Vascular Injuries

Arterial Injuries

Fifty-eight percent of neurovascular injuries in children are associated with orthopaedic injuries. Typically, the artery involved is near the fracture; for example, the common femoral artery is often associated with intertrochanteric fractures of the hip and hip dislocation, and the superficial and profunda femoral arteries are associated with subtrochanteric and midshaft fractures. The femoral artery can be injured at the adductor hiatus by a supracondylar femoral fracture. Injury to the popliteal artery or to a combination of the anterior and posterior tibial arteries is usually associated with fracture of the distal femoral ( Fig. 7-1 ) or proximal tibial epiphysis or knee dislocation (32% to 64%).

A , Supracondylar fracture of the femur in an 8-year-old boy with complete displacement of the distal femoral epiphysis. Decreased pulses and this fracture pattern are suggestive of a vascular injury. B , An arteriogram demonstrates attenuation of the popliteal artery, but it is still intact. The fracture was reduced and fixed with crossed pins; subsequent premature growth arrest occurred.

As in adults, massive bleeding and arterial hemorrhaging can occur in children with pelvic fractures. In one study, the mortality rate was 5% in children and 17% in adults. The fracture patterns are usually a combination of anterior and posterior injuries to the pelvic ring, either unilateral or bilateral. O’Neill and colleagues noted that posterior arterial bleeding (internal iliac and posterior branches) was more common in patients with unstable posterior pelvic fractures, whereas anterior arterial bleeding through the pudendal and obturator arteries was more often associated with lateral compression injuries. Injury to the superior gluteal artery was the most common injury associated with posterior pelvic fractures. Angiography to identify the arterial hemorrhage and embolization to control bleeding have been helpful. Similarly, skeletal fixation to reduce the fracture can help control bleeding in pediatric patients at high risk of life-threatening hemorrhages. One typically associates vascular injuries with extremity or pelvis trauma, but Tolhurst and colleagues documented an 11% incidence of cervical vascular injury in 61 patients evaluated for blunt cervical trauma. Central thoracic and abdominal vascular injuries have been associated with blunt motor vehicle trauma.

The usual signs of vascular compromise are (1) absent distal pulses, (2) lower skin temperature, and (3) poor skin circulation with diminished capillary and venous filling distal to the injury. Angiogram or vascular ultrasound studies should be considered whenever vascular injury is suspected. Absolute indications for vascular imaging are a diminished or absent pulse, a large or expanding hematoma, external bleeding, unexplained hypotension, a bruit, and peripheral nerve injury. If the period of ischemia approaches 6 hours, operative exploration should proceed immediately, and it may be necessary to obtain vascular imaging in the operating room. Skeletal injury in the proximity of a major vessel accompanied by a pulse deficit was 100% predictive of a vascular injury in one study.

Pulses may initially be palpable and then disappear (delayed loss of pulse). Such delayed loss is usually caused by damage to the intima with subsequent development of thrombosis. Damage to the popliteal artery from a knee dislocation is commonly limited to the intima. In children, intimal damage is often more extensive than apparent on simple inspection. Children are particularly prone to ischemia and gangrene because of arterial spasm, a rare problem in adults. The patient should be further evaluated if the pulse does not return after reduction of the fracture or dislocation ( Fig. 7-2 ). Observation of a warm pulseless leg after dislocation of the knee is insufficient. Frequently, these patients have good capillary flow because the amount of flow required to maintain viability of the skin and subcutaneous tissue is much less than that required by muscle. In these circumstances, Green and Allen reported that 90% of the limbs either eventually underwent amputation or had claudication or incapacitating muscle fibrosis and contracture.

A , Supracondylar fracture of the humerus in a 7-year-old patient with absent pulses despite satisfactory reduction and pinning. B , Arteriogram demonstrating good collateral circulation but a complete block of the brachial artery. The artery was explored, an intimal flap was found and resected, and a successful end-to-end anastomosis was performed.

In general, the indications for limb salvage are extended in children because of their greater capacity for healing; however, no data have established the limits of salvage. Of all limbs, 90% can be salvaged if the circulation is reestablished within 6 hours, whereas revascularization after 8 hours from the time of injury can result in an amputation rate of 72% to 90%. One must consider the seriousness of associated polytrauma, the degree of damage to the ipsilateral foot, the time required to obtain soft tissue coverage and bone healing, and the potential for rehabilitation. With massive crush injuries and collateral vessel damage, the 6-hour period of warm ischemia may be too long. In children, autogenous vein grafts are recommended rather than synthetic or bovine material. Spatulation of the ends of the vessels allows for a longer suture line that will accommodate a later increase in vessel size without stricture. In contradistinction to proximal injuries, isolated single vessel injuries distal to the elbow or knee may, on occasion, be treated by vessel ligation.

Distal compartment syndromes are common after late diagnosis or repair of vascular injuries. Fasciotomy should be considered after vascular repair so that a late compartment syndrome is avoided; however, fibulectomy is not recommended because of the potential for valgus deformity of the ankle. Patients should be monitored in the early postoperative period for myoglobinuria or a rise in creatinine or phosphokinase levels. Signs and symptoms of renal insufficiency should also be sought because both are consistent with the diagnosis of rhabdomyolysis. Repair of a proximal artery may not result in saving the entire limb but may preserve the knee, which has important functional implications.

