Causes

If the load on a limb exceeds the strength of the bone, joint capsule or ligaments, then a fracture, dislocation, or joint sprain will occur. If the load is normal but the bone is weak, then this is a pathological fracture e.g fractured neck of femur in an elderly female. Repetitive loading may cause a stress fracture as in long-ditShape and direction of injurysance runners.

Shape and direction of injury

1 Shape of the fracture. This is determined by the direction of force applied:

Spiral fractures result from twisting.
Crush fractures result from excess longitudinal load.
Transverse fractures result from bending forces.
Very high impact energies tend to explode the bone.

2 Dislocation. A joint is more susceptible to dislocation if the patient has lax ligaments or if there is damage to the capsule from a previous dislocation.

History

The patient will be able to describe what they have felt or heard. Dislocations may relocate spontaneously, so the patient’s description of what happened is valuable.

Examination

Do not forget to check distal neurovascular status, then use the ‘look, feel, move’ system to check for:

Wounds on the skin.
Bleeding into the soft tissues.
Deformity of bones and joints.

Movement needs to be performed carefully, watching the patient’s face, testing for ruptures of muscles and ligaments, instability of joints and even crepitus in bones. Don’t forget: if there is enough energy for one injury, then there is plenty for more, so check the whole body.