Elbow injuries in children are complex and frequently complicated. Supracondylar fractures are most common. Fracture combinations sometimes occur. The combinations involve the olecranon and medial epicondyle and the olecranon and radial neck.
Physical examination Note the location and extent of soft tissue swelling. Lateral condylar fractures produce unilateral swelling that may prompt additional views should the standard radiographs show no fracture. Evaluate nerve function, including the anterior interosseous nerve and circulation. Fractures can be complicated by compromised circulation and compartment syndromes.
Imaging In every significant injury, an accurate diagnosis is essential. Order radiographs specifically to best show the suspected site of injury. Often the elbow cannot be fully extended for an anteroposterior view. Order either a distal humeral or proximal radial view. Recall the ossification sequence about the elbow. Observe the alignment of the elbow on the distal humeral AP radiograph, as this will often differentiate the common types of injuries. If conventional radiographs are nondiagnostic, consider MRI, arthrography, or ultrasound. Avoid diagnostic arthroscopy. Special studies are most likely to be necessary in early childhood, when ossification is limited.
Pulled elbow, or nursemaids elbow, occurs in about 1% of children each year. Half have no history of a pull. Whether it is more common in hypermobile children is controversial. Girls are more commonly affected. The pathology is uncertain, although capsular interposition is the most favored theory.
Clinical Features The arm is in slight flexion and the forearm pronated; the child resists moving the elbow or extremity. Swelling and tenderness are absent. The diagnosis is clinical, and radiographs are necessary only if the situation or findings are atypical.
Management Unless there is a history of a prior pulled elbow, consider taking a prereduction radiograph to rule out an occult injury. Rotate the forearm through 180° to free the interposed soft tissue. Often a snap is felt. Repeat in 15 minutes if the first attempt is unsuccessful. Return of function is immediate but may be delayed, especially in infants. Recurrence is not uncommon. Inability to free the interposition with manipulation does occur. In such cases, place the arm in a sling and see the child the next day to repeat the manipulation.
Physeal Separation of the Distal Humerus
These uncommon injuries usually occur in infants and may be due to child abuse. The fracture may be misdiagnosed as an elbow dislocation. Suspect this diagnosis by the young age and posteromedial displacement of the proximal radius relative to the humeral shaft. If necessary, confirm the diagnosis by ultrasound or arthrography. Manage similar to a supracondylar fracture. Because cubitus varus is a common complication, consider fixation with percutaneous pins.
Supracondylar fractures are most common elbow injuries. Serious neurovascular injuries and residual cubitus varus deformities are common. This is one of most challenging pediatric fractures. It results mainly from falls at home in children 4 years of age or less and on the playground after 4 years of age. It occurs mostly in girls and in the left arm.
These fractures are classified into three major categories.
Type 1—Undisplaced fractures These are stable and can be managed in a splint for 3 weeks.
Type 2—Extension injuries with posterior hinge These are stable with the elbow flexed to a right angle. The difficult types are those with impaction. Impaction may occur in varus or valgus. Impaction fractures with varus deformity of >5° and valgus deformity of >10° should be reduced and percutaneously pinned.
Type 3—Complete and displaced fractures These fractures are most at risk for associated vascular injury. The majority are the extension type. The flexion type are less common but may be difficult to reduce because of a medial metaphyseal spike.
Examine carefully, as problems are common with this fracture.
Skin Check the skin to be sure there is no laceration over the metaphyseal spike, making it an open fracture.
Vascular status Check pulses, capillary filling in nail-beds, and discomfort on finger extension. Vascular injuries occur in 2––3% of type 3 fractures. Be aware that a simple loss of radial pulse is not a definite sign of vascular impairment.
Neurologic status Nerve injuries occur in about 10% of type 3 injuries. Nerve injuries most commonly affect the anterior interosseous, median, radial, and ulnar nerves, in that order.
Carrying angle In type 1 and 2 injuries, gently extend the elbow and observe the carrying angle. Varus or valgus deformities are not uncommon in type 2 injuries and are better diagnosed on physical examination than by radiographs. Following fixation of type 4 injury, gently extend the elbow to assess the carrying angle.
Baumann angle is sometimes used to assess the carrying angle by radiographs. This is an angle between the axis of the humerus and capitellar epiphysis. Assess on both sides. The normal range is usually from 87° to 93°. Make certain the radiographic and clinical findings agree.
Keep in mind vascular compromise and cubitus varus—the major complications of this fracture. Most fractures are managed by cast immobilization or percutaneous pinning. Traction treatment is rarely used.
Type 1 Manage with the elbow flexed to a right angle and immobilized in a posterior splint for 2–3 weeks. Allow motion to recover naturally.
Type 2 Look for evidence of varus or valgus impaction. If deformity exceeds about 5° of varus or 10° of valgus, reduce under anesthesia and fix with percutaneous pins. Otherwise, manage as with type 1 fractures with the elbow flexed.
