Distal phalanx fractures

INTRODUCTION — Finger fractures are among the most common fractures managed by primary care and emergency clinicians. An understanding of basic finger anatomy and common injury patterns provides the basis for diagnosing and treating these injuries.

This topic review will discuss fractures of the distal phalanx. Finger anatomy and other common finger injuries are reviewed elsewhere. (See "Extensor tendon injury of the distal interphalangeal joint (mallet finger)" and "Evaluation and management of fingertip injuries" and "Subungual hematoma" and "Middle phalanx fractures" and "Finger and thumb anatomy".)

EPIDEMIOLOGY AND INJURY LOCATION — Distal phalanx fractures represent common sports and work-related injuries, accounting for approximately half of all hand fractures [1-3]. These fractures are commonly caused by trauma or crush injuries. The middle finger is most often affected, followed by the thumb. The distal metaphysis, which anchors the complex nail matrix and nail plate, is often affected by distal fractures.

In children, the annual incidence of phalangeal fractures is 2.7 percent [4]. Toddlers and preschool-aged children are more likely to sustain an injury at home, such as a crush injury or laceration [5]. Older children are more likely to be injured in sport [5]. Tuft fractures are the most common type of distal phalanx fracture in children [6]. Two-thirds of phalangeal fractures occur in males. Seymour fractures, displaced juxta-epiphyseal fractures of the distal phalanx with associated nailbed injury, occur in children and have been reported to have relatively high complication rates [6]. (See 'Pediatric Seymour fracture' below.)

ANATOMY — Anatomy of special importance to distal phalanx fractures is described below. A more detailed discussion of finger anatomy is found elsewhere. (See "Finger and thumb anatomy".)

The range of motion of the distal phalanx is limited in flexion by the flexor digitorum profundus, while extension is limited by the extensor terminal slip. The terminal slip of the extensor tendon inserts on the dorsal surface of the distal phalanx, while the flexor digitorum profundus (FDP) inserts at the volar base of the distal phalanx [7,8]. The FDP tendon causes the distal phalanx to flex after avulsion of the extensor tendon (creating a classic "mallet" deformity). Multiple fibrous septa attach the tuft of the distal phalanx to the volar skin. This contributes to bony stability and minimizes displacement with distal phalanx fractures (figure 1 and figure 2). The nail matrix is the tissue under the nail that permits nail growth and migration. Its longitudinal fibers anchor the dermis to the periosteum of the distal phalanx (figure 3 and picture 1 and figure 4).

A physis is located at the proximal end of the distal phalanx. The unmineralized physis is biomechanically weaker than the surrounding ligaments and bone, making the area more susceptible to fracture, and such fractures are indeed more common in children [6]. The terminal slip of the extensor tendon attaches at the dorsal epiphysis of the distal phalanx, while the flexor digitorum profundus and flexor pollicis longus insert on the metadiaphyseal region of the distal phalanx. The relative weakness at the epiphyseal-metaphyseal junction and the forces exerted via the different tendon insertion sites can lead to a so-called Seymour fracture in children, involving nailbed injury, physeal widening, and a distal phalanx fracture with apex dorsal angulation [9].

MECHANISM OF INJURY — Fractures of the distal phalanx are often caused by a direct blow or a crush injury, which can produce significant soft tissue damage [10]. A number of other potential mechanisms exist, including lacerations, hyperextension, hyperflexion, rotation, and, less commonly, axial load. An axial load can create a fracture through the base of the distal phalanx with associated displacement and instability [2]. Shearing forces can lead to fractures around the physeal plate in children [6].

CLINICAL PRESENTATION AND PHYSICAL EXAMINATION — Patients with a distal phalanx fracture usually complain of pain and swelling at the end of the finger [7].

During the initial physical examination, the clinician should focus on identifying any complicating factors that require urgent treatment, including: open injury, neurovascular deficits, malalignment, rotation (picture 2), or dislocation, and tendon dysfunction.

