Compartment syndrome in children can present differently than adults. Increased analgesic need should be considered the first sign of evolving compartment syndrome in children. Children with supracondylar humerus fractures, floating elbow injuries, operatively treated forearm fractures, and tibia fractures are at high risk for developing compartment syndrome. Elbow flexion beyond 90° in supracondylar humerus fractures and closed treatment of forearm fractures in floating elbow injuries are associated with increased risk of compartment syndrome. Prompt diagnosis and treatment with fasciotomy in children result in excellent long-term outcomes.
Key points
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Increased analgesic needs is the first sign of compartment syndrome in children.
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Children with supracondylar humerus fractures, floating elbow injuries, and tibial shaft fractures are at high risk for compartment syndrome.
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Excellent outcome can occur with a timely diagnosis.
Introduction
Compartment syndrome is one of the true orthopedic emergencies. Regardless of the cause, the combination of rapid influx of fluid into a closed fascial compartment causes elevated intracompartmental pressure. Rising tissue pressure causes decreasing perfusion pressure and ultimately muscle and nerve ischemia. Prolonged ischemia can result in long-term morbidity due to the irreversible damage to muscles, nerves, blood vessels, and skin. Identifying at-risk patients, prompt diagnosis, and treatment are of significant importance. Most cases of compartment syndrome are caused by fractures. Soft tissue injuries in the absence of fractures (especially in children with bleeding disorders) can also lead to compartment syndrome.
Compartment syndrome is a clinical diagnosis, and patient-reported symptoms play a crucial role in recognition of a developing compartment syndrome. Young children cannot properly communicate pain and paresthesia, which can potentially impact the ability of the physician to make the diagnosis of compartment syndrome in a timely fashion. These patients may be admitted to pediatric floors that routinely do not care for orthopedic patients and whose staff may not be familiar with signs and symptoms of increased intracompartmental pressures. Physicians and other health care professionals (nurses, physician assistants, and others) taking care of children should be aware of unique features of compartment syndrome in children and should be able to identify at-risk patients that benefit from close monitoring.
The best approach to compartment syndrome relies on constant vigilance and decisive action to avert irreversible tissue damage. In addition, from a medicolegal standpoint, early diagnosis is very important. Only 44% of cases of compartment syndrome are closed in favor of treating physician compared with 75% of cases in other orthopedic malpractice claims.
Introduction
Compartment syndrome is one of the true orthopedic emergencies. Regardless of the cause, the combination of rapid influx of fluid into a closed fascial compartment causes elevated intracompartmental pressure. Rising tissue pressure causes decreasing perfusion pressure and ultimately muscle and nerve ischemia. Prolonged ischemia can result in long-term morbidity due to the irreversible damage to muscles, nerves, blood vessels, and skin. Identifying at-risk patients, prompt diagnosis, and treatment are of significant importance. Most cases of compartment syndrome are caused by fractures. Soft tissue injuries in the absence of fractures (especially in children with bleeding disorders) can also lead to compartment syndrome.
Compartment syndrome is a clinical diagnosis, and patient-reported symptoms play a crucial role in recognition of a developing compartment syndrome. Young children cannot properly communicate pain and paresthesia, which can potentially impact the ability of the physician to make the diagnosis of compartment syndrome in a timely fashion. These patients may be admitted to pediatric floors that routinely do not care for orthopedic patients and whose staff may not be familiar with signs and symptoms of increased intracompartmental pressures. Physicians and other health care professionals (nurses, physician assistants, and others) taking care of children should be aware of unique features of compartment syndrome in children and should be able to identify at-risk patients that benefit from close monitoring.
The best approach to compartment syndrome relies on constant vigilance and decisive action to avert irreversible tissue damage. In addition, from a medicolegal standpoint, early diagnosis is very important. Only 44% of cases of compartment syndrome are closed in favor of treating physician compared with 75% of cases in other orthopedic malpractice claims.
Classification
Compartment syndrome can be classified into the following types.