Fracture stabilization can be accomplished by a variety of means. Ideally, if time permits, reduction and fixation of the fracture should precede vascular repair. Initial bony fixation provides maximal skeletal stability and reduces further trauma to the soft tissues, nerves, and collateral blood vessels. Similarly, surgical repair of nerve lacerations is facilitated by bony stabilization. If soft tissue coverage can be achieved, internal fixation is preferred. External fixation, particularly in a severely traumatized limb, has many advantages, including a short operative time. Zehntner and colleagues found that complications were less frequent with initial external fixation of lower extremity fractures than with internal fixation. Indwelling arterial and venous shunts can be helpful in selected cases for reduction of the risk of further vessel damage and compartment syndrome. Similarly, temporary shunting can provide a satisfactory solution to the clinical problem of whether an ischemic limb should be revascularized before fracture fixation. Surgical shortening of the bone may facilitate vascular repair, and the leg-length discrepancy can be resolved at a later time.

Early complications include wound infection, below-knee amputation, deep vein thrombosis, and motor and sensory deficits. Revascularization does not eliminate the possibility of abnormal growth (i.e., overgrowth and undergrowth). All children should be monitored with scanograms until limb lengths stabilize. Loss of normal pulsatile blood flow influences growth; as the child ages, the collateral circulation may not be adequate to meet the increased physiologic demands, and ischemia-like symptoms may be triggered by activity.

Compartment Syndromes

Compartment syndromes can occur in a multiply injured child with the same frequency as in an adult. The condition is caused by swelling and increased pressure in a closed space, such as a fascial compartment, but it can also occur from tight skin or a circumferential cast. If not treated promptly, it results in complete death of the structures within the compartment and Volkmann ischemic contracture ( Fig. 7-3 ). Compartment syndromes occur in the interosseous compartments of the hand and foot, the volar and dorsal compartments of the forearm, the thigh, and all four compartments of the leg. Crush and wringer injuries are the classic causes, but more commonly, compartment syndromes are associated with fractures, severe contusion, drug overdose with limb compression, burns, and vigorous exercise. In children, compartment syndrome can accompany a vascular injury or osteotomy of a bone, especially the proximal end of the tibia. Multiple traumatic injuries predispose a child to compartment syndrome because of additional high-risk factors such as hypotension, vascular injury, and high-energy blunt trauma, which increase tissue necrosis. Patients with longer operative times and those who required more intraoperative fluoroscopy are at high risk of developing compartment syndrome, which reflects the difficulty of the reductions and likely more manipulation of the fractures. Compartment syndromes in the thigh have been reported in teenagers after blunt trauma and because of systemic hypertension, external compression with antishock trousers, and vascular injury with or without fracture of the femur. Even children with femoral shaft fractures treated by skin traction or early spica cast use may be subject to compartment syndromes. It is recommended that 90/90 spica casting not be applied with traction.

Volkmann ischemic contracture of the forearm after treatment of a both-bones fracture and unrecognized compartment syndrome. Note the contracture of the fingers, which are partially insensitive.

Compartment syndrome may occur after simple Salter–Harris type I or II fracture of the distal end of the radius or proximal part of the tibia and in both open and closed injuries. A common misconception is that an open injury will decompress the compartment. However, not all compartments are successfully relieved by an open injury. Similarly, closed fractures, such as femoral fractures that are treated with closed intramedullary fixation, are susceptible to compartment ischemia. In restoring femoral length, the muscles are pulled to length, and the integrity of the compartments is restored; however, a compartment syndrome can occur. As flexible intramedullary nailing of forearm and tibia fractures has become more popular, a corresponding rise has been seen in the number of patients experiencing compartment syndrome with this technique. Risk factors associated with developing compartment syndrome include longer operating time, a high-energy injury, and associated neurologic deficit. Compartment syndromes of the foot in children are usually due to crush injuries and may not be associated with osseous injury; in addition, a neurovascular deficit is infrequent. Compartment syndromes in the foot are most commonly associated with a Lisfranc fracture–dislocation but have also been reported with fractures of the metatarsals and phalanges.

As the pressure increases within the space, the first finding or complaint is a decrease in sensation, or paresthesia. Pain, swelling, and tenseness of the compartment are found on physical examination. These symptoms may be difficult to recognize in children who are too young to cooperate with the examination or in those who have a head injury.

Bae and colleagues, in their study of children with acute compartment syndrome, found that pain, pallor, paresthesia, paralysis, and pulselessness were relatively unreliable signs and symptoms. An increasing analgesia requirement in combination with clinical symptoms was a more sensitive indicator. All 10 of their patients who had access to patient-controlled or nurse-administered analgesia had an increasing requirement for pain medication that preceded other clinical signs or symptoms by an average of 7 hours. Noonan and McCarthy have stressed the importance of recognizing the three A s of pediatric compartment syndrome—agitation, anxiety, and increasing analgesic requirement—which often precede the classic presentation by several hours. Pulse oximetry is not helpful in the diagnosis of compartment syndrome because a normal reading does not imply adequate tissue perfusion.

With continued ischemia, voluntary use of the muscles is decreased, and eventually complete paralysis ensues. Pain on stretching the involved muscles is a common finding but is subjective and may be the result of trauma. Early ischemia of the nerve may cause anesthesia and obscure this very sensitive finding. An excellent example of this diagnostic dilemma is the loss of toe dorsiflexion after a metaphyseal fracture of the proximal end of the tibia, which may be caused by a direct injury to the peroneal nerve or anterior tibial artery or by an anterior compartment syndrome.

Compartment pressures are seldom high enough to occlude a major artery, so the peripheral pulses are often palpable, and capillary filling is routinely demonstrated in the skin of the hand or foot. With a tissue pressure exceeding 30 mm Hg, capillary pressure is not sufficient to maintain blood flow to the muscles, and necrosis results. With severe intercompartmental edema, the nerves show a gradual decline in action potential amplitude. A complete conduction block can be obtained with a pressure as low as 50 mm Hg and, after 6 to 8 hours of sustained pressure, a pressure of 30 or 40 mm Hg.

