Lecture 8.1 Fractures and Fracture Healing

• Unintentional traumatic musculoskeletal injuries are the number one cause of death for people aged 1 to 44.

Fractures

• Fractures can be complete or incomplete, open or closed.
• Highest incidence of fractures is in young males (15-24) and adults over 65.
• A complete fracture means the bone is broken into pieces.
• An incomplete fracture is not completely through the bone.
• An open fracture involves a break in the skin, while a closed fracture does not.
• Greenstick fractures perforate one cortex and splinter spongy bone, relatively stable.
• Transverse fractures are horizontal breaks.
• Spiral fractures curve around the bone, caused by twisting injuries.
• Boeing fractures usually involve paired bones, where one fractures and the other bows, preventing fracture.

Fracture Healing

• Bleeding from damaged bones forms a hematoma.
• Necrotic tissue causes an inflammatory response, including vasodilation and infiltration of leukocytes and mast cells.
• Platelet-derived growth factor and prostaglandins promote healing.
• Osteoblasts and osteoclasts are activated.
• Healing occurs in inflammatory, repair, and remodeling phases.

Fracture Treatment

• Treatment involves realigning bone fragments to the correct position and holding them in place.
• Traction maintains alignment of bone fragments; skin traction is used when only a few pounds of force are needed.
• Open reduction internal fixation involves exposing the fracture site, aligning fragments under direct visualization, and using hardware to maintain reduction.
• Callus formation occurs prior to remodeling.
• Bone is remodeled to remove and reshape the bone.
• External fixation devices can be used.
• Nonunion is the failure of bone ends to grow together.
• Delayed union occurs approximately 8 to 9 months after a fracture.
• Malunion is the healing of bone in a non-anatomic position.

Dislocation and Subluxation

• Dislocation is the temporary displacement of a bone from its normal position in a joint; if a fracture is involved, it's termed a complex dislocation.
• Subluxation is when contact between two joints is partially list.
• Dislocation or subluxation often occurs in the shoulder, elbow, wrist, finger, hip, and knee joints.

Tendons and Ligaments

• A tendon attaches skeletal muscle to bone.
• A ligament connects bones at a joint.
• Tendons and ligaments can be torn, ruptured, or completely separated from the bone.
• A strain is a tear or injury to a tendon.
• A sprain is a tear or injury to a ligament.
• Avulsion is a complete separation of a tendon or ligament from its bony attachment site.

Strains and Sprains Healing

• An inflammatory cascade begins within 3 to 4 days after injury.
• Collagen formation begins randomly, then organizes parallel to stress lines.
• Vascular fibrous tissue fuses with the new surrounding tissues.
• Healed tendon or ligament lacks sufficient strength for 4 to 5 weeks.

Tendonitis and Bursitis

• Trauma and overuse injuries can cause tendonitis, inflammation of tendons.
• Tendon gnosis is painful degradation of collagen fibers.
• Bursitis is inflammation in the bursal sacs.

Muscle Strains

• Muscle strains are local muscle damage often from sudden force or motion.
• Involves stretching muscles beyond normal capacity.
• Often involves the tendon.

Rhabdomyolysis

• Rhabdomyolysis is the rapid breakdown of muscle that releases intracellular contents, including myoglobin, into the bloodstream.
• Causes hyperkalemia, metabolic acidosis, and acute renal failure.
• Can possibly cause disseminated intravascular coagulation (DIC).
• Cancer, marathon running, and overexertion can be causes.
• Treatment includes IV hydration and possibly hemodialysis for hyperkalemia.

Osteoporosis

• Osteoporosis is a common bone disease characterized by low bone mineral density, impaired structural integrity, decreased bone strength, and increased fracture risk.
• It is not necessarily a consequence of aging.
• Can be generalized or regional.
• Prevention is paramount, focused on preventing fractures and maintaining optimal bone function.
• Recommendations include 1000 to 1500 milligrams a day of calcium.
• Long-term diet history of high fruits and vegetables correlates with high bone mass density.

Osteomalacia

• Osteomalacia is a metabolic disease characterized by inadequate and delayed mineralization of the asteroid.
• Bone volume remains unchanged, but bone is replaced with soft asteroid.
• Requires adequate concentrations of calcium phosphate along with vitamin D.
• Vitamin D regulates and enhances calcium absorption.

Osteomyelitis

• Osteomyelitis is a bone infection often caused by bacteria.
• Can be caused by fungi, mycobacteria, parasites, and viruses.
• Endogenous osteomyelitis is caused by pathogens carried in the blood.
• Exogenous osteomyelitis enters from outside the body.
• Inflammation seals off the area, leading to necrosis.
• Osteoblasts are intensely stimulated, laying down new bone.
• Clinical manifestations include fever and pain.
• Treatment: antibiotics, debridement, surgery, and hyperbaric oxygen therapy.

Bone Tumors

• Primary bone cancer is rare, but metastatic disease commonly affects bone.
• Bone tumors are categorized according to their tissue of origin (osteo genic, androgenic, collagenic, or Milo genic).

Rheumatoid Arthritis

• Rheumatoid arthritis is a systemic autoimmune destruction of synovial membranes and joints.
• Anti-rheumatic drugs (methotrexate and hydroxychloroquine) are the mainstays of treatment.
• Other treatments include non-steroidal anti-inflammatory drugs, glucocorticoids, and intra-articular steroid injections.
• Chronic steroid use inhibits synthesis of endogenous glucocorticoids, reducing cortisol response to stress and potentially causing acute adrenal insufficiency.

Ankylosing Spondylitis

• Ankylosing spondylitis is a chronic inflammatory joint disease characterized by stiffening and fusion of the spine and sacroiliac joints.
• Lumbar lordosis diminishes and kyphosis increases.
• Treatment consists of non-steroidal anti-inflammatory drugs and physical therapy.
• Stiffening of the spine and joints raises concerns for intubation.

Muscle Disorders

• Weakness and fatigue are common symptoms of disorders of the skeletal muscles.
• Can be from secondary causes or stress induced.
• Disuse atrophy is a pathologic reduction in the size of muscle fibres.

Myotonia

• Muscle relaxation is delayed after voluntary contraction.
• Thought to be from a shift in chloride ions, increasing membrane excitability and disrupting the sodium-potassium ion balance.

Periodic Paralysis

• The muscle membrane resting potential is reduced, making it unresponsive to stimulus.
• Usually transient, accompanied by a change in serum potassium levels.

Overview of fractures, including complete vs incomplete, open vs closed. Discussion of greenstick, transverse, spiral, and bowing fractures, and the stages of bone healing. Explanation of hematoma formation, inflammation, and bone remodeling.