The hand is an intricate structure that provides us with the dexterity needed for our everyday lives. Unfortunately, we see many patients in the emergency department who take this functionality for granted until they lose all or part of it. The attention spent on flexor tendon injuries is pervasive throughout the literature, whereas the more common extensor tendon injuries have not garnered as much attention.1 As emergency physicians, we have the opportunity to decrease the amount of impairment that patients sustain from these extensor tendon injuries by providing them with the appropriate treatment that they deserve.
Diagnosing an extensor tendon injury takes a thorough physical exam, with time spent by the provider to isolate each joint and test the range of motion against resistance. (See “Management of Extensor Tendon Injuries” for more on the exam.)2 The potential impairment that may occur without proper treatment is reason enough to have a low threshold to treat these patients for a tendon injury if there is any doubt in your mind. Even a small discrepancy in your exam may indicate a partial tendon laceration that can progress to a complete laceration if not treated appropriately. Kleinert and Verdan developed a classification system for extensor tendon lacerations that divides the dorsal part of the hand into eight different zones (see Figure 1).3 This classification system is used below as a reference point to provide emergency physicians guidance in treating their next extensor tendon injury.
Extensor Tendon Injuries and Lacerations
Zone I: This zone encompasses the distal interphalangeal (DIP) joint and the remaining part of the finger distal to the joint. Most commonly, these injuries are closed and require immobilization in hyperextension of the DIP for six to eight weeks and outpatient follow-up with the hand surgeon.4 Besides outpatient follow-up with a hand surgeon, patients are truly responsible for how well these injuries will heal because it’s been shown that compliance with the splint is the biggest factor affecting successful treatment.5