Acute Compartment Syndrome
Acute compartment syndrome is the most common form of compartment syndrome caused by an acute increase in the intracompartmental pressure, causing tissue ischemia. Currently, acute compartment syndrome of the leg is the most commonly seen scenario in children.
Exercise-induced Compartment Syndrome
Exercised-induced compartment syndrome is caused by reversible tissue ischemia caused by noncomplaint fascial compartment that cannot accommodate muscle expansion in exercise. It has been reported in both upper and lower extremities.
Neonatal Compartment Syndrome
Neonatal compartment syndrome is a rare form of compartment syndrome caused potentially by birth trauma and low perfusion of the extremities. It has only been reported in the upper extremity.
Volkmann Ischemic Contracture
Volkmann ischemic contracture is the consequence of prolonged ischemia and irreversible tissue loss, which is most commonly associated with supracondylar humerus fractures in children.
Pathophysiology
Acute compartment syndrome can be caused by either fracture or reperfusion injury with unique pathophysiology regarding both causes. This article focuses on compartment syndrome relating to fracture. Acute compartment syndrome is caused by either bleeding or edema within a closed osseofascial compartment, leading to a reduction in perfusion of the contained muscles and nerves. Most studies of compartment syndrome have been undertaken as retrospective reviews of adult trauma patients or induced within animal models.
Early studies sought to determine the pathophysiology of compartment syndrome in hopes of determining the critical thresholds before it must be addressed. The underlying pathogenesis, however, has remained elusive, and still some controversy exists as to the underlying cause. Initially, 3 main theories persisted. Some have hypothesized its origin is from venous obstruction. Others thought the basic problem was that of diminished arterial inflow. Finally, others thought the root cause to be obstruction of inflow due to arterial spasm. Recently, the underlying root cause of compartment syndrome was elucidated with the use of a novel animal system using hamster-striated muscle and in vivo fluorescence microscopy. The main determinant of diminished compartment perfusion was determined to be due to increasing intracompartmental pressure causing venular compression. This compression thereby causes a diminution in the arteriovenous pressure gradient, thus decreasing blood flow and perfusion to the compartmental skeletal muscle and nervous tissue. Normal cellular metabolism requires an oxygen tension of at least 5 to 7 mm Hg to sustain life. Once blood flow decreases and oxygen is used up, the oxygen tension quickly decreases, resulting in ischemia, and normal cellular metabolism can no longer be sustained.
As a result of ischemia, muscle and nerve tissue quickly lose their function. Nerve demonstrates the most sensitivity to initial ischemia with functional abnormalities, including paresthesia and hypoesthesia within 30 minutes of ischemic onset. However, irreversible functional loss does not occur until after 12 to 24 hours of continued ischemia. Muscle, on the other hand, demonstrates prolonged functional capacity for at least 2 to 4 hours following onset of ischemia; however, muscle begins to exhibit irreversible functional loss beginning at 4 hours after ischemic onset. Because of these landmark studies, the authors have been able to determine optimal time to treatment for this limb- and sometimes life-threatening complication.
Diagnosis
Compartment syndrome is a clinical diagnosis, and patient-reported symptoms play a crucial role in the recognition of a developing compartment syndrome. Identifying an evolving compartment syndrome in a young child is difficult because of the child’s limited ability to properly communicate and the potential anxiety during examination. Orthopedic surgeons have been trained for generations to look for the 5 Ps (pain, paresthesia, paralysis, pallor, and pulselessness) associated with compartment syndrome. Pain out of proportion and pain with passive stretch are known as the first signs of an evolving compartment syndrome. Examining an anxious young child is difficult, and documenting the amount of pain may not be practical in children.
