The term lateral epicondyle refers to two separate structures in the body that perform a similar function. The lateral epicondyle of the humerus, which is the large arm bone in the upper arm, is a protrusion located near the elbow to which tendons attach. The lateral epicondyle of the femur, the large leg bone of the thigh, performs a similar function and is located near the knee joint. Both protrusions lie on the outer side of the respective joint and can be seen as a bump on the knee or elbow.
One common arm injury associated with the lateral epicondyle is tennis elbow. This type of injury is one of the most common seen in orthopedics and involves strain and tearing to the ligaments that attach to the elbow joint. Tennis elbow is sometimes referred to as lateral epicondylitis. Although this literally means swelling to the outside of the elbow bone, the bone itself does not swell, but the arm pain is often centered in the area of the lateral epicondyle. This strain to the muscles or tendons of the arm is usually treated with heat, cold, reduced activity and non-steroidal anti-inflammatory drugs.
Leg pain also can center in the area of the lateral epicondyle of the femur. One example is iliotibial band friction syndrome (ITBFS). The iliotibial band is a muscle that attaches at the hip on one end and just below the lateral epicondyle on the other. Though the band does not attach directly at this bone protrusion, doctors can use this bone landmark to determine the exact location and nature of the leg pain that the patient is experiencing. ITBFS occurs because of activity that causes the iliotibial band to rub across the bone, such as running or cycling.
Fractures to the lateral epicondyle are not uncommon, especially in children. About one-fifth of elbow fractures in children between six and 10 are fractures to the lateral epicondyle. These fractures can be difficult to treat because of the complexity of the elbow joint and the likelihood that the fracture will be disturbed during the healing process by the natural, continuous tension of the muscles that attach to the lateral epicondyle. If the fracture does not heal properly, stiffness can result in the elbow. These common elbow fractures usually are treated with immobilization to avoid problems that could occur if the elbow does not heal properly.