Fractures of the Scaphoid: Evolving Concepts

INTRODUCTION Standard management of scaphoid fractures is based largely on tradition and anecdote. Technological advances such as improved imaging, wrist arthroscopy, and cannulated screws are contributing to a rapid evolution in the diagnosis and management of scaphoid fractures and their sequelae. This review outlines some of the controversies surrounding scaphoid fractures, in the context of current developments and some of the research projects underway in the Massachusetts General Hospital Orthopaedic Hand and Upper Extremity Service. BACKGROUND TRADITIONAL CONCEPTS Some well-accepted observations regarding fractures of the scaphoid are that some fractures are not visible on standard radiographs; there is a 5 to 10 percent nonunion rate with nonoperative treatment; and nonunions are usually symptomatic and always lead to arthrosis.1,2 The idea that even invisible scaphoid fractures can fail to heal has created a great deal of concern among physicians treating wrist injuries. The standard treatment of patients with “snuffbox tenderness” after a fall is substantial, including a minimum of two weeks of immobilization, repeat examination and radiographs and even a bone scan.2 Attempts to explain the substantial nonunion rate of immobilized fractures of the scaphoid have focused on its meager blood supply and the mechanical stresses to which it is subjected.2,3 Known fractures are immobilized for a minimum of 10 weeks, often much longer. This cast usually includes the thumb and often extends above the elbow.4 NEWER CONCEPTS An alternative interpretation of these observations may also have merit. Few studies of scaphoid fractures have accounted for displacement,1 despite the fact that displacement may be the single most important factor associated with healing problems.5 The five to ten percent nonunion rate in most series could simply be a reflection of the incidence of displaced fractures. Non-displaced fractures of the scaphoid probably heal if adequately protected. As evidence in favor of this, a protocol underway in London, Ontario has treated over 50 patients with CT-confirmed non-displaced fractures of the scaphoid in a below elbow thumb spica cast for 10 weeks with no healing problems (personal communication, Graham King, MD). This has been our experience as well. Because scaphoid fractures occur in young, active people, nonunion after a radiographically invisible fracture may also reflect reinjury of an incompletely healed fracture in a person who returns to unprotected activity too soon. The initially undisplaced fracture may displace in a subsequent injury and ultimately fail to heal (Figure 1).