Orthopaedic Surgery - Compartment Syndrome

Basics

Compartment syndrome occurs when pressure rises within a closed fascial space, reducing tissue perfusion and compromising the function and viability of the muscles, nerves, and vessels contained within that compartment.

Acute compartment syndrome is a limb-threatening surgical emergency. In contrast, chronic or exertional compartment syndrome is usually an exercise-related condition that is symptomatic but not immediately limb threatening.

Tissue Ischemia

As intracompartmental pressure increases, local blood flow falls below the metabolic requirements of the tissues.

Continued ischemia can lead to muscle necrosis, nerve injury, ischemic contracture, weakness, numbness, or irreversible loss of limb function.

Systemic Consequences

Extensive muscle necrosis can produce rhabdomyolysis.

Release of intracellular contents may lead to myoglobinuria, hyperkalemia, acute tubular necrosis, and acute kidney failure.

For this reason, severe compartment syndrome can become a systemic as well as a local emergency.

General Prevention

A high index of suspicion is essential.

Diagnosis is particularly difficult in obtunded trauma patients, sedated or anesthetized patients, patients with drug intoxication, and young children, because pain and other clinical findings may be unreliable.

Anatomic Locations

The leg and forearm are the most commonly involved regions.

However, compartment syndrome can also occur in the thigh, hand, foot, arm, fingers, and gluteal region.

Epidemiology

Acute compartment syndrome is associated most frequently with fractures and high-energy extremity trauma.

Reported incidence includes approximately 1–5% of tibial fractures, 0.25% of distal radius fractures, 3% of forearm fractures, and up to 10% of displaced calcaneal fractures.

Risk Factors

Important risk factors include high-energy trauma, crush injury, prolonged pressure on a dependent limb, anesthesia, drug overdose, altered mental status, fractures, osteotomies, vascular injury, reperfusion, burns, tight casts, constrictive dressings, and tight surgical closure.

High-Risk Patients

Young adult males with tibial or forearm fractures are particularly vulnerable.

Children with displaced supracondylar humerus fractures also require careful surveillance.

Prolonged Procedures and Positioning

Long surgical procedures can produce compartment syndrome because of prolonged external pressure or positioning.

An unconscious or anesthetized patient cannot report progressive pain, making recognition more difficult.

Vascular and Reperfusion Injury

Ischemic injury followed by restoration of blood flow can produce marked tissue edema.

This reperfusion injury may rapidly increase intracompartmental pressure after vascular repair.

Soft-Tissue Causes

Soft-tissue injury alone can produce compartment syndrome.

Examples include severe contusions, crush injury, snake bites, and extensive muscle damage with hemorrhage and edema.

Iatrogenic Causes

Iatrogenic causes include tight casts, restrictive dressings, infiltration of intravenous fluid, intraosseous infusion, antishock garments, and overly tight surgical closure.

Intracompartmental Hemorrhage

Bleeding into a closed compartment can elevate pressure significantly.

Patients with coagulopathy or anticoagulation may therefore be at increased risk.

Pathophysiology

The central mechanism is failure of local tissue perfusion to satisfy metabolic demand.

As tissue pressure rises, the arteriovenous perfusion gradient decreases, resulting in progressive ischemia.

Ischemic Cascade

Muscle ischemia causes cellular swelling, which further increases compartment pressure.

This produces a vicious cycle of increasing pressure, worsening perfusion, greater edema, and progressive tissue necrosis.

Etiology

Any condition that either increases the volume within a compartment or decreases the size of the compartment can produce compartment syndrome.

External Compression

External compression may result from casts, splints, dressings, body positioning, or other constrictive devices.

Removing the external source of compression is an immediate priority when compartment syndrome is suspected.

Fracture-Related Hemorrhage

Fractures may produce substantial bleeding and swelling within a compartment.

Pressure can rise after the initial injury or following fracture manipulation.

Both open and closed fractures can be associated with compartment syndrome.

Vascular Injury

Arterial or venous injury can cause bleeding into a closed space.

Reperfusion following vascular repair can further increase swelling.

Crush Injury

Severe crush injury causes direct muscle damage, hemorrhage, and cell death.

Leakage of intracellular and extracellular fluid then contributes to rapid compartment expansion and pressure elevation.

Associated Conditions

Conditions associated with compartment syndrome include coagulopathy and altered mental status.

Both can increase risk or make diagnosis more difficult.

Diagnosis

Signs and Symptoms

The traditional findings are described as the five P’s: pain, pallor, paresthesia, paralysis, and pulselessness.

However, not all of these findings are present early.

Pain and pain with passive stretch are generally more useful early findings, whereas paralysis and pulselessness are late and ominous signs.

