Fracture definition classification causes clinical features healing of fracture and complications
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Fractures: Definition, Classification, Causes, Clinical Features, Healing & Complications
1. Definition
A fracture is a break in the continuity of bone. This includes complete breaks, partial breaks (fissures/cracks), and microfractures, regardless of whether the bone is displaced or not. Fractures may involve cortical bone, cancellous bone, or both, and may or may not be associated with soft tissue injury.
General Anatomy and Musculoskeletal System (THIEME Atlas)
2. Classification
Fractures are classified along several axes:
A. By Mechanism / Cause
| Type | Description |
|---|---|
| Traumatic fracture | Caused by direct force (transverse or comminuted fracture) or indirect force (lever/rotational, e.g., torsion fracture of the lower leg in a ski crash) |
| Pathologic fracture | Due to preexisting bone disease (tumor, osteomyelitis, osteoporosis); can occur with minimal or no force |
| Stress/Fatigue fracture | Repeated moderate force at the same site (e.g., march fracture of the 2nd metatarsal) |
B. By Fracture Morphology (Pattern)
| Pattern | Description |
|---|---|
| Transverse | Perpendicular to long axis; slower to heal |
| Oblique | At an angle; greater surface contact → faster healing |
| Spiral/Torsion | Twisting force; helical fracture line |
| Comminuted | >2 fragments (>6 = highly comminuted) |
| Avulsion | Fragment pulled off by ligament/tendon |
| Bending/Wedge | Bending force with a third "butterfly" fragment |
| Greenstick | Cortex fractures on one side; periosteum intact (children only) |
| Fissure/Hairline | Incomplete crack; no displacement |
C. By Soft Tissue Involvement
- Closed fracture: No communication with skin
- Open (compound) fracture: Communicates with the exterior; classified by Gustilo-Anderson system:
| Grade | Description |
|---|---|
| I | Wound <1 cm; low energy; minimal contamination |
| II | 1–10 cm wound; moderate contamination/comminution |
| IIIA | Extensive soft tissue stripping of bone |
| IIIB | Periosteal stripping |
| IIIC | Major vascular injury present |
D. By Location (in long bones)
- Epiphyseal (may involve growth plate in children — Salter-Harris classification)
- Metaphyseal
- Diaphyseal (shaft)
- Intra-articular vs. extra-articular
E. By Displacement
- Undisplaced: Bone ends remain in alignment
- Displaced: Sideways, axial, angular, rotational, or overlapping
3. Causes
Traumatic
- Falls, road traffic accidents, sports injuries, crush injuries
- Direct force: breaks bone at point of impact
- Indirect force: force transmitted to a distant site (e.g., fall on outstretched hand → distal radius fracture)
Pathologic
- Metabolic: Osteoporosis (most common), osteomalacia, Paget's disease
- Neoplastic: Primary bone tumours, metastatic deposits
- Infection: Osteomyelitis
- Endocrine: Hyperparathyroidism, hyperthyroidism, Cushing's syndrome
- Iatrogenic: Prolonged corticosteroid use
Stress / Fatigue
- Repetitive loading: military recruits (metatarsal "march fractures"), runners (tibial stress fractures)
4. Clinical Features
Definitive (Certain) Signs
- Abnormal mobility: Movement at a site that should be rigid
- Crepitus: Palpable/audible grating from bone ends moving against each other
- Visible deformity: Angulation, shortening, rotation
Probable Signs
- Localized pain and tenderness at the fracture site
- Swelling and ecchymosis from haematoma
- Loss of function: Patient unable or unwilling to use the limb
- Neurovascular deficit distal to the fracture (paraesthesia, pallor, pulselessness)
Important Associations
- Certain fractures have characteristic nerve injuries (Table below):
| Fracture/Injury | Nerve at Risk |
|---|---|
| Distal radius | Median nerve |
| Elbow | Median or ulnar nerve |
| Humeral shaft | Radial nerve |
| Shoulder dislocation | Axillary nerve |
| Acetabulum fracture | Sciatic nerve |
| Lateral tibial plateau | Peroneal nerve |
| Sacral fracture | Cauda equina |
Rosen's Emergency Medicine, 6th ed.
