Chapter 30: Injuries of the Upper Extremities

• Small children with a clavicle fracture may present with refusal to move the arm after a fall.

• Children are more likely to suffer a Salter–Harris type II fracture separation of the proximal humerus than a true shoulder dislocation.

• Indirect radiographic evidence of elbow fracture includes the presence of a posterior fat pad, an exaggerated anterior fat pad, and an abnormal radiocapitellar or anterior humeral line.

• Supracondylar fractures of the humerus can be associated with acute and delayed neurovascular compromise and require immediate orthopedic consultation.

• Fracture of the radius or ulna requires x-ray evaluation of the elbow and wrist to determine if a Monteggia or Galeazzi fracture is present.

• The normal cascade of the resting hand shows increasing flexion from the index to little fingers and from the distal interphalangeal (DIP) joints to the metacarpophalangeal (MCP) joints. Deviation from this normal cascade implies a tendon laceration.

• A Salter–Harris type I or II fracture of the distal phalanx may not be seen on x-ray. Look for a mallet deformity and inability to extend the DIP joint.

• As in adults, scaphoid fractures are the most commonly encountered carpal fracture.

Children are prone to injuries of the upper extremity due to their natural curiosity, being active in sports, and risk-taking behaviors. Boys incur more injuries than girls with the highest incidence of injuries occurring between 10 and 18 years of age. This chapter will review the diagnosis and management of injuries to the upper extremities and hands.

The clavicle is the most commonly fractured bone during delivery and is the fourth most commonly fractured bone in older children. The vast majority of injuries involve the area between the middle and distal third of the clavicle (>90%).¹ The majority of fractures are due to a direct fall onto the lateral aspect of the shoulder. Direct blows only account for about 10% of midshaft fractures and an indirect mechanism, such as falling on an outstretched hand, accounts for less than 5% of these injuries.² Young children can sustain incomplete injuries (green-stick or bowing fractures).

Fractures of the medial clavicle are rare in children. The medial clavicular epiphysis is the last growth plate to close, allowing physeal injuries to occur up to age 25. In contrast to adults, in whom sternoclavicular (SC) joint dislocations occur more frequently, children are most likely to experience a posteriorly displaced Salter–Harris type I or II fracture of the medial clavicular physis, with or without epiphyseal separation. It is important to distinguish a medial physeal injury from a posterior dislocation of the SC joint. Posterior dislocations of the SC joint, though very rare, are often associated with other complications such as brachial plexus injuries, pneumothorax, and neurovascular compromise from compression of mediastinal structures. Accurate determination of medial clavicular fractures is often difficult by plain film alone. If this injury is suspected a CT scan should be obtained to determine the exact injury. Treatment is open reduction and stabilization of the SC and costoclavicular ligaments.^3,4

The most common mechanism for a midshaft clavicle fracture is a fall on the shoulder. If the fall is unwitnessed, the only history may be refusal to move the arm. The patient typically presents with decreased or painful movement of the arm. The child may have point tenderness over the middle of the clavicle, localized swelling, crepitus, and tenting of the overlying skin. Radiographs will confirm the suspected injury (Fig. 30-1). Obtain two views, with one view directed 30 degrees cephalad. Search for associated vascular injury in the presence of a displaced clavicle fracture as laceration or compression of the subclavian vessels can occur with posterior displacement of the fracture fragments, prompting emergent orthopedic and vascular consultation. Shoulder compression during delivery often results in fracture of the clavicle. The clavicle is the most common fracture during delivery. The injury may be asymptomatic or present as pseudoparalysis (the infant will not move the arm, but hand and forearm movement is normal).⁵ Exuberant callus formation may call attention to the fracture a few weeks later. Remodeling occurs and results in a normal appearance of the bone in 6 to 12 months.

Most clavicle fractures heal well without complication, and reduction is rarely necessary in children less than 12 to 13 years of age. A displaced clavicular fracture in a skeletally immature patient has a low risk of malunion and excellent healing and remodeling potential. Although controversial, there is increasing evidence that operative fixation in skeletally mature adolescents with displaced clavicular fractures results in a lower nonunion rate and earlier return to normal function. Therefore, referral to an orthopedic surgeon for management of displaced clavicular fractures in this older age group is recommended.² Operative intervention is indicated in the presence of an open fracture, compromised skin, or vascular complication.

Young children are placed in either a sling or a shoulder strap; older patients can be managed with a sling and swathe. Some children may find the sling more comfortable than the shoulder strap or clavicle brace. Adequate pain control is important as these fractures can be very painful.⁶ Parents should be told to expect a bump from callus formation to appear after about a month as the bone heals.

