13.2 Common Fractures, Compartment Syndrome & Pediatric Orthopedics

Orthopedics: Compartment Syndrome

Compartment syndrome is a surgical emergency characterized by increased pressure within a closed fascial space, leading to compromised tissue perfusion, ischemia, and potential necrosis of muscle and nerve tissue. It most commonly occurs after long bone fractures, particularly of the tibia or forearm, but can also result from crush injuries, tight casts, or severe burns. The classic presentation is remembered by the '6 Ps':

1. Pain out of proportion to the apparent injury (often the earliest and most prominent symptom).
2. Pain with passive stretch of the muscles in the affected compartment (a highly sensitive early clinical sign).
3. Paresthesia (tingling or numbness due to nerve ischemia, another early sign).
4. Pallor (pale skin color).
5. Pulselessness (a very late and ominous sign; pulses are often palpable until the terminal stages).
6. Paralysis (a late sign indicating significant muscle and nerve damage).

Diagnosis is primarily clinical, but direct measurement of intracompartmental pressure can confirm the diagnosis, especially in uncooperative or unconscious patients. A delta pressure (diastolic blood pressure minus compartment pressure) of less than 30 mmHg strongly indicates compartment syndrome. Management requires immediate removal of any constrictive dressings or casts. If symptoms persist or if pressures are definitively elevated, urgent surgical fasciotomy of all involved compartments is mandatory to decompress the tissues and prevent irreversible ischemic damage.

Common Adult Fractures

Scaphoid Fractures: The scaphoid is the most commonly fractured carpal bone, typically resulting from a fall on an outstretched hand (FOOSH). Patients present with pain and tenderness in the anatomical snuffbox. A critical feature of scaphoid fractures is that initial radiographs may be negative in up to 20% of cases. Due to the scaphoid's tenuous retrograde blood supply, particularly to its proximal pole, missed fractures run a high risk of avascular necrosis and nonunion. Therefore, any patient with snuffbox tenderness following trauma should be empirically treated with a thumb spica splint and re-evaluated with repeat radiographs in 10-14 days, or advanced imaging (MRI) should be obtained acutely to confirm the diagnosis.

Colles' Fracture: This is a distal radius fracture with dorsal angulation and displacement, often termed a 'dinner fork' deformity. It is extremely common in elderly osteoporotic women following a FOOSH. Treatment involves closed reduction and cast immobilization; unstable fractures may require surgical fixation.

Hip Fractures: These are a major cause of morbidity and mortality in the elderly. They are broadly classified into intracapsular (femoral neck) and extracapsular (intertrochanteric or subtrochanteric) fractures. Intracapsular fractures carry a higher risk of avascular necrosis of the femoral head because the injury disrupts the retinacular blood supply. Patients typically present with a shortened and externally rotated leg. Management is almost universally surgical (hemiarthroplasty, total hip arthroplasty, or internal fixation) to allow for early mobilization and prevent complications of prolonged bed rest.

Pediatric Orthopedics

Developmental Dysplasia of the Hip (DDH): DDH is an abnormal development of the hip joint, ranging from shallow acetabulum to complete dislocation. Risk factors include breech presentation, female sex, and family history. Screening in neonates is performed using the Ortolani maneuver (reduces a dislocated hip) and Barlow maneuver (dislocates an unstable hip). Asymmetry of gluteal folds or limited hip abduction are also suspicious signs. Ultrasound is the imaging modality of choice for infants less than 4-6 months of age, as the femoral head is largely cartilaginous. After 6 months, when ossification centers appear, plain radiographs are preferred. Early treatment with a Pavlik harness is highly successful in achieving normal hip development.

Slipped Capital Femoral Epiphysis (SCFE): SCFE involves the displacement of the proximal femoral epiphysis relative to the metaphysis through the growth plate. It classically occurs in obese adolescents during periods of rapid growth. Patients present with hip, groin, thigh, or poorly localized knee pain and a limp. Examination reveals restricted internal rotation, and the hip may obligately externally rotate when flexed. Bilateral AP and frog-leg lateral radiographs of the pelvis confirm the diagnosis, showing the 'ice cream falling off the cone' appearance. SCFE is an orthopedic urgency requiring non-weight bearing status and prompt surgical pinning in situ to prevent further slippage and reduce the risk of avascular necrosis.

Salter-Harris Classification: This system categorizes fractures involving the growth plate (physis) in children, which is crucial because physis injuries can affect future bone growth. The classification is from Type I to V. Type II, where the fracture extends through the physis and exits through the metaphysis, is by far the most common type.