Diagnosis or exclusion of compartment syndrome on clinical grounds alone may be impossible. The easiest and quickest method to make the diagnosis is by measuring compartment pressure. It is mandatory that anyone who is managing trauma in children be able to determine these values. Generally, a pressure greater than 30 mm Hg is considered abnormal and demands close observation; a pressure more than 40 mm Hg warrants surgical decompression. Compartment pressures between 30 and 40 mm Hg can be managed nonoperatively unless clinical symptoms suggest the presence of compartment syndrome. Muscle damage is significant when intercompartmental pressures are greater than 30 mm Hg for a period of 6 to 8 hours. Patients who have increased compartment pressure without an associated fracture (usually a crush injury) are more likely to have muscle necrosis.

Battaglia and associates measured compartment pressure in children with supracondylar fractures before and after reduction. They found that pressure is greatest in the deep volar compartment and closest to the fracture site. Fracture reduction did not have a consistent or immediate effect on reducing pressure. They recommended that the elbow not be flexed beyond 90°, which was associated with significant (the greatest) pressure elevation. If a fasciotomy is necessary, one must adequately decompress the deep volar musculature. None of their patients exhibited signs and symptoms of compartment syndrome, which suggests that absolute pressure thresholds, no matter how great, are inadequate as indicators of impending compartment syndrome and support the concept that the absence of clinical indications alone is insufficient as an indication for fasciotomy.

Initial treatment should include splitting a tight cast and removal of occlusive dressing material and cast padding, all of which will decrease compartment pressure. Elevation of the limb may increase compartment pressure and may be counterproductive if coupled with a decrease in perfusion; this combination may be the mechanism by which ischemic contractures occur after femoral fractures in children. Placing the limb at approximately the same level as the heart may be optimal.

Compartment syndrome does not seem to affect healing of the fracture, and nonunion or delayed union is seldom associated with it. However, the healing time for closed fractures associated with compartment syndrome was noted by Turen and associates to be longer, 30.2 versus 17.3 weeks. Interestingly, compartment syndrome lengthens the time for healing of closed fractures, but the healing time was approximately the same as for an open fracture. The method of fixation does not affect the healing time.

The duration of the compartment syndrome before definitive surgical decompression is the most important factor in determining functional outcome. If decompression is accomplished during the early swelling phase of compartment syndrome, most patients will have normal function. Late surgical decompression exposes devitalized muscles, which require débridement, and, in some instances, infection can ensue and necessitate multiple débridement procedures and antibiotics. Chuang and colleagues recommended exploration and excision of the infarcted muscle within 3 weeks of injury. They found that such a time frame preserves intrinsic hand function and sensation by removing the ischemic environment and preventing the fibrosis that may add to nerve compression and damage.

Fat Embolism

Fat embolism is a syndrome associated with long bone fractures in which fat emboli to the lungs lead to respiratory problems. It is believed to be caused by dissolution of normal circulating fat; however, the exact mechanism is still unexplained. This condition may be due to actual leaking of fat into the bloodstream or a metabolic change that allows normal circulating fat to become free fatty acids. Mudd and associates examined patients who died of fat embolism syndrome after blunt trauma. They found no particular source of the fat, nor was evidence of bone marrow or myeloid tissue seen in the lung sections. Many children have fat emboli after injury, but the clinical syndrome develops in very few. Fabian and colleagues found the an incidence of fat emboli in pediatric and adolescent long bone fractures to be as high as 10%. Fat embolism is more often seen in teenagers and late adolescents, and the onset is usually shortly after the injury (within the first 2 to 3 days). Mudd and colleagues found no correlation with the number or severity of fractures; rather, fat embolism syndrome was more likely to be related to the extensive nature of the soft tissue injuries. The pulmonary changes prevent exchange of oxygen across the alveolar–capillary membrane. In adults, this condition is referred to as adult respiratory distress syndrome. The incidence of fat embolism syndrome is markedly decreased by immediate internal stabilization of long bone fractures as opposed to treatment by traction or late reduction. Intramedullary fixation of long bones (particularly diaphyseal fractures of the femur) is preferred because it reduces the risk of fat embolism syndrome. However, reaming for the nail can cause an increase in circulation and can potentially increase the risk of a fat embolism to the lung. Fat embolism syndrome has been reported in children with muscular dystrophy and as a complication of closed femoral shortening. Patients who are at risk of developing fat embolism syndrome should be monitored with pulse oximetry.

With the full-blown syndrome, children have respiratory distress, tachypnea, and a deterioration in blood gas values, particularly O ₂ saturation. Clinically, the child may appear restless and confused; if untreated, stupor and coma may ensue. Petechiae may develop on the skin of the chest, axilla, and base of the neck, but they may be transient and are frequently missed. The most significant laboratory finding is a decrease in arterial oxygen tension. Examination for fat in urine and sputum is of little value relative to more modern diagnostic measures. Recently, bronchoalveolar lavage for detection of fat-containing cells and retinal examination for cotton-wool spots and retinal hemorrhages have been reported to be helpful in early diagnosis. A chest radiograph classically demonstrates interstitial edema and increased peripheral vascular markings.

If untreated, fat embolism can be lethal; however, early diagnosis and prompt management can usually sustain the patient until the problem clears. Treatment consists of supportive measures for the respiratory problem, including improvement in oxygen saturation (70 mm Hg), and may require endotracheal positive-pressure breathing. The blood volume should be restored, and fluid and electrolyte balance should be maintained. Adequate oxygenation is the most important part of treatment because respiratory failure is the most common cause of death. Treatment with steroids and heparin remains controversial.