Direct trauma to the lateral clavicle produces metaphyseal fractures in young children rather than true acromioclavicular joint separations as seen in adolescents and adults. Acromioclavicular separation is very rare before age 16. Children will usually present with tenderness and swelling over the acromioclavicular joint. Radiographs will show an increased distance between the coracoid process and the clavicle. Weighted x-ray views are not recommended. Treatment is conservative, with the use of a sling and swathe or clavicle brace, and surgery is rarely indicated.

Fractures of the scapula are very rare in children and infrequent in adolescents. They are often associated with high-energy injuries and the patient should be evaluated for more serious injuries.⁷ A lateral scapular (trans-scapular) view, combined with an anteroposterior shoulder view, provides a two-plane assessment of the scapula. A lateral axillary view isolates the coracoid process and helps to delineate associated shoulder dislocations. Tangential oblique views may aid in the evaluation of small or subtle scapular body fractures.

The treatment of a scapular fracture is similar to a clavicle fracture.

The same forces that result in shoulder dislocation in adults usually cause displaced Salter–Harris type II fracture separation of the proximal humerus in young children. Less than 2% of shoulder dislocations occur in patients younger than 10 years and 20% occur in patients aged 10 to 20 years. As with adults, anterior dislocations are much more common than posterior or inferior dislocations.^3,8

Inspection of the anteriorly dislocated shoulder reveals loss of the normally rounded contour, creating a squared-off appearance. The arm is held in slight abduction and external rotation, and the humeral head may be palpated anterior to the glenoid fossa. Radiographs should include an anteroposterior (AP) view of the shoulder and either a true lateral scapular or a transaxillary view. Provide adequate analgesia and relaxation before attempting reduction with traction and countertraction, scapular manipulation, or external rotation techniques. Obtain postreduction radiographs to identify any occult fractures. After the reduction, immobilize the arm for 3 to 6 weeks then begin rehabilitation therapy. Posterior shoulder dislocations are most often seen following seizures, electrical injuries, or after collisions in football lineman. The arm is held in adduction and internal rotation. The anterior shoulder appears abnormally flat, and the displaced humeral head may be palpable posteriorly. Orthopedic consultation is recommended in all cases of posterior shoulder dislocation.

Both the axillary nerve and artery may be injured. Therefore, sensation over the deltoid muscle should be assessed before and after reduction. Also assess distal pulse strength and examine the patient for the presence of a protruding axillary hematoma. Other complications include greater tuberosity fractures, damage to the glenoid labrum, Hill–Sachs deformity (a commonly associated compression fracture of the posterolateral humeral head), rotator cuff injury, and recurrent dislocation. Younger patients with instability have a much higher rate of recurrence than older adults, with the risk of recurrence up to 95% in patients that suffer their first dislocation under the age of 20. Patients in this age group should be referred to an orthopedic surgeon for possible arthroscopic assessment at an early stage.^2,7

Proximal Humerus Fracture

The proximal humerus epiphyseal ossification center appears at 6 months of age. The greater tuberosity ossification center appears at 3 years and the lesser tuberosity center at 5 years. The physis closes at age 14 to 17 years in girls, and 16 to 18 years in boys. Nearly 80% of the longitudinal growth of the humerus takes place at the proximal humeral epiphysis. Accordingly, the potential for remodeling is great.⁹ The normal proximal humerus growth plate is often mistaken for a fracture. A comparison view of the uninjured shoulder may be helpful.

Salter–Harris type I and type II fractures of the proximal humerus are frequently encountered. Type I fractures and proximal metaphyseal injuries, including greenstick and torus fractures, typically occur in youngsters aged 5 to 11 years. Children of age 11 to 15 years suffer the majority of proximal humerus fractures, usually type II injuries. Most proximal humerus fractures are nondisplaced due to the presence of a strong periosteal sleeve. Salter–Harris fracture types III, IV, and V are rare in this region.³

Patients with proximal humerus fractures will have point tenderness at the fracture site and swelling or an obvious deformity. Radiographic evaluation should include at least two views of the humerus at right angles to each other. Films should include the distal clavicle and acromion to look for an associated injury.

Most fractures of the proximal humerus heal well with only a sling and swathe. The decision for closed reduction or operative treatment depends on the age of the patient, the degree of angulation, and the amount of displacement. The younger the child, the more likely the fracture will heal without intervention.

Humerus Shaft Fractures

Most humeral shaft fractures are the result of a direct blow to the area. The degree of displacement depends on the location of the fracture and the surrounding muscle attachments, which may pull the fragments out of alignment. A torsional force from a fall or severe twist may result in a spiral diaphyseal fracture. Nonaccidental trauma should be excluded in children younger than 3 years with a spiral humerus fracture.

