fracture = break in surface of bone

dislocation = complete and persistent displacement of a joint; pt. can't move it; loss of contact bet. articular surfaces

subluxation = partial dislocation of a joint, where bones are partially separated from one another, and articular surfaces are no longer congruent.

sprain = temporary subluxation of a joint, where the articular surfaces return to normal alignment; no deformity other than swelling

closed fracture: overlying skin remains intact; the periosteal blood vessels and the vessels within the surrounding soft tissue are torn; hematoma occurs; compression of the surrounding soft tissue by the hematoma limits the expansion of the hematoma and its ultimate size

1. closed fracture of the femur may result in up to 1 liter of blood loss

open fracture: the skin overlying the fracture has been broken.

complications of open fractures:

(1) decreased rate of healing

(2) increased risk of infection

(3) greater (even life threatening) blood loss

Fracture sites

A. Diaphyseal bone - shaft of long bone

B. Metaphyseal bone - flared portion of the bone at the ends of the shaft.

C. Epiphyseal bone - involving the ends of the bones, forming part of the adjacent joint. Fractures here may affect growth of bone in later life.

D. Intra-articular bone - may result in post-traumatic arthritis

Fracture Patterns

Transverse - a fracture that is perpendicular to the shaft of the bone

Oblique - an angulated fracture line

Spiral - a multiplanar and complex fracture

Comminuted - more than two fracture fragments.

Segmental - a communicated fracture with three large fragments in the shaft of a long bone.

Intra-articular - the fracture line crosses the articular cartilate and enters the joint.

[image]

Avulsion: results from a muscle pull that tears the musculotendinous insertion on the bone from the remaining mass of bone

Compression fractures: crushing injury, particularly common in cancellous flat bones - i.e. vertebrae. These fractures are typical in patients with osteoporosis.

Pathologic fractures: occur when the bone is weakened by tumor or other disease such as osteoporosis

Greenstick fractures: (children) fracture is in shaft of bone; the cortex on the convex side of the deformity is broken, while the cortex on the concave side remains intact, like breaking a green stick.

Buckle fracture: (children) occurs in the metaphysis of long bones in response to excessive compressive loading; usually occurs after a fall from on an outstretched hand

Movement

A. Non-displaced: no associated defomrity other than swelling. Muscloskeletal injuries must cause pain, swelling, bruising, and point tenderness to palpation. These symptoms should be evaluated by X-ray to rule out fracture.

B. Displaced: fractures are described by the type of defromity the displacement produces.

1. Angular: There may be angulation in the frontal plane (varus or valgus) or angulation in the sagittal plane (anterior or posterior)

2. Rotational: After a fracture, the pull of gravity or muscle spasm rotates the distal fragment along the long axis of the bone, resulting in either internal or external rotation.

3. Shortening: When surrounding muscles go into spasm, the spasm pulls on the fracture fragments causing them to overlap => limb shortening. bayoneted fracture: when the distal fragment of bone overlaps the proximal fragment

Children have softer bones that allow them to bend, leading to both greenstick and buckle fractures.

This is a common presentation for child abuse.

Neurovascular injuries:

Are the distal pulses present?

Capillary refill time?

Nerves intact?

Radial nerve palsy: fracture or over aggressive manipulation of a fracture of the humeral shaft (the radial nerve lies within the spiral groove) => wrist drop

hyperextension injury of the elbow: leads to a supracondylar fracture of the humerous => anterior displacement of the humeral shaft fragment that impinges on the radial nerve, median nerve, and brachial artery.

posterior dislocation of the hip: results in damage to the sciatic nerve (5-15%) of the time => foot drop

Compartment syndrome: leg and forearm

Mechanism: accumulation of fluid at high pressure within a closed muscle compartment decreases perfusion beyond a point critical for muscle viability => muscle and nerve ischemia => necrosis

Symptoms:

severe pain on stretching long muscles

sensory deficit (paresthesias, hyper, hypo, or an-)

decreased capillary filling

May also result from casting, where swelling inside the cast compresses the soft tissues to the point of decreased perfusion.

ARDS (adult respiratory distress syndrome)

Respiratory failure - devlops within the first 72 hours after a long bone fracture;

thought to be secondary to release of free fatty acids into the bloodstream from the site of fracture

Avascular necrosis

Mechanism: occurs when blood supply to bone is interrupted

Bones most commonly affected:

(1) femoral neck fractures: blood supply to the femoral head traverses the femoral neck. When the femoral neck is broken, the femoral head undergoes avascular necrosis.

(2) Legg-Calve-Perthes syndrome - avascular necrosis of the femoral head occurs w/o fracture in children (3-12 year old)

(3) slipped capital femoral epiphysis - leads to avascular necrosis; femoral epiphysis slips posteriorly, leading to ischemia of the femoral head; obese children early in adolescence (12-13 y/o)

(4) schapoid fractures - patients fall on outstretched hand => ischemia of the proximal segment of the bone because blood is supplied ot the distal scaphoid only = > avascular necrosis