Mallet finger, also called baseball finger or drop finger, refers to disruption of the extensor tendon, which normally inserts at the base of the small bone at the tip of the finger. The joint immediately next to the nail assumes a flexed position and patients cannot actively straighten the tip of the finger. The delicate balance between opposing tendons is disrupted and there can be associated changes at the middle joint of the finger.
What causes mallet finger?
Mallet finger frequently occurs following sports or occupational injuries. Sudden, acute, forceful flexion at the end of the of the finger ruptures the extensor tendon. The ruptured tendon can include a small flake of bone, or a large corner of the bone which can extend into the joint. Patients complain of a “jamming” injury, such as occurs in a basketball or baseball game. The injury can be minor enough that patients may not notice any problems for several days or weeks.
Mallet fingers can occur following a sharp laceration. For example, accidentally cutting the top of the finger approximately 1 inch below the base of the nail will disrupt the extensor tendon, resulting in a mallet deformity.
There are two options to treat mallet fingers: non-operative and operative. Non-operative treatment involves wearing a small splint holding the end of the finger completely straight. These splints are worn continuously for eight weeks to allow the tendon to heal. The splints can be removed once a day in order to give the skin a chance to breathe. However, while the splint is off the tip of the finger must be maintained in full extension or hyperextension with the adjacent thumb, or by resting the tip of the finger on a table top. The splints are then reapplied with conventional tape. Allowing the tip of the finger to bend even once the splint is removed will stretch or disrupt the healing process.
The splints are comfortable enough that they can be worn while performing virtually all daily activities. Light activities such as computer use or writing are acceptable. However, vigorous activities such as gripping, squeezing or torquing are prohibited until the tendon has completely healed. The splint is worn continuously for eight weeks, followed by two to three weeks of nighttime splinting.
Splinting can be successfully performed in over 90 percent of individuals. Occasionally, after eight weeks of splinting, the finger may resume a mallet posture, and an additional two months of full-time continuous splinting is necessary. Splinting may be successful even though the injury is several months old.
Operative treatment involves surgically repairing the tendon or bone fragments. Surgery is performed as an outpatient, usually under local anesthesia. The results of surgery are usually not as successful as splinting. Patients typically lose both flexion and extension of the tip of the finger. The surgical incision can remain tender and slightly swollen for several months.
Following complete healing, either with splinting or surgical intervention, patients can usually resume their normal activities without restrictions. Patients typically lose a few degrees of full extension or straightening of the finger, which usually does not result in any functional limitations. This occurs due to stretching of the tendon fibers. If the tendon injury is associated with a small fracture of fleck of bone, it may take several months for the pain and swelling to resolve and no specific treatment is necessary. The risk of a recurrent deformity is very low, unless there is a second injury. Your physician can answer additional questions about individual circumstances.