- Traumatic flexion deformity of the distal joint of any digit.
- This injury may be opened or closed.
- Typical history is a blow to the end of an outstretched finger or a laceration dorsally over the distal joint of the digit.
Initial Diagnosis and Management
- Examination: There is typically a loss of full active extension with retained full passive extension.
- AP and Lateral radiographs of the digit should be obtained and may reveal a bony avulsion fragment of variable size. The reason for radiographic assessment, however, is to assure that the distal interphalangeal joint (DIPJ) is not subluxated or dislocated.
- Initial management is full extension (or slight hyperextension) of the DIPJ continuously for 6 to 8 weeks. This treatment is done for both bony and soft tissue mallet deformities and may be accomplished by a Stack splint (prefabricated splint) or by a dorsal or volar splint (made of foam-backed aluminum) that extends the DIPJ without limiting the proximal interphalangeal joint (PIPJ).
- To prevent skin problems, any type of splint must be removed several times a day (at least 3 to 4 times per day) to check the skin to ensure it is not macerated or developing breakdown on the dorsal surface. This condition is more commonly a problem with plastic stack splints. Maintain the DIPJ in full extension while removing splint.
Ongoing Management and Objectives
After the DIPJ has been maintained in continuous extension for 6 to 8 weeks, the splint may be removed and active, and later, active assisted flexion exercises may be initiated. For the first 2 weeks following discontinuance of the continuous splint, an extension splint for the DIPJ should be worn during sleep. A mild extension lag and/or a mild to moderate dorsal bump are acceptable outcomes.
Indications for Specialty Care Referral
- An open mallet finger requiring wound care.
- A cosmetically or functionally unacceptable result after adequate splinting.
- Chronic mallet finger deformity (greater than 3 months from injury without any initial treatment) that is either painful, deformed, or functionally limiting. An initial presentation with some degree of DIPJ joint subluxation.
- Occupational requirements that necessitate the hands getting wet or that will not allow wearing of a splint.
Criteria for Return to Primary Care
Successful surgical treatment of either an acute or chronic mallet finger with completion of necessary post-operative follow-up.