In this report, the incidence of simple elbow dislocations each year in the United States is reported. The authors also provide some demographics (details about age, race, sex, cause of injury) for the patients studied. The goal in understanding more about elbow dislocations is to prevent these injuries from ever happening.
The term simple elbow dislocation may be a bit of an oxymoron (contradicting terms). There's nothing simple about the elbow or dislocations. What the expression "simple" elbow dislocations means is that surgery was not needed to put the elbow back in place and there were no bone fractures. But with any trauma severe enough to dislocate a joint, there can be some soft tissue damage.
The elbow is made up of three bones: the humerus (the upper arm bone), the ulna (the larger bone of the forearm, on the opposite side of the thumb), and the radius (the smaller bone of the forearm on the same side as the thumb).
The elbow itself is essentially a hinge joint, meaning it bends and straightens like a hinge. But there is a second joint where the end of the radius (the radial head) meets the humerus. This joint is complicated because the radius has to rotate so that you can turn your hand palm up and palm down.
At the same time, it has to slide against the end of the humerus as the elbow bends and straightens. The joint is even more complex because the radius has to slide against the ulna as it rotates the wrist as well. As a result, the end of the radius at the elbow is shaped like a smooth knob with a cup at the end to fit on the end of the humerus. The edges are also smooth where it glides against the ulna.
There are also ligaments, tendons, muscles, cartilage, nerves, and of course, blood vessels in and around the elbow. Any of these structures can be stretched or otherwise damaged during the dislocation. Simple elbow dislocations heal well with few (if any) problems. Once the joint is reduced (put back in place), any residual problems may become apparent.
There may notice a slight loss of elbow motion, especially when trying to straighten the arm. There can be altered joint proprioception (sense of position), weakness and impaired motor control. Any of these problems can make sports participation or athletic activities difficult.
So, how often do simple elbow dislocations occur? Based on data collected from 102 hospital-based emergency departments or trauma centers, there are approximately 37,000 cases of simple elbow dislocation in the United States each year.
The majority of those occur from falls in 10 to 19 year olds engaged in sports activities. Football, wrestling, and basketball seem to be the activities males are involved in most often when this type of injury occurs. Younger males sustain elbow dislocations more often than females. In older adults, the tables are turned and women are more likely to experience elbow dislocations.
Young females with elbow dislocations are more likely to be participating in gymnastics or skating at the time of the injury. Elbow dislocations were also reported in both males and females as a result of biking accidents, skiing or snowboarding, hockey, lacrosse, track, volleyball, and trampoline.
Before summarizing the data, the authors made note of the fact that children younger than 10 were not included in this report. This was due to a technical problem with diagnostic codes used to describe injuries. Thus, injuries from baby walkers and nursemaid elbow (elbow dislocation from lifting the child by the arm) were not included.
In conclusion, the overall incidence of acute, simple elbow dislocations is activity based with high-risk activities being football, wrestling, and basketball for males. Gymnastics and skating (in-line, ice skating, skate boarding, or roller skating) are the high-risk activities for females. With this knowledge, efforts can be made to prevent such injuries. The proper use of protective equipment along with education and training may reduce the incidence of simple elbow dislocations.
Reference: Jason W. Stoneback, MD, et al. Incidence of Elbow Dislocations in the United States Population. In The Journal of Bone and Joint Surgery. February 1, 2012. Vol. 94A. No. 3. Pp. 240-245.