5. Fracture Healing
Phases of Healing
Fracture healing passes through three overlapping phases:
Phase 1 — Inflammatory Phase (Days 1–7)
- Microvessels crossing the fracture line are severed → haematoma forms
- Bone ends undergo necrosis, triggering classic inflammation
- Neutrophils, macrophages, and lymphocytes migrate; cytokines promote revascularization
- This phase is brief but creates the tissue environment for repair
- Clinical note: This is why fracture lines become MORE visible on X-ray at 10–14 days (localized bone resorption + hyperemia)
Phase 2 — Reparative Phase (Weeks 2–6)
- Granulation tissue infiltrates; specialised cells form collagen, cartilage, and bone → callus
- Soft callus (fibrocartilaginous callus) forms first, providing no structural rigidity but bridging fragments
- Progressive mineralisation → hard (osseous) callus over 6–8 weeks
- Osteoclasts resorb necrotic bone ends
- Callus visible on X-ray at 2–4 weeks, initially mottled then dense
Phase 3 — Remodelling Phase (Months to years)
- Superfluous callus is resorbed; bone is laid down along lines of stress (Wolff's law)
- Trabecular bone formed for maximum strength
- Bone gradually regains original shape
Two Modes of Healing
| Mode | Description | Requirements |
|---|---|---|
| Indirect (secondary) | Via cartilaginous callus formation (most common) | Conservative or standard internal fixation |
| Direct (primary) | Osteons grow directly across fracture gap; no cartilaginous callus | Rigid surgical fixation, gap ≤0.5 mm |
Approximate Healing Times (healthy adult)
- Humerus: ~2 months
- Femur: ~4 months
- Cancellous bone heals faster than cortical bone
- Oblique fractures heal faster than transverse (greater surface contact + buttressing effect)
Factors Affecting Healing
Promoting healing: Adequate immobilisation, good blood supply, cancellous bone, proximity to bone end, age (youth), appropriate weight-bearing at the right time
Impeding healing: Poor vascular supply, excessive/insufficient strain, corticosteroid use, smoking, hyperthyroidism, illness requiring prolonged immobilisation, malnutrition, comminution, large gap, infection
Tintinalli's Emergency Medicine; Rosen's Emergency Medicine
6. Complications
Early Complications
1. Haemorrhage
Fractures cause significant blood loss due to the rich skeletal blood supply:
| Site | Blood Loss |
|---|---|
| Radius/Ulna | 150–250 mL |
| Humerus | 250 mL |
| Tibia/Fibula | 500 mL |
| Femur | ~1,000 mL |
| Pelvis | 1,500–3,000 mL |
Pelvic fractures are especially dangerous as tamponade is inadequate.
2. Vascular Injury
- Fractures around the knee (popliteal artery), femoral neck (blood supply to femoral head), and supracondylar humerus (brachial artery) are high-risk
- Presentation: the 5 Ps — Pain, Paraesthesia, Pallor, Pulselessness, Paralysis
- Late consequences: thrombosis, arteriovenous fistula, aneurysm, tissue ischaemia, amputation
3. Nerve Injury (three grades)
- Neurapraxia: contusion/traction of intact nerve; transient conduction block; full recovery expected
- Axonotmesis: axon and myelin severed but endoneurium intact; slow spontaneous recovery possible
- Neurotmesis: complete nerve and stroma severed; requires surgical repair
4. Compartment Syndrome
- Increased pressure within an osseofascial compartment after fracture/crush → ischaemia
- Classically: tibia fractures, but also forearm, thigh, hand, foot
- Hallmarks: severe pain out of proportion, tenseness, paraesthesia
- Consequences if missed: ischaemic contracture, gangrene, myoglobinuria, renal failure, amputation
5. Open Fracture / Infection (Osteomyelitis)
- Open fractures = orthopaedic emergencies
- Risk of osteomyelitis requires urgent: IV antibiotics (cefazolin ± aminoglycoside), wound irrigation/debridement, tetanus prophylaxis
Late Complications
| Complication | Definition |
|---|---|
| Delayed union | Healing taking longer than expected (usually >6 months) |
| Malunion | Healing with residual deformity (angulation, rotation, shortening) |
| Nonunion | Failure of fracture to unite; if a false joint forms → pseudarthrosis |
| Avascular necrosis (AVN) | Interruption of blood supply to bone → bone death (especially femoral head, scaphoid, talus) |
| Post-traumatic arthritis | Especially with intra-articular fractures and malunion |
| Myositis ossificans | Heterotopic bone formation in muscle after haematoma |
| Sudeck's atrophy (CRPS) | Complex regional pain syndrome post-fracture |
| Fat embolism | Release of marrow fat into circulation → respiratory failure, petechiae, confusion |
| DVT / Pulmonary embolism | Immobilisation + endothelial damage → thrombosis |
| Growth disturbance | Children only — physeal damage → premature closure → limb length discrepancy |
Rosen's Emergency Medicine; Tintinalli's Emergency Medicine; General Anatomy and Musculoskeletal System (THIEME Atlas); Rockwood and Green's Fractures in Adults 10th ed.
Key Summary Table
| Aspect | Key Points |
|---|---|
| Definition | Break in continuity of bone |
| Common classification axes | Mechanism, morphology, soft tissue, location, displacement |
| Hallmark clinical signs | Crepitus, abnormal mobility, deformity |
| Healing phases | Inflammatory → Reparative (callus) → Remodelling |
| Healing modes | Indirect (callus) vs. Direct (primary, requires rigid fixation) |
| Early complications | Haemorrhage, vascular injury, nerve injury, compartment syndrome, infection |
| Late complications | Nonunion, malunion, AVN, post-traumatic arthritis, fat embolism, DVT |
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