Fracture Repair & Classification

Lecture Introduction

• Remember to check into each session via Osler.
• The lecture will cover fracture repair and classification.
• Joan Roehl is the Assistant Professor for this topic.
• Bond University acknowledges the Kombumerri people, the traditional Owners and Custodians of the land on which the University now stands, and pays respect to Elders past, present and emerging.

Civilization and Healing

• Anthropologist Margaret Mead considered a healed femur (thighbone) the first sign of civilization.
• In the animal kingdom, a broken leg is fatal.
• A healed femur indicates someone took the time to care for the injured.
• Helping others through difficulty is where civilization begins.

Learning Outcomes for the Week

• Classify fractures
• Describe the major features of the process of fracture repair

Learning Outcomes for the Session

• Identify the causes of bone fractures
• Know the structure of bone across the lifespan and how mechanisms of injuries result in the appearances of fractures
• Understand the types and classifications of bone fractures
• Explain the process of bone repair and what types of fracture healing exist

Fracture Definition

• A fracture is a break in a bone from force applied that exceeds its tensile or compressive strength.

Causes of Bone Fractures

• Fractures are grouped by cause into three major categories:
• Sudden injury
• Fatigue or stress fractures
• Pathologic fractures

Incidence of Bone Fractures

• The highest incidence of fractures is in young males (15-24) and the elderly (65+).
• In healthy young people, fractures are from trauma to the tibia, clavicle, distal humerus, hands and feet.
• In older people, fractures are often associated with bone disease and affect the proximal femur, proximal humerus, vertebrae, wrist, and pelvis.

Risk Factors for Fractures

• Influencing factors include age, sex, health, diet, smoking, alcohol, occupation, and impact.

Classification of Fractures

• A bone can be completely or partially fractured.
• A complete fracture is a bone broken all the way through.
• An incomplete fracture is a bone damaged, but still in one piece.
• Severity depends on bone type, injury nature/cause, and the person's age/health.

Types of Fractures

• Closed (simple): Non-communicating wound between bone and skin
• Open (compound): Communicating wound between bone and skin
• Comminuted: Multiple bone fragments
• Oblique: Fracture line at an angle to long axis of bone
• Transverse: Fracture line perpendicular to long axis of bone
• Pathologic: Fracture at a point where bone has been weakened by disease (e.g. by tumors or osteoporosis)
• Compression: Fracture wedged/squeezed together on one side of bone
• Displaced: Fracture with one, both, or all fragments out of normal alignment
• Greenstick: Break in one cortex of bone with splintering of inner bone surface; commonly occurs in children
• Stress: Microfracture

Classifications of Specific Fractures

• Fractures can simply be named by their conditions with bone breakage and overlying tissue
• Closed Fractures
  • The skin is not broken
• Open (compound)
  • The skin is broken
  • Complications include soft tissue trauma, moderate to severe force, infection and external bleeding
  • It is a medical emergency
• Displaced Fractures
  • The bone is broken into two or more pieces and the pieces have moved out of normal alignment
• Comminuted Factures
  • The bone has broken into three or more pieces generally due to high energy trauma
• Transverse Fractures
  • A horizontal fracture line/is at a right angle (perpendicular) to the bone's axis
  • Usually caused by direct force to fracture site
• Oblique Fractures
  • This type of fracture has an angled pattern caused by direct or indirect energy and some compression
• Pathologic Fractures
  • Fracture at site of pre-existing abnormality -tumours, -osteoporosis, -infections, -metabolic bone disorders
  • Bone weakened by disease and usually by a force that would not fracture a normal bone
    • 75yo, female, and has painful, swollen left upper arm from falling at home.
    • Has a displaced fracture of the proximal diaphysis of the humerus with moth eaten appearance
• Compression Fractures
  • Bone is crushed, causing it to be wider or flatter in appearance when vertebrae are forced against each other
  • Older people and those with osteoporosis are at higher risk
• Greenstick Fractures
  • Disrupts the outer cortex, bone is fractured on one side only, and bent on the other side (like a young tree branch bent sharply)
  • Typically proximal tibia, radius and ulna
  • Commonly occurs in children
• Stress Fractures
  • A hairline crack in a bone caused by repetitive force
  • Fatigue(overuse)
    • Chronic application of abnormal stress (e.g. running) on normal bone, resulting in microfractures and eventually macroscopic failure typically in bones of legs and feet.
  • Insufficiency Fracture
    • Normal stress on weakened bone due to metabolic abnormalities(e.g. osteoporosis) or genetic abnormalities(e.g. osteogenesis imperfecta

Bone Healing Overview

• Bone generally heals in two ways: direct/primary and indirect/secondary.

Bone Healing - Direct/Primary

• Micro gap <1mm
• Little to no callus formation
• Haversian remodeling osteoblast/osteoclast activity
• When the bone ends are held close together, intramembranous

Bone Healing - Indirect/Secondary

• Gap >1mm
• Callus formation
• More common than direct healing
• Endochondral healing

Bone Healing - Indirect/Secondary Bone Healing Phases

• Haematoma Phase
• Inflammatory Phase
• Reparative Phase
• Remodelling Phase

Factors Influencing Bone Healing

• Age
• Nutrition
• Treatment/stress on fracture site
• Immunocompetency/blood supply/infections
• Health/comorbidities/medications
• Nature and extent of injury

Healing Complications

• Malunion, delayed union, or non-union.