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Your elbow is made up of your upper arm bone (humerus) and the two bones in your forearm (radius and ulna).

On the inner and outer sides of the elbow, strong ligaments (collateral ligaments) hold the elbow joint together and work to prevent dislocation. The two important ligaments are the lateral (outside) collateral ligament and medial (inside) collateral ligament. The muscles that cross the elbow joint also contribute to the stability of the joint.

(Left) The bones of the elbow and forearm shown with the palm facing forward. (Right) The ligaments of the elbow.

Reproduced with permission from J Bernstein, ed: Musculoskeletal Medicine. Rosemont, IL, American Academy of Orthopaedic Surgeons, 2003.

There are three different types of recurrent elbow instability:

• Posterolateral rotatory instability. The elbow slides in and out of the joint due to an injury of the lateral collateral ligament complex, a soft tissue structure located on the outside of the elbow. This is the most common type of recurrent elbow instability. Associated fractures can also occur with this type of instability.
• Valgus instability. The elbow is unstable due to an injury of the medial collateral ligament, a soft tissue structure located on the inside of the elbow.
• Varus posteromedial rotatory instability. The elbow slides in and out of the joint due to an injury of the lateral collateral ligament complex, in addition to a fracture of the coronoid portion of the ulna bone on the inside of the elbow.

A fracture of the coronoid process and a dislocation may lead to an unstable elbow that requires surgery.

There are different causes for each of the different patterns of recurrent elbow instability:

• Posterolateral rotatory instability is typically caused by a trauma, such as a fall on an outstretched hand. It may also develop as a result of a previous surgery, or longstanding elbow deformity.
• Valgus instability is most often caused by repetitive stress as seen in overhead athletes (such as baseball pitchers). Like the other forms of recurrent elbow instability, it may also result from a traumatic event.
• Varus posteromedial rotatory instability is typically caused by a traumatic event, such as a fall.

Recurrent elbow instability may cause locking, catching, or clicking of the elbow. You may also have a sense of the elbow feeling like it might pop out of place. This feeling commonly occurs while pushing off from a chair.

Overhead athletes may have pain on the inside of their elbow when throwing, or a loss in throwing velocity (speed) and ball control.

Nonsurgical treatment options are effective at managing symptoms in most patients with valgus instability. However, a highly competitive overhead athlete who has a complete medial collateral ligament tear may require surgery to return to full function.

Some cases of posterolateral rotatory instability can also improve with nonsurgical treatment, but surgery may be needed if there is chronic stress of the lateral collateral ligament or significant associated fractures.

People with varus posteromedial instability almost always require surgery to repair the broken bone and the ligament injury. Without surgery, this injury may lead to continued instability and