Scaphoid fracture

A scaphoid fracture is a break of the scaphoid bone in the wrist. Symptoms generally includes pain at the base of the thumb which is worse with use of the hand. The anatomic snuffbox is generally tender and swelling may occur. Complications may include nonunion of the fracture, avascular necrosis of the proximal part of the bone, and arthritis. Scaphoid fractures are most commonly caused by a fall on an outstretched hand. Diagnosis is generally based on a combination of clinical examination and medical imaging. Some fractures may not be visible on plain X-rays. In such cases the affected area may be immobilised in a splint or cast and reviewed with repeat X-rays in two weeks, or alternatively an MRI or bone scan may be performed. The fracture may be preventable by using wrist guards during certain activities. In those in whom the fracture remains well aligned a cast is generally sufficient. If the fracture is displaced then surgery is generally recommended. Healing may take up to six months. It is the most commonly fractured carpal bone. Males are affected more often than females. People with scaphoid fractures generally have snuffbox tenderness. Focal tenderness is usually present in one of three places: 1) volar prominence at the distal wrist for distal pole fractures; 2) anatomic snuff box for waist or midbody fractures; 3) distal to Lister's tubercle for proximal pole fractures. Avascular necrosis (AVN) is one complication of scaphoid fracture. Since the scaphoid receives its arterial supply in a retrograde fashion (i.e. from distal to proximal pole), the part proximal to the fracture is usually affected. Risk of AVN depends on the location of the fracture. Fractures in the proximal third have a high incidence of AVN (~30%) Waist fractures in the middle third is the most frequent fracture site and has moderate risk of AVN. Fractures in the distal third are rarely complicated by AVN. Non union can also occur from undiagnosed or undertreated scaphoid fractures. Arterial flow to the scaphoid enters via the distal pole and travels to the proximal pole.