Residency · Residency · Emergency Medicine

Orthopedic Emergencies: Fractures, Dislocations, and Compartment Syndrome

General Principles

Fracture Description

Fractures should always be described systematically: open versus closed, location (proximal, mid-shaft, or distal), pattern (transverse, oblique, spiral, comminuted, or segmental), displacement, angulation, and rotation. Joint involvement must be noted because intra-articular fractures require anatomic reduction. Associated neurovascular injury must be assessed and documented both before and after any reduction attempt.

Open Fracture Classification (Gustilo-Anderson)

The Gustilo-Anderson classification grades open fractures by wound size and soft tissue damage. Type I involves a wound less than 1 cm with minimal soft tissue damage and a clean wound. Type II involves a wound of 1 to 10 cm with moderate soft tissue damage but no flaps or avulsions. Type IIIA involves a wound greater than 10 cm where adequate soft tissue coverage is still possible. Type IIIB involves extensive soft tissue loss requiring flap coverage. Type IIIC involves an arterial injury requiring repair. All open fractures require antibiotics (a cephalosporin for type I and II, with the addition of an aminoglycoside for type III), tetanus prophylaxis, emergent orthopedic consultation, wound irrigation, and operative debridement.

Neurovascular Assessment

Pulses, sensation, motor function, and capillary refill should be documented. Several high-risk fracture-nerve injury associations must be kept in mind: humeral shaft fractures are associated with radial nerve injury (causing wrist drop), elbow dislocations with ulnar nerve and brachial artery injury, knee dislocations with popliteal artery and common peroneal nerve injury (causing foot drop), fibular neck fractures with common peroneal nerve injury, and hip dislocations with sciatic nerve injury.

Time-Sensitive Fractures and Dislocations

Hip Dislocation

Posterior hip dislocation accounts for 90 percent of cases and presents with the femur flexed, adducted, and internally rotated, typically from a dashboard mechanism. Anterior dislocation (10 percent) presents with the femur extended, abducted, and externally rotated. Associated sciatic nerve injury occurs in 10 to 20 percent of posterior dislocations. Reduction should be performed within 6 hours to reduce the risk of avascular necrosis of the femoral head. A post-reduction CT is obtained to evaluate for associated acetabular fracture and intra-articular fragments.

Knee Dislocation

Knee dislocation is a high-energy injury with significant ligamentous disruption. Popliteal artery injury occurs in up to 30 to 40 percent of cases, and common peroneal nerve injury in 25 percent. The knee may spontaneously reduce before arrival, so a high index of suspicion should be maintained when multi-ligament injury is present. Vascular assessment is mandatory: an ankle-brachial index (ABI) is measured, and if the ABI is below 0.9, CT angiography is indicated. Even with a normal ABI, serial vascular exams should be performed for 24 to 48 hours.

Shoulder Dislocation

Anterior dislocation accounts for 95 percent of shoulder dislocations and presents with the arm abducted and externally rotated, with loss of the normal deltoid contour. Posterior dislocation is rare and associated with seizures and electrocution; the arm is internally rotated and adducted, and the dislocation may be missed on AP X-ray (the lightbulb sign is the clue). Axillary nerve injury occurs in 5 to 10 percent of cases and is tested by assessing deltoid function and lateral shoulder sensation over the regimental badge area. Reduction techniques include external rotation, Cunningham, traction-countertraction, and Stimson methods. A post-reduction X-ray confirms relocation and evaluates for associated fractures (Hill-Sachs and Bankart lesions).

Elbow Dislocation

Posterior dislocation is the most common type. Associated injuries include ulnar nerve injury and brachial artery injury. Median, ulnar, and radial nerve function should be assessed, along with the brachial artery pulse. Reduction involves traction on the forearm with countertraction on the humerus, correcting medial and lateral displacement first. After reduction, stability is assessed through range of motion, and a posterior splint at 90 degrees is applied.

Specific High-Risk Fractures

Femoral Neck Fracture

Femoral neck fractures are classified by the Garden classification (I through IV). The risk of avascular necrosis increases with displacement — Garden III and IV fractures carry the highest risk. Non-displaced fractures (Garden I and II) are treated with internal fixation. Displaced fractures (Garden III and IV) are treated with hemiarthroplasty or total hip arthroplasty in elderly patients. In young patients, emergent fixation is pursued to preserve the femoral head.

