11.3 Principles of Fracture Management & Common Dislocation
Key Takeaways
- Bone fracture healing proceeds sequentially through 3 overlapping biological phases: Inflammatory (hematoma formation), Reparative (soft callus turning to hard woven callus), and Remodeling (lamellar bone restoration per Wolff's law).
- Open fractures require emergency management based on the Gustilo-Anderson classification (Types I to IIIC), dictating antibiotic prophylaxis, radical wound debridement, and timing of fixation.
- Compartment Syndrome is an orthopaedic emergency characterized by elevated intra-compartmental pressure (>30 mmHg); diagnosis relies on the 6 Ps, with passive stretch pain being the earliest and most sensitive sign, treated by immediate fasciotomy.
- Anterior Shoulder Dislocation is the most common joint dislocation (95%), presenting with loss of normal shoulder contour, positive Dugas test, and potential axillary nerve injury, reduced via Kocher's or Stimson's technique.
- Supracondylar fracture of the humerus in children carries a high risk of brachial artery injury and anterior interosseous nerve involvement, leading to Volkmann's Ischaemic Contracture if compartment syndrome is missed.
Principles of Fracture Healing, Open Fractures & Compartment Syndrome
A fracture is a breach in the structural continuity of a bone. Understanding the biology of bone healing and acute orthopaedic emergencies is essential for surgical practice and UPSC CMS examinations.
Biology of Bone Healing
Secondary bone healing (healing with callus formation under non-rigid fixation) follows 3 distinct overlapping phases:
- Inflammatory Phase (Day 1 - 7): Fracture causes microvascular disruption resulting in fracture hematoma. Platelets release Growth Factors (PDGF, TGF-beta). Polymorphonuclear leukocytes and macrophages clear necrotic debris and initiate angiogenesis.
- Reparative Phase (Week 2 - 6):
- Soft Callus Formation: Pluripotent mesenchymal stem cells differentiate into chondrocytes and fibroblasts, producing a fibrocartilaginous bridge uniting the bone ends.
- Hard Callus Formation: Osteoblasts deposit osteoid which mineralizes into woven bone (immature non-lamellar bone). Endochondral ossification converts soft callus into hard callus, rendering the fracture clinically stable and pain-free.
- Remodeling Phase (Months to Years): Woven bone is progressively resorbed by osteoclasts and replaced by organized lamellar bone along lines of mechanical stress according to Wolff's Law. The medullary cavity is reconstituted.
Primary bone healing occurs without callus formation under rigid absolute stability (e.g., compression plating) via direct haversian remodeling across the fracture gap.
Open Fractures & Gustilo-Anderson Classification
An open (compound) fracture communicates directly with the external environment through a skin wound, creating a high risk of osteomyelitis and wound infection.
| Gustilo Grade | Wound Size | Soft Tissue Injury / Contamination | Bone Coverage & Vascular Status | Recommended Surgical Treatment |
|---|---|---|---|---|
| Type I | Clean wound < 1 cm | Minimal soft tissue damage; simple fracture pattern | Adequate bone coverage | Debridement + Primary closure + IV 1st Gen Cephalosporin |
| Type II | Wound 1 - 10 cm | Moderate muscle damage, moderate contamination | Adequate soft tissue cover | Debridement + Primary closure or delayed primary closure |
| Type IIIA | Wound > 10 cm | Extensive soft tissue laceration/flaps, high contamination | Adequate periosteal bone coverage despite extensive laceration | Radical debridement + Internal fixation or External fixation |
| Type IIIB | Wound > 10 cm | Extensive soft tissue loss with periosteal stripping | Bone exposed, requires local/free flap coverage | Debridement + External Fixation + Reconstructive Flap |
| Type IIIC | Any open wound size | Associated with arterial injury requiring repair | Vascular repair required to preserve limb viability | Emergency Arterial Shunt/Repair + External Fixation |
Emergency Management Protocol for Open Fractures
- Resuscitate (ATLS principles), splint limb, cover wound with sterile saline-soaked dressing.
- Administer IV antibiotics immediately (Cefazolin for Type I/II; add Gentamicin for Type III; add Penicillin G for soil/farm contamination to prevent Clostridium perfringens gas gangrene).
- Tetanus toxoid / immunoglobulin prophylaxis.
- Urgent radical wound debridement ("toilet and debridement") within 6 hours in the operating room.
