A scaphoid fracture, also known as a navicular fracture, is a break of one of the small bones in the wrist. Fracturing this bone is common, can occur in people of all ages, and has no specific risk factors. The main symptom is pain, though people often dismiss it as simple wrist fatigue. Treatments vary based on the type of fracture and how the fragments align; if left untreated, a scaphoid fracture can result in complications.
Your wrist is made up of the two main bones of the forearm -- the ulna and the radius -- as well as eight small carpal bones. Those eight bones align in two rows of four at the base of your hand. The scaphoid bone is the small carpal bone located at the base of the thumb and just above the radius. It is responsible for stability and plays a part in wrist motion.
Scaphoid fractures are broken down into two classifications. A non-displaced fracture occurs when the fragments of the scaphoid bone remain aligned after the break. A displaced fracture occurs when the pieces of the scaphoid bone move away from their normal alignment, causing gapping or overlapping of the bone.
The most common cause of a scaphoid fracture is a forward fall onto outstretched hands. This kind of accident places most of the body weight in the palms. Often, a fracture of the radius bone occurs as well. Roller skating is one common activity that can lead to such an injury, as can reaching out the hands during a car accident.
As with most fractures and breaks, pain is the main symptom, centering on the thumb side of the wrist and injured individuals may experience more severe pain when moving the thumb. In fractures where the bones remain aligned, pain is often minimal and can be mistaken for a wrist sprain. Wrist or thumb pain after an accident may require an x-ray to look for fractures.
A non-displaced fracture with a break occurring closer to the thumb part of the bone will likely require a simple cast or splint worn below the elbow for a few weeks -- this is often protection for healing. This top area of the bone has a good blood supply, so healing and bone regrowth are often possible without medical assistance.
A break that occurs near the middle of the scaphoid bone or at the proximal end, closest to the forearm, can impair healing because the blood supply in these areas is not as strong. If the doctor decides to cast the injury, the cast typically extends beyond the elbow; this better stabilizes the broken bone.
If the bone is not healing, the doctor may choose to use a bone stimulator, a device that uses low-intensity ultrasonic waves to stimulate natural healing processes. People with severe breaks resulting in displaced bones may require surgery to stabilize the bone. A surgeon may manually place the bones into alignment or use metal screws, pins, and wires to help hold the broken pieces in place as they heal. Some people may require a bone graft.
How long it takes to heal depends on the fracture. Simple fractures can heal within a few weeks, while others can take months. Keeping the bone stabilized is essential during the healing process, as movement can slow healing. Injured individuals should avoid using their arms as much as possible, even if the wrist has a cast.
Two complications of scaphoid fractures are nonunion and avascular necrosis. In nonunion necrosis, the fractured pieces do not come together and do not heal, often because of poor blood supply. If a fracture is not healing with conservative treatment, it may require surgery to get the pieces to come together. Avascular necrosis occurs when the blood supply to the bones is disrupted or lost completely, a complication more common with displaced fractures. When the bone fragment loses its blood supply, cells die, and the bone cannot heal. Such injuries may require bone grafts.
With any fracture, later development of arthritis is possible. In the case of the scaphoid, arthritis more commonly develops with displaced fractures and following complications. Symptoms of arthritis include stiffness of the wrist, pain when using the wrist, and some decreased range of motion and function.
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