In a retrospective report of 33 children diagnosed with compartment syndrome at Boston Children’s Hospital, Bae and colleagues reported the traditional 5 Ps to be relatively unreliable in children. They reported that increasing analgesic need was found on average 7 hours before change in the vascular status and was a more sensitive indicator of compartment syndrome in children. They recommended that children at risk for compartment syndrome be monitored for the 3 As (increasing analgesic requirement, anxiety, and agitation) ( Table 1 ).
| 5 Ps | 3 As |
|---|---|
| P ain P aresthesia P allor P aralysis P ulselessness | Increased A nalgesic requirement A nxiety A gitation |
Measurement of compartment pressure can be helpful in decision-making in certain clinical scenarios. Compartment pressure measurement in an obtunded child or a child with mental disability can help confirm or rule out the diagnosis.
Normal resting leg compartment pressures in children are reported to be higher compared with adults. Staudt and colleagues reported compartment pressure measurements in 4 lower leg compartments in 20 healthy children and compared that with 20 healthy adults using the same technique. Measured compartment pressures in children in 4 leg compartments varied between 13.3 mm Hg and 16.6 mm Hg, and compartment pressure measurements in adults varied between 5.2 mm Hg and 9.7 mm Hg, which indicates a higher normal resting pressure in lower leg compartments in children. The clinical relevance of this finding is not yet defined.
Compartment pressures are reported to be highest within 5 cm of the fracture site and should be measured close to fracture site when clinically indicated. The pressure threshold that would require fasciotomy is debatable. Intracompartmental pressures of 30 to 45 mm Hg or measurements less than 30 mm Hg of diastolic blood pressure (ΔP = diastolic blood pressure − compartment pressure) are recommended by some investigators as the cutoff points. These cutoff values cannot be used as reliably in children because of the differences in resting normal compartment pressures between children and adults. Compartment pressure measurement is painful and can be difficult in an agitated and awake child. The utility of near-infrared spectroscopy in the diagnosis of increased compartment pressure has been reported. This method uses differential light absorption properties of oxygenated hemoglobin to measure tissue ischemia similar to the method used in pulse oximetry. Near-infrared spectroscopy is able to sample deeper tissue (3 cm below the skin level) than pulse oximetry. In a report of near-infrared spectroscopy findings of 14 adults with acute compartment syndrome, Shuler and colleagues reported that lower tissue oxygenation levels correlated with increased intracompartmental pressures but were not able to define a cutoff value for which measurements would indicate significant tissue ischemia. The use of near-infrared spectroscopy for diagnosis of compartment syndrome in children is also recently reported.
Compartment syndrome remains a clinical diagnosis. Clinicians should be proactive in those scenarios where increased risk exists. Informing family and staff about the signs and symptoms of this syndrome and close monitoring of analgesic use are critical. Compartment pressure measurement is used when diagnosis is not clear, but these values should be interpreted with caution.
Children at high risk for acute compartment syndrome after trauma
Children with certain injuries are at high risk for compartment syndrome. These injuries are discussed in detail later.
Supracondylar Humerus Fracture
Compartment syndrome is reported to develop in 0.1% to 0.3% of children with supracondylar humerus fractures. Volar compartment of the forearm is the most common affected compartment in this group of patients. Elbow flexion more than 90° in a cast and vascular injury put these children at increased risk of compartment syndrome. In a report of 9 cases of compartment syndrome in the volar compartment of the forearm after supracondylar humerus fractures, 8 of 9 cases were attributed to elbow flexion beyond 90° after closed reduction. Highest compartment pressures after supracondylar humerus fractures are reported in the deep volar compartment of the forearm close to the fracture site. Significant increase in compartment pressures was also reported with elbow flexion beyond 90°.
Choi and colleagues reported 2 cases of compartment syndrome in 9 patients with supracondylar humerus fractures who presented without a pulse and without adequate hand perfusion. No cases of compartment syndrome were seen in 24 children who presented with pulseless but well perfused hand in the same case series.