High Index of Suspicion

Clinical findings alone may be unreliable.

This is especially true in children, unconscious patients, heavily sedated patients, and those with distracting injuries.

Serial examinations are therefore essential.

Pain Out of Proportion

The classic early symptom is pain that appears excessive compared with the apparent severity of the injury.

The patient may report escalating discomfort despite appropriate immobilization and analgesia.

Increasing Analgesic Requirement

An increasing requirement for pain medication can be an important warning sign.

This may be particularly useful in children, who may show increasing agitation or analgesic requirements before other findings appear.

Loss of Pain

The disappearance of pain does not necessarily indicate improvement.

If nerves become ischemic and lose function, pain may diminish despite worsening tissue necrosis.

Thus, absence of pain in advanced compartment syndrome is a late and poor prognostic sign.

Paresthesias

Numbness or tingling may develop as sensory nerves become ischemic.

Paresthesias can precede frank sensory loss.

Physical Examination

Mental Status

The patient’s level of consciousness should be documented.

A reliable examination requires the patient to be awake and able to describe symptoms accurately.

Vital Signs

Vital signs should be assessed, with particular attention to the diastolic blood pressure, because the relationship between diastolic pressure and compartment pressure is used in determining tissue perfusion.

Motor Examination

Motor function of muscles within and distal to the involved compartment should be tested and documented serially.

New weakness may indicate progressive nerve or muscle ischemia.

Sensory Examination

Sensation should be examined carefully in the distribution of nerves passing through the affected compartment.

New sensory changes are concerning for nerve compromise.

Hand Compartment Syndrome

Hand compartment syndrome may not cause obvious sensory loss because the major digital sensory nerves are relatively superficial and may lie outside the affected muscle compartments.

Therefore, a normal sensory examination does not exclude compartment syndrome of the hand.

Compartment Tenseness

The involved compartment may feel firm, swollen, or tense to palpation.

This finding can support the diagnosis but is subjective.

Deep Posterior Compartment

The deep posterior compartment of the leg is difficult to assess by palpation because of its location.

A clinically soft superficial compartment does not exclude elevated pressure in the deep posterior compartment.

Pain With Passive Stretch

Pain produced by passively stretching muscles that cross the involved compartment is an important early sign.

For example, passive toe movement may stretch ischemic muscles in the leg and reproduce severe pain.

Pulses

Distal pulses should be assessed and compared with the opposite extremity.

However, preserved pulses do not exclude compartment syndrome because arterial pressure can remain sufficient to maintain flow even when microvascular perfusion is critically impaired.

Pulselessness is generally a late finding.

Compartment Pressure Measurement

General Principles

Direct measurement of intracompartmental pressure is useful when the diagnosis is uncertain or the patient cannot provide a reliable examination.

Pressure measurement should not delay surgery when the clinical diagnosis is clear.

Leg Compartments

The leg contains four major compartments that may require assessment:

Anterior compartment

Lateral compartment

Superficial posterior compartment

Deep posterior compartment

Thigh Compartments

The thigh contains anterior, posterior, and medial compartments.

Hand Compartments

Relevant hand compartments include the thenar, hypothenar, interosseous, adductor pollicis, and carpal tunnel compartments.

Foot Compartments

The foot contains several compartments, including medial, lateral, central, and intrinsic muscle compartments.

Forearm Compartments

The forearm includes volar, dorsal, and mobile-wad compartments.

Arm Compartments

The upper arm contains anterior and posterior compartments, with the deltoid region also considered when clinically appropriate.

Gluteal Compartment

Gluteal compartment syndrome typically involves the gluteus maximus region and may occur after prolonged unconsciousness or high-energy trauma.

Fingers

Compartment syndrome of the fingers is primarily a clinical diagnosis.

Pressure measurements are less commonly used.

Pressure Thresholds

Historically, an absolute compartment pressure of approximately 40 mm Hg has been considered concerning.

More commonly, the delta pressure, calculated as diastolic blood pressure minus compartment pressure, is used.

A delta pressure of 30 mm Hg or less is generally considered an indication for urgent decompression when consistent with the clinical setting.

Serial Pressure Monitoring

When the diagnosis remains uncertain, pressure measurements may be repeated every few hours.

The measurement should be obtained close to the suspected site of injury because pressures may vary within the compartment.

Chronic Compartment Syndrome

Chronic exertional compartment syndrome is characterized by elevated pressure during exercise or delayed normalization after activity.

Its diagnosis and treatment differ from those of acute compartment syndrome.

Laboratory Studies

Basic Metabolic Panel

Electrolytes should be checked when extensive muscle injury is suspected.