Midshaft fractures heal well even with angulation of up to 15 to 20 degrees and as much as 2 cm of overriding, due to bony remodeling and longitudinal overgrowth that occurs in response to the fracture. A sling and swathe should be applied to young children. A sugar-tong splint can be used for adolescents.

Fractures involving the junction of the middle and distal thirds of the humerus may be associated with injury to the radial nerve. Assess motor and sensory functions initially and following any manipulation. Acute radial nerve palsy has an excellent long-term prognosis, with reports of 80% to 100% recovery of function without surgery.¹⁰

With injury to the elbow, radiographic interpretation is complicated by the presence of numerous epiphyses and ossification centers that appear and fuse at different but characteristic ages (Table 30-1). Matters are further complicated by the need for precise anatomic reduction of fracture fragments in order to avoid both early and late complications.

An adequate radiographic evaluation of the elbow consists of an AP view with the joint in extension and a true lateral view with the elbow flexed at a right angle. Frequently, adequate pain control is needed to flex the elbow fully for a true lateral radiograph and should be provided prior to x-rays. The anterior fat pad is located within the coronoid fossa and normally appears as a small lucency just anterior to the fossa on a true lateral x-ray of the elbow (Fig. 30-2). Joint space fluid collection may also cause the anterior fat pad to be pushed away from the joint and appear as a wind-blown sail—the “sail sign.” The posterior fat pad sits deep down in the olecranon fossa and is not visible under normal circumstances. The presence of a posterior fat pad on a true lateral view of the elbow is always abnormal and suggests blood within the joint capsule. These abnormal fat pad signs are radiographic evidence of occult fracture of the distal humerus, proximal ulna, or radius (Fig. 30-3) and can only be detected with the elbow fully flexed at 90 degrees.

There are two reference lines that are useful in assessing elbow radiographs and help to identify occult injury. The anterior humeral line, drawn along the anterior cortex of the distal humerus on a true lateral view of the elbow, should normally intersect the middle third of the capitellum distally. Posterior displacement of the capitellum may be consistent with an otherwise radiographically inapparent supracondylar fracture. The radiocapitellar line is drawn down the axis of the proximal radius on the true lateral view of the elbow and should bisect the capitellum regardless of the degree of flexion or extension present. Failure to do so suggests the presence of an occult radial neck fracture or radial head dislocation. Any question about the anatomic relationships can be further investigated using comparison views of the uninjured elbow.

Supracondylar fractures account for 50% to 60% of all elbow fractures in children 3 to 10 years of age. A fall onto an outstretched hand causing violent hyperextension of the elbow is the usual mechanism of injury with supracondylar fractures of the distal humeral metaphysis. The olecranon process is forcibly thrust into the olecranon fossa, resulting in fracture with posterior displacement of the distal fragment. On examination, there will be pain, swelling, deformity, and functional impairment. A careful neurovascular examination is crucial to identify an associated injury (Table 30-2). Obtain an AP and lateral radiograph (Fig. 30-4). Oblique views may be useful to demonstrate occult fractures.¹¹

Gartland distinguished three types of supracondylar fractures (Table 30-3).¹² Recently, Leitch proposed the addition of a type IV fracture to the Gartland classification. Type IV fractures are unstable in both flexion and extension because of complete loss of a periosteal hinge.¹³ Use of the anterior humeral line may be useful in determining whether the fracture is a type I or II (Fig. 30-4). Supracondylar humerus fractures are associated with a high incidence of early neurovascular complications (Fig. 30-5). Although puncture or actual laceration of the brachial artery is rare, the vessel may be compressed or contused or may undergo vasospasm at the fracture site. Signs of significant distal ischemia such as pallor and cyanosis of the fingers, prolonged capillary refill, or absence of the radial pulse indicate the need for prompt reduction of the fracture. If the vascular status is not improved, then surgical exploration is indicated. Patients are at risk of developing a forearm compartment syndrome, especially those with an ipsilateral corresponding diaphyseal forearm fracture. Unrecognized, this will lead to Volkmann's ischemic contracture and a nonfunctional hand and wrist. Forearm pain with passive flexion or extension of the fingers or distal parasthesias is an ominous early sign of compartment syndrome. Nerve impairment is reported to occur in as many as 11.3% of children with supracondylar fractures, yet the prognosis for return of function is good. Anterior interosseous nerve injury is the most common nerve injured in extension-type supracondylar fractures, followed by median, radial, and ulnar nerve injuries.^13,14 A late complication of supracondylar humerus fractures is cubitus varus, a change in the carrying angle of the elbow.