Several recent reports have shown that a delay of 8 to 12 hours in the treatment of Gartland type 2 and type 3 supracondylar humerus fractures does not increase the rate of compartment syndrome. These studies did not recommend treatment delays in patients who present without a radial pulse or with a neurologic deficit. A recent multicenter case series reported 11 cases of acute compartment syndrome in patients who initially presented with a low-energy supracondylar humerus fracture and intact radial pulse. All these patients presented with severe swelling and had a mean delay of 22 hours (6–64 hours) before surgery. Diagnosis of acute compartment syndrome can be challenging in patients with supracondylar humerus fractures and median nerve palsy due to decreased pain sensation caused by the nerve palsy. Based on the above-mentioned reports, the authors do not recommend delayed treatment of children with supracondylar humerus fracture who present with a neurologic deficit or absent pulse and recommend close monitoring of patients with severe swelling.
Although volar compartment of the forearm is mostly affected in cases of compartment syndrome seen in patients with supracondylar humerus fractures, compartment syndrome of the mobile wad, anterior arm compartment, and posterior arm compartment are also reported in the literature.
Floating Elbow
Children with ipsilateral displaced distal humerus and forearm fractures are reported to be at high risk for compartment syndrome. Blakemore and colleagues reported 3 cases of acute compartment syndrome among 9 patients (33%) who presented with displaced extension-type supracondylar humerus and displaced ipsilateral forearm fractures. A report of 16 children who presented with displaced ipsilateral distal humerus and forearm fractures to Boston Children’s Hospital showed 2 cases of acute compartment syndrome and 4 cases of impending compartment syndrome among 10 patients who were treated by closed reduction and circumferential casting for forearm fractures. No signs of compartment syndrome were reported in the 6 patients who were treated by K-wire fixation of both distal humerus and forearm fractures. Based on the above-mentioned reports, the authors do not recommend circumferential casting to treat displaced forearm fractures in children presenting with floating elbow injuries.
In a recent report of the largest series of children with floating elbow injuries, Muchow and colleagues did not report any cases of compartment syndrome among 150 children who presented with ipsilateral distal humerus and forearm fractures. They reported a higher rate of neurologic deficit at presentation among children with floating elbow injuries when compared with children with isolated distal humerus fractures.
Forearm Fractures
Children with fractures of the radius and ulnar shaft can develop acute compartment syndrome. Haasbeek and Cole reported 5 cases of acute compartment syndrome among 46 children (11%) with open forearm fractures. In a report of cases of compartment syndrome after intramedullary nailing of forearm fractures in children, Yuan and colleagues reported 3 cases of compartment syndrome (6%) among 50 patients with open forearm fractures and 3 cases of compartment syndrome among 30 patients with closed forearm fractures treated by closed reduction and intramedullary nailing. In this study, the increased intraoperative time was associated with the increased risk of developing postoperative compartment syndrome. The investigators discussed the prolonged closed manipulation of forearm fractures before intramedullary nailing as a risk factor for the development of postoperative compartment syndrome. In this study, no cases of compartment syndrome were reported among 205 forearm fractures treated by closed reduction and casting.
Flynn and colleagues reported 2 cases of acute compartment syndrome among 30 patients treated with intramedullary nailing within 24 hours of injury and did not report any cases of compartment syndrome in 73 patients treated with intramedullary nailing after 24 hours of the injury. In this study, intramedullary nailing within the first 24 hours from the injury was reported as a risk factor for developing compartment syndrome in children with radius and ulna fractures.
Blackman and colleagues reported 3 cases of acute compartment syndrome among 39 patients (7.7%) with open forearm fractures and did not report any cases of compartment syndrome in 74 children with closed forearm fractures treated operatively. In this case series, a small incision was made to facilitate reduction in 38 of 74 patients with closed fractures (51.4%) in order to decrease the closed manipulation time and operative time. The rate of compartment syndrome after intramedullary nailing of closed forearm fractures in this series is lower than other reports in the literature, which could be due to the decreased closed manipulation and operative time.
