The terminal tendon or part of the extensor tendon that attaches at the very end of the finger is very thin and subject injury. When the end of the finger is loaded or flexed against resistance the extensor tendon may tear off of the left bone or distal phalanx. It may also pull off of the distal phalanx, taking a part of the bone with it. this produces an injury noted the mallet finger or mallet fracture, respectively. this has also been called a “baseball finger”, which should be called a “basketball finger” because of the high incidence in basketball players. patient's described pushing with her finger against resistance and having it suddenly flex, producing and injury were described to him on the fingertip with an object such as a basketball, suddenly flexing the finger. the result is the mallet deformity where the left joint ,or DIP joint, is flexed or droopy. See figure 1
Examination reveals that the finger is drooped or faxed at the DIP joint with inability to extend the finger against any resistance. Ability to flex the finger is usually still intact. X-rays may reveal the presence of a mallet fracture, with a small piece of bone retracted towards the hand along with the extensor tendon.
Conservative treatment is usually the first choice for mallet finger/mallet fracture injuries. The finger is placed in a plastic stack splint, which holds the DIP joint straight. In the case of mallet fractures, an x-ray was taken after straightening the finger in a splint to make sure that the fracture fragments are back in place. It is important to maintain day PIP joint in the straight position for 6 to 8 weeks in order for the tendon or fracture to heal. If the splint is removed at all during that time the DIP joint must be maintained in straight position. With proper conservative treatment, success rates are approximately 80%. Some patients will have a minor droop at the PIP joint but will be functional.
If the splint fails to properly position the joint, such as cases where a large fracture fragment has been pulled off and leaves the joint unstable, splinting may not adequately treat the injury. For these cases and cases where the conservative treatment has not worked and there is a residual significant droop of the DIP joint, surgical repair is necessary. This surgery is usually performed as an outpatient under general anesthesia or regional block anesthesia. A small incision is made over the top of dorsum of the finger near the attachment of the extensor tendon. The fracture is repaired if the fragments are large enough or the fragment attached to the extensor tendon is removed and the extensor tendon is repaired to the bone with a small anchor. A pin may be placed across the DIP joint to hold it in extension while the tendon heals. The skin is closed and a protective dressing and splint are applied. the pin is usually removed in the office at 6 weeks when the tendon or fracture is healed. Therapy is then initiated. Risks with the surgery are anesthesia related risks, wound healing problems or infection, stiffness of the joint or poor healing of the tendon/fracture. In a very small group of patient's where the surgically prepared tender or fracture does not heal, the DIP joint may require surgical fusion in a functionally correct position.