The potential for significant complications with supracondylar humerus fractures mandates accurate diagnosis and urgent orthopedic consultation. Rotational and angular deformities must be meticulously reduced in order to preserve normal elbow function and prevent vascular compromise. Type I and some type II supracondylar fractures can be managed with casting but most type II and all type III and IV fractures require reduction and internal fixation in the operating room.¹³ Many children are admitted for 12 to 24 hours of observation postoperatively so that the neurovascular status of the extremity can be reassessed frequently. Open reduction and internal fixation may be necessary, especially if the injury is more than 12 hours old.¹⁵

Fractures involving the articular surface of the lateral condyle (capitellum) comprise 15% of all pediatric elbow fractures; however, they are missed more often than any elbow fracture in children. The peak in incidence is at 6 years of age. The mechanism of injury is frequently unknown but often involves a fall on the outstretched arm with forearm supination or elbow flexion. Salter–Harris type IV fractures are common. The fracture fragment may become displaced and rotated, and the diagnosis is radiographically obvious if the ossified capitellum is notably displaced from the trochlea or radiocapitellar line. Clinically, swelling and tenderness are most pronounced at the lateral elbow. These fractures require aggressive intervention to prevent later complications such as nonunion, loss of elbow mobility, and growth arrest of the lateral condylar physis leading to cubitus valgus and tardy ulnar palsy. Management is usually operative in all but nondisplaced fractures (<2 mm).¹⁶

Fractures of the articular surface of the medial condyle, or trochlea, occur only rarely, but when present require precise anatomic reduction due to the intra-articular nature of the injury (Fig. 30-6). The most frequent complications associated with medial condylar fractures are nonunion and ulnar nerve neuropraxia.

The epicondyles are located just proximal to the articulating surface of the distal humerus. The medial epicondyle is a traction apophysis to which the forearm flexors are attached. Fractures of the medial epicondyle are rarely encountered in children younger than 4 years, occurring most commonly in children aged 7 to 15 years. These may occur as an avulsion injury due to a fall on the arm with forced hyperextension of the wrist and fingers. The vast majority of medial epicondylar fractures, however, are associated with elbow dislocations, occurring approximately 60% of the time (Fig. 30-6). The medial epicondyle may dislocate and then block reduction or become entrapped intra-articularly. The medial epicondyle must be identified as extra-articular after any elbow reduction. A more insidious injury to the medial epicondyle may occur with repetitive traction stress by the forearm flexors (Little Leaguer's elbow). Treatment is usually nonoperative; however, operative management may be considered with severe displacement, valgus instability, or ulnar nerve dysfunction.¹⁷

Although uncommon, this injury is important because of its association with nonaccidental trauma, such as with violent arm twisting. When present in children younger than 3 years, physical abuse should be suspected. The fracture can also occur following birth trauma. This injury is rare past age 3, after which supracondylar fractures predominate. Differentiation from elbow dislocation can be very difficult due to the lack of capitellar ossification. Orthopedic consultation is warranted, and closed reduction usually provides adequate healing.

Pediatric elbow dislocations occur infrequently, as most forces that would result in dislocations in adults usually cause fractures in children (Fig. 30-7). When elbow dislocations do occur, they are usually the result of a fall onto the slightly flexed, outstretched arm in an adolescent. Most dislocations are posterior.

Associated fractures are the rule and most commonly involve fracture of the medial epicondyle, coronoid process, radial head, or olecranon. Significant damage to the surrounding soft tissues also occurs, with damage to the nerves more commonly than brachial artery injury. Recovery of function of the ulnar nerve can be expected, but the prognosis is less optimistic with median nerve injury. Vascular compromise complicates up to 7% of pediatric elbow dislocations.¹⁸

Most dislocations can be reduced after providing adequate analgesia and muscle relaxation. The elbow should be flexed to 60 to 70 degrees and the forearm placed in supination. The proximal humerus is then stabilized by an assistant while longitudinal traction is applied at the wrist. Upon successful reduction, the elbow should be gently flexed and immobilized and the neurovascular status of the arm reappraised. Obtain a postreduction radiograph with attention to verifying the location of the medial epicondyle as extra-articular.

“Nursemaid elbow” or “pulled elbow” is a common pediatric injury. It occurs when abrupt axial traction is applied to the wrist or hand of the extended, pronated forearm of a child younger than 5 years, causing the annular ligament to slip free of the radial head and become entrapped between the radial head and capitellum. Left-sided injuries occur more commonly because of traction by predominantly right-handed adults walking at the child's side.¹⁹

A history of the patient being lifted by the arm may be obtained, but the precipitating event is often neither witnessed nor recognized. On presentation, the child appears comfortable yet refuses to reach for objects with the affected arm. On examination, the forearm is held in pronation with the elbow in slight flexion or fully extended. There is a remarkable lack of swelling and only mild tenderness over the radial head. The child resists all attempts at passive range of motion. Pain is worse with supination or pronation. Radiographic evaluation is not necessary in the presence of a clear history of arm traction. Figure 30-8 shows a useful algorithm for determining whether radiographs should be obtained prior to reduction. If there is swelling present or a history of a fall, obtain radiographs. A nursemaid's elbow will not have appreciable swelling on examination.

