Within the wrist, there are eight small bones known as the carpal bones. Two of them, in particular, are subject to fractures that are often not painful enough to seek attention immediately after the injury. Furthermore, even when a patient does present acutely after such an injury, the fractures are often either not initially visible on x-rays or if they are, they are missed on the x-ray reading. To make matters worse, when these fractures are not diagnosed early, it becomes much more difficult to get them to heal later on.
The first such bone is the scaphoid, also known as the carpal navicular. It is located on the thumb side of the wrist. The typical mechanism of injury is a fall onto an outstretched hand. Sometimes the patient will have immediate pain on the thumb side of the wrist but oftentimes, especially when this is an injury that occurs while playing sports, the pain is not so bad that the athlete feels it necessary to stop playing. Therefore, one would be well advised to seek orthopedic evaluation if wrist pain persists for more than 24-48 hours, even if mild, after a fall onto an outstretched hand. If x-rays do, in fact, reveal a fracture, further evaluation may be necessary with a CAT scan or MRI to assess whether or not the pieces into which the scaphoid broke are properly lined up to allow healing without surgery. If casting seems feasible, the duration of immobilization is between 6 and 12 weeks. This particularly long stretch of time has to do with the somewhat unique anatomy of the blood supply of the scaphoid bone. Specifically, the number of blood vessels that enter the bone is quite limited and therefore, the ability of the bone to heal itself is less robust compared to other bones. Surgery is the preferred treatment option when the pieces of the scaphoid are found initially to be significantly displaced from one another, when there is no evidence of healing after 6-12 weeks of immobilization in a cast, or when patient-specific work or sports demands preclude having the liberty to undergo as much as 3 months of casting only to find out that the scaphoid may not have healed, making surgery necessary. Lastly, when a patient fails to present for evaluation early enough, the fracture will likely go on to what is known as a “nonunion”, the medical term for the circumstance where the bone fails to heal. Once the fracture becomes an established nonunion, surgery, except in some very young patients (children), becomes the only viable option to try to achieve a healed bone. It should be noted that the success rate of surgery in an established nonunion is measurably lower than when either surgical and nonsurgical treatment options are instituted soon after the actual injury. Consequently, the take-home message is, again, to seek medical attention when falls onto an outstretched hand occur and wrist pain persists for more than 24 hours.
The second bone to be discussed is the hamate, located more on the small finger side of the wrist. One section of this bone is called the “hook”. It projects off the palmar surface of this bone towards the palm. The hook is hard to visualize on plain x-rays and unless specifically suspected as possibly being injured, can be missed when it is fractured. Two common sports-related mechanisms by which the hook of the hamate can be fractured are (1) taking a large divot when swinging a golf club and (2) having an unusually forceful or off-center contact between a baseball bat and the ball. As in the case of the scaphoid, pain, even if present at first, is often not that bad and is ignored by the patient. The pain is typically located at the base of the palm in line with the ring finger. Any type of forceful gripping or weight bearing on the hand usually makes this pain worse. Orthopedic evaluation includes pressing directly on the area of the hook of the hamate to see if that increases pain and as well, to get specific x-ray views that better visualize this bone. Sometimes a CAT scan or MRI is necessary to definitively make the diagnosis. If caught early, hook-of-the-hamate fractures can often be successfully treated with casting alone for approximately 4-6 weeks. When first encountered late after the injury, and an established nonunion has occurred, the treatment of choice, if in fact the pain is significant, is to excise the broken piece of bone rather than trying to get it to heal.
In conclusion, wrist pain that persists for more than 24-48 hours after a definable injury such as a fall onto an outstretched hand or sudden pain after taking a bad golf or baseball swing deserves attention sooner than later. Doing so we will increase the likelihood of success of treatment and shortened the duration of time necessary for that treatment.
Steven Graff, MD