Supracondylar Humerus Fracture (Pediatric)

The supracondylar humerus fracture is the most common elbow fracture in children, typically occurring between ages 5 and 7. It carries a risk of brachial artery injury and anterior interosseous nerve (AIN) palsy. The AIN is tested by asking the patient to pinch between the thumb and index finger (the OK sign), which tests the flexor pollicis longus and flexor digitorum profundus to the index finger. The Gartland classification grades the injury as type I (non-displaced), type II (angulated with an intact posterior cortex), or type III (completely displaced). Type III fractures require emergent reduction and fixation, and vascular compromise constitutes a surgical emergency.

Scaphoid Fracture

Scaphoid fractures result from a fall on an outstretched hand (FOOSH) and present with anatomic snuffbox tenderness. Initial X-rays are negative in 15 to 20 percent of cases. When clinical suspicion is high despite negative X-rays, a thumb spica splint is applied and repeat imaging is obtained in 10 to 14 days (X-ray or MRI). Proximal pole fractures carry the highest risk of avascular necrosis because of the scaphoid's retrograde blood supply. MRI is the gold standard for detecting occult scaphoid fractures.

Ankle Fractures

The Ottawa Ankle Rules state that an ankle X-ray is required only if there is bone tenderness at the posterior edge or tip of either malleolus, or inability to bear weight for four steps. The Weber classification is based on the fibular fracture level relative to the syndesmosis: type A (below), type B (at), and type C (above). Weber C and unstable Weber B fractures require operative fixation. Associated injuries include syndesmotic injury (high ankle sprain) and the Maisonneuve fracture — a proximal fibula fracture with syndesmotic disruption — which is why the proximal fibula must always be examined in ankle injuries.

Compartment Syndrome

Pathophysiology

Compartment syndrome occurs when increased pressure within a closed fascial compartment compromises tissue perfusion. The pathologic cycle begins with injury causing edema, which increases compartment pressure, decreases capillary perfusion, produces ischemia, and generates more edema. Irreversible damage begins after 6 to 8 hours of ischemia. Muscle necrosis leads to rhabdomyolysis, hyperkalemia, and renal failure.

Most Common Locations

The leg is the most common site, with the anterior compartment most frequently affected (the leg has four compartments). The forearm volar compartment is also commonly involved, with Volkmann's ischemic contracture as the dreaded complication. Other locations include the thigh, hand, foot, and gluteal region.

Clinical Features — The 6 P's (Unreliable)

The traditional teaching of the six P's — pain, pain with passive stretch, pressure, paresthesias, paralysis, and pulselessness — is important to know but unreliable as a complete diagnostic framework. Pain out of proportion to injury is the earliest and most sensitive finding. Pain with passive stretch of the involved muscles is the most reliable early finding. Pressure refers to a tense compartment on palpation. Paresthesias indicate sensory nerve ischemia. Paralysis is a late finding indicating significant damage has already occurred. Pulselessness is a very late finding because compartment syndrome is not a vascular occlusion — pulses are typically preserved until very late in the process. Pain out of proportion and pain with passive stretch are the two most clinically useful findings.

Compartment Pressure Measurement

Normal compartment pressure is 0 to 8 mmHg. There is debate over the threshold for fasciotomy. The absolute threshold approach defines pressures greater than 30 mmHg (Whitesides) as an indication for fasciotomy. The delta pressure approach — diastolic blood pressure minus compartment pressure less than 30 mmHg — is the Stryker recommendation and is preferred by most orthopedic trauma surgeons because it accounts for hypotensive patients. Measurement is performed with a needle manometer (Stryker device) or arterial line transducer. The clinical diagnosis should prevail — fasciotomy should not be delayed for pressure measurement if the clinical picture is clear.

Management

All circumferential dressings, casts, and splints should be removed immediately. The limb should be maintained at the level of the heart, not elevated, because elevation reduces perfusion pressure. Emergent fasciotomy is the definitive treatment. In the leg, a four-compartment fasciotomy is performed through two incisions (anterolateral and medial). In the forearm, a volar fasciotomy is performed, and carpal tunnel release may be needed. Post-fasciotomy wounds are left open with delayed primary closure or skin grafting at 48 to 72 hours. Complications of missed compartment syndrome include Volkmann's ischemic contracture, rhabdomyolysis, myoglobinuric renal failure, and amputation.