There are two methods of reduction: supination and pronation. In the supination method, face the patient, place your thumb over the radial head, and place your opposite hand around the wrist. The forearm is supinated and flexed at the elbow. In the pronation method, the arm is extended at the elbow, a finger is placed over the radial head, and the forearm is pronated. A palpable or audible “pop” usually signals successful reduction. If the pronation method does not work, one should try supination. The pronation method may be less painful and there is some evidence to support that it may be more effective.^20,21 Most of the time, the patient reaches for objects with the affected arm within 5 to 10 minutes of reduction. Offering a Popsicle may hasten recovery after successful reduction. No further treatment is necessary. The parents should be instructed not to lift their children by the wrists and informed about recurrence as it may be as high as 30%.

Several attempts at reduction may be necessary before the patient resumes normal use of the arm. Occasionally, radial traction prior to supination and flexion is necessary. If the subluxation occurred several hours earlier, it may be longer before normal function of the arm is observed. If normal use does not follow reduction attempts, obtain radiographs and consider alternative diagnoses. Immobilization with prompt orthopedic follow-up is then indicated.

The radius and ulna are the most frequently fractured bones during childhood. Three-quarters of all injuries involve the distal third of the forearm. Although an isolated fracture of one of the bones can occur, a high index of suspicion must be maintained for concomitant injury to the paired bone. The force precipitating a readily apparent injury may be transmitted to the paired bone and result in bowing, a greenstick fracture, or dislocation at a location distant from the obvious fracture site. For this reason, forearm x-rays should always include the wrist and elbow. Most fractures of the radius and ulna heal without significant complications.

A fall onto an extended, supinated arm with a valgus stress can result in fracture of the radial head or neck. Most proximal radius fractures in young children involve the narrow metaphyseal neck since the head is cartilaginous until ossification begins at age 5 years. Salter–Harris type I and type II radial neck fractures are most common. Salter–Harris type IV radial head fractures may be encountered in older children. Proximal radius fractures can occur in conjunction with elbow dislocations and are often associated with concomitant injury to the medial epicondyle, olecranon, and coronoid process.

An abnormal fat pad sign or abnormal radiocapitellar line on x-ray points to the presence of an occult radial head or radial neck fracture. Minimally displaced or nondisplaced fractures can be treated in a posterior splint with the elbow flexed at 90 degrees. Complications include restriction of pronation and supination, as well as myositis ossificans.

Olecranon fractures are most likely to occur in combination with other elbow injuries, such as radial head dislocations, radial neck fractures, and fractures of the medial epicondyle. Isolated olecranon epiphyseal fractures are rare and are usually associated with puberty and osteogenesis imperfecta. They are often due to a direct blow to the posterior elbow. Injuries with <2 mm of intrafragmentary displacement may be treated in a posterior splint.²² Healing usually takes place without complications, although nonunion and ulnar nerve neuropraxia do occur infrequently.

Most forearm diaphyseal fractures are either greenstick or bowing injuries. Both bones may suffer greenstick or bowing injuries, or one bone may have a greenstick fracture while the paired bone is bowed (Fig. 30-9). The potential for remodeling of a bowing injury, or plastic deformation, is minimal in children older than 4 years. Bowing may restrict pronation and supination as well as result in permanent deformity of the extremity.

Overriding of fracture fragments in the presence of an isolated fracture of one of the forearm bones suggests either a Monteggia or Galeazzi fracture. An isolated fracture of the proximal ulna may be associated with concomitant dislocation of the radial head (Monteggia fracture). This combined injury may be inadvertently overlooked initially because attention is focused on the obvious ulnar fracture. An aberrant radiocapitellar line on plain x-ray is evidence of the accompanying radial head dislocation (Fig. 30-10). Closed reduction is usually successful. A fracture at the junction of the middle and distal thirds of the radius in association with distal radioulnar joint dislocation is called a Galeazzi fracture and is rare in children (Fig. 30-11).²³

