9.27 Extensor Tendon Avulsion - Distal Phalanx (Baseball or Mallet Finger)

agk’s Library of Common Simple Emergencies

Presentation

There is a history of a sudden resisted flexion of the distal interphalangeal (DIP) joint, such as when the finger tip is jammed or struck by a ball, resulting in pain and tender ecchymotic discoloration over the dorsum of the base of the distal phalanx. When the finger is held in extension the injured DIP joint remains in slight flexion.

What to do:

• Instruct the patient to keep the splint in place continuously and seek orthopedic followup care within one week.
• Prescrlbe an analgesic as needed.

What not to do:

• Do not assume there is no significant injury just because the x ray is negative. With or without a fracture the tendon avulsion requires splinting.
• Do not forcefully hyperextend the joint. This can result in ischemia and skin breakdown over the joint.

Discussion

Adequate splinting usually restores full range and strength to DIP joint extension, but the patient will require 6 weeks of immobilization, and should be informed that healing might be inadequate, requiring surgical repair. A wide variety of splints are commercially available for splinting this injury (e.g. Stack, “frog”) but, in a pinch, a tape-covered paper clip will do. A dorsal splint allows more use of the finger, but requires more padding and may contribute to ischemia of the skin overlying the DIP joint.

Illustration

-----------------------------------------------------
from Buttaravoli & Stair: COMMON SIMPLE EMERGENCIES © 
Longwood Information LLC 4822 Quebec St NW Washington DC 20016-3229 
1.202.237.0971 fax 1.202.244.8393 electra@clark.net
-----------------------------------------------------