Acute Compartment Syndrome & Specific High-Yield Fractures/Dislocations
Acute Compartment Syndrome
Compartment syndrome occurs when increased tissue pressure within a closed osteofascial compartment compromises capillary perfusion, leading to tissue ischemia, muscle necrosis, and irreversible nerve dysfunction. Normal compartment pressure is 0-8 mmHg; tissue ischemia occurs when pressure exceeds 30 mmHg or comes within 30 mmHg of diastolic blood pressure (Delta P = Diastolic BP - Compartment Pressure ≤ 30 mmHg).
Clinical Diagnosis: The 6 Ps
- Pain out of proportion to injury and pain on passive stretch of muscles in the compartment (earliest and most sensitive clinical sign).
- Paresthesia (in the distribution of nerves traversing the compartment - e.g., deep peroneal nerve in anterior leg compartment).
- Pressure (tense, wooden, swollen compartment on palpation).
- Pallor (late sign).
- Paralysis (late sign indicating muscle infarction).
- Pulselessness (extremely late sign; presence of distal pulse does NOT rule out compartment syndrome!).
Treatment
Emergency decompressive fasciotomy releasing all tight fascial compartments of the limb. Delayed release (>12 hours) leads to Volkmann's Ischaemic Contracture (flexion contracture of wrist and fingers due to ischemic necrosis of flexor digitorum profundus and flexor pollicis longus).
Specific High-Yield Upper & Lower Limb Lesions
| Fracture / Dislocation | Typical Mechanism & Deformity | Associated Nerve / Vessel Injury | Key Clinical Test & Management |
|---|---|---|---|
| Anterior Shoulder Dislocation | Abduction, external rotation, and extension trauma. Loss of normal rounded shoulder contour (flattening of shoulder / square shoulder deformity). | Axillary Nerve (loss of sensation over regimental badge area & deltoid paralysis). | Positive Dugas Test (hand cannot touch opposite shoulder while elbow touches chest). Reduced by Kocher's, Hippocratic, or Stimson's technique. |
| Supracondylar Fracture Humerus | Fall on outstretched hand in children (5-8 yrs). Extension type (95%). Proximal fragment drives anteriorly. | Brachial Artery (loss of radial pulse) & Anterior Interosseous Nerve (AIN) (branch of Median nerve - inability to make 'OK' sign). | Three-point bony relationship of elbow (olecranon & epicondyles) remains normal (distinguishes from posterior elbow dislocation). Closed reduction + percutaneous K-wire fixation. |
| Colles' Fracture | Extra-articular fracture of distal radius <2.5 cm from articular surface with dorsal tilt, dorsal displacement, supination. Fall on outstretched hand in elderly females. | Median nerve compression (Carpal Tunnel Syndrome). | Dinner-fork deformity. Management: Closed reduction (traction + palmarflexion + ulnar deviation) & Colles' cast (below-elbow) for 6 weeks. |
| Smith's Fracture | Extra-articular distal radius fracture with volar tilt and volar displacement ("reverse Colles'"). Fall on flexed wrist. | Median nerve injury. | Garden-spade deformity. Closed reduction + volar plaster slab or ORIF with buttress plate. |
| Scaphoid Fracture | Fall on palm. Fracture at waist of scaphoid is most common. High incidence of Avascular Necrosis (AVN) of proximal pole (blood supply enters distally via dorsal carpal branch of radial artery). | Radial artery involvement. | Point tenderness in Anatomical Snuffbox. Radiograph: Scaphoid view. Treatment: Scaphoid cast (thumb spica) for 8-12 weeks or Herbert screw fixation. |
| Fracture Neck of Femur | Intracapsular fracture in elderly osteoporotic patients following minor slip. Classed by Garden Classification (I-IV). | Medial Circumflex Femoral Artery disruption leading to high rate of Avascular Necrosis (AVN) and Non-union. | Limb is shortened, adducted, and externally rotated. Treatment: Young patients (<60 yrs) = Emergency ORIF with Cannulated Screws; Elderly (>60 yrs) = Hemiarthroplasty or Total Hip Arthroplasty (THA). |
A 22-year-old male sustains an anterior dislocation of the right glenohumeral joint following a motor vehicle collision. Which nerve is at highest risk of injury, resulting in sensory loss over the 'regimental badge' area?
An 8-year-old boy falls from a playground ladder onto his outstretched hand and presents with severe elbow swelling and deformity. Radiographs confirm an extension-type supracondylar fracture of the humerus. Which nerve is most commonly injured in this specific fracture pattern?
What is the immediate, definitive surgical treatment for acute compartment syndrome of the leg to prevent ischemic muscle necrosis and permanent nerve paralysis?
If an intracapsular fracture of the neck of the femur is displaced in an elderly patient, which major blood vessel disruption is primarily responsible for the high incidence of avascular necrosis (AVN) of the femoral head?