The neurovascular status of fingers is evaluated using two-point discrimination and capillary refill time. Although values for both of these tests increase with age and certain disease states (eg, diabetes), normal two-point discrimination is approximately 4 to 5 mm, while normal capillary refill is generally less than two seconds [11]. (See "Finger and thumb anatomy".)

Examination of the distal phalanx should include assessment of the volar subcutaneous tissue. The fibrous septae that connect the bone to the skin create a network of miniature compartments that may swell with blood or fluid, creating severe pain [2].

The nail bed adheres closely to the dorsum of the phalanx and may show signs of injury, such as a nail avulsion or a subungual hematoma (picture 3). Drainage of the hematoma may relieve pain in some instances. Management of subungual hematoma is discussed separately. (See "Subungual hematoma".)

Whenever possible, the clinician should assess the function of the flexor and extensor tendons of the distal phalanx, as a tendon injury may accompany distal phalanx fractures, particularly if the mechanism involved hyperflexion or hyperextension (picture 4A-B). The alignment and rotation of the finger should be carefully evaluated and compared to the opposite hand. A digital block can be performed if significant pain limits the evaluation of alignment or soft tissue injury [12]. (See "Digital nerve block".)

Pediatric Seymour fracture — A Seymour fracture is a Salter Harris Type I or II injury or juxta-epiphyseal fracture (transverse fractures of the proximal metaphysis within 1 to 2 mm of the physis) with an associated nail bed injury. Children with a subungual hematoma or frank blood at the base of the nail should be evaluated closely for a Seymour fracture, as delayed management can lead to complications. With this fracture, the nailbed injury causes the proximal edge of the nail plate to lie superficial to the eponychial fold, making the lunula appear large and the nail appear longer than the contralateral uninjured digit (picture 5) [13]. The distal interphalangeal (DIP) joint develops a flexed position, similar to a mallet finger. (See 'Management of pediatric Seymour fractures' below.)

DIAGNOSTIC IMAGING — Radiographic evaluation of the distal phalanx should include three views: postero-anterior (PA), lateral, and oblique (image 1). The four most common types of distal phalanx fractures include comminuted distal tuft fractures, longitudinal fractures, transverse fractures, avulsion fractures, and intra-articular fractures of the base (figure 5 and figure 6) [14].

A fracture of the fine cancellous bone at the distal tip of the phalanx is termed a tuft fracture (image 2). Comminuted fractures of the distal phalanx are common, especially at the tuft, and are generally stable due to the adherence of the fibrous septa. Longitudinal fractures are usually nondisplaced and stable (image 3 and image 4). Transverse fractures should be evaluated for angulation as these are at greater risk of displacement (image 5) [7,14]. Widening of the fracture line may indicate entrapment of the nail bed within a transverse distal phalanx fracture. Fractures of the proximal base of the distal phalanx can be associated with tendon injury and may become displaced. These tendon injuries are discussed separately. (See "Extensor tendon injury of the distal interphalangeal joint (mallet finger)" and "Flexor tendon injury of the distal interphalangeal joint (jersey finger)".)

A Seymour fracture is a Salter Harris type I or II injury or juxta-epiphyseal fracture (transverse fractures of the proximal metaphysis within 1 to 2 mm of the physis) with an associated nailbed injury. Widening of the physis may be seen on PA radiographs. Lateral radiographs show the Salter Harris or juxta-epiphyseal fracture with widened physis and an apex dorsal angulation (image 6).

INDICATIONS FOR SURGICAL REFERRAL — Immediate consultation with a hand surgeon should be obtained for open fractures with extensive soft tissue or bony injury (eg, severe crush injury or comminution) and fractures associated with vascular compromise.

