Acute Sports Injuries - BONES

This post focuses on acute bone injuries in sport - fractures and periosteal contusion.

In the absence of a bone pathology that is causing localised or generalised bone fragility, large forces are required to fracture a bone. These forces can result from direct trauma such as a blow or indirect trauma such as an awkward fall or twisting motion.

Traumatic fractures can be dichotomised as either closed (simple) or open (compound). The skin remains intact over the fracture site in closed fractures whereas skin integrity is often lost in open fractures, usually due to penetration from within by the fractured bone. The presence of a skin wound in open fractures enables pathogens to enter and contribute to bone infection. Individuals with an open fracture should be treated with prophylactic antibiotic therapy.

The primary aim of fracture management is to allow the fracture to heal in the most anatomical position possible so that the mechanical function of the bone can be restored. A fracture that heals in an abnormal position (e.g. malunited fracture) can lead to the long-term development of secondary complications such as osteoarthritis. In addition to reducing a fracture and providing an environment that is permissive of bone regeneration, it is necessary to assess and monitor for other possible complication of fracture, such as acute compartment syndrome, associated injuries (e.g. nerve/vessel), deep venous thrombosis/pulmonary embolism, and delayed or non-union.

Soft tissue injury, such as ligament or muscle damage, is often associated with a fracture and may cause more long-term problems than the fracture itself. It is important to address any concomitant soft tissue injury. Sometimes deep venous thrombosis or pulmonary embolism can occur following a fracture, especially in the lower limbs. This should be prevented by early movement and active muscle contraction.

Delayed or non-union of a fracture causes persistent pain and disability. It can be caused by excessive or insufficient fracture site stabilisation, presence of a complicated fracture type, insufficient or disrupted blood supply (e.g. due to abnormal regional anatomy or the presence of comorbid conditions such as diabetes) and lifestyle factors such as smoking, excessive alcohol intake or poor nutrition. Management options for delayed or non-united fractures include non-surgical treatments such as low-intensity pulsed ultrasound and electromagnetic therapies, as well as surgical treatments such as bone grafts or bone graft substitutes, internal and/or external fixation. In the future, biological compounds and small molecule pharmaceuticals may become available.

As well as a bone fracture, periosteal contusion is also an acute sports injury. The periosteum is a dense, fibrous tissue that is firmly attached to the outer surface of bones. It is highly vascular and innervated. At subcutaneous skeletal sites (e.g. medial surface of the tibia and iliac crest), the periosteum is susceptible to acute trauma from a direct blow with an external object, such as a ball, stick, opponent or playing surface. The blow damages periosteal blood vessels and results in the development of a subperiosteal haematoma (periosteal contusion).

The confined space beneath the periosteum limits the spread of the haematoma, occasionally leading to the development of a palpable lump. The raised periosteum is tensed and irritated/inflamed. The nociceptive nerve endings are stimulated to cause considerable pain, especially upon palpation and on contraction of the muscles attaching to the injured region. A periosteal contusion at the iliac crest, often referred to as a 'hip pointer' injury, can be extremely painful due to the involvement of the cluneal nerve which runs along the iliac crest.

Management of periosteal contusions focuses initially on minimising the extent of the haematoma using conventional first aid approaches followed by a gradual return to activity. Protective equipment such as shin pads/guards should be considered for future prevention of injury in the athlete.

I'm really enjoying writing these posts and they are coming thick and fast at the moment! Stay tuned for the next post in the series, examining acute injuries of the hyaline cartilage....

REFERENCES

Brukner, P., 2012. Brukner & Khan's clinical sports medicine. North Ryde: McGraw-Hill.