Hypercalcemia of Immobilization

Many children exhibit hypercalcemia after immobilization for a fracture. Cristofaro and Brink reported that 7 of 20 children demonstrated increased serum calcium levels of 10.7 to 13.2 dL (normal, 8.5 to 10.5 dL). Urinary excretion of calcium peaks approximately 4 weeks after immobilization begins and can be expected to return to normal levels with activity. This increased urinary calcium excretion is believed to be part of the normal reparative process. In those who have preexisting metabolic bone disease, such as rickets or parathyroid disease, immobilization can further increase serum calcium levels. Similarly, for unexplained reasons, some young patients, usually those 9 to 14 years of age, may have significantly high calcium blood levels and systemic symptoms.

Symptoms include anorexia, nausea, vomiting, and increased irritability; if the condition is severe, generalized seizures, pain with movement, flaccid paralysis, muscle hypertonia, and blurred vision can occur. If hypercalcemia is not controlled, renal calculi can develop. The serum alkaline phosphatase concentration is usually normal, unlike in the case of hyperparathyroidism, in which the serum level is generally high. However, to definitively distinguish the two conditions, a parathyroid hormone assay should be performed.

Intravenous administration of fluids and corticosteroids has been reported to be successful in lowering the serum calcium level until mobilization can be accomplished. Usually, a low-calcium diet is recommended. Plicamycin (also known as mithramycin) also effectively lowers calcium either by direct antagonism of bone resorption or by interference with the metabolism of parathyroid hormone. In addition, calcitonin has been reported to be effective in immediately lowering serum calcium levels by inhibiting bone resorption. Finally, bisphosphonates have also been used to successfully treat hypercalcemia of immobilization. Appropriate hydration and diuresis can help, as can immediate weight-bearing and movement.

Another problem that is similar in nature is acute hypercalcemia after quadriplegia. Particularly in young people, this condition can be troublesome and should be routinely evaluated during the first 6 weeks after the onset of paralysis.

Ectopic Bone Formation

Ectopic bone has been reported to appear around all major joints, most often the hip, elbow, and knee ( Fig. 7-4 ). The condition is more common in teenagers, but any age group is at risk. Ectopic bone formation is typically associated with head injuries and burns. Myositis ossificans is associated with burns about the shoulder, distal end of the femur, elbow, and proximal part of the tibia, usually within 4 months after a thermal injury. Mital and colleagues found that heterotopic bone developed in 15% of head-injured children and that coma and spasticity were the most commonly related factors. Fractures about the pelvis and extensive surgical approaches to repair pelvic fractures increase the risk of myositis ossificans.

Ectopic bone formation leading to complete elbow ankylosis. Radiographs were obtained before surgery (6 months after a head injury) (A) and 6 months after surgical excision (B) .

(From Mital MA, Garber JE, Stinson JT: Ectopic bone formation in children and adolescents with head injuries: its management. J Pediatr Orthop 7:83, 1987.)

The process is usually preceded by an inflammatory response and tenderness near the affected joint in an area of soft tissue and bone trauma. Elevated levels of serum alkaline phosphatase usually precede ossification and remain elevated during active bone formation. Radiographic evidence is apparent within 3 to 4 weeks after the injury. MRI may be helpful in the early diagnosis of this condition. A rim with low signal intensity is a common finding, but no unique pattern characterizes myositis ossificans. Initially, the process lacks definable borders and then progresses to a more focal mass with a high central intensity that eventually becomes bone. This pattern is common in the intramuscular type and less so with the periosteal type. Involution is more evident in the intramuscular type. Some resorption may occur after joint movement has begun. Attempts to excise the heterotopic bone should be delayed until the process is completely mature, usually about a year after injury. Some reports have indicated that pharmacologic agents can reduce the incidence of ectopic bone formation. Mital and colleagues found that, in head-injured children, salicylates can help minimize or eliminate ectopic bone, particularly after excision. Similarly, indomethacin has been reported to be helpful. Diphosphonates have been used, but because of problems with bone metabolism, they are not currently recommended. Most children can be treated successfully by observation, and the condition can be allowed to run its course because few children have long-term problems.

Superior Mesenteric Artery Syndrome (Cast Syndrome)

Superior mesenteric artery syndrome consists of acute gastric dilatation and vomiting. In the past, this syndrome was most often recognized in those treated with a hip spica or body cast, hence, the older name cast syndrome . However, in more recent times, it has been reported to occur in the absence of a cast, such as after traction for extended periods, after spine surgery with instrumentation, particularly after correction of kyphosis, and after a severe traumatic brain injury. The problem is caused by mechanical obstruction of the third portion of the duodenum by the superior mesenteric artery ( Fig. 7-5 ). It can be caused by hyperlordosis positioning in the cast, but more often it is associated with weight loss and a decrease in the fat protecting the superior mesenteric artery from the duodenum. The angle between the superior mesenteric artery and the aorta becomes more acute and compresses the duodenum. Those with an asthenic body habitus and those who have an alteration in spinal curvature are at greatest risk. If this condition is not treated aggressively, the problem becomes difficult to manage, and patients are subject to progressive weight loss, hypokalemia, and life-threatening dehydration and electrolyte abnormalities.

An upper gastrointestinal series in a patient with superior mesenteric artery syndrome (cast syndrome) demonstrates compression of the fourth portion of the duodenum from the superior mesenteric artery. Complete resolution followed aggressive intravenous hyperalimentation.

The syndrome can be reversed by increasing the bulk of retroperitoneal fat. Treatment consists of passing a feeding tube beyond the obstruction or intravenous hyperalimentation plus repositioning (side-lying) to encourage appropriate duodenal drainage. If a cast is hyperextending the spine, it should be modified. Medical treatment duration of 6 weeks may be necessary. In extreme cases that do not resolve with conservative treatment, complete derotation of the duodenum and colon with stabilization of the mesenteric artery (Ladd procedure) can resolve the obstruction.

