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Cutting-Edge Research Gives Surgeons Elbow Room--Literally

Problems can arise when a surgeon has to cut through ligaments, tendons, or muscles to get to bone. This is especially true in the case of repairing a broken bone in the elbow or replacing the elbow joint with a new one. Surgeons need to know if cutting through one or both of the ligaments on the outside of the elbow will give the patient an unstable or "loose" joint after surgery.

Most people aren't willing to let doctors "cut now and see what happens later." That's the work of researchers in a laboratory. By using arms from cadavers (human bodies preserved for study), researchers can study joint motion under various conditions. Several studies have been published related to the ligaments on the outside (lateral side) of the elbow.

There are three important ligaments holding the lateral elbow in place. One of these ligaments comes from the outside of the elbow across the front. The other two are on the outer part of the elbow between the bones of the upper and lower arm. These two are so close together that even the researchers had to devote part of their work to deciding where each one begins and ends. Describing the location of each ligament in anatomical terms is very helpful to surgeons.

One study looked at whether these two ligaments were both necessary for a stable elbow joint. The researchers used 12 arms divided into two groups of six. Using incisions a surgeon would make, they cut one ligament in six of the specimens and the other ligament in the remaining six. Then they tested each elbow's ability to hold steady. In all 12 cases, the elbow remained stable.

It wasn't until both ligaments were cut that the elbow started showing signs of instability. This is important information for surgeons planning to operate on the elbow. It means that when the surgeon is trying to get into the elbow, one (but not both) of the ligaments on the outside can be cut and still keep a stable joint. Once both ligaments are disrupted, the amount of rotation and shifting of bones increases significantly.

References: Cynthia Dunning, PhD, et al. Ligamentous Stabilizers Against Posterolateral Rotatory Instability of the Elbow. In The Journal of Bone and Joint Surgery. December 2001. Vol. 83-A. No. 12. Pp. 1823-1828.

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