7.1 Pediatric Musculoskeletal Injuries & Fractures

7.1 Pediatric Musculoskeletal Injuries & Fractures

Pediatric musculoskeletal emergencies represent a significant portion of emergency department visits. Children possess unique skeletal anatomy and physiology that distinguish their fracture patterns, healing capabilities, and injury risks from adults. Understanding pediatric bone growth dynamics, physeal (growth plate) anatomy, acute neurovascular compromise, and joint infection clinical decision rules is essential for the Certified Pediatric Emergency Nurse (CPEN).

Pediatric Skeletal Anatomy & Physiology

Pediatric bones differ fundamentally from adult bones in several physiological aspects:

• Physis (Growth Plate): The cartilaginous zone near the ends of long bones responsible for longitudinal growth. The physis is the weakest link in the pediatric skeleton, making it more vulnerable to shear and avulsion forces than adjacent dense ligaments.
• Thick, Active Periosteum: The periosteum in children is thick, highly vascularized, and loosely attached to the diaphysis. This surrounding sheath provides rapid fracture healing, substantial remodeling potential, and often maintains alignment even when cortical bone is disrupted.
• Increased Collagen and Lower Mineral Density: Pediatric bone is more porous and flexible, allowing it to bend and absorb energy before breaking completely. This elasticity leads to unique incomplete fracture patterns such as greenstick and torus fractures.

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Salter-Harris Fracture Classification

Physeal injuries are classified using the Salter-Harris system (Types I through V). This system aids emergency nurses and orthopedic specialists in predicting the risk of growth arrest and angular limb deformities.

Mnemonic: SALTR — Straight across (I), Above physis (II), Lower (III), Through (IV), Rammed/Crushed (V).

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Pediatric Incomplete Fractures: Greenstick vs. Torus

Because of the high collagen content and flexible matrix of pediatric bone, incomplete fractures are extremely common in infants and young children.

Greenstick Fractures

A greenstick fracture occurs when a bending force causes a break in the cortex on the tension side (convex side) of the bone while the cortex on the compression side (concave side) remains intact but bent.

• Clinical Presentation: Pain, localized swelling, deformity, and reduced movement of the affected extremity (most commonly the radius or ulna).
• Management: Requires reduction to correct angular deformity, followed by immobilization in a long-arm or long-leg cast.

Torus (Buckle) Fractures

A torus fracture results from axial loading or compression forces (such as a fall on an outstretched hand [FOOSH]) that cause the cortex to buckle or wrinkle without complete disruption of either side.

• Clinical Presentation: Mild localized pain, minimal swelling, and point tenderness without overt deformity.
• Management: Torus fractures are inherently stable. They heal rapidly and are typically managed with a removable wrist splint or short cast for 3 to 4 weeks.

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Compartment Syndrome in Pediatric Patients

Compartment syndrome is an orthopedic emergency resulting from increased tissue pressure within a closed fascial space, leading to microvascular compromise, tissue hypoxia, nerve damage, and irreversible muscle necrosis. In children, supracondylar humerus fractures and tibia shaft fractures pose the highest risk.

The 6 Ps of Compartment Syndrome

1. Pain out of proportion to the injury and pain with passive stretching of affected muscles (Earliest and most reliable clinical indicators).
2. Paresthesia (numbness, tingling, or sensory loss in distal nerve distribution).
3. Pallor (pale, cool extremity with prolonged capillary refill).
4. Poikilothermia (temperature equalizing to ambient environment).
5. Pulselessness (absent distal pulses; a late and ominous finding).
6. Paralysis (inability to move distal digits; indicates advanced neuromuscular death).

Clinical Warning: In infants and young non-verbal children, classic reporting of pain is impossible. Emergency nurses must look for increased anxiety, agitation, escalating analgesic requirements, and uncontrollable crying despite appropriate opioid administration.

Emergency Nursing Interventions

• Position the affected extremity at heart level (do NOT elevate above heart level, as elevation reduces arterial perfusion pressure; do NOT place in dependent position, as it increases venous pressure).
• Immediately remove or split all circumferential casts, splints, and dressings down to the bare skin.
• Notify the orthopedic surgeon immediately for urgent compartment pressure measurement (pressures within 30 mmHg of diastolic blood pressure indicate ischemia) and emergency fasciotomy.

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Nursemaid’s Elbow (Radial Head Subluxation)

Nursemaid’s elbow is the most common musculoskeletal injury in children aged 1 to 4 years. It occurs when sudden axial traction is applied to an extended, pronated arm—such as pulling a child up by the wrist or swinging a child by their hands.

Pathophysiology & Clinical Features

The sudden pull slips the immature annular ligament over the head of the radius, where it becomes trapped in the radiohumeral joint.

• Presentation: The child holds the affected arm flexed at the elbow and pronated across the abdomen. The child refuses to use the arm and cries if movement is attempted. Localized tenderness, swelling, ecchymosis, and deformity are absent.

Reduction Techniques

1. Hyperpronation Technique: The clinician supports the child's elbow, places a thumb over the radial head, and firmly hyperpronates the forearm. A subtle "click" or "pop" is palpated at the radial head. This technique boasts a higher first-attempt success rate than supination.
2. Supination-Flexion Technique: The clinician supinates the forearm while applying pressure over the radial head, then fully flexes the elbow toward the shoulder.

Within 5 to 30 minutes following successful reduction, the child begins using the arm normally without pain. Radiographs are unnecessary unless there is focal swelling, tenderness, or a history of direct trauma.

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Septic Arthritis vs. Toxic Synovitis

Differentiating septic arthritis (bacterial infection of the joint space) from toxic synovitis (transient, self-limiting post-viral inflammatory arthritis) is a critical diagnostic challenge in pediatric emergency care, most frequently presenting as acute hip pain or limping.

The Kocher Criteria for Septic Arthritis of the Hip

The Kocher criteria utilize four clinical and laboratory variables to predict the probability of septic arthritis in a child presenting with a painful hip:

1. Non-weight-bearing on the affected side.
2. Fever > 38.5°C (101.3°F).
3. Erythrocyte Sedimentation Rate (ESR) > 40 mm/hr.
4. Serum White Blood Cell (WBC) count > 12,000 /mcL.

Probability of Septic Arthritis:

• 1 Criterion: ~3% risk
• 2 Criteria: ~40% risk
• 3 Criteria: ~93% risk
• 4 Criteria: >99% risk

(Note: Serum C-reactive protein [CRP] > 20 mg/L is frequently used as a 5th independent predictor to increase sensitivity.)

Emergency management of suspected septic arthritis requires immediate ultrasound-guided arthrocentesis for synovial fluid Gram stain and culture before administering broad-spectrum intravenous antibiotics, followed by surgical irrigation and debridement to prevent permanent cartilage destruction and ischemic necrosis of the femoral head.