When assessing a painful extremity, vascular compromise must be excluded first.
A patient who has fallen on an outstretched hand and has tenderness in the anatomical snuffbox of the wrist and a negative radiograph should have a thumb spica splint placed until a scaphoid fracture is definitively excluded.
Avoid nonsteroidal anti-inflammatory drugs after fractures. These medications inhibit bone healing.
In the upper extremity, compartment syndrome is most common in the forearm, especially after displaced supracondylar fractures in children.
Traumatic injuries to the upper extremity are common presenting emergency department (ED) complaints. It is the clinician's objective to distinguish benign (eg, sprains, contusions) from emergent injuries (eg, open fractures, dislocations, vascular compromise). A systematic approach to identifying and classifying orthopedic injuries is needed to properly manage, treat, and disposition patients. This requires a thorough knowledge of orthopedic anatomy and function. The upper extremity contains several important articulations and long bones, which are at risk for dislocations and fractures during falls or by direct force.
Shoulder and Arm Injuries
The glenohumeral joint of the shoulder is the most mobile joint in the body and, unsurprisingly, the most commonly dislocated joint, accounting for 50% of all major dislocations seen in the ED. Anterior dislocations account for 95% of all shoulder dislocations (Figure 90-1). They occur most commonly when the arm is abducted, externally rotated, and extended and a posterior directed force is applied to the humerus. Axillary nerve injury is present in 12% of cases and is noted by testing sensation over the deltoid muscle and strength of abduction. Posterior dislocations are less common (5%) and present with inability to abduct and externally rotate. The classic mechanism that causes a posterior shoulder dislocation is a seizure.
AP view of an anterior shoulder dislocation.
Shoulder separation is a soft tissue injury to the acromioclavicular and coracoclavicular ligaments, which provide stability to the acromioclavicular joint. These typically occur after a fall with direct impact onto the shoulder and are divided by severity into first-, second-, and third-degree injuries. First-degree injuries are sprains of the acromioclavicular ligament without significant separation of the acromion and clavicle. Second-degree injuries are the result of complete disruption of the acromioclavicular ligament but an intact coracoclavicular ligament. Widening of the acromioclavicular joint is present on radiographs. Third-degree injuries occur when both ligaments are disrupted, producing widening of the acromioclavicular joint and cephalad displacement of the clavicle.
Humerus fractures occur anywhere on the shaft of the humerus (Figure 90-2). Fractures of the distal third of the humerus are associated with radial nerve injuries in 5–15% of cases.
Humerus fracture. This fracture is described as a spiral, distal-third humerus fracture, with comminution, 100% displacement, and no angulation.