Traction-Induced Hypertension

An uncommon event is hypertension associated with traction for a long bone fracture. Hypertension has also been reported to occur during limb lengthening as a result of traction on the bone and its adjacent soft tissue. It may be caused by tension on the sciatic nerve, activation of the renin–angiotensin system, or prolonged immobilization. Hamdan and colleagues noted elevated blood pressure in 68% of patients undergoing traction, three of whom required treatment. This problem can be controlled by modification of the traction and by hypertension medication until the primary condition has resolved.

Spontaneous Deep Vein Thrombosis

This complication is very uncommon in childhood: only scattered reports exist in the literature. Generally, the clinical findings are similar to those found in adults and consist of local discomfort, tenderness and warmth, and, often, swelling of the extremity. Deep vein thrombosis should be confirmed by appropriate noninvasive testing and perhaps venograms. The majority of children who develop thrombophlebitis or have a pulmonary embolism have an inherited or congenital thrombophilia. Activated protein C–resistant antithrombin III deficiency, dysfibrinogenemia, impaired fibrolysis, protein C deficiency, protein S deficiency, and factor V Leiden are the more common conditions associated with the increased incidence of thrombophlebitis in children. When a child is identified with this condition, the near relatives should be screened because they may also have the condition and require prophylaxis. A serum lipoprotein(a) (Lp[a]) concentration greater than 30 mg/dL is an important risk factor for thromboembolism in childhood. Children who have venous thromboembolic events should be screened for elevated serum Lp(a). It is likely that many cases go unrecognized. Most children respond to routine treatment, similar to adults. Initial treatment consists of heparin followed by warfarin (Coumadin) over an appropriate period. The problem occurs more often in older teenagers, the obese, and those with local infection in the extremity. Critically ill children and those requiring a central venous catheter have been shown to be at increased risk. Acute pulmonary embolism is extremely rare, but it has been reported and should be managed with the same caution as for an adult. Pulmonary angiography is still the gold standard in diagnosing pulmonary embolism. Several other examinations are useful for detecting the presence of a pulmonary embolism, for instance, ventilation–perfusion lung scanning can allow the diagnosis to be made 85% of the time. Helical computed tomography (CT) with contrast agents has recently gained popularity.

Malunion

The most common malunion experienced by children occurs after a supracondylar fracture of the humerus, usually resulting in a cubitus varus deformity ( Fig. 7-6 ). In the past, the deformity was attributed to a disturbance in elbow growth. However, clinical and experimental evidence indicates that the more common cause is an initial unsatisfactory reduction or early loss of reduction. Unfortunately, the cross section of the proximal humeral fragment is narrow, and unless the distal fragment is reduced anatomically, it is easy for this fragment to rotate and tilt medially, causing subsequent cubitus varus deformity and limitation of elbow flexion. Growth at the distal end of the humerus contributes only 10% of the length of the upper extremity, and as a consequence, the potential for subsequent remodeling is limited. The recent popularity of closed reduction with exact anatomic alignment maintained by pin fixation has lessened the frequency of this complication.

A 4-year-old patient with a supracondylar fracture of the humerus that healed with a cubitus varus deformity.

Most children do not have a functional deficit but may have a significant cosmetic deformity. If the deformity is present after 1 year and is posing problems, it may be managed by corrective osteotomy. Several authors have described a variety of ways to achieve angular correction. It is not necessary to correct all the deformity of the supracondylar region. Correction of the rotation, however, is much more difficult; however, the shoulder usually adequately compensates for it. Most authors prefer a lateral closing wedge to correct only the angular alignment and are not concerned about the rotation or flexion–extension aspects of the deformity. Barrett and associates in their review of this procedure found that patients were generally pleased with this approach. Fixation of the osteotomy is a problem because of the small size and peculiar shape of the distal end of the humerus, which does not lend itself to standard fixation methods. Blasier recommended a triceps-splitting approach to the supracondylar region that provides excellent visualization and facilitates the osteotomy. Pin fixation can be done under direct visualization with greater ease than with a lateral approach.

Unrecognized angular malunion of the ulna in Monteggia injuries can lead to persistent subluxation or dislocation of the radial head and significant loss of pronation and supination. A Monteggia lesion consists of a fracture of the ulna and dislocation of the ipsilateral radial head. This lesion can be subtle; in a small child, it may be difficult to assess the relationship of the radial head to the capitellum, and associated deformation of the ulna may be subtle. As a consequence, an acute lesion is often misdiagnosed ( Fig. 7-7 ). Similarly, displacement or angulation of the ulna and subluxation of the radial head may occur in the weeks after reduction (approximately 20%), especially when the ulnar fracture is oblique. Rodgers and associates published a review of complications and results of reconstruction of Monteggia lesions in children. Attempts at late repair of this lesion were met with considerable problems, including decreased rotation of the forearm, transient motor and sensory ulnar nerve palsies, and residual weakness. However, they believe that the long-term sequelae (pain and weakness) of chronic Monteggia lesions warrant intervention in a skeletally immature patient. If malunion of the ulna prevents reduction, an osteotomy should be performed, preferably one rigidly fixed with a plate. Steinmann pins can be placed antegrade down the ulnar. Inoue and Shionoya recommend overcorrecting the ulna using plate fixation, particularly in situations in which the radial head reduction is unstable. The deformity of the head caused by growth in a dislocated position makes restoration of the normal radial–ulnar–capitellar relationship difficult. If the radial head is not stable, a temporary pin can be placed to transfix the radiocapitellar joint If the annular ligament is incompetent, it can be replaced or reconstructed with the use of a strip of triceps fascia as described by Bell Tawse in the article by Rodgers and colleagues.