Type 3 Determine whether it is the extension or flexion type.
Percutaneous Pinning of Supracondylar Fractures
IT is the preferred method of managing displaced supracondylar fractures. The technique provides good fixation with the least number of complications. This procedure is indicated for displaced fractures without serious vascular compromise.
Preoperative preparations Evaluate carefully before undertaking the procedure. Have available 1 and 2 mm smooth pins, a power driver, an imaging device, and an assistant. Position thoughtfully. This is a matter of preference. The prone position allows gravity to help maintain the reduction while placing the pins.
Reduction Apply traction and hyperextension. First realign in frontal plane. The second step is to align in the sagittal plane. Confirm the reduction by AP and lateral imaging. Maintain reduction by flexing the elbow. Perform a surgical skin prep and continue utilizing sterile technique.
Pin fixation Crossed pins, 2 or 3 lateral pins are acceptable fixation configurations. Using only lateral pins, avoid risks of injury to the ulnar nerve. Place a pin over the elbow and image to visualize the best position for the pins. When the elbow is very swollen, determine a starting point with lateral imaging. Insert the lateral pin at about 45° to the axis of the humerus. Be certain to penetrate the proximal fragment. Confirm position by AP and lateral imaging. Make a decision regarding additional pins. If elbow is very swollen, consider placing two more lateral pins in diverging configuration to enhance stability. Usually a medial pin is placed with care to avoid the ulnar nerve. If the elbow is very swollen, consider making a small incision to visualize the ulnar nerve to prevent nerve injury from the pin. Advance the pin under image control to engage a proximal fragment. Confirm pin placement with imaging in two planes. Extend the elbow gently to assess carrying angle. If the angle seems abnormal, check the accuracy of reduction. Once satisfied that reduction is accurate and fixation secure, bend over ends of pins outside skin and cut pins. Assess vascular status of limb in different degrees of flexion. Dress and splint the arm in the degree of flexion that permits optimal circulation.
Place the splinted arm in a sling. Monitor circulation and avoid narcotics to avoid masking ischemia. Discharge home the next day. Advise the family to call if the child has undue pain. Allow gradual return to activities and sports at 12 weeks. Follow monthly to assess motion. Allow reestablishment of range of motion to occur naturally. Physical therapy is unnecessary and may be harmful.
Reduce risk of compartment syndrome by careful monitoring, achieving an accurate reduction, and avoiding excessive flexion postfixation. Reduce risk of cubitus varus by accurate reduction and secure fixation. Reduce risk of ulnar nerve injury by careful pin placement.
Flexion fractures account for about 10%. The posterior angulation is less pronounced, and a medial metaphyseal spike is often present. This spike makes reduction more difficult. The reduction may be facilitated by applying a towel clip through the olecranon and applying traction to the distal fragment. Sometimes open reduction is necessary. Once reduced, fix with percutaneous pins. An alternative in the young child is to immobilize the arm in extension.
Open reduction Indications for reduction are vascular injuries and fractures that cannot be reduced adequately for placement of percutaneous pins.
Vascular compromise Vascular injuries pose an urgent problem. If detected upon arrival, attempt to position the arm in a neutral alignment with about 30° of flexion. Plan early reduction under anesthesia. Be prepared to perform an open reduction. A simple loss of the radial pulse and good capillary filling is not an indication for arterial exploration. If, after reduction in the operating room, vascularity is not restored, then brachial artery exploration is indicated. Avoid delays. Consider alerting a vascular surgeon of the problem. Avoid arteriography. Explore the artery. Usually the artery is compressed by the fracture fragments, and once freed, circulation is restored. Rarely, arterial repair or bypass grafting is necessary.
Nerve injury Nearly all nerve injuries recover spontaneously in 2 weeks to 4 months. Exploration is not indicated before 6 months. See the patient frequently, as the family may need ongoing reassurance during the period of recovery. EMG, nerve conduction, and other studies are not necessary.
Postoperative management Immobilize for about 3 weeks. Then place the arm in a sling for an additional 1 to 2 weeks. Motion recovers spontaneously. Avoid stretching. Physical therapy is not helpful. Recovery of motion usually requires several months. Allow return to full activities in about 3 months.
Hyperextension is common. This deformity tends to improve with time. Always compare with the opposite elbow, as hyperextension is common in loose-jointed children. This deformity alone is not an indication for operative correction. The deformity is commonly associated with the cubitus varus deformity. Both components are corrected by osteotomy.
Cubitus varus This complication is common with traction and uncommon with pin fixation treatment. The normal carrying angle is about 5°–10° of valgus. A cubitus varus deformity causes a cosmetic and some functional disability. The deformity is due to malunion and can usually be avoided by careful management. The deformity becomes apparent once the elbow can be fully extended. It is seldom improved by remodeling. Operative correction by osteotomy may be necessary.