Introduction
Background
The term mallet finger has long been used to describe the deformity produced by disruption of the terminal extensor mechanism at the distal interphalangeal (DIP) joint.1,2,3 Mallet finger is the most common closed tendon injury that is seen in athletes; this injury is also common in nonathletes after "innocent" trauma. Mallet finger has also been referred to as drop, hammer, or baseball finger (although baseball accounts for only a small percentage of such injuries).
Athletes and coaches often believe mallet injuries to be minor, and many cases go untreated. All individuals with finger injuries, including suspected mallet finger, should have a systematic evaluation performed. Good results can usually be obtained with early treatment of such injuries, whereas delay or lack of treatment may produce permanent disability.
For excellent patient education resources, visit eMedicine's Hand, Wrist, Elbow, and Shoulder Center and Sports Injury Center. Also, see eMedicine's patient education articles Mallet Finger and Broken Finger.
Related eMedicine topics:
Hand, Finger Nail and Tip Injuries
Hand, Fracture and Dislocations: Phalangeal
Jammed Finger
Mallet Finger
Swan-Neck Deformity
Related Medscape topics:
Resource Center Adolescent Medicine
Resource Center Exercise and Sports Medicine
Specialty Site Orthopaedics
Functional Anatomy
The tendinous mallet injury represents a disruption of the terminal extensor tendon at its insertion on the distal phalanx. Mallet injury is most commonly caused by forced flexion against an actively extended digit (eg, when a ball strikes the end of a finger); a direct blow over the dorsum of the DIP joint may also produce a mallet finger. The resultant deformity occurs by unopposed flexion of the distal phalanx.
Mallet deformity can also be associated with a fracture of the dorsal articular surface of the distal phalanx. Radiographically, these bony avulsions can be characterized into 3 common patterns, as follows:
- A tiny fleck of bone that involves less than 25% of the articular surface
- A large bony fragment that involves 30% or more of the articular surface
- An avulsion of any size that is associated with palmar subluxation of the distal phalanx
Generally, fleck fractures and nondisplaced avulsions that involve up to 40% of the joint surface are believed to be stable injuries.2 Individuals with stable injuries are candidates for conservative treatment.
Clinical
History
Typically, the athlete with a mallet fracture has a history of a direct blow to the finger, followed by pain and swelling at the DIP joint and by the inability to actively fully extend the DIP joint.
Related Medscape topics:
Resource Center Exercise and Sports Medicine
Resource Center Joint Disorders
Resource Center Trauma
Physical
The physical examination findings of mallet finger include the following (see Images 1-5):
- Localized swelling and tenderness to palpation at the affected DIP joint
- Inability to actively extend the injured DIP joint
- In some individuals, hyperextension may be noted at the proximal interphalangeal (PIP) joint because of imbalance of the extensor mechanism. This " swan-neck deformity " is more often a late finding in untreated injuries.
More on Mallet Fracture |
 Overview: Mallet Fracture |
| Differential Diagnoses & Workup: Mallet Fracture |
| Treatment & Medication: Mallet Fracture |
| Follow-up: Mallet Fracture |
| Multimedia: Mallet Fracture |
| References |
| Next Page » |
References
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Browner BD, Jupiter JB, Levine AM, Trafton PG, eds. Skeletal Trauma: Fractures, Dislocations, Ligamentous Injuries. Philadelphia, Pa: WB Saunders Co; 1992.
Wang QC, Johnson BA. Fingertip injuries. Am Fam Physician. May 15 2001;63(10):1961-6. [Medline]. [Full Text].
Jablecki J, Syrko M. Zone 1 extensor tendon lesions: current treatment methods and a review of literature [Polish, English]. Ortop Traumatol Rehabil. Jan-Feb 2007;9(1):52-62. [Medline]. [Full Text].
Simpson D, McQueen MM, Kumar P. Mallet deformity in sport. J Hand Surg [Br]. Feb 2001;26(1):32-3. [Medline].
Ulusoy MG, Karalezli N, Koçer U, et al. Pull-in suture technique for the treatment of mallet finger. Plast Reconstr Surg. Sep 2006;118(3):696-702. [Medline].
Hoffman DF, Schaffer TC. Management of common finger injuries. Am Fam Physician. May 1991;43(5):1594-607. [Medline].
Leibovic SJ. Arthrodesis of the interphalangeal joints with headless compression screws. J Hand Surg [Am]. Sep 2007;32(7):1113-9. [Medline].
Peterson JJ, Bancroft LW. Injuries of the fingers and thumb in the athlete. Clin Sports Med. Jul 2006;25(3):527-42, vii-viii. [Medline].
Rettig AC. Epidemiology of hand and wrist injuries in sports. Clin Sports Med. Jul 1998;17(3):401-6. [Medline].
Rocchi L, Genitiempo M, Fanfani F. Percutaneous fixation of mallet fractures by the "umbrella handle" technique. J Hand Surg [Br]. Aug 2006;31(4):407-12. [Medline].
Teoh LC, Lee JY. Mallet fractures: a novel approach to internal fixation using a hook plate. J Hand Surg Eur Vol. Feb 2007;32(1):24-30. [Medline].
Further Reading
Keywords
baseball finger, drop finger, hammer finger, swan-neck deformity, mallet finger, mallet deformity, phalangeal fractures