There is little published evidence upon which to base recommendations for surgical referral of distal phalanx fractures. We believe the following injuries should be referred to a hand surgeon within approximately three or four days of the injury:

●Fractures associated with tendon dysfunction

●Fractures associated with nerve dysfunction (eg, loss of two point discrimination)

●Displaced or angulated transverse fractures

●Intra-articular fractures

●Severe nail bed or nail plate injuries

●Rotational deformity (picture 2)

●Seymour fracture (see 'Diagnostic imaging' above)

Transverse distal phalanx fractures that are displaced or angulated can be difficult to reduce due to soft tissue involvement. As an example, a transverse fracture between the terminal insertions of the extensor and flexor tendons is an unstable fracture pattern due to the opposing deforming forces and usually has an apex dorsal angulation due to the greater pull of the flexor tendon (figure 7). If a fracture reduction cannot be maintained with conservative measures, then referral for surgical fixation is necessary. Transverse angulated fractures are generally treated by inserting a K-wire longitudinally through the fracture and the distal interphalangeal (DIP) joint (picture 6 and figure 8) [2].

MANAGEMENT

Initial treatment — All fractures are treated with ice and elevation during the first 24 to 48 hours to reduce soft tissue swelling.

Nondisplaced distal phalanx fractures should be splinted with the distal interphalangeal (DIP) joint in extension for a minimum of two to four weeks. The splint should extend past the tip of the distal phalanx to protect it from injury (picture 7). A U-shaped ("clamshell") splint can be used to isolate the DIP joint while allowing for full range of motion of the proximal interphalangeal (PIP) joint [2]. The author prefers AlumaFoam or custom thermoplastic splints. When molding the splint, take care not to make it too tight so soft tissue swelling can be accommodated [15]. Initial splinting may include short-term immobilization of the PIP joint if motion there causes significant pain. Immobilization past four weeks may lead to excessive joint stiffness and some degree of function loss [10].

The clinician should not attempt to reduce comminuted fractures of the distal portion of the distal phalanx. The fibrous septae of the distal phalanx or tuft usually support the fragments when splinted [2]. Compression around the tip can facilitate fragment approximation and decrease pain and swelling [16].

Nail injuries are commonly associated with distal phalanx fractures. Significant nail bed lacerations should be cleaned and repaired. The management of nail bed injuries and hematomas is discussed in detail separately. (See "Subungual hematoma" and "Evaluation and management of fingertip injuries", section on 'Isolated open nail bed injury'.)

If initial evaluation or treatment of a child is limited by pain or compliance, it best to refer the patient to a hand surgeon for management.

Prophylactic antibiotics — The use of prophylactic antibiotics in adults is controversial. We suggest that systemic antibiotics be used only for open wounds that are either grossly contaminated or occur in high-risk patients (eg, diabetic); prophylactic antibiotics in patients not at increased risk is not supported by the available evidence [17,18]. In such cases, treatment with a first generation cephalosporin for seven days is reasonable. One double-blinded randomized clinical trial involving 193 adults with open distal phalanx fractures found no difference in infection rates between patients treated with prophylactic antibiotics and those who received placebo [18]. Topical antibiotics may be placed on any wound prior to dressing.

Children with a Seymour fracture should be treated with prophylactic antibiotics, which decrease complication rates. Although evidence is limited, it is reasonable to give prophylactic antibiotics to children with a distal phalanx fracture associated with a laceration or nailbed injury [6]. (See 'Management of pediatric Seymour fractures' below and "Subungual hematoma", section on 'Evaluation'.)

Follow-up — Most distal phalanx fractures heal well with conservative treatment, which includes approximately three to four weeks of splinting [7,14,19,20]. Transverse shaft fractures may require slightly longer immobilization. The duration of therapy is determined by radiologic healing in displaced transverse fractures and by pain-free range of motion and clinical healing in all other fractures.

Patients with stable fractures should be encouraged to begin moving the joints of the affected digit within one to three weeks to avoid stiffness [16,21]. As the finger pulp and nail bed are densely innervated, covering the area with a finger cap or compression sleeve may help to decrease swelling and pain [16].

Repeat radiographs to confirm that the reduction is maintained are recommended for all displaced transverse fractures treated with closed reduction [7]. These are obtained at one week and then again at two to three weeks. Otherwise, follow-up radiographs are unnecessary in patients whose symptoms show steady improvement.

