The hand is the most frequently injured part of a child’s body.1 The majority of hand fractures in children occur in the phalanges, especially the proximal and the distal phalanges.2,3 The incidence of hand fractures in children follows a bimodal age distribution, with young children sustaining household injuries and older children sustaining predominantly sports-related injuries. The incidence of hand injuries in children appears to be increasing,4 although the causes of this increase are unknown. Although the majority of pediatric hand and finger fractures can be treated conservatively with excellent results, a subset of these fractures requires more specific treatment.5 Therefore, it behooves the pediatric orthopaedic surgeon to be aware of the pitfalls in the treatment of these common injuries.
No single pediatric phalangeal fracture classification is in widespread use today. However, not all fractures behave in a similar manner, and fractures should be individually considered on the basis of the patient’s age, fracture location, involvement of the physis, and local soft tissue anatomy. Similar fractures in patients of different ages may vary by energy of injury, fracture pattern, stability imparted by the periosteal sleeve, and the potential for remodeling. In general, younger children fare better than older children, although no discrete age cutoffs exist for certain fracture treatment options. The location of fracture is important, including which phalanx is injured, and where in the phalanx the fracture is. For instance, a Salter-Harris type 2 fracture of the distal phalanx often involves a laceration of the nail matrix, making it an open fracture prone to infection, but a Salter-Harris type 2 fracture of the proximal phalanx rarely involves meaningful soft-tissue injury. Similarly, a tuft fracture of the distal phalanx carries with it few of the risks associated with an epiphyseal fracture of the same bone. Physeal involvement should be identified, as it carries with it the risk of growth disturbance, especially if the fracture is open. Finally, knowledge of the local soft tissue anatomy is critical, especially in the setting of avulsion fractures. For example, an avulsion fracture of the volar lip of the base of the middle phalanx implies an injury to the volar plate, whereas an identical fracture on the dorsal lip of the same bone implies an injury to the central slip of the extensor mechanism. The former requires early mobilization to prevent stiffness, expecting a radiographic nonunion, whereas the latter requires immobilization to achieve radiographic union and to prevent a boutonniere deformity.
INDICATIONS AND TECHNIQUES FOR NONOPERATIVE TREATMENT
The majority of pediatric finger fractures can be treated with closed means. Buckle fractures of the phalanges are inherently stable and amenable to many forms of closed immobilization, ranging from buddy taping to splints or casts. Many displaced fractures can be treated with closed immobilization without reduction, given the remodeling potential in young children. For instance, a metacarpal neck fracture angulated at 30 degrees of flexion in a 10-year-old boy will remodel completely without reduction. Many fractures that are displaced enough to require reduction are stable after reduction because of the thick periosteal sleeve. For example, a Salter-Harris type 2 fracture of the small finger proximal phalanx in a 6-year-old will heal reliably in a cast after a successful closed reduction.
Before nonoperative treatment is recommended for any pediatric hand fracture, however, care must be taken to perform a thorough physical examination and radiographic evaluation. As the physical examination of a child’s injured hand may be difficult, passive tests and clinical signs can be particularly useful. Rotational alignment of the digits can be assessed using passive wrist extension to obtain tenodesis flexion of the fingers when the patient will not actively flex the injured finger. Compression of the flexor muscle mass in the forearm can accentuate this effect. Similarly, examining the resting cascade of the digits can give clues to the loss of flexor tendon competence. For radiographic evaluation of an injured digit, specific radiographs of that digit are essential. A leading cause of poor outcome after finger fractures in children is the failure to appreciate the displacement on initial radiographs.1 This failure most often occurs in the attempt to evaluate the sagittal alignment of a finger fracture on radiographs of the hand, with the fingers overlapping on the lateral view. Therefore, it is essential that each injured digit be evaluated with dedicated lateral views of each finger in addition to standard posteroanterior views.
A discussion of the indications and various techniques for nonoperative treatment of pediatric finger fractures is beyond the scope of this paper, and is not the focus. Instead, the paper will discuss the various fractures for which specific treatment is required to avoid an “ugly” outcome.
INDICATIONS AND TECHNIQUES FOR OPERATIVE TREATMENT
The following section will discuss several specific fractures that deserve increased scrutiny and specific treatment. This list is not meant to be all-inclusive, as many other fracture types in a child’s fingers can produce challenges and complications. However, discussion of these specific fractures will highlight several important principles in the care of a child’s injured finger.
