1. BONE FRACTURE MED121/LECTURE44 DR ZEENAT N.P. PATHOLOGIST COLLEGE OF MEDICINE MAJMAAH

2. OBJECTIVES a.Define fracture & healing. b.Enlist common fractures. c.Describe traumatic & pathological fractures. d.Explain process of healing.

3. Define fracture- Disconitnuity in the bone alignment Traumatic Nontraumatic fractures Most common pathologic conditions affecting bone. Fractures are classified as Complete or incomplete Closed (simple) when the overlying tissue is intact &.Open Compound when the fracture site communicates with the skin surface Comminuted when the bone is splintered Displaced when the ends of the bone at the fracture site are not aligned. If the break occurs in bone already altered by a disease process, it is described as a pathologic fracture. A stress fracture is a slowly developing fracture that follows a period of increased physical activity in which the bone is subjected to new repetitive loads—as in sports training or marching in military boot camp.

4. ENLIST COMMON FRACTURES Transverse fracture. In this type of fracture, the break is a straight horizontal line going across the femoral shaft. Oblique fracture. This type of fracture has an angled line across the shaft. Spiral fracture. The fracture line encircles the shaft like the stripes on a candy cane. A twisting force to the thigh causes this type of fracture. Comminuted fracture. In this type of fracture, the bone has broken into three or more pieces. In most cases, the number of bone fragments corresponds with the amount of force required to break the bone.

8. Greenstick Occurs in children: bones soft and bend without fracturing completely

9. Open fracture. If a bone breaks in such a way that bone fragments stick out through the skin or a wound penetrates down to the broken bone, the fracture is called an open or compound fracture. Open fractures often involve much more damage to the surrounding muscles, tendons, and ligaments. They have a higher risk for complications — especially infections— and take a longer time to heal.

10. Statistics Fractures of extremities most common More common in men up to 45 years of age More common in women over 45 years of age Before 75 years wrist fractures (Colle’s) most common After 75 years hip fractures most common

11. C/F of fractures: Impaired function. Deformity (unnatural alignment). Swelling. Muscle spasm. Tenderness. Pain. Impaired sensation.

12. Functions of the X-ray Localises fracture and number of fragments Indicates degree of displacement Evidence of pre-existing disease in bone Foreign bodies or air in tissues May show other fractures MRI, CT or ultrasound to reveal soft tissue damage

13. FRACTURE HEALING The process involves regulated expression of a multitude of genes can be separated into overlapping stages with particular molecular, biochemical, histologic, and biomechanical features.

14. Bone Healing 1. Fracture hematoma – blood from broken vessels forms a clot. – 6-8 hours after injury – swelling and inflammation to dead bone cells at fracture site

15. Immediately after fracture, rupture of blood vessels results in a hematoma, which fills the fracture gap and surrounds the area of bone injury. The clotted blood provides a fibrin mesh, which helps seal off the fracture site and at the same time creates a framework for the influx of inflammatory cells and ingrowth of fibroblasts and new capillary vessels. Simultaneously, degranulated platelets and migrating inflammatory cells release PDGF, TGF-β, FGF, and interleukins, which activate the osteoprogenitor cells in the periosteum, medullary cavity, and surrounding soft tissues and stimulate osteoclastic and osteoblastic activity

16. 2. Fibrocartilaginous callus (lasts about 3 weeks (up to 1 Month) – new capillaries organize fracture hematoma into granulation tissue - ‘procallus’ – Fibroblasts and osteogenic cells invade procallus. – Make collagen fibers which connect ends together – Chondroblasts begin to produce fibrocartilage,

17. 3. Bony callus (after 3 weeks and lasts about 3-4 months) – osteoblasts make woven bone.

19. by end of the first week Hematoma is organizing, the adjacent tissue is being modulated for future matrix production, and the fractured ends of the bones are being remodeled. This fusiform and predominantly uncalcified tissue— called soft-tissue callus or procallus—provides some anchorage between the ends of the fractured bones but offers no structural rigidity for weight bearing.

20. Subsequently, the activated osteoprogenitor cells deposit subperiosteal trabeculae of woven bone that are oriented perpendicular to the cortical axis and within the medullary cavity. In some cases the activated mesenchymal cells in the soft tissues and bone surrounding the fracture line also differentiate into chondroblasts that make fibrocartilage and hyaline cartilage. In an uncomplicated fracture, the repair tissue reaches its maximal girth at the end of the second or third week, which helps stabilize the fracture site

21. The newly formed cartilage along the fracture line undergoes enchondral ossification, such as normally occurs at the growth plate, forming a network of bone that connects to the reactive trabeculae deposited elsewhere in the medullary cavity and beneath the periosteum. In this fashion the fractured ends are bridged by a bony callus, and as it mineralizes the stiffness and strength of the callus increases to the point that controlled weight bearing can be tolerated

22. In the early stages of callus formation an excess of fibrous tissue, cartilage, and bone is produced. If the bones are not perfectly aligned, the volume of callus is greatest in the concave portion of the fracture site. As the callus matures and is subjected to weight- bearing forces, the portions that are not physically stressed are resorbed, and in this manner the callus is reduced in size until the shape and outline of the fractured bone have been re-established. The medullary cavity is also restored, and after this has been completed it may be impossible to demonstrate the site of previous injury

23. COMPLICATIONS OF FRACTURE HEALING The sequence of events in the healing of a fracture can be easily impeded or even blocked. For example, displaced and comminuted fractures frequently result in some deformity, Inadequate immobilization permits constant movement at the fracture site, so that the normal constituents of callus do not form, resulting in delayed union and nonunion. If a nonunion allows too much motion along the fracture gap, the central portion of the callus undergoes cystic degeneration, And the luminal surface can actually become lined by synovial- like cells, creating a false joint or pseudoarthrosis. A serious obstacle to healing is infection of the fracture site, which is a risk in comminuted and open fractures. The infection must be eradicated before bony union can be achieved.

24. In children and young adults, in whom most uncomplicated fractures are found, near perfect reconstitution is the norm. In older age groups in whom fractures tend to occur on a background of some other disease (e.g., osteoporosis and osteomalacia) repair is more often imperfect and may require mechanical immobilization (e.g., placement of stabilizing pins).

25. MEDICAL MANAGEMENT

26. SURGICAL TREATMENT External fixation

27. Intramedullary nailing provides strong, stable, full-length fixation.

29. COMPLICATIONS FROM SURGERY Infection Injury to nerves and blood vessels Blood clots Fat embolism (bone marrow enters the blood stream and can travel to the lungs; this can also happen from the fracture itself without surgery) Malalignment or the inability to correctly position the broken bone fragments Delayed union or nonunion (when the fracture heals slower than usual or not at all) Hardware irritation (sometimes the end of the nail or the screw can irritate the overlying muscles and tendons)

30. THANK YOU