Finger fractures and dislocations are commonly seen in the primary care setting, and finger fractures are the most common type of fracture in sports.¹ Patients often present with a deformity, swelling, and bruising with loss of function. Radiography can identify fractures and distinguish uncomplicated injuries that can be managed by a primary care physician. Appropriate management strategies help the patient return to normal function while minimizing complications.

Fractures

To evaluate suspected finger fractures, anteroposterior, lateral, and oblique radiography should be performed.² Primary care physicians can manage most nondisplaced, well-approximated fractures with simple immobilization. Diagnosis and management recommendations for finger fractures are outlined in Table 1. The recommendations for fractures in this article apply to adolescent and adult patients without evidence of open growth plates on plain radiography and do not apply to children.

DISTAL PHALANX

Distal phalanx fractures are typically the result of a crush or axial load injury (i.e., direct force to the end of the finger). Physical examination usually shows swelling, bruising, or a subungual hematoma. Radiography demonstrates the location and degree of the bony injury. 

It is important to assess the patient's ability to fully flex and extend the distal interphalangeal (DIP) joint. Distal sensation should also be evaluated. The inability to flex or extend the joint, loss of distal sensation, and complex fractures warrant evaluation by an orthopedic specialist. 

In the absence of these concerns, splinting the DIP joint in full extension for four to six weeks is usually sufficient.³ Large (greater than 50% of the nail surface) or painful subungual hematomas benefit from drainage through the nail using a sterile bore or a heat or cautery instrument.⁴

DORSAL AVULSION FRACTURE OR EXTENSOR TENDON RUPTURE (MALLET FINGER)

Mallet finger occurs when the DIP joint is forced to flex against resistance (Figure 1⁵). This can cause avulsion of the extensor tendon from its attachment at the dorsal base of the distal phalanx, with or without avulsion of a bone fragment at the end of the tendon.⁶ Absence of a bony avulsion indicates a pure tendon rupture.

Patients with mallet finger have swelling, bruising, pain, and the inability to actively extend the DIP joint, which is typically slightly flexed due to the unopposed flexor tendon. Radiography is needed to evaluate intra-articular involvement because injuries involving greater than one-third of the joint surface require referral for possible surgical repair. Injuries in which the joint cannot be passively extended require referral to an orthopedic specialist.⁷ 

In the absence of indications for referral, mallet finger (with or without an avulsion fracture) can be effectively treated with strict immobilization.⁸ The DIP joint should be splinted in full extension to slight hyperextension for eight weeks.^9,10 A dorsally padded aluminum splint, a volar splint, or a thermoplastic stack splint can be used.¹¹ It is important to adhere to the immobilization period because premature flexion of the DIP joint can disrupt the healing process and require an additional eight weeks of hyperextension from the time of premature flexion.

FLEXOR DIGITORUM PROFUNDUS AVULSION FRACTURE

A flexor digitorum profundus avulsion fracture (jersey finger) is typically caused by forceful extension of the DIP joint when in a flexed position (Figure 2⁵). This forceful extension leads to an avulsion fracture at the site where the flexor digitorum profundus tendon attaches to the volar base of the distal phalanx.⁵ Although flexor digitorum profundus avulsion fractures can occur in any finger, they most commonly affect the ring finger.

The examination usually reveals swelling, volar-sided pain, and a slightly extended finger when at rest, and patients are usually unable to actively flex the DIP joint.¹² These findings alone (regardless of radiography results) require expedited referral to an orthopedic specialist because flexor digitorum profundus avulsion fractures can benefit from surgery within seven to 10 days.