Fractures of the distal third of the radius and ulna are among the most common orthopedic injuries in children 6 to 12 years of age, often occurring after a fall onto an outstretched hand. There is a peak incidence in boys aged 12 to 14 years and girls aged 10 to 12 years. Torus fractures of the distal radius and ulna can be treated in a removable splint (Fig. 30-12).²⁴ These fractures can be very subtle. Tenderness over the physis of the distal radius with a normal radiograph suggests nondisplaced Salter–Harris type I injury, and splinting with orthopedic follow-up is appropriate. Greenstick and complete fractures of the distal radius require closed reduction in the ED if they are unacceptably angulated. The definition of acceptable angulation is dependent largely on the age of the child, location of the fracture, and individual practice patterns.²⁵

The capacity for angular remodeling after forearm fracture is great, but rotational remodeling does not occur and rotational abnormalities must be accurately corrected. The strong periosteal sleeve of the bones makes nonunion rare. Complications are uncommon, but vascular compromise or compartment syndrome can develop with any forearm fracture.²³

Hand and Wrist Injuries

Fractures of the hand occur less frequently in children than in adults. In younger children, the most common mechanism is to get the hand caught in a closing door resulting in a crush injury to the distal phalanxes. Approximately 25% of such injuries result in fractures. Amputations and tendon injuries are found occasionally. In the older age groups, injuries tend to occur as a result of athletic competition. Hand and wrist injuries occur in 3% to 9% of all sports injuries. Sprains are the most common, followed by contusions and fractures. Pediatric hand fractures represent 5% to 7% of all pediatric fractures. These injuries are sometimes difficult to diagnose and may be associated with long-term morbidity. This makes appropriate initial evaluation and treatment imperative. Fortunately, healing is rapid, tendon and joint complications are rare, and their ability to remodel is remarkable.

Observation

The physical examination of the hand begins with observation. Look for lacerations, puncture wounds, soft-tissue swelling, deformity, and color. The resting hand should demonstrate increasing flexion from the index through little finger and increasing flexion of the joints, from the distal interphalangeal (DIP) through metacarpophalangeal (MCP) joints. Disruption of this normal cascade implies a laceration to an extensor or flexor tendon. A complete flexor tendon laceration results in straightening of the finger due to the unopposed extensors. A complete extensor tendon laceration results in flexion of the finger due to the unopposed flexors.

Malrotation as a result of a phalangeal or metacarpal fracture will occur occasionally. Alignment may appear normal in extension but be grossly abnormal with the fingers flexed. Malrotation may lead to significant cosmetic and functional impairment, so the diagnosis should be made on initial presentation to avoid permanent disability. A useful method to test for malrotation is to have the patient alternately flex the fingers to the palm. Each finger converges to the same place on the palm, the tubercle of the scaphoid. Patients with significant malrotation will violate this pattern with the affected finger. Another method is to compare the planes of the fingernails with the fingers in flexion. The nail plates should be approximately parallel and symmetric to the opposite hand. Any abnormal tilting is evidence of a rotational deformity.

Palpation

Gently palpate the injured hand. The examination should be performed with the patient's hand resting comfortably on a flat surface. One may use a fingertip or an object such as the eraser end of a pencil or the end of a cotton-tipped applicator to find the exact area of maximal tenderness. Maximal tenderness over the radial or ulnar aspect of an interphalangeal joint indicates a collateral ligament tear. Tenderness over the volar aspect of an interphalangeal joint indicates volar plate injury. Tenderness over the ulnar aspect of the thumb MCP joint indicates a gamekeeper's thumb (torn ulnar collateral ligament of the thumb). Pain elicited with palpation over the anatomic snuff-box is presumptive evidence for a scaphoid fracture.

Circulation

Circulation is best assessed by observing color, testing for capillary refill, and determining skin temperature. A cyanotic, edematous hand indicates venous insufficiency. A pale cool hand or a finger with poor capillary filling indicates arterial insufficiency. Doppler ultrasound or an Allen test may determine adequacy or circulation. Brisk arterial bleeding can be managed by pressure. Blindly clamping arterial bleeders may cause further harm by damaging nerves, arteries, tendons, and muscle. Arterial bleeding from a volar laceration implies laceration of the digital nerve since these nerves are located superficial to the artery.

Sensation

Sensation in the cooperative patient is best tested by two-point discrimination. Each digital nerve is tested. This may be performed with a bent paper clip gently touching the tip of the finger along the longitudinal axis. Normal two-point discrimination is 3 to 5 mm. In children too young or too afraid to cooperate, two other methods of sensory testing have been reported: loss of skin wrinkling and loss of sweating. After the hand is soaked in warm water for 30 minutes, the skin wrinkling is lost after digital nerve injury. Skin sweating is responsible for the “tackiness” of the fingertips and relies on intact sympathetic innervation. Following digital nerve injury, the ability to sweat is lost, and the skin takes on a smooth, silky texture. This may be tested by moving a smooth object, such as the barrel of a pen, over the fingertip. In the injured finger, the barrel will move smoothly; in the normal finger, there will be resistance. As always, a high index of suspicion is required for successful diagnosis.