Particular attention should be paid to serum potassium, because muscle necrosis may cause life-threatening hyperkalemia.

Creatine Kinase

Serial creatine kinase measurements may help quantify the extent of muscle breakdown when significant rhabdomyolysis is suspected.

Marked elevations support substantial muscle injury but do not diagnose compartment syndrome by themselves.

Urine Myoglobin

Urinalysis can identify myoglobinuria caused by muscle necrosis.

Dark urine may occur when myoglobin levels are high.

Hematocrit

Hematocrit may be useful when substantial hemorrhage into a large compartment, such as the thigh, is suspected.

Preoperative Tests

Standard preoperative laboratory studies are obtained according to the clinical condition and urgency of surgery.

They should not delay decompression in a limb-threatening emergency.

Imaging

Plain Radiographs

Radiographs are used mainly to identify associated fractures or other skeletal injuries.

Imaging is supportive and should never delay treatment when acute compartment syndrome is clinically evident.

Pathological Findings

At fasciotomy, affected muscle may bulge outward once the fascia is opened because of the high intracompartmental pressure.

If diagnosis has been delayed, areas of ischemic or necrotic muscle may be present.

Differential Diagnosis

Arterial Occlusion

Acute arterial occlusion can also produce pain, pallor, paresthesia, weakness, and pulselessness.

However, arterial occlusion does not necessarily produce a tense compartment or elevated intracompartmental pressure.

Neurapraxia

Peripheral neurapraxia can produce weakness or numbness after trauma.

Unlike compartment syndrome, it is not associated with increased compartment pressure or marked compartment tenseness.

Treatment

General Measures

Acute compartment syndrome is a surgical emergency.

Once the diagnosis is established, treatment requires prompt decompression to prevent irreversible muscle and nerve injury.

Remove External Compression

Any cast, splint, dressing, or circumferential bandage should be split, loosened, or removed immediately if compartment syndrome is suspected.

Padding beneath a cast may also need to be completely divided.

Limb Position

When a developing compartment syndrome is being observed, the extremity should generally be maintained at approximately the level of the heart.

Excessive elevation may further reduce arterial perfusion, while dependent positioning can worsen venous congestion and swelling.

Bed Rest

Patients with suspected acute compartment syndrome should remain at rest while urgent assessment proceeds.

Activity that increases tissue demand or swelling should be avoided.

Nursing Care

Frequent neurovascular examinations are essential.

Changes in pain, motor function, sensation, compartment firmness, and analgesic requirements should be reported promptly.

Medical Management

Rhabdomyolysis

When myoglobinuria or major muscle necrosis is present, intravenous fluids may be administered to maintain renal perfusion.

Urine alkalinization may be considered in selected cases, depending on the clinical context.

Hyperkalemia

Hyperkalemia should be treated urgently because of the risk of cardiac arrhythmia.

Electrolytes should be monitored serially in patients with extensive muscle injury.

Treatment of Underlying Conditions

Associated problems may require separate treatment.

Examples include antibiotics for an open fracture or contaminated wound and anticoagulation for a confirmed deep vein thrombosis when appropriate.

Such treatment does not replace surgical decompression of an acute compartment syndrome.

Surgery

Fasciotomy

Definitive treatment consists of longitudinal opening of the fascia surrounding the involved compartment or compartments.

This allows swollen tissues to expand and restores the pressure gradient necessary for adequate perfusion.

Wound Management

Fasciotomy wounds are usually left open initially because immediate closure may recreate elevated compartment pressure.

Delayed primary closure or skin grafting is performed after swelling has subsided.

Negative-Pressure Wound Therapy

Postoperative wounds may be managed with moist dressings or negative-pressure wound therapy.

The choice depends on wound size, swelling, contamination, and institutional practice.

Postoperative Elevation

After decompression, the limb is usually elevated appropriately to reduce swelling while maintaining adequate perfusion.

Leg Fasciotomy

Two-Incision Technique

The leg is commonly decompressed through one lateral and one medial incision.

The lateral incision releases the anterior and lateral compartments.

The medial incision releases the superficial and deep posterior compartments.

Thigh Fasciotomy

Lateral Approach

A lateral incision is commonly used to release the anterior compartment.

The posterior compartment can often be released through the same exposure if necessary.

Medial Compartment

A separate medial incision may be required to decompress the medial thigh compartment.

Hand Fasciotomy

Dorsal Incisions

Two dorsal incisions, commonly placed over the second and fourth metacarpals, can be used to decompress the interosseous compartments.

Palmar Incisions

Additional palmar incisions may be required to decompress the thenar compartment and carpal tunnel.