A Monteggia lesion in a 4-year-old that was undiscovered for approximately 8 months. The ulnar fracture is healed, yet the radial head remains dislocated. Reduction may require osteotomy of the ulna with rigid plate fixation, reconstruction of the annular ligament, or replacement with the triceps fascia (Bell Tawse procedure).

Fractures of the forearm in children are a common cause of malunion because the reduction can easily be lost and can be difficult to regain ( Fig. 7-8 ). Young children can occasionally remodel the fracture dramatically; as a consequence, physicians have a tendency to depend heavily on remodeling and accept a less than adequate reduction. Midshaft fractures are particularly at risk of deformity. Price and colleagues recommend acceptance of up to 10° of angulation, 45° of malrotation, and complete displacement before attempting remanipulation or resorting to open reduction and internal fixation.

Fracture of the radius and ulna in a 12-year-old girl. Anteroposterior (A) and lateral (B) views of the injury after satisfactory reduction and cast immobilization. C and D , Fracture reduction was lost because of early removal of the cast, and open reduction plus plate fixation was required to restore satisfactory alignment. In a girl of this age, spontaneous correction cannot be expected.

Nietosvaara and colleagues found that 48% of distal radial fractures healed in malunion, despite anatomic primary reduction in 85% of the cases. The displacement correlated with marked initial malposition of the fracture (greater than 50% displacement or 20% angulation). An independent risk factor for complications and redisplacement was a nonanatomic reduction of the fracture. In some cases redisplacement in the cast did not occur until 2 weeks after the injury. They suggested pin fixation should be considered if there is an associated injury, compartment syndrome, or a second fracture in the same extremity (floating elbow) and in children with less than 1 year of growth remaining.

Although angulatory deformities have a limited potential for remodeling, rotational deformities do not improve, and they should initially be treated aggressively. A residual rotational deformity can compromise pronation and supination of the forearm, although the clinical significance of this limited rotation has not been clearly established. Remodeling of an angulatory deformity is better in the distal third of the radius and ulna than in the midshaft or proximal third and is better in younger children. A study by Crawford and Lee showed that completely displaced, overriding fractures of the distal radius and ulna could be treated without reduction or sedation in a short arm molded to correct only angulation. Diaphyseal fractures of the forearm with radial or ulnar angulation are less likely to remodel completely. In general, midshaft fractures in children younger than 8 years tend to remodel almost completely; however, in children 11 years or older (particularly girls, who mature earlier), spontaneous correction cannot be anticipated and is unpredictable. Malunion in older patients with diaphyseal forearm fractures may be avoided with the use of intramedullary or plate fixation, and good results have been reported.

Price and Knapp have reported a simple method of deformity correction for malunion of forearm shaft fractures. If the deformity is angulated less than 20° and the child is 9 years or younger, the forearm has excellent remodeling potential and generally leads to satisfactory function with an acceptable cosmetic result. Angular deformity of the shaft of the radius–ulna greater than 30° rarely remodels sufficiently in any age group and should be realigned soon after the injury is healed. A brief period of observation (6 months) may be appropriate because of the tremendous ability to remodel. Malunited fractures of the forearm that were surgically corrected less than 1 year after injury had an average improvement of 80° of rotation, whereas those that were managed after 1 year gained only 30° on average.

Length discrepancy, angulation, and encroachment on the interosseous space are unpredictable indicators of loss of motion. Loss of motion may be caused by soft tissue scarring that produces tension on the interosseous membrane; a few patients with complete remodeling have failed to regain motion. Angulation in the diaphysis is often associated with loss of motion, whereas distal metaphyseal fractures tend to correct themselves, and complete range of motion returns. Similarly, anatomic restoration of alignment by open reduction and internal fixation does not always restore full range of motion. Price and colleagues suggest that the shortening resulting from fracture displacement allows for relaxation of the interosseous membrane, which preserves motion. The combination of a proximal fracture with angulation, malrotation, and encroachment carries the greatest risk of loss of motion. Price and colleagues recommend open reduction and internal fixation after a refracture because of the greater likelihood in this circumstance of losing forearm rotation.

Much recent attention has been focused on clavicular fracture malunion. A randomized prospective study performed by the Canadian Trauma Society demonstrated significantly improved outcome scores in adult patients treated with open reduction and internal fixation of clavicular fractures when compared with nonoperative treatment. However, Bae and colleagues have questioned whether similar outcomes can be expected in pediatric and adolescent patients. In their study, 16 pediatric patients with fracture displacement greater than 2 cm treated nonoperatively subsequently developed malunion but showed no meaningful loss of shoulder motion or strength.

In the lower extremity, malunion has the potential to lead to degenerative arthritis. In a study of 74 pediatric and adolescent femur fractures followed a mean of 21 years, Palmu and associates noted a positive correlation between knee arthritis and angular deformity in children older than 10 years at the time of their fractures. Several factors have been associated with femoral or tibial fracture malunion. If comminution of more than 25% is present and the femoral fracture is stabilized with intramedullary nails, an increased risk of shortening, angulation, and loss of reduction has been reported. Malunion or loss of reduction requiring reoperation was strongly associated with the mismatched diameter of flexible nails. Femoral fractures in the subtrochanteric and supracondylar region are less ideally suited to flexible intramedullary fixation and may have a higher malunion rate. Injury severity should also be considered a risk factor for malunion. Bohn and Durbin called attention to the problem of the floating knee, or ipsilateral fracture of the femur and tibia. In this group, operative stabilization of the femoral fracture was associated with fewer complications and better results. Pandya and Edmonds reported the use of flexible intramedullary nails in the treatment of open tibial fractures and described a high union rate but increased incidence of bone healing complications.