Motor

The ulnar nerve is tested by having the patient abduct the index finger against resistance while palpating the first dorsal interosseous muscle. The median nerve is tested by having the patient palmar abduct the thumb against resistance while the examiner palpates the belly of the abductor pollicis brevis muscle, located on the radial aspect of the thenar eminence. The radial nerve is tested by having the patient extend the fingers and wrist against resistance. The anterior interosseous nerve (a branch of the median nerve) is evaluated by flexion of the distal phalanx of the index finger.

Tendon

Examination of the hand for tendon injury is particularly difficult in small children. The child's pain, anxiety, and unwillingness to cooperate, as well as partial tendon lacerations, can thwart the unwary examiner. The flexor digitorum profundus is tested by immobilizing the PIP and MCP joints and allowing the patient to flex the DIP joint against resistance. The flexor pollicis longus is tested by immobilizing the MCP joint of the thumb and allowing the patient to flex the interphalangeal (IP) joint. The flexor digitorum superficialis is tested by immobilizing the MCP joint and allowing the patient to flex the PIP joint against resistance. This test does not work for the index finger since the flexor digitorum profundus cannot be immobilized. To test the index finger, have the patient hyperextend the DIP joint with force against the thumb (thumb index pinch). If the patient is able to do this, the superficialis is intact. Patients with a superficialis laceration will not be able to hyperextend the DIP joint but will accomplish pinch by flexion of the DIP joint. The flexor carpi radialis is tested by flexion and radial deviation of the wrist against resistance. The flexor carpi ulnaris is tested by flexion and ulnar deviation of the wrist against resistance.

Since evaluating young patients is difficult, depending on age and willingness to cooperate, other tests may be required to determine tendon function. With the elbow resting on the table, allow the wrist to naturally fall into flexion. It is noted that the fingers fall into extension. When the wrist is relaxed in extension, the fingers fall into the normal cascade of flexion. This normal flexion and extension of the fingers relies on an intact tendon system. Another method to assess the flexor tendons is palpation of the forearm to create passive motion of the fingers. This is performed by pressing or squeezing the forearm at the junction of the middle and distal thirds on the ulnar–volar surface. This will cause flexion of the fingers, especially the three ulnar fingers. A similar test can be performed for the flexor pollicis longus by pressing on the distal forearm on the midvolar aspect. An intact flexor pollicis longus will result in flexion of the interphalangeal joint of the thumb. The flexor tendons and associated functions are listed in Table 30-4. The extensor tendons are tested as described in Table 30-5. Note that the extensor tendons are divided into six different compartments.

Radiographs

Obtain oblique views of the fingers along with the standard AP and lateral views of the hand. The epiphyses of the phalanxes and first metacarpal are located proximally. The epiphyses of the rest of the metacarpals are distal. Accessory bones should not be confused as fractures. In the lateral view, each finger should have more flexion than the next to avoid overlapping of finger images. A scaphoid or navicular view elongates the profile of the scaphoid and may improve fracture identification.

Distal Phalanx

Pediatric distal phalanx fractures are either a crush or hyperextension injuries. Crush injuries are quite common. In these injuries, the soft-tissue damage is more significant than the orthopedic injury. Wound care must be meticulous, the nail bed approximated with absorbable suture, and the finger splinted. Some authors recommend replacing the nail plate in the nail fold; however, there is no evidence yet to suggest that this improves outcome. There is often an associated tuft fracture associated with nail bed injuries (Fig. 30-13). Some authors recommend prophylactic antibiotics when a tuft fracture is accompanied by a nail bed laceration but there is no evidence to suggest that there is a difference in outcome (see Chapter 32).

A hyperflexion force applied to the tip of the finger may result in one of two types of pediatric injuries (Fig. 30-14). In the preadolescent, a Salter–Harris type I or II fracture occurs with a mallet deformity which is the result of an avulsion of the extensor tendon from the base of the distal phalanx. If a child has a mallet finger and inability to extend the distal phalanx, this injury should be assumed even if a fracture cannot be identified on radiographs. In the adolescent hyperflexion injury, a displaced Salter–Harris type III fracture occurs. These injuries are treated by wound care, closed reduction, and splinting in slight hyperextension. If adequate reduction is not obtained, then open reduction and Kirschner-wire fixation is performed.²⁶

Middle and Proximal Phalanx

Middle and proximal phalangeal fractures commonly occur at the physis. These fractures are usually Salter–Harris type II fractures. They are reduced by flexion of the MCP joint and adduction of the finger. The wrist is placed in an ulnar gutter splint, and the patient is referred to an orthopedist. Salter–Harris type III fractures are ligament or tendon avulsion injuries. Displaced fractures usually require Kirschner-wire fixation. Fractures of the phalangeal shaft are not common in children. These fractures are usually minimally displaced. Splinting and referral is all that is necessary. Displaced fractures of the shaft or neck require splinting and urgent referral.

