Fracture Principles & Common Fractures

Describing and managing a fracture

Standard description. Describe every fracture the same way: bone and location (proximal, shaft or distal), pattern, displacement, angulation, open versus closed, and intra-articular extension. Patterns include transverse, oblique, spiral, comminuted (more than 2 fragments) and segmental (two separate fracture lines isolating a free segment of shaft). A spiral fracture implies a rotational or twisting force. Children's pliable bones also produce incomplete patterns such as torus (buckle) and greenstick fractures.

A spiral long-bone fracture in a non-ambulatory infant should raise concern for non-accidental trauma.

Operative fixation. Displaced, unstable, or intra-articular fractures usually need open reduction and internal fixation (ORIF), because a residual articular step-off leads to post-traumatic arthritis.

Emergencies: open fracture and compartment syndrome

Open (compound) fracture. A wound that communicates with the fracture is a surgical emergency because contamination leads to osteomyelitis. After the ABCs, the priorities are early IV antibiotics and tetanus, then operative debridement. Do not simply close the wound in the ED.

Gustilo grade guides antibiotics. Grade I (clean wound <1 cm) and grade II (1–10 cm, moderate soft-tissue injury) fractures receive cefazolin. Grade III injuries (extensive soft-tissue damage, high energy or heavy contamination) add gram-negative coverage such as an aminoglycoside, and soil or farm contamination adds anaerobic (clostridial) coverage, classically penicillin.

Compartment syndrome. Rising pressure inside a closed fascial compartment cuts off capillary perfusion, causing muscle and nerve ischemia. It is common after tibial fractures and pediatric supracondylar humerus fractures, and also follows crush injury, reperfusion after arterial repair, and tight casts. Pain out of proportion to the injury and pain on passive stretch of the compartment's muscles are the earliest and most sensitive findings. The other classic Ps (paresthesia, pallor, pulselessness, paralysis, poikilothermia) come later.

Management. The diagnosis is clinical; measure compartment pressure (thresholds above) when the exam is equivocal or unreliable, as in a sedated patient. Remove or split any cast and constrictive dressing, keep the limb at heart level rather than elevated (elevation further lowers arterial inflow), and perform emergent fasciotomy. A missed forearm compartment syndrome after a supracondylar fracture ends in Volkmann ischemic contracture.

Pulselessness is a late, ominous sign, and distal pulses are often still palpable in established compartment syndrome; never wait for it to act.

Scaphoid and distal radius fractures

Scaphoid. The scaphoid is the most commonly fractured carpal bone, typically after a fall on an outstretched hand (FOOSH) in a young adult, and it produces anatomic snuffbox tenderness. The initial X-ray is often normal, so immobilize in a thumb spica splint and re-image in 1–2 weeks, or obtain MRI, which detects occult fractures early. Blood enters the scaphoid distally and flows retrograde, so a proximal fracture starves the proximal fragment, risking avascular necrosis (AVN) and nonunion; displaced or proximal-pole fractures usually need ORIF.

Distal radius. A Colles fracture (distal radius with dorsal displacement, giving the dinner-fork deformity) is the classic FOOSH injury in an osteoporotic older adult and should prompt an osteoporosis evaluation. A Smith fracture is the reverse, with volar displacement, usually after a fall onto a flexed wrist.

Hip fractures in older adults

Presentation. An older adult who cannot bear weight after a fall, with groin pain and a leg that is shortened and externally rotated, has a hip (proximal femur) fracture until proven otherwise. If radiographs are negative but suspicion remains, MRI detects an occult fracture.

Perioperative care. Operate within 24 to 48 hours, since delay increases complications and mortality; give VTE prophylaxis, mobilize early and prevent delirium. A hip fracture from a low-energy fall is a fragility fracture, so evaluate and treat osteoporosis.

Growth-plate injuries and stress fractures

Salter-Harris classification. The SALTR mnemonic grades pediatric physeal fractures from I to V. Higher grades (III–V) cross the joint or crush the plate and carry more risk of growth arrest, limb-length discrepancy and angular deformity; intra-articular types III and IV need anatomic, often operative, reduction.

Stress fractures. Repetitive loading in runners and military recruits causes stress fractures, favoring the metatarsals (march fracture, classically the second metatarsal) and the tibia. Early X-rays are often normal, so use MRI or bone scan; treatment is relative rest with protected weight-bearing.

Female athlete triad. In a female athlete with a stress fracture, ask about low energy availability (with or without disordered eating), menstrual dysfunction and low bone density.

Fat embolism, healing problems and avascular necrosis

Fat embolism syndrome. It appears 24–72 hours after long-bone (especially femoral) or pelvic fractures with the triad of hypoxemic respiratory distress, neurologic changes such as confusion, and a petechial rash over the axillae, conjunctivae and upper chest. Care is supportive; early fracture fixation lowers the risk.

Union problems. Delayed union is slow healing, nonunion is failed healing, and malunion is healing in poor alignment. Nonunion risk factors are smoking, infection, poor blood supply, diabetes, NSAIDs and motion at the fracture site. Scaphoid and tibial shaft fractures are prone to nonunion, as is the Jones fracture at the metaphyseal-diaphyseal junction (zone 2) of the fifth metatarsal, which lies in a vascular watershed.

AVN-prone fractures. Fractures that interrupt a retrograde or tenuous blood supply cause AVN of the fragment beyond the break and need prompt, sometimes operative, management:

• Scaphoid proximal pole
• Femoral neck (femoral head)
• Talar neck (talus)
• Humeral head (anatomic neck fractures)