Malunion may also occur in children with head or spinal cord injuries. Ninety percent of head-injured children recover from coma in less than 48 hours. In long-term follow-up, 84% of children who were initially in deep coma (score of 5 to 7 on the Glasgow Coma Scale) were eventually able to walk freely. Thus one must assume full neurologic recovery. Rigid fixation of long bone fractures aids in nursing care and rehabilitation efforts. Muscle spasticity in the first few days often displaces or angulates fractures immobilized in casts or leads to overriding of fractures in traction ( Fig. 7-9 ). Nonoperative management of fractures in these children results in healing but also produces an unacceptable incidence of malunion, angulation, and shortening ( Fig. 7-10 ). Skin insensitivity combined with disorientation may result in skin breakdown with the potential for secondary osteomyelitis. If the child must be moved for special studies, such as CT or MRI, or requires extensive dressing changes, multiple débridement in the operating room, or whirlpool treatments for burns, the fracture should be stabilized because manipulation of the fracture may increase intracranial pressure. In children with acute quadriplegia or paraplegia, fracture fixation decreases the incidence of skin problems and pressure sores from cast immobilization and the need for external support, which may compromise nursing and rehabilitative efforts.

Fifteen-year-old boy with a serious head injury treated with traction for a femoral shaft fracture. Note the shortening and overriding. The patient has recovered and walks with a cane. The leg-length discrepancy has caused numerous problems.

Angulation of a femoral shaft fracture in a 13-year-old head-injured patient who was treated with skeletal traction.

Synostosis (Cross Union)

Cross union is a rare and serious complication of fractures of the forearm. Rotation of the forearm is impossible and may lead to a serious compromise in function. Cross union must be distinguished from myositis ossificans, which is more common and typically less disabling. Most cross unions are confined to the proximal third of the radius and ulna. Most authors recommend that if open reduction of forearm fractures is required, the surgery be performed through two incisions; however, this technique does not necessarily prevent cross union. Similarly, synostosis has been reported after intramedullary fixation of fractures. Other predisposing factors include severe initial displacement, residual displacement, periosteal interposition, delayed surgery, remanipulation, and fracture at the same level of the radius and ulna.

Vince and Miller recommend at least a 1-year interval before excision of a cross union. A bone scan may be useful for establishing that the healing reaction is complete and that isotope uptake has returned to the same level as that in the surrounding bone. When a synostosis is excised, it is important that the bone bridge and its periosteum be removed intact to lessen the chance of recurrence. Several authors suggest interposing fat, muscle, or silicone elastomer (Silastic) between the radius and ulna to prevent recurrence; however, only a few patients had a recurrence, and follow-up data are limited. If surgery is delayed too long, soft tissue contractures may preclude recovery of maximal range of pronation and supination ( Fig. 7-11 ).

A , Anteroposterior and oblique views of the distal end of the forearm and wrist of a 7-year-old boy who sustained a fracture of both bones of the forearm. The fracture healed in a malrotated and angulated position with subsequent synostosis that is easily seen on the oblique view, which separates the radius and ulna. B , The traumatic synostosis was resected with interposition of fat. Preoperatively, the patient had no forearm rotation; postoperatively, he regained 50° of forearm rotation.

(Courtesy of Dr. Neil E. Green. Vanderbilt University, Nashville, TN. (same as Dr Mencio))

The same problem can develop between the tibia and the fibula. Tibial–fibular synostosis is associated with high-energy trauma that results in displaced fractures of the distal tibia and fibula at the same level. In a child, this may lead to disproportionate growth. One should allow 3 months to 1 year for the synostosis to mature before excision. A similar surgical recommendation could be considered to keep the fibula moving freely at the ankle joint. Another alternative is resection of a portion of the fibula and screw fixation of the distal end of the fibula to the tibial epiphysis.

Late Angulation

Late angulation is a common problem with fractures of the proximal tibial metaphysis in a young child. Typically, the fracture is a relatively nondisplaced or easily reducible fracture of the proximal tibial metaphysis. It heals uneventfully, but over the ensuing months, progressive valgus angulation develops in the limb and can be alarming in its appearance ( Fig. 7-12 ). Many improve spontaneously, and one should wait at least 18 months to 2 years to be confident that maximal improvement has occurred ( Fig. 7-13 ). Usually, this condition is not associated with a fracture of the fibula, but it has been reported with fractures of both bones. Although many theories have been advanced, the most likely mechanism is an increased vascular response leading to stimulation of growth of the medial metaphysis of the proximal end of the tibia.

Clinical appearance of a 2½-year-old patient in whom valgus angulation developed secondary to a fracture of the proximal tibial metaphysis.

A , A 7-year-old patient with persistent valgus deformity several years after sustaining a fracture of the proximal tibial metaphysis. Spontaneous remodeling has not occurred. B , Radiograph after a proximal tibial osteotomy to correct the deformity.

Interestingly, proximal metaphyseal osteotomy of the tibia and fibula for correction of the deformity can also initiate a progressive valgus deformity with an unacceptably high rate of recurrence of the angulation. Guided growth techniques with the use of a staple or small plate are less morbid and have largely replaced tibial osteotomy as treatment for this condition in the growing child.

Injury to the Triradiate Cartilage

Traumatic disruption of the acetabular triradiate physeal cartilage occurs infrequently. However, children whose bones are fractured during the active growth phase have a great potential for early closure and development of a shallow acetabulum. Experimentally induced triradiate cartilage closure in rabbits further supports this paradigm. This problem is more common in children younger than 10 years, and in this situation it can lead to incongruity of the hip joint and progressive subluxation requiring acetabular reconstruction. In older children with less growth potential, this pattern is not as troublesome. Simple displacement of the triradiate cartilage has a more favorable prognosis. In contrast, severe crushing frequently ends in early closure and the worst prognosis. A severe, more crushing type of injury may be difficult to detect on initial radiographs, in which case CT scans are helpful. If a definite osseous bridge can be identified, resection with fat or methyl methacrylate (Cranioplast) interposition is recommended. However, the problem is often not discovered until complete closure of the triradiate cartilage has occurred.

