A 20-year-old man presents to the emergency department (ED) directly from the scene of a fall from a bicycle, where he lost balance and landed on his outstretched hand. He complains of pain both in the palm of his hand and in the wrist. Sound familiar? We see 2.6 million hand and wrist injuries annually in the United States and when we miss an occult or subtle injury it can be very morbid for our patients and not uncommonly leads to litigation.^1,2 For every patient who presents to the ED with a fall on outstretched hand injury (FOOSH), we need to consider not only the common distal radius fracture clearly seen on X-ray, but also five sometimes occult injuries:

• Occult distal radius fracture
• Hook-of-hamate fracture
• Distal radial-ulnar joint injury (DRUJ)
• Scapholunate injury
• Occult scaphoid fracture

I outline some of the general principles of assessing the patient after a FOOSH injury and highlight the key clinical features.

Common Things Being Common

Let’s start with the most common of these subtle injuries. The most common wrist or hand injury occult to X-ray is not the scaphoid—it’s the distal radius.³ Tenderness over the distal radial metaphysis after wrist injury is strongly suggestive of a distal radius fracture despite normal plain radiographs and fluoroscopic images.⁴ Hence, these patients should be placed in a radial wrist splint with orthopedic follow up rather than be labeled as a “wrist sprain” and sent home without a splint or appropriate follow up. Remember that age-related prevalence, when constructing an orthopedic differential diagnosis, is critical. Children and older adults have weaker long bones than young adults and are more likely to sustain a distal radius fracture after a FOOSH than a carpal bone injury.

DRUJ Injury

Often associated with distal radius fractures, but underappreciated, are DRUJ injuries. This should be considered especially when the distal radius fracture occurs with a concomitant ulnar styloid fracture.⁵ The DRUJ injury has been coined “the forgotten joint of the wrist” as missed DRUJ injuries are common.⁶ A missed DRUJ injury may lead to chronic wrist supination deficit and pain, which can be prevented with surgery in some cases, so early diagnosis in the ED is important. There is a spectrum of DRUJ injuries from minor sprain to subluxation to dislocation. The mechanism of injury may be a sudden supination or pronation force or a FOOSH. Patients may report a clicking sensation with forearm supination or pronation. On physical exam it is imperative to screen for an associated DRUJ injury in all patients with wrist injuries, especially those with distal radius and ulnar styloid fractures. We sometimes tend to palpate the distal radius, suspect a distal radius fracture, and stop there. The three most useful physical exam findings of DRUJ instability are point tenderness to palpation over the divot between the distal radius and ulnar styloid, limited range of motion with supination and pronation and the ballottement test.⁶ This test involves grasping the ulnar styloid while stabilizing the distal radius to assess for increased movement compared to the contralateral wrist, an often overlooked physical exam maneuver that should be considered in all wrist-injured patients. DRUJ injuries are often occult to X-rays, but it is imperative to scrutinize the lateral wrist X-ray for a widening of greater than 2 mm of the DRUJ or a loss of overlap of the distal radius and ulna on the lateral film suggesting a subluxation or dislocation of the DRUJ. While most patients with distal radius fractures can be managed in the ED with a below-elbow splint with the forearm in a neutral position, patients with associated DRUJ injuries should be placed in an above-elbow splint with their forearm in supination to prevent pronation of the wrist.