Some distal phalanx fractures fail to demonstrate complete radiographic healing after four weeks despite the absence of symptoms [7,10]. This occurs most commonly in tuft fractures. Fibrous unions of tuft fractures can take months before ossification is apparent on radiographs. Provided there is improvement in symptoms, this is not a concern. A cap splint may provide better protection.

We suggest clinical evaluation of all distal phalanx fractures at one week and then every one to two weeks thereafter to evaluate for complications until symptoms have resolved. A referral to hand therapy is suggested for patients with significant swelling, loss of motion, or those in need of more specialized splinting.

Patients should be advised that some form of nail deformity is possible despite appropriate immobilization and treatment but the full extent of such injuries cannot be determined for four to five months.

Children with stable distal phalanx fractures should be treated in a splint for two to three weeks, similar to adults. If the physis is involved, follow-up radiographs are generally obtained at two to three weeks to ensure proper healing [6].

Management of pediatric Seymour fractures — A Seymour fracture is a Salter Harris Type I or II injury or juxta-epiphyseal fracture (transverse fractures of the proximal metaphysis within 1 to 2 mm of the physis) with an associated nail bed injury (image 6). (See 'Pediatric Seymour fracture' above and 'Diagnostic imaging' above.)

All Seymour fractures should be evaluated on the day of presentation (ideally the day the injury was sustained) by an orthopedic or plastic surgeon. These injuries require irrigation, debridement, antibiotics for prophylaxis or therapy, and exploration to remove the proximal nail plate from any site of incarceration. Once this is performed, the fracture may be reducible, although some may require wire fixation.

Treatment has varied among studies, but many patients receive parental or oral beta-lactam antibiotics. A seven-day course of a beta-lactam antibiotic (eg, first-generation cephalosporin) is a reasonable approach.

Delayed presentation or treatment of a Seymour fracture may result in soft tissue infection, osteomyelitis, growth arrest, nail bed deformity, and persistent mallet deformity of the distal phalanx [9,22-28]. The importance of early treatment was highlighted by a systematic review of 10 nonrandomized studies involving 355 fractures [28]. This review found substantial reductions in the risk of infection and malunion when debridement was performed within 48 hours (risk ratios [RRs] 0.28; 95% CI 0.12-0.64 and 0.25; 95% CI 0.07-0.99, respectively). When administered within 24 hours, prophylactic antibiotics significantly reduced the risk of infection (RR 0.21; 95% CI 0.10-0.43). Data was insufficient to determine the most effective duration for antibiotic prophylaxis.

RETURN TO WORK OR SPORT — Patients with transverse fractures should not return to play or strenuous work until there is radiographic healing and the finger is painless, due to the possibility of displacement of the fracture fragments. Patients with longitudinal or tuft fractures can return to play or work, while wearing proper splinting, as soon as symptoms are tolerable. Splints must comply with local regulations, which may vary by sport.

COMPLICATIONS — The large majority of distal phalanx fractures heal without complications [21]. Nonunion is rare and generally occurs with tuft fractures. Other complications that may occur include joint stiffness, numbness and hypersensitivity, and nail deformities. These may create difficulties with fine motor tasks such as buttoning clothes or picking up small objects. Comminuted fractures more often result in poor outcomes.

As one would expect, fractures that occur as a result of more severe trauma are more likely to involve complications and require additional time for healing. As an example, a study of 98 patients with distal phalanx fractures sustained through crush injuries, penetrating injuries, or lacerations found that fewer than 30 percent of patients had fully recovered at six months [29]. Full recovery was defined as normal two point discrimination, ability to flex the distal interphalangeal (DIP) joint more than 45 degrees, and a normal nail bed. The most common disabilities described were difficulty picking up small objects or managing buttons, pain in the digit during cold weather, and the inability to write normally using a pen or pencil. Most complications (63 percent) occurred in patients with tuft or shaft fractures [29].

Complications of pediatric distal phalanx fractures are generally similar to adults. Special attention should be paid to children with Seymour fractures or other fractures involving the physis. Seymour fractures, particularly those that present late for medical care, may be complicated by infection, premature physeal closure, or deformity. (See 'Management of pediatric Seymour fractures' above.)