Acetabular injury may be suspected with indirect signs such as concurrent fracture of the neck of the femur, detachment of the proximal femoral epiphysis, traumatic dislocation of the hip, or other pelvic fractures. CT scanning can be helpful in the assessment of pelvic fractures, particularly in patients who may have an osteochondral injury with a retained fragment. Persistent joint widening should arouse suspicion, even in the absence of a clear history of hip dislocation. An arthrogram may not always be diagnostic. Surgical reduction of pelvic fractures should be considered only in cases of hip instability and severe displacement of the femoral head.

Fractures of the Femoral Shaft: The Overgrowth Phenomenon

It is well known that a fracture of the femur may lead to overgrowth averaging 1 cm (range, 0.4 to 2.7 cm). Nork and colleagues and Shapiro suggested that overgrowth was independent of age, level of the fracture, or position of the fracture at the time of healing (shortened, lengthened, or distracted). Overgrowth occurs in the entire limb, and interestingly, overgrowth of the ipsilateral tibia often also occurs. This phenomenon has been reported to occur in 82% of patients, and 78% of overgrowth occurs in the first 18 months after a fracture. In 9%, overgrowth continued throughout the period of remaining growth, although at a slower rate. Staheli noted slightly greater overgrowth in children 4 to 8 years of age. The available evidence suggests that such overgrowth is caused by an increase in vascularity to the bone as a result of the healing reaction. It is an obligatory phenomenon rather than a mechanism to compensate for shortening. This phenomenon has led to the clinical suggestion that the fracture fragments be overlapped approximately 1 to 1.5 cm in a young child, with the expectation that such overlapping will lessen the problem of overgrowth. It may become more troublesome as more femoral shaft fractures are managed by intramedullary fixation or external fixation, which restores the fracture to length. Submuscular plating has recently gained popularity as an effective treatment for length-unstable femur fractures. A recent report suggests the potential for overgrowth resulting in length discrepancy and valgus alignment in a small percentage of patients treated with this technique.

Overgrowth is infrequently reported in the upper extremity. In a large study of forearm fractures, overgrowth in the radius or ulna is infrequent and averages 0.44 cm. Davids and colleagues noted that lateral condylar fractures of the humerus can, on occasion, be complicated by lateral overgrowth and an unsightly appearance.

Growth Disturbances

Physeal Fractures

The complex geometry, large cross-sectional area, and force required for fractures all contribute to a high incidence of growth disturbance after a fracture of the distal femoral physis, even after relatively simple type I and type II Salter–Harris fractures. In contrast, growth disturbance is a rare occurrence after injury in smaller physes, such as the distal end of the radius. The proximal part of the tibia and distal end of the femur account for only 3% of all physeal injuries but are responsible for most bony bars. This finding is particularly troublesome because they account for 60% to 70% of the growth of the respective bones. Riseborough and colleagues found an alarmingly high rate of complications after femoral physeal injury: growth arrest and a limb-length discrepancy of more than 2.4 cm developed in 56%, and angular deformities greater than 5° requiring osteotomy developed in 26% (see Fig. 7-1 , A ). Growth problems correlate well with the severity of the injury and were seen in all the Salter–Harris types. Salter–Harris type III and IV fractures of the distal tibia have also been identified as being especially troublesome: open, anatomic reduction and internal fixation are recommended for prevention of premature physeal closure. Physeal fractures in children younger than age 11 years have the poorest prognosis; growth problems develop in 83% of these children.

Riseborough and colleagues recommend anatomic reduction and greater use of internal fixation, but this technique is not guaranteed to restore normal growth in those who have sustained a severe injury to the growth plate. With a type II fracture–separation, internal fixation of the large metaphyseal fragment provides better results. Because the potential for growth arrest is so high, children should be monitored closely over the period of remaining growth. Imaging for growth arrest has evolved: initially, trispiral tomograms were preferred, then MRI, and now high-resolution helical CT scanning with coronal and sagittal reconstruction imaging is the preferred imaging modality. If the resultant bridge is of moderate size, less than 40% of the cross-sectional area, and surgically accessible, it can be excised. Scanograms should be taken to determine the precise length of the extremities and to evaluate the hand and wrist for bone age before planning surgical resection. If the projected leg-length discrepancy is less than 4.8 cm, Riseborough and colleagues advise contralateral distal femoral arrest. Importantly, such arrest does not correct any existing discrepancy but serves only to further limit leg-length inequality. For an anticipated length discrepancy greater than 5 cm, limb lengthening will have to be considered. Growth arrest can occur after adjacent fractures in the metaphysis or, less often, the diaphysis, especially with fractures above the femur and near the knee. Such injury often results in delayed recognition of the physeal injury until a gross angular deformity develops. Berson and colleagues and Hresko and Kasser recommend that all adolescents’ injuries be monitored expectantly so that a physeal injury can be detected early.

Changes in the tibiofibular relationship because of growth disturbances after ankle fractures are frequent in children. Fortunately, most occur near the end of growth and, as a consequence, cause only minor problems. Growth arrest of the distal end of the fibula and continued growth of the tibia may initially be compensated for by distal sliding of the fibula as a result of traction from the ankle ligaments. If the deformity is of long duration, a valgus deformity will occur ( Fig. 7-14 ). Growth arrest of the distal end of the tibia may cause a varus deformity if the fibula continues to grow ( Fig. 7-15 ). However, the fibula may slide proximally to compensate for tibial overgrowth; thus the fibular head may become more prominent at the knee. Distal fibular growth arrest may be necessary.

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