Based on the current data in the literature, children with open forearm fractures and children with forearm fractures treated by closed reduction and intramedullary nailing are at increased risk of developing acute compartment syndrome especially if intramedullary nailing is performed within 24 hours of the injury and/or if prolonged closed manipulation of the fracture is performed during surgery. The authors recommend close monitoring of all children treated operatively for forearm fractures, especially children who have the above-mentioned risk factors. Prolonged closed manipulation before intramedullary nailing is not recommended because of the potential increased risk of compartment syndrome.
Tibia Fractures
Currently, the most common scenario for compartment syndrome in children is the acute compartment syndrome of the leg. Children with tibia fractures, especially those caused by motor vehicle accidents, are at risk for developing compartment syndrome. In one report, compartment syndrome is reported in 4 of 92 children (4%) with open tibia fractures.
Children with tibial tubercle fractures are at increased risk of developing compartment syndrome because of the concomitant vascular injury seen with this fracture (injury to anterior tibial recurrent artery). In one report, compartment syndrome or vascular compromise was seen in 4 of 40 patients with tibial tubercle fractures.
Flynn and colleagues reported 43 cases of acute compartment syndrome of the leg in 42 skeletally immature children from 2 pediatric trauma centers. Thirty-five (83%) of the 42 cases were seen in children with tibia and fibula fractures caused by motor vehicle accidents. Average reported time from injury to fasciotomy was 20.5 hours (3.9–118 hours) in this study. This study shows a potential slow development and delayed presentation or delayed diagnosis of acute compartment syndrome of the leg in children.
In a recent report from Boston Children’s Hospital, 25 cases of acute compartment syndrome were reported among 216 patients (11.6%) with tibia fractures. Acute compartment syndrome was diagnosed clinically or by compartment pressure measurements in this study. The investigators reported that children with motor vehicle accidents and children older than 14 are at higher risk for acute compartment syndrome after tibia fractures. In this study, compartment syndrome developed in 12 (48%) of 25 children older than 14 years of age who sustained a motor vehicle accident. The rate of compartment syndrome after tibia fractures reported in this study is higher than previously reported rates in the literature, which could be due to the frequent use of compartment pressure measurements for the diagnosis of compartment syndrome in this study.
Close monitoring of children with high-energy tibial shaft fractures and children with tibial tubercle fractures for signs of compartment syndrome is recommended.
Mubarak reported 6 patients with distal tibial physeal fractures who presented with severe pain and swelling of the ankle, hypoesthesia in the first web space, weakness of the extensor hallucis longus and the extensor digitorum communis muscles, and pain with passive flexion of the toes. Compartment pressure measurements showed measurements more than 40 mm Hg beneath the extensor retinaculum and less than 20 mm Hg in the anterior compartment in all 6 patients. Prompt relief of the pain and improved sensation and strength within 24 hours of the release of the superior extensor retinaculum and fracture stabilization were reported in all of these patients. This study reported a unique type of increased intracompartmental pressure in children with distal tibia fractures that would benefit from fascial release.
Femur Fractures
Compartment syndrome after femur fractures is not common and may be related to casting techniques. Compartment syndrome and Volkmann contracture are reported after 90 of 90 spica casting of femur fractures in children. In one report, 9 cases of calf compartment syndrome and Volkmann contracture were reported in children with femur fractures treated in 90 of 90 spica casts. One specific technique while applying the cast (applying the short leg cast first and applying traction through the short leg cast) was attributed to this complication by the investigators. This technique must be avoided when applying long leg casts and spica casts in children. The investigators recommended an alternative method of applying spica casts, which is beyond the scope of this review.
Miscellaneous and Nontraumatic Causes of Compartment Syndrome
Neonatal compartment syndrome is very rare, and the diagnosis is often missed. It is thought to be caused by a combination of low neonatal blood pressure and birth trauma. Ragland and colleagues reported 24 cases of neonatal compartment syndrome. In their series, the diagnosis was made within 24 hours in only 1 patient, which resulted in good clinical outcome. They described a “sentinel skin lesion” ( Fig. 1 ) on the forearm of these patients as the sign of neonatal compartment syndrome. High clinical suspicion is the key to early diagnosis and treatment of this rare abnormality.
