Hand
C. Douglas Wallace
Vidyadhar Upasani
INTRODUCTION
Hand injuries in the pediatric population frequently lead to an emergency department (ED) visit for evaluation and management. The mechanisms vary from the proverbial fall on an outstretched hand to torsional injuries of the digits in sports, crush injuries from children dropping heavy objects on their own or others’ hands, plus a myriad of other causes from the vigorous lifestyle of a normal, active child.
“Most people would succeed in small things, if they were not troubled with great ambitions”
—Henry Wadsworth Longfellow
 Figure 11-1 Angular malalignment is usually easy to detect with the digits extended. This patient has a fracture of the little finger proximal phalanx. |
Because of the intricate nature of hand function, attention to detail is required, and there is debate as to which of these injuries a “pediatric hand specialist” should manage. Children are well known for their ability to remodel fractures that have healed with some angulation. Pediatric hand fractures are no exception to this; however, certain limitations exist in the remodeling capacity of a pediatric hand injury. Similar to forearm fractures, hand fractures that occur close to a physis have substantially greater ability to remodel than do those that occur distant to the physis.
While angular malalignment directly adjacent to a phalangeal physis may be well tolerated, malalignment distally in the same phalanx may lead to permanent deformity and dysfunction. Malrotation has not been demonstrated to remodel in hand injuries.
This chapter will present only the most common children’s hand fractures. Many specialized texts are available for more complex injuries.
PHYSICAL EVALUATION
Evaluation of a child’s hand injury can be challenging because children in general fear strangers, particularly those in white coats. A child with a painful hand injury can be extraordinarily uncooperative and difficult to evaluate. Nonetheless, the responsibility falls on the treating physician to evaluate the child’s hand for important characteristics that can be gleaned from careful observation of the child’s hand with minimal contact.
One should look closely at the child’s digits for evidence of rotatory or angular malalignment (Fig. 11-1). This can occasionally be seen with observation alone. More accurate assessments can be made by combining observation with gentle manipulation of the hand to study the functional alignment of each joint within the hand. Specific observation of the rotation of the nail beds with the digits both extended and flexed aid in determining rotatory problems.
Angular malalignment is usually easiest to detect with the digits in an extended position; however, on occasion the swelling in juxtaarticular fractures can either mask or create an angular deformity.
When palpating the digits for tenderness, the examiner should consider the structures that pass beneath the skin and their potential for
underlying damage. Vascular assessments, specifically the digital Allen test, are more practical for the older, more cooperative child. Certainly, capillary refill and digital color can be readily evaluated, even in a young, screaming child.
underlying damage. Vascular assessments, specifically the digital Allen test, are more practical for the older, more cooperative child. Certainly, capillary refill and digital color can be readily evaluated, even in a young, screaming child.
Common Abbreviations Used by Hand Surgeons
IP = interphalangeal (finger)
PIP = proximal interphalangeal (finger)
DIP = distal interphalangeal (finger)
MP = metacarpal-phalangeal
CMC = carpal-metacarpal joint
TFCC = triangular fibrocartilage complex (at distal radioulnar joint)
 Figure 11-2 Standard AP, lateral, and oblique plain films are generally adequate to assess hand injuries. |
Neurologic function of an acutely injured digit is difficult to assess, particularly in the uncooperative child. Sharp/dull discrimination and two-point discrimination becomes a reasonable measurement of nerve function beginning at approximately age 5 years. In younger patients, pin prick can be used as a gross measure of sensation, though it does not engender trust of the doctor.
RADIOGRAPHS/IMAGING
Standard AP and lateral plain films (plus obliques as needed) are generally adequate to assess hand injuries (Fig. 11-2). Oblique views are very helpful to assess carpal and metacarpal fractures. In the presence of tenderness in the anatomic snuffbox, a more detailed evaluation of the scaphoid is warranted and a scaphoid oblique should be obtained. In cases of ulnar-sided wrist pain, one can consider an intra-articular contrast MRI in an attempt to elucidate injury to the TFCC and interosseous ligaments.
INITIAL MANAGEMENT
Following examination and initial imaging studies, definitive versus temporizing treatment should be determined and implemented. When immobilizing IP joints, full extension is the preferred position (unless there are reasons in regard to correcting an angular or rotatory deformity to position the digits otherwise). The metacarpophalangeal joints should be immobilized in flexion to put the collateral ligaments on stretch and speed recovery of their flexion/extension (Fig. 11-3). If the nature of the injury precludes this position, then the bony injury should be managed primarily with the attention to soft tissue tensions as a secondary consideration. When immobilizing a child with a suspected scaphoid injury, a thumb spica component should be added to the immobilization device (usually cast—occasionally splint).
 Figure 11-3 Properly positioned ulnar gutter splint. When immobilizing the hand, ideally the MP joints should be flexed and the IP joints extended to avoid contracture of the intrinsic muscle. This is not so important in children, who rarely get stiff. |
 Figure 11-4 Classic Salter-Harris III type fracture, which leads to a mallet finger if left untreated. This child was treated with the dorsal “suspension” splint method. |
 Figure 11-5 Operative intervention is warranted when joint congruity is lost. |
INDIVIDUAL INJURIES
The vast majority of pediatric hand fractures can be treated non-operatively. Injuries frequently requiring surgical intervention include mallet finger deformities with loss of articular congruity, phalangeal neck fractures with extension or malrotation, intra-articular fractures of the IP joints, and a more generic set of fractures that occur secondary to a crush injury.
