(A) Buddy taping
(B) Extension block splinting
(C) Stack splinting
(D) Closed reduction and longitudinal pin fixation
(E) Open reduction and internal fixation

The correct response is Option D.

This patient has a type IV mallet injury in which greater than 30% of the articular surface of the distal phalanx has been avulsed. The most appropriate management of this patient's fracture is closed reduction and longitudinal pin fixation. Because most of the collateral ligament remains attached to the avulsed fragment, the distal phalanx is subluxed on the middle phalanx. In order to correct this deformity, closed reduction and longitudinal Kirschner wire immobilization or open reduction with a pull-out wire technique should be performed. This will restore articular congruity and reduce the subluxed joint, preventing the development of osteoarthritis. Most type IV mallet injuries can be reduced with a closed technique alone; open reduction should be considered only if closed reduction cannot be achieved.

Buddy taping is more appropriate for dislocations of the metacarpophalangeal and proximal interphalangeal joints but will not immobilize the distal interphalangeal joint in extension. Extension block splinting, which again does not immobilize the distal interphalangeal joint, is a useful rehabilitation technique in patients with dorsal dislocations of the proximal interphalangeal joint.
Stack splinting is more appropriate for correction of a type I mallet injury in which the tendon is avulsed from the proximal dorsal base of the distal phalanx. The stack splint immobilizes the distal interphalangeal joint in extension, allowing healing of the avulsed tendon to the distal phalanx. Stack splinting should also be used following suture repair in a patient with a type II mallet injury, which manifests as an open laceration of the terminal extensor tendon.

References
1. Doyle JR. Extensor tendons - acute injuries. In: Green DP, Hotchkiss RN, Pederson WC, eds. Operative Hand Surgery. 4th ed. New York, NY: Churchill Livingstone, Inc; 1999;2:1963.
2. Rockwell WB, Butler PN, Byrne BA. Extensor tendon: anatomy, injury, and reconstruction. Plast Reconstr Surg. 2000;106:1592.
3. Stark HH, Gainor BJ, Ashworth CR, et al. Operative treatment of intra-articular fractures of the dorsal aspect of the distal phalanx of digits. J Bone Joint Surg. 1987;69A:892-896.

The radiograph shown above is from a 12-year-old boy who sustained a thumb fracture. According to the Salter-Harris fracture classification, which of the following is the most appropriate classification of this fracture?

(A) Type I
(B) Type II
(C) Type III
(D) Type IV
(E) Type V

The correct response is Option B.

Findings on this child's radiograph are consistent with a Salter-Harris type II fracture in which the fracture has proceeded through the diaphysis of the proximal phalanx of the thumb and the epiphyseal plate.

PHOTO

The Salter-Harris classification describes fractures involving the epiphyseal plate in children. The degree of growth disturbance correlates directly with the level of fracture classification. In type I fractures, the epiphysis is separated from the metaphysis; the diaphysis and articular surface are unaffected. Type II fractures involve a small fracture of the metaphysis and separation of the epiphysis from the metaphysis. In type III fractures, the epiphysis is fractured and the articular surface is involved. Patients with type IV fractures have involvement of the diaphysis, epiphyseal plate, and articular surface. In type V fractures, the epiphyseal plate is compressed; the metaphysis is unaffected.

In children with Salter-Harris type I or type II fractures, appropriate management is closed reduction, followed by casting or pin fixation. Management of type III, type IV, and type V fractures is similar but should also include restoration of the articular surface.

References
1. Fernandez DL, Palmer AK. Fractures of the distal radius. In: Green DP, Hotchkiss RN, Pederson WC, eds. Operative Hand Surgery. 4th ed. New York, NY: Churchill Livingstone, Inc; 1999;1:979.
2. Leclerca C, Korn W. Articular fractures of the fingers in children. Hand Clin. 2000;16:525-527.
3. Le TB, Hentz VR. Hand and wrist injuries in young athletes. Hand Clin. 2000;16:598-602.