Scaphoid fractures

If you have a scaphoid fracture of your wrist, there are probably a lot of questions you have regarding this problem. This sheet is designed to answer the most commonly questions asked by patients.

What is the scaphoid bone or navicular bone?
The scaphoid and navicular are two names for the same bone. This small bone is entirely within the wrist joint. (The navicular is now used almost exclusively to describe a bone in the foot).

Who gets this fracture?
In adolescents and young adults, fracture of this bone is the most common fracture around the wrist. Men are ten times more likely to fracture this bone than women. Although the bone is small, it takes a lot to break it. Oddly enough, twice as much force is required to break the scaphoid bone as to break one of the bigger forearm bones. Because of this, most patients who have broken their scaphoid have done it while participating in sports, such as football, basketball, riding a motorcycle or in an automobile accident. Usually the patient falls on the outstretched hand and hyperextends the wrist joint.

What is so special about this fracture?
Because the bone is entirely inside the joint, there are some unique things about this fracture. The patient frequently overlooks the fracture because it feels like "just a sprain." There is often only a little swelling and a variable amount of pain may be present. Usually, the swelling will go away in a few days. Unlike the forearm, hand, and finger bones, fractures of the scaphoid almost never show any obvious deformity of the wrist. "It doesn't look broken." These factors can make it common for the diagnosis to be delayed for weeks, months or occasionally even years after the initial injury because the patient or his doctor thinks it is just a common wrist sprain.

How do I know it is broken?
Often, an x-ray of the wrist can detect a scaphoid fracture. The fracture may occasionally be invisible on the first x-ray, only to show up on an x-ray examination taken weeks or months later. Many patients with a suspected scaphoid fracture will often require a "bone scan" to determine if the fracture is present. This test can be performed 3 days after the injury to assist in the diagnosis, if needed.

What does the bone look like?
This little bone is about the size of a peanut shell and is almost completely covered in articular cartilage. It functions much like a ball bearing in your wrist joint. Because of this, its' blood supply is very fragile, and sometimes the fracture leaves part of the bone without any blood flow. (Unfortunately, the blood supply is "backwards," supplying the top of the bone better than the base). This is very important. Although our bones are as hard as wood, they are alive and need blood coursing through them in order to function normally. Sometimes when a scaphoid bone breaks and loses its blood flow, it undergoes a process called avascular necrosis. This may cause the bone to crumble, and the wrist joint may be destroyed.

What happens if my scaphoid bone does not heal?
When a scaphoid fracture fails to heal, the patient may initially get better for a while until the pieces of broken bone, which are loose inside the wrist joint, cause a deterioration of the wrist joint called traumatic arthritis. In this condition, the joint becomes painful and stiff, decreases grip strength and limits a person's ability to carry out even moderate activities. The time required for the arthritis to develop is variable depending upon how heavily the wrist is being used. Traumatic arthritis is different from rheumatoid or osteoarthritis. This process only occurs in the injured joint and does not spread to other joints if the body.

What about ligament injuries in addition to a scaphoid fracture?
Since it takes such a violent injury to fracture the scaphoid bone, additional injuries to the surrounding ligaments of the wrist often occur along with a scaphoid fracture. When this happens, it is much more difficult to obtain healing of the scaphoid in just a cast. If the wrist is not stabilized surgically, collapse of the wrist bones occurs causing deterioration and permanent stiffness of the wrist joint.

What is the difference between a fresh fracture and fracture nonunion?
The word "nonunion" means something special to an orthopedic surgeon. It means that the bone has failed to heal. A nonunion may occur for a number of reasons. Simple immobilization in a cast will not lead to healing of the bone. This scaphoid bone is particularly prone to this for several reasons: there is the possibility of the fracture being missed at the initial injury leading to a delay in treatment; secondly, the bone has a poor blood supply. The fact that it is inside the joint and is constantly being bathed by synovial fluid also contributes to the development of a nonunion. A nonunion, in other words, is a failure on the part of the patient's bone to complete the healing process. A "false joint" occurs at the nonunion since the ends of the broken scaphoid are attached to ligaments at each end of the bone, further separating the fracture and preventing healing. The term "fresh fracture" is used when the injury is less than two to four weeks old. Although this is the optimum time for treating scaphoid fractures, frequently the patient is not seen during this period.

How should my fractured scaphoid be treated?
The answer to this question depends on the type of fracture, the presence of any associated ligament damage, and the severity of the ligament damage. The location of the fracture in the bone is also important since fractures of some parts of the bone statistically heal better in a cast than others.
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