PHALANGEAL FRACTURES
Distal Phalangeal Fractures
Tuft fractures are frequent, and the vast majority requires solely symptomatic treatment with protection and splinting for several weeks to allow early healing of the soft tissue and osseous damage. The patients may return to activities when comfortable. Follow-up radiographs are generally not required and can in fact be worrisome as they often demonstrate fibrous union of the tuft injury.
Mallet Finger
The pediatric mallet finger (named mallet because of its appearance if not treated) is important to recognize because of potential long-term disability from missed injuries (Fig. 11-4). The mallet finger generally occurs from a jamming-type injury, axially loading the DIP joint.
There may or may not be a fracture involved. Classically, in the pediatric population this involves the Salter-Harris III type injury in which the extensor mechanism is attached to the epiphyseal fragment that displaces dorsally. Although this is the most frequent etiology of the juvenile mallet finger deformity, these can also be due to terminal tendon disruption with a negative radiograph.
Management of the mallet finger involves extension splinting across solely the DIP joint. It is important to assure maintenance of congruity of the DIP joint on the lateral view. In cases in which the distal phalanx migrates volarly with loss of the articular congruity with the distal aspect of the middle phalanx, operative intervention is warranted (Fig. 11-5). The degree of displacement of the dorsal fragment in general is not the indication for surgical intervention. Articular congruity is the more important indication.
It is also important to stress that splinting should be in extension, but not hyperextension. Generally, a dorsally placed splint that extends from the PIP joint to a point distal to the tip of the finger held on with tape produces adequate immobilization. Minimal extension may be added to the splint. A perfect lateral radiograph centered on the DIP joint should be obtained to evaluate articular congruity. The splint
can be adjusted as necessary to provide the best closed alignment. With preserved articular congruity, 6 weeks of uninterrupted splinting should be adequate to treat this injury.
can be adjusted as necessary to provide the best closed alignment. With preserved articular congruity, 6 weeks of uninterrupted splinting should be adequate to treat this injury.
Suspension Taping Method for Mallet Finger Treatment
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The longitudinal taping “suspension taping” method of dorsal splinting to treat a mallet finger.
Modified from Lester B, et al. (see Suggested Readings). Note that Lester advised leaving the PIP joint free—in children (hand is smaller) we usually incorporate the PIP joint as well to be sure the splint doesn’t slide off.
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At the termination of immobilization at 6 weeks, the splint can be worn while the child is active for an additional 1-2 weeks, but taken off for bathing and sleeping purposes to allow gentle reintroduction of motion to the DIP joint.
Indications for surgical intervention in a mallet finger include volar subluxation of the distal phalangeal fragment. With loss of articular congruity, long-term function of the joint cannot be assured. Therefore, closed versus open reduction and pin fixation is warranted in this instance. A caveat exists in patients with hyperextensible PIP joints. They are at risk for developing swan-neck deformity of the digit due to overpull of the central slip with either a bony or soft tissue mallet injury. Evidence of early asymmetric swan-neck appearance of the
digit may warrant early surgical management even in cases with maintenance of articular congruity.
digit may warrant early surgical management even in cases with maintenance of articular congruity.
 Figure 11-6 Kirner deformity—This congenital deformity of the distal phalanx of the 5th finger can be confused with a fracture. |
 Figure 11-7 Angulated and unstable phalangeal neck fracture requiring reduction plus percutaneous K-wire fixation. |
In addition to this, a Salter-Harris I versus II fracture of the base of the distal phalanx (Seymour fracture) with significant angulation will have the appearance of a typical mallet finger deformity but can be associated with a nail bed disruption and open injury. In these instances, the fingertip droops with bleeding from the eponychial fold. Radiographs typically demonstrate an intact epiphysis; however, the metaphyseal component is angulated. Treatment includes recreating the deformity for exposure, irrigation and debridement of any foreign material from the fracture site, careful reduction of the nail back into the eponychial fold, and fracture reduction, often with K-wire fixation across the DIP joint. This procedure can be performed under a digital block in the ED; however, we often take younger patients to the operating room.
A congenital deformity that can mimic a mallet deformity and present as such is called a Kirner deformity. A Kirner deformity of the distal phalanx is formed in a hooked configuration, which gives the finger the appearance of a drooping tip (Fig. 11-6). This has been known to be overlooked until the child has an injury to the digit, the parent’s attention focuses on this, and they are brought in for evaluation of the finger injury. A lateral radiograph generally will establish the diagnosis because of the characteristic curved growth pattern of the distal phalanx.
Phalangeal Neck Fractures
The pediatric phalangeal neck fracture can be a diagnostic dilemma in a very young child. In general, these injuries tend to have the distal fragment pushed into an extended position (with apex volar angulation). In the older child, this is obvious on x-ray because the volar subcondylar fossa has been obliterated by the extension and dorsal translation of the condyles. In the young child with nonossified condyles, it can be extremely difficult to detect. The only indication may be a swollen IP joint with some malalignment of the phalangeal shafts, which is visible on plain films. Even then, it may not be apparent on plain radiographs.
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