ADDITIONAL INFORMATION — Several UpToDate topics provide additional information about fractures, including the physiology of fracture healing, how to describe radiographs of fractures to consultants, acute and definitive fracture care (including how to make a cast), and the complications associated with fractures. These topics can be accessed using the links below:

●(See "General principles of fracture management: Bone healing and fracture description".)

●(See "General principles of fracture management: Fracture patterns and description in children".)

●(See "General principles of acute fracture management".)

●(See "General principles of definitive fracture management".)

●(See "General principles of fracture management: Early and late complications".)

SOCIETY GUIDELINE LINKS — Links to society and government-sponsored guidelines from selected countries and regions around the world are provided separately. (See "Society guideline links: Fractures of the skull, face, and upper extremity in adults" and "Society guideline links: Acute pain management".)

INFORMATION FOR PATIENTS — UpToDate offers two types of patient education materials, "The Basics" and "Beyond the Basics." The Basics patient education pieces are written in plain language, at the 5^th to 6^th grade reading level, and they answer the four or five key questions a patient might have about a given condition. These articles are best for patients who want a general overview and who prefer short, easy-to-read materials. Beyond the Basics patient education pieces are longer, more sophisticated, and more detailed. These articles are written at the 10^th to 12^th grade reading level and are best for patients who want in-depth information and are comfortable with some medical jargon.

Here are the patient education articles that are relevant to this topic. We encourage you to print or e-mail these topics to your patients. (You can also locate patient education articles on a variety of subjects by searching on "patient info" and the keyword(s) of interest.)

●Basics topic (see "Patient education: Finger fracture (The Basics)")

SUMMARY AND RECOMMENDATIONS

●Epidemiology and mechanism of injury – Distal phalanx fractures are common, accounting for over half of all hand fractures. They are often caused by a direct blow or a crush injury, which can produce significant soft tissue damage and nail bed injuries. (See 'Anatomy' above and 'Epidemiology and injury location' above and 'Mechanism of injury' above and "Evaluation and management of fingertip injuries".)

●Clinical presentation and physical examination – Patients usually complain of tenderness and swelling at the end of the finger. The initial examination should focus on identifying any complicating factors that require urgent treatment, including: open injury, neurovascular deficits, malalignment or dislocation, and tendon dysfunction. A neurovascular examination including two-point discrimination and capillary refill should be performed. (See 'Clinical presentation and physical examination' above.)

●Diagnostic imaging – Radiographic evaluation of the distal phalanx should include anterior-posterior (AP), lateral, and oblique views. Transverse distal phalanx fractures (image 5) that present with angulation are generally unstable. Most longitudinal, comminuted, and tuft fractures are stable. (See 'Diagnostic imaging' above.)

●Nail bed injuries – Nail bed injuries are common in distal phalanx fractures. Their management is reviewed separately. (See "Subungual hematoma" and "Evaluation and management of fingertip injuries".)

●Indications for surgical referral – Immediate consultation with a hand surgeon should be obtained for open fractures with extensive soft tissue or bony injury (eg, severe crush injury) and fractures associated with vascular compromise. The indications for nonemergency referral to a hand surgeon are described in the text. (See 'Indications for surgical referral' above.)

A Seymour fracture is a Salter Harris type I or II injury or juxta-epiphyseal fracture (image 6) with an associated nailbed injury. These injuries should be evaluated on the day they are diagnosed by a hand surgeon; they require urgent debridement and antibiotics. (See 'Pediatric Seymour fracture' above and 'Diagnostic imaging' above and 'Management of pediatric Seymour fractures' above.)

●Management of nondisplaced fracture – Nondisplaced distal phalanx fractures are treated for three to four weeks in a distal interphalangeal (DIP) splint until clinical healing is evident. We suggest that prophylactic antibiotics NOT be given (Grade 2C), unless a grossly contaminated open wound is present or the patient is at high risk from infection (eg, immunocompromised). (See 'Initial treatment' above and 'Prophylactic antibiotics' above.)