should noramlly show a normal neck curvature (also known as ‘neck lordosis’).  If the lordosis disappears, and the neck appears straight on x-ray, this can be a tell-tale sign of serious neck injury:

Loss of the normal lordosis

Treatment of vertebral fracture involves immobilization.  The next phase of treatment will include reduction and fusion if necessary.  Rehabilitation is also an important part of treatment as patients often suffer neurological deficits.

Return to activity after neck injury

There are no clear rules regarding return to sports after neck injury.  Of course no sport activity can be endorsed while there is still neck pain and the range of motion is not full.  On the other hand stingers and burners are not contraindications for resuming activity.

Sometimes the mechanism of injury or the specific treatment influence the decision of whether an athlete can resume activity.  Contraindications for athletic activity include:

• C1-2 fusion
• Multi-level neck injury
• Laminectomy
• Neck instability

Sneakers (sports shoes) have been around since the end of the 19th century.  However, it was not until the 1940′s (1924 – Adidas) that truly modern running shoes came to the world.

Although various shoe manufacturers claim very different technologies, there are actually some basic shoe characteristics that are common to all companies (brooks, nike, adidas, saucony etc.).  Having said that, most serious athletes tend to hone in on one shoe type that suits them the best and in which they feel the most comfortable and safe from injury.

Sneaker structures

Outer shoe sole – is made of blown rubber or carbon rubber or a combination.

Mid-sole – the shoe mid sole is the most important part of the sport shoe.  Mid soles are made of EVA (ethylene vinyl acetate) or PU (polyurythene).  The midsole also has a stabilizing material, usually on the medial part, usually to prevent over-pronation.

Last – External shoe structure -This is the form around which the shoe is built, and is usually classified as either straight (for flat feet), semicurved (for normal feet), or curved (for a high arch).  Curved lasts are also good for sprinters who run on the front of their feet.

Sneaker upper – the upper is the material sewn to the mid-sole (usually a type of nylon).  The upper should offer support, comfort and ventilation.

Heal counter – the heal counter is a rigid or semi-rigid structure that supports the heal part.  It minimizes excessive supination or pronation.  The heal counter needs to be rigid and even more so for people who need more stability.

Toe box – the toe box is the front part of the shoe (technically, the toe box is the front of the upper).  The toe box should fit without pressure so that toe injury will be avoided.

Shoe tongue - the tongue of the shoe should be thick enough to protect the foot from the laces, but not too thick as to put pressure on the foot.

Sneaker types

Sneakers are divided to various types that are meant to differ according to activity.  Some shoe characteristics pertain to the way the shoe protects the athlete while others are relevant to shoe durability.  In other cases the different shoe types are just there to sell more shoes…

• Motion control
• Stability
• Cushioned
• Lightweight training
• Trail

Foot shape and characteristics dictate the type of sneakers that should be used by each athlete from a particular type of sneakers.  One very important characteristic to take into account is the foot arch type and rigidness:

According to foot shape, sneakers are also built in various forms.  Shoe shape can be generally divided into three types:

• Semi-curved – A normal shoe that is meant for most people, with regularly shaped feet.
• Straight – These shoes provide more medial support and are meant for people with flatter feet.
• Curved – Curved shoes allow more curvature on the medial (i.e. inner) side and are meant for people with higher arched feet.  They also provide support for people who tend to run on their tiptoes (e.g. sprinters).