Procedural Sedation for Orthopedic Emergencies

Agent Selection

Ketamine (1 to 2 mg/kg IV) provides dissociative sedation with good analgesia and maintains airway reflexes, making it preferred in children. Emergence reactions in adults can be mitigated with midazolam. Propofol (0.5 to 1 mg/kg IV) has rapid onset and offset but provides no analgesia (it should be paired with fentanyl) and carries risks of hypotension and apnea. Ketofol, a 50:50 mixture, offers theoretical combination advantages and is used in many EDs. Etomidate (0.1 to 0.15 mg/kg IV) has rapid onset and minimal hemodynamic effects but causes myoclonus. Regarding fasting status, traditional NPO guidelines do not apply to ED procedural sedation — multiple studies have shown no increased aspiration risk regardless of fasting status.

Monitoring

Monitoring includes continuous pulse oximetry, capnography (the most sensitive indicator of early hypoventilation), cardiac monitoring, and blood pressure measurement. A dedicated provider for sedation, separate from the procedure operator, is required. Resuscitation equipment and airway supplies must be at the bedside.

<image>A four-panel diagram showing compartment syndrome of the leg. Panel 1: Cross-sectional anatomy of the lower leg at the mid-tibia level showing four compartments — anterior (tibialis anterior, extensor hallucis longus, extensor digitorum longus, deep peroneal nerve, anterior tibial artery), lateral (peroneal muscles, superficial peroneal nerve), deep posterior (tibialis posterior, flexor digitorum longus, flexor hallucis longus, posterior tibial artery, tibial nerve), and superficial posterior (gastrocnemius, soleus, sural nerve). Panel 2: The two-incision four-compartment fasciotomy approach with anterolateral and medial incision lines marked on a leg outline. Panel 3: Clinical photo appearance of a tense, swollen leg. Panel 4: A Stryker compartment pressure monitor with the needle inserted into the anterior compartment, showing a reading above 30 mmHg.</image>

<image>A radiographic series showing common dislocations. Panel 1: Anterior shoulder dislocation on AP X-ray — humeral head inferior and medial to the glenoid. Panel 2: Posterior shoulder dislocation on AP X-ray showing the "lightbulb sign" with internal rotation of the humeral head. Panel 3: Posterior hip dislocation on AP pelvis X-ray showing the femoral head displaced superiorly and laterally to the acetabulum with the femur adducted and internally rotated. Panel 4: Posterior elbow dislocation on lateral X-ray with the olecranon displaced posteriorly relative to the distal humerus.</image>

<image>A flowchart for management of suspected compartment syndrome. Starting with clinical suspicion (pain out of proportion, pain with passive stretch, tense compartment). If the clinical picture is obvious, proceed directly to emergent fasciotomy. If equivocal, measure compartment pressures. If absolute pressure is above 30 mmHg or delta pressure (diastolic BP minus compartment pressure) is less than 30 mmHg, proceed to emergent fasciotomy. If pressures are normal, serial clinical exams and repeat pressure measurements in 2-4 hours. Also lists: remove all constrictive dressings, maintain limb at heart level, do NOT elevate, consult orthopedics emergently.</image>

Clinical Pearls

Neurovascular status must always be assessed and documented before and after any fracture reduction — this is both clinically essential and medicolegally critical. Knee dislocation equals popliteal artery injury until proven otherwise, and an ABI below 0.9 mandates CT angiography. Posterior shoulder dislocation is the "great masquerader" — suspicion should be maintained in seizure and electrocution patients, and axillary or scapular-Y views should be obtained. Pain out of proportion is the earliest sign of compartment syndrome, and clinicians must not wait for the full six P's because pulselessness is a very late finding. Compartment syndrome is a clinical diagnosis — pressure measurement supports but does not replace clinical judgment. Limbs with suspected compartment syndrome should be maintained at heart level, not elevated. The proximal fibula should always be examined in ankle injuries because a Maisonneuve fracture (proximal fibula fracture with syndesmotic disruption) changes management entirely. Scaphoid fractures may have negative initial X-rays, so if the injury is clinically suspected, the wrist should be immobilized and follow-up imaging arranged.

References

• Whitesides TE, et al. Tissue pressure measurements as a determinant for the need of fasciotomy. Clin Orthop. 1975;113:43-51.
• McQueen MM, Court-Brown CM. Compartment monitoring in tibial fractures: the pressure threshold for decompression. J Bone Joint Surg Br. 1996;78:99-104.
• Gustilo RB, Anderson JT. Prevention of infection in the treatment of 1025 open fractures of long bones. J Bone Joint Surg Am. 1976;58:453-458.
• Green NE, Allen BL. Vascular injuries associated with dislocation of the knee. J Bone Joint Surg Am. 1977;59:236-239.
• Stiell IG, et al. Ottawa Ankle Rules for radiography of ankle injuries. JAMA. 1994;271:827-832.

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