Violence or trauma leads to a break in the bone as well as injury to the underlying structures and soft tissues. There is tear in the periosteum which covers the bone. The blood vessels which supply the bone and the periosteum are ruptured leading to haemorrhage. The haemorrhage leads to the formation of a haematoma (a swelling containing clotted blood) around the fracture site.
In severe fracture, nerves, skin and muscles around the fracture site may be damaged producing severe pain and loss of function. Pain may also be produced as a result of severe swelling arising from bleeding from the damaged vessels and inflammatory reaction. Complete break across bone shaft brings about deformity which presents with change in alignment and contour e.g. angulation, rotation of a limb or shortening of a limb.
When there are bone fragments over the site of fracture as occurs in comminuted fracture there is crepitation on palpation or on attempt to move injured limb. Severe pain and shortening of the affected limb also occur as a result of spasm of the surrounding muscles. Severe pain and haemorrhage as occurs in open fracture produce shock.
Injury to underlying organs or tissues e. g. Brain, lungs, urinary bladder, spinal cord etc may occur as the broken bone ends penetrate into them thereby leading to brain injury, pneumothorax, bladder perforation, or paralysis. The bone may also damage the nerve supply to the part thereby causing thereby causing paralysis e.g. injury to the radial nerve as a result of fracture of the Radius can cause paralysis of the arm.
Communication of the bone end with the exterior and presence of an open wound give opportunity for micro-organisms to infect the wound. This may lead to osteomyelitis (Inflammation of the bone marrow) if not properly handled.
Signs and symptoms of fracture
1. Severe pain: Fracture is usually accompanied by a very severe pain. Pain from fracture is about the worst pain so far. The kind of pain sometimes is enough to make the patient go into a state of shock if not controlled.
2. Deformity: Deformity occurs especially with fracture of the limbs. The part below the affected limb can be rotated outwards or inwards. In some cases the affected limb is shorter than the second.
3. Loss of function: The individual is unable to make use of the affected part due to pain, tenderness or deformity. One obvious sign of fracture of the lower limb is that patient cannot walk with the affected limb. In case of the arm the patient can also not lift with the affected limb or move it above the head.
4. Muscle spasm: There is usually involuntary muscle contraction around the fracture site. This is often responsible for the severe pain and shortening of the limb.
5. Oedema: There is severe swelling around and below the fracture site as a result of effusion of blood into the surrounding tissues. Oedema could also be due to inflammatory reaction from the injury.
6. Crepitation: Crepitation is heard or felt as the patient attempts to move the affected part or on palpation. This is due to the bone fragments rubbing against one another.
7. Paralysis: Paralysis of the affected part may occur if the broken bone end pierces the nerve supplying the part. For example if the broken bone of the femur hits the femoral nerve there is going to be paralysis of the leg. Fracture to the forearm could lead to bone fragment piercing the radial nerve and subsequently paralysis of the forearm and the hand.
8. Discoloration: Discoloration of the site occurs as a result of the effusion of blood under the skin. This is referred to as ecchymosis.
Diagnosis of fracture
1. Presenting signs and symptoms: Signs and symptoms such as Crepitation, shortening, outward or inward rotations are diagnostic.
2. X-ray: This will reveal part of the bone that is broken.