Bone fractures and healing

Dr AMMAR JAWAD, MBChB, MPHIMS

Management & Science University

Blood Supply to Bone:

Musculoskeletal Injuries

•Contusion▫Damage to soft tissue , sub-q structures, and

muscle•Strains

▫Tear to the musculotendinous unit•Sprains

▫Trauma to joint, ligament may be completely torn or stretched

•Dislocation▫Displacement of the normal position

Fractures

• A bone fracture is a medical condition in which there is a break in the continuity of the bone

• While many fractures are the result of high force impact or stress, bone fracture can also occur as a result of certain medical conditions that weaken the bones, such as osteoporosis, certain types of cancer, or osteogenesis imperfecta, where the fracture is then termed pathological fracture

•The proper healing of a fracture depends on whether or not, the blood supply and cellular components of the periosteum and endosteum survive.

Causes of fractures

•1-traumatic•2-pathological

pathological

•The second common times in life for fractures to occur are during elderly

Symptoms

•A visibly out-of-place or misshapen limb or joint

•Swelling, bruising, or bleeding•Intense pain•Numbness and tingling•Broken skin with bone protruding•Limited mobility or inability to move a

limb

Fracture Types FRX or FX• Fractures are often classified according to the position of the bone ends

after the break:Open (compound): Bone ends penetrate the skin.

Closed (simple): Bone ends don’t penetrate the skin.

Comminuted: Bone fragments into 3 or more pieces. Common in the elderly

(brittle bones).

Greenstick: Bone breaks incompletely. One side bent, one side broken.

Common in children whose bone contains more collagen and are less mineralized.

Spiral: Ragged break caused by excessive twisting forces. Sports injury/Injury

of abuse.

Impacted: One bone fragment is driven into the medullary space or spongy

bone of another bone

Common Types of Fractures

Table 6.2.1

Common Types of Fractures

Table 6.2.2

Common Types of Fractures

Table 6.2.3

avulsion fracture separation of a small fragment of bone cortex at the site of attachment of a ligament or tendon.

•Closed fractures are those in which the skin is intact, while Open fractures involve wounds that communicate with the fracture and may expose bone contamination (need antibiotics).

•They require urgent surgical treatment.•This involves removal of all dirt, contamination and

dead tissue.

Open (compound) fractures

• High risk of infection• Can be associated with gross soft tissue damage, severe

haemorrhage or vascular injury

Fracture Healing•The natural process of healing a fracture starts when

the injured bone and surrounding tissues bleed.

•The blood coagulates to form a blood clot situated between the broken fragments.

•Within a few days blood vessels grow into the jelly-like matrix of the blood clot.

•The new blood vessels bring white blood cells to the area, which gradually remove the non-viable material.

Fracture Healing

•The blood vessels also bring fibroblasts in the walls of the vessels and these multiply and produce collagen fibres.

• In this way the blood clot is replaced by a matrix of collagen.

•Collagen's rubbery consistency allows bone fragments to move only a small amount unless severe or persistent force is applied.

Fracture Healing

•At this stage, some of the fibroblasts begin to lay down bone matrix (calcium) in the form of insoluble crystals.

•This mineralization of the collagen matrix stiffens it and transforms it into bone.

•Healing bone callus is on average sufficiently mineralized to show up on X-ray within 6 weeks in adults and less in children.

Fracture Healing

•This initial "woven" bone does not have the strong mechanical properties of mature bone.

• By a process of remodeling, the woven bone is replaced by mature "lamellar" bone.

•The whole process can take up to 18 months, but in adults the strength of the healing bone is usually 80% of normal by 3 months after the injury.

Healing times

•Neonatal period▫2-4 weeks

•Early childhood▫4 weeks

•Later childhood▫6-8 weeks

•Adolescence▫8-12 weeks

Healing in Bone:

1D - Hematoma formation (fibrin mesh)

3D - Inflammation – PDGF, IL, TGF 1W - Soft callus – granulation, matrix. 3-6W - Callus – ossification, woven

bone 8+W - Re-modeling – absorb/deposit,

strength, lamellate.