Metacarpal fractures may occur in the epiphysis, physis, neck, shaft, or base. The neck is the most common area to be fractured. A displaced intra-articular metacarpal fracture of the base of the thumb, equivalent to the adult Bennett's fracture, is rare in children. These fractures are unstable Salter–Harris type III fractures and are treated by open reduction and Kirschner-wire fixation. Most other metacarpal fractures are undisplaced or minimally displaced and are treated initially by splint immobilization. Displaced fractures can generally be treated with closed reduction and splinting, but occasionally Kirschner-wire fixation is required.

The most common hand fracture is of the fifth metacarpal.²⁷ Typically, it results from striking someone or a solid object with a closed fist (Boxer's fracture). Closed reduction is indicated if there is more than 30 to 40 degrees of angulation. These fractures can be treated with an ulnar gutter splint with orthopedic referral.²⁶

Fractures of the carpal bones in children are exceedingly rare. The carpus is surrounded by cartilage that acts as a “shock absorber.” Diagnosis of a carpal fracture can be difficult because of their rarity and obscurity with initial radiographs. Nafie found that 37% of carpal fractures were not seen on initial radiographs.²⁸ Scaphoid fractures are the most commonly encountered fracture of the carpal bones. The ossification center of the scaphoid appears by age 5 to 6 years. The peak age for scaphoid fractures is early adolescence. The usual mechanism of injury is a fall on an outstretched hand. Physical examination may reveal limitation of range of motion from pain and swelling and tenderness in the “anatomic snuffbox.” Initial x-rays often appear normal. Application of a short-arm thumb spica splint with orthopedic referral is appropriate. Nonunion and avascular necrosis is rare in children because most injuries are avulsions or nondisplaced fractures through the distal third of the bone rather than fractures through the waist, as in adults. Other carpal bone fractures are very rare in children and are treated as in adults with splinting and orthopedic referral.²⁹

Distal Interphalangeal Joint

DIP dislocations result from a hyperextension force. This dislocation generally displaces dorsally and is often open, due to the tight adherence of skin to bone in this area. Reduction is usually uncomplicated and consists of traction countertraction followed by flexion. Test active motion to ensure that the extensor and flexor tendons are functioning and that the volar plate is not interposed in the joint.

Proximal Interphalangeal Joint

PIP dislocations can occur in dorsal, volar, radial, or ulnar directions. Dorsal dislocations are the most common. These dislocations occur as a result of an axial load with concomitant hyperextension. Reduction is accomplished through slight hyperextension and longitudinal traction applied to the middle phalanx while correcting the ulnar or radial deformity. The finger is then gently flexed into position. Active range of motion is tested, and stress testing of the collateral ligaments and volar plate is performed. The finger is placed in a splint to immobilize the PIP (20–30 degrees of flexion) and MCP joints (60–70 degrees of flexion). Orthopedic referral is recommended. Volar dislocations are rare and may be irreducible due to entrapment of the proximal phalangeal condyle between the central tendon and lateral band. These dislocations may result in avulsion of the central slip of the extensor tendon leading to a late boutonnière deformity. Orthopedic referral is required.²⁶

Metacarpophalangeal Joint

MCP joint dislocations sometimes occur in the pediatric age group. As in the adult, the thumb MCP dislocation is the most common (Fig. 30-15). It occurs as a result of a hyperextension force, usually from a fall on an outstretched hand. Dislocations are classified as simple reducible or complex irreducible. In the simple reducible dislocation, the proximal phalanx assumes a dorsal point at a 90-degree angle to the metacarpal. This dislocation can be reduced by gentle traction countertraction. Joint stability is assessed, the finger splinted, and the patient referred. The complex irreducible dislocation has the same mechanism of injury, but here, the proximal phalanx assumes a bayonet position parallel to the metacarpal. The volar plate is interposed in the joint, and the metacarpal head may also be trapped in the substance of the intrinsic muscles. Closed reduction is impossible. This dislocation can only be reduced by open reduction. Some authors recommend one attempt at gently performed closed reduction. Vigorous traction is to be avoided since this may convert a simple reducible dislocation to a complex irreducible one.

Carpometacarpal Joint

Carpometacarpal dislocations are rare in the pediatric age group. These injuries are generally a result of violent trauma that results in multiple dislocations or multiple fracture dislocations. These injuries require prompt orthopedic consultation for surgical intervention.