A separate incision may be used for the hypothenar compartment when necessary.

Forearm Fasciotomy

Volar Release

The volar compartment is commonly released through an extended lazy-S incision.

This approach can be continued distally to release the carpal tunnel if necessary.

Dorsal Compartment

A separate dorsal release may be required when the dorsal compartment is involved, although it is not always necessary.

Foot Fasciotomy

Medial and Dorsal Approaches

The foot may be decompressed through a medial incision, with additional dorsal incisions over the second and fourth metatarsals as required.

Because compartment anatomy of the foot is complex, complete decompression requires careful surgical planning.

Arm Fasciotomy

Medial Approach

The arm may be decompressed through a medial approach, particularly when associated vascular exploration is required.

Both anterior and posterior compartments should be addressed when involved.

Finger Decompression

For digital compartment syndrome, release is generally performed on the ulnar side of the index and middle fingers and the radial side of the ring and little fingers to reduce risk to the dominant neurovascular structures.

Gluteal Fasciotomy

Gluteal compartment syndrome is treated with decompression through an incision over the gluteus maximus region, with release of the involved compartments.

Rehabilitation

Physical Therapy

Postoperative rehabilitation depends on the severity of the soft-tissue, nerve, muscle, and bony injuries.

Physical therapy may focus on range of motion, strengthening, gait training, mobility, and prevention of contracture.

Occupational Therapy

Occupational therapy is particularly useful after upper-extremity compartment syndrome.

Treatment may include hand strengthening, dexterity training, adaptive equipment, and specialized splinting.

Orthotic Referral

Persistent weakness such as foot drop may require an ankle-foot orthosis or another supportive brace.

Prosthetic Referral

If irreversible tissue damage results in limb loss, early prosthetic rehabilitation may improve long-term functional recovery.

Plastic Surgery

Plastic surgical consultation may be required for difficult fasciotomy wounds, soft-tissue coverage, skin grafting, or reconstructive procedures.

Follow-Up

Prognosis

The best outcomes occur when diagnosis is made rapidly and fasciotomy is performed before irreversible muscle and nerve injury develops.

Delay in treatment substantially increases the risk of permanent disability.

Fasciotomy Morbidity

Fasciotomy itself is not a minor procedure.

Large open wounds, painful scars, skin grafting, infection, and chronic venous problems may occur.

Nevertheless, these risks are outweighed by the consequences of untreated acute compartment syndrome.

Motor Recovery

Established paresis caused by prolonged nerve or muscle ischemia frequently has limited recovery.

Motor deficits that are already present at the time of delayed decompression may become permanent.

Sensory Recovery

Persistent numbness from advanced nerve ischemia may also fail to improve.

Sensory loss can predispose the limb to secondary injuries.

Complications

Motor Deficit

Permanent motor complications include weakness, paresis, and foot drop.

These deficits may result from muscle necrosis, nerve injury, or both.

Volkmann Ischemic Contracture

Untreated or inadequately treated forearm compartment syndrome can lead to Volkmann ischemic contracture.

Fibrosis and shortening of necrotic flexor muscles produce a characteristic fixed deformity of the wrist and hand.

Sensory Deficit

Permanent sensory loss may leave the extremity insensate.

Patients are then at increased risk of pressure ulcers, burns, infections, and repetitive unnoticed trauma.

Kidney Failure

Severe rhabdomyolysis can produce myoglobin-mediated renal injury and acute kidney failure.

Aggressive recognition and systemic management are therefore important.

Infection

Necrotic muscle and large fasciotomy wounds increase the risk of infection.

Repeated debridement may be required when nonviable tissue is present.

Chronic Venous Stasis

Chronic swelling and venous insufficiency may develop after severe compartment syndrome or fasciotomy.

Limb Loss

Extensive irreversible ischemia, infection, or vascular injury may ultimately require amputation.

Complex Regional Pain Syndrome

Some patients develop complex regional pain syndrome, historically referred to as reflex sympathetic dystrophy.

This may cause persistent pain, autonomic disturbance, stiffness, and functional impairment.

Patient Monitoring

Intraoperative Monitoring

Compartment pressures can be remeasured after fasciotomy when necessary to confirm that adequate decompression has been achieved.

The surgeon should also directly assess muscle viability.

Post-Closure Monitoring

After delayed wound closure, continued monitoring is necessary because recurrent swelling can recreate elevated compartment pressures.

Serial Neurovascular Examination

Ongoing assessment should include pain, motor strength, sensation, compartment firmness, pulses, capillary refill, renal function, and evidence of systemic rhabdomyolysis.

Any deterioration requires immediate reassessment.