The so-called “Seymour fracture”6 is a physeal or juxtaphyseal fracture of the distal phalanx with an associated laceration of the nail matrix and avulsion of the proximal end of the nail plate (Figs. 1A–D). In most cases, the nail is completely avulsed from the eponychial fold but is still adherent to the sterile matrix distally. The eponychium itself is not lacerated, but the nail matrix laceration beneath it exposes the fracture to the environment as the nail plate is avulsed. Conversely, the avulsion of the nail plate may not be complete, and the nail may still remain beneath the eponychial fold at presentation. However, in such cases, the cuticle seal is disrupted, as indicated by bleeding emanating from beneath the eponychial fold and atop the nail plate. This disruption of the cuticle seal exposes the fracture site to contamination and possible infection. In either case, radiographs reveal a typical physeal or juxtaphyseal fracture of the distal phalanx with the fracture flexed through the fracture site. In some cases, the radiographic abnormality only appears as a dorsal widening of the physis.
If a Seymour fracture is suspected, the nail plate must be removed to allow inspection of the nail matrix. If identification of a nail matrix laceration confirms the presence of an open fracture, thorough but gentle irrigation and debridement of the fracture site is required. Once the fracture is irrigated, the flap of torn nail matrix that typically falls into the fracture site is removed and the fracture is reduced. In many cases, the fracture is stable after reduction, especially in older children in whom the metaphyseal and epiphyseal surfaces of the physis interlock. However, in younger children, the fracture often remains unstable, and percutaneous pinning is required to prevent recurrent flexion through the fracture from the volar pull of the flexor tendon insertion onto the diaphysis and the dorsal pull of the terminal extensor tendon onto the epiphysis. Once fracture reduction and stability are obtained, the nail matrix can be repaired with absorbable sutures, although often the matrix laceration is too proximal and too complex to repair easily. In such cases, nail matrix healing is adequate without direct repair. Whether or not the matrix is sutured, the nail plate should be replaced beneath the eponychial fold and sutured to the lateral nail folds to prevent synechia formation in the germinal matrix. The use of prophylactic antibiotics, chosen according to local flora, is prudent to help prevent infection after irrigation and debridement. Fracture healing generally occurs in approximately 3 to 4 weeks, at which point the pin can be pulled and immobilization discontinued.
Seymour fractures turn ugly when they are not initially recognized and a thorough irrigation is not performed. Attempts at closed reduction (without removing the nail plate and irrigating the fracture site) are frequently met with infection, osteomyelitis, and growth arrest. Delayed presentation or treatment usually results in similar complications. The immediate infection can be treated with irrigation and debridement, and osteomyelitis is not impossible to treat given the good vascularity of the distal phalanx. However, a growth arrest cannot be reliably corrected. As the mechanism of injury in a Seymour fracture typically involves axial loading, the middle finger is often injured. A growth arrest of the distal phalanx in the middle finger has the potential to alter the normal arcade of finger lengths and result in cosmetic deformity.
Phalangeal Neck and Condyle Fractures
Periarticular fractures of the distal end of the proximal and middle phalanges present particular problems, similar to those occurring at the distal end of the humerus. The phalangeal neck fracture is an extra-articular transverse or oblique fracture equivalent to a supracondylar humerus fracture, whereas a phalangeal condyle fracture is an intra-articular fracture equivalent to a lateral condyle or T-condylar fracture of a distal humerus. Placing these phalangeal fractures into the context of the more commonly encountered distal humerus fractures underscores for the pediatric orthopaedic surgeon the potential threats these fractures pose to adjacent joint function.
Phalangeal neck fractures almost exclusively occur in children, and are usually displaced.7 The fracture typically displaces into hyperextension, as does a supracondylar humerus fracture, and the volar spike of the proximal fragment creates a block to adjacent joint flexion (Figs. 2A, B), as does the anterior spike of the distal humerus in an extension-type supracondylar fracture. Coronal angulation and rotation are also common. However, 2 important differences exist between phalangeal neck fractures and supracondylar humerus fractures. First, the remodeling potential of phalangeal neck fractures is very limited. In the phalanges, only a proximal physis is present, making remodeling (which only occurs in the sagittal plane) of distal fractures very slow.8 Second, rotational malunions of the phalanges cause overlapping of the digits during flexion and are poorly tolerated in contrast to a rotational malunion of the humerus that can be overcome with compensatory shoulder rotation.
Displaced phalangeal neck fractures are notoriously unstable and require pin fixation to maintain stability after reduction.7 Reduction can be obtained by closed means before percutaneous pinning if the reduction is performed within the first 1 to 2 weeks after injury. Beyond 3 weeks after injury, however, closed reduction is usually not possible. It is at this point, however, that open reduction begins to lead to an increased risk of avascular necrosis of the condyles.9 For this reason, techniques have been developed to achieve reduction of incipient malunions of phalangeal neck fractures with percutaneous osteoclasis.10 Once reduction is achieved, pins are inserted in a crossed or divergent configuration depending on the obliquity of the fracture (Figs. 3A, B). The pins are protected in a cast for 3 to 4 weeks and then pulled once radiographs demonstrate adequate healing.
