A 15 year old male presents to the ED with right wrist and hand pain two hours after falling on his out-stretched (extended) right hand. The patient was jogging along the sidewalk when he lost his balance, tripped on the curb and broke his fall by landing on his out-stretched right hand. There was no loss of consciousness and the only area of pain was his right wrist.
Except for some very superficial palmar abrasions, there were no other visible signs of external trauma over the entire right upper extremity from the clavicle to the tips of the fingers. The shoulder and elbow both demonstrated full range of motion without any pain. His fingers were all pink with intact neurovascular integrity.
Upon closer examination of the wrist, the patient complained of point tenderness in the floor of the anatomic snuff box. This point tenderness was exacerbated with wrist flexion, extension and radial deviation.
Because of point tenderness in this area, radiographs were obtained to rule out a fracture.
The lateral view of the wrist was not contributory so it is not included here. A scaphoid view was also taken because of the area of tenderness over the scaphoid.
What is the significance of point tenderness in the area of the scaphoid (navicular) bone?[DDET Answer and explanation]
Point tenderness in the “anatomic snuff box” region should always alert one to the possibility of a scaphoid (navicular) fracture. The scaphoid bone is the most commonly fractured carpal bone. These types of fractures are most commonly seen in patients between 15 and 35 years of age as a result of a forceful hyperextension type injury to the wrist.[/DDET]
How would you interpret the radiographs shown above?[DDET Answer and explanation]
This set of radiographs were initially read by the emergency physician as normal. However, a fracture was still suspected and the patient was placed in a thumb spica splint and given orthopedic referral arrangements. A radiologist then read the radiographs as showing a tiny fracture of the scaphoid. On the enlarged views of the scaphoid, there is a slight irregularity of the cortex on the lateral side. A second radiologist disagreed and insisted that these radiographs were normal. [/DDET]
What are the complications of this type of injury?[DDET Answer and explanation]
The blood supply to the scaphoid penetrates the cortex at both the distal aspect (on the dorsal aspect near the scaphoid turbercle) and the waist (middle third of the scaphoid). Because of this tenuous blood supply, there is no direct blood supply to the proximal third of the scaphoid. Therefore, scaphoid fractures (even if properly diagnosed and treated) have a tendency for dreaded complications, such as avascular necrosis of the proximal third and non-union. In general, the more proximal the fracture, the greater the likelihood of avascular necrosis.[/DDET]
How should these types of injuries be managed in the ED and when should you consult an orthopaedic surgeon?[DDET Answer and explanation]
Although adults are more likely to present with fractures involving the middle third or proximal aspect of the scaphoid, children have a higher incidence of fractures involving the distal third of the scaphoid. If one is clinically suspicious of a scaphoid fracture, always be sure to obtain isolated scaphoid views in addition to the standard AP, lateral and oblique views of the wrist. Even if there is no obvious radiographic evidence of a scaphoid fracture, all patients with point tenderness over the anatomic snuff box region should be properly immobilised in the ED and referred to an orthopaedic surgeon for further evaluation and management.
Proper immobilisation of a scaphoid fracture should prevent wrist flexion/extension, radial wrist deviation and any movement of the thumb metacarpal. Therefore a simple volar wrist splint would NOT be considered proper immobilisation for a scaphoid fracture. A more adequate immobilisation technique would be to apply a thumb spica/radial gutter splint (which could also be combined with a volar wrist splint).
Only the radial gutter and thumb immobilising portion of the splint is shown here without the overlying elastic wrap. The thumb is immobilised to prevent wrist ab/ad-duction and first metacarpal movement. A volar splint can be added to this.
Definitive treatment by an orthopaedic surgeon usually involves a thumb spica cast for 6-12 weeks.[/DDET]
Other examples of scaphoid fractures
This patient complained of distal forearm pain. The scaphoid region was not specifically examined. This pitfall must be avoided. A forearm film which included the wrist was obtained. A distal radius fracture and an ulnar styloid fracture were noted. At the very top of the film, where it ends, a fracture through the scaphoid was noted. Patients may not complain of pain exactly over the fracture site, especially when there are fractures elsewhere. However, examination for the location(s) of point tenderness will usually improve the clinician’s ability to locate the site of injury.
This radiograph shows another scaphoid fracture. However even in the absence of such a radiographically evident fracture, point tenderness over the scaphoid warrants the same treatment.
The arrow points to the floor of the anatomic snuff box. The scaphoid bone forms the floor of the anatomic snuff box. Tenderness in the area should raise the suspicion of a scaphoid fracture.
Simon RR, Koenigsknecht SJ: Emergency Orthopedics: The Extremities (second edition). Appleton & Lange, pp. 81-84, 1987.
Letts RM: Management of Pediatric Fractures. Churchill Livingston, pp. 389-396, 1994.
Etzwiler LS. Hand and Wrist Injuries. In: Barkin R (ed). Pediatric Emergency Medicine Concepts and Clinical Practice. Chicago, Mosby Year Book, 1992, p. 332.