Stages of wound healing

Time after injury

Hemostasis

Inflammation

Proliferation

Resolution/ Remodeling

PMNs, Macrophages, Lymphocytes

Reepithelialization, Angiogenesis, Fibrogenesis,

Vessel regression, Collagen remodeling

Fibrin clot, platelet deposition

1D 3D 1wk 6wk 8wk

Healing in Bone:

Healing in Bone:

Bone Fracture Repair

Bone Fracture Repair (cont’d)

STAGES OF BONE FRACTURE REPAIR

Bone fracturesBone fractures

Compound Fracture

Fracture Head of Humerus

Immobilization – Plaster cast

Bone healing: Callus

Factors affecting Healing:•Systemic & Local factors•Immobilization•Improper reduction – abnormal position•Infection. Debris, dead tissue in wound•Joint involvement

Bone Fractures & Healing

Complications:• Delayed healing.

• Non healing.

• Joint involvement – ankylosis (stiffness of a joint due to abnormal adhesion and rigidity of the bones of the joint)

• Abnormal position – arthritis.

• Bone necrosis – nutrient artery

•Involucrum formation. (a layer of new bone growth outside existing bone usually in OM )

•Fat embolism•DVT/PE•Bed sores•Depression/PTSD •Tetanus •Infections

•Malunion▫ Healing of fragments of a fracture in a faulty position.

•Delayed union▫ Any fracture that takes longer to heal than the average fracture

at that anatomic location.

•Non-union▫ The fracture healing process has completely stopped and the

fragments will remain un-united even with prolonged immobilization.

Treatment of fracture

•1) Reduce•2) Maintain reduction (+ hold until union)•3) Rehabilitate – restore function•4) Prevent or treat complications

Reduction

•Does the fracture require reduction? ▫ Is it displaced?▫ Does it need to be

reduced?

Reduction

• If necessary, what reduction technique?

• 1) Closed reduction▫ Need anaesthesia/sedation, analgesia, x-ray facilities,

equipment, knowledge▫ Used for minimally displaced fractures and most

fractures of children 1) Distal part of limb pulled in line of bone 2) As fragments disengage, they are repositioned (reverse

original direction of deforming force) Alignment adjusted in each plane

• 2) Open reduction▫ Above + theatre staff + additional equipment▫ Risks

Maintain reduction

•Necessary?1) Relieve pain

2) Prevent mal-union – nature heals the fracture, we keep it in a good position

3) Minimise non-union – maintenance of reduction should be continuous

Nutritional Effects on Bone

•Normal bone growth/maintenance cannot occur without sufficient dietary intake of calcium and phosphate salts.

•Calcium and phosphate are not absorbed in the intestine unless the hormone calcitriol is present. Calcitriol synthesis is dependent on the availability of the (Vitamin D) which synthesized in the skin or obtained from the diet.

•Vitamins C, A, K, and B12 are all necessary for bone growth as well.

Nutritional Effects on Bone

•What can you do to take care of your skeletal system?

Hormonal Effects on Bone

•Growth hormone, produced by the pituitary gland, and thyroxine, produced by the thyroid gland, stimulate bone growth.▫GH stimulates protein synthesis and cell growth

throughout the body.▫Thyroxine stimulates cell metabolism and increases the

rate of osteoblast activity.

• Clinical Conditions• Osteomalacia

▫ Literally “soft bones.”▫ Includes many disorders in which osteoid is produced but inadequately

mineralized. Causes can include insufficient dietary calcium Insufficient vitamin D fortification or insufficient exposure to sun light.

• Rickets▫ Children's form of osteomalacia▫ More detrimental due to the fact that their bones are still growing.▫ Signs include bowed legs, and deformities of the pelvis, ribs, and skull.

Rickets

Osteoporosis

▫ Group of diseases in which bone resorption occurs at a faster rate than bone deposition.

▫ Bone mass drops and bones become increasingly porous.▫ Compression fractures of the vertebrae and fractures of the

femur are common.▫ Often seen in postmenopausal women because they experience

a rapid decline in estrogen secretion; estrogen stimulates osteoblast and inhibits osteoclast activity.

Skeletal System

Gigantism

▫Childhood hypersecretion of growth hormone by the pituitary gland causes excessive growth.

Acromegaly

•Acromegaly ▫Adult-hood hyper-secretion of GH causes overgrowth

of bony areas still responsive to GH such as the bones of the face, feet, and hands.

•Pituitary dwarfism▫GH deficiency in children resulting in extremely short

long bones and maximum stature of 4 feet.

•When you were born, you had more than 300 bones. By the time you stop growing, you’ll have 206.

Definitions

•1. osteohypertrophy: overgrowth of bone.•2. osteosarcoma: tumor of the bone.•3. osteosclerosis: abnormal hardening or eburnation of bone.•4. osteoporosis: progressive reduction in quantity of bone.•5. osteopenia: decreased calcification or density of

bone.