Phalangeal condyle fractures are intra-articular fractures that may appear innocuous on initial radiographs but progress to intra-articular malunion relatively quickly. The initial displacement of a phalangeal condyle fracture may be best viewed on the lateral radiograph of the digit, on which a double ring sign of the translated condyles is seen (Figs. 4A, B). Intra-articular remodeling of a phalangeal condyle fracture is not possible, as in a malunited lateral humeral condyle fracture, and therefore anatomic reduction is required. Such a reduction may be achieved percutaneously or through open reduction, although attention must be paid to the soft tissue attachments on the fragment to preserve its vascularity during open reduction. Pin or screw fixation is required until fracture healing, which may be slower than for phalangeal neck fractures. Premature removal of pins may allow late redisplacement. Osteotomy of a malunited phalangeal condyle fracture is technically possible but carries a risk of avascular necrosis of the condyle.
Phalangeal neck and condyle fractures turn ugly when the initial displacement is underappreciated or when the displaced fracture is treated with closed reduction without pinning, leading to a malunion. Such fractures can also be complicated by avascular necrosis and nonunion, either from late open reduction or crushing injury mechanisms. Malunions create cosmetic deformities and adjacent interphalangeal joint dysfunction and are particularly difficult to treat safely.
Volar Plate Fractures
A hyperextension injury to the proximal interphalangeal joint of a finger typically causes an avulsion fracture at the insertion of the volar plate on the base of the middle phalanx. Such fractures are typically seen as a small fleck of bone avulsed from the epiphysis of the middle phalanx on the lateral or oblique radiographic view (Fig. 5). A history of dorsal dislocation may also be present. Such fractures are easily treated with early mobilization, with 1 week of splinting or buddy taping and another 2 weeks of active range-of-motion exercises. Among athletes, return to play is advised upon restoration of the normal range of motion, usually 2 to 3 weeks after injury. Longer immobilization may be required if the joint is unstable, with either coronal instability or dorsal subluxation of the joint in extension. A radiographic nonunion is the expected outcome, although full finger function is expected to return despite the persistent radiographic abnormality.
Volar plate fractures turn ugly when prolonged immobilization is used in an attempt to achieve radiographic union of the avulsed fleck of bone. Permanent stiffness may result from immobilization beyond 1 to 2 weeks, even in children. Such fractures also turn ugly when the fracture fragment involves a substantial portion of the articular surface, instead representing the more typical adult fracture pattern of shearing rather than avulsion. These fractures are rare in the skeletally immature, but may appear as a Salter-Harris type 4 fracture (Fig. 6). In such fractures, joint congruity must be established and maintained until fracture healing, which may require transarticular pinning, open reduction and internal fixation of the fracture, or both.
A 4-year-old boy sustained a crush injury to his index finger, leading to a comminuted proximal phalanx fracture (Fig. 7A). Initial closed reduction and pin fixation were limited because of severe proximal comminution and resulted in a nonunion of the phalangeal neck component (Fig. 7B). Revision fixation and bone grafting achieved bony union, but with redisplacement after fixation leading to a rotational malunion (Fig. 7C). A proximal rotational osteotomy restored bony alignment (Fig. 7D), but led to extensor tendon adhesions and an extensor lag that was only partially corrected by a subsequent tenolysis.
An 11-year-old boy sustained an injury to his middle finger in a fight. Initial radiographs revealed a Salter-Harris type 4 fracture of the base of the middle phalanx with <1 mm of displacement at the articular surface (Fig. 8A). The loss of joint congruity was not appreciated, however, and the fracture was treated in a splint, leading to late joint dislocation (Fig. 8B). A late open reduction and internal fixation of the fracture with temporary transarticular pinning restored anatomic joint alignment (Fig. 8C). Excellent range of motion was maintained at last follow-up 14 months postoperatively (Fig. 8D).
SUMMARY OF 3 MOST IMPORTANT POINTS
- A thorough physical examination and dedicated radiographic evaluation of each injured digit is required to avoid poor outcomes.
- Phalangeal neck and condyle fractures of the fingers require anatomic reduction and stable fixation to avoid problematic malunion.
- Knowledge of soft tissue anatomy is essential to avoid complications from Seymour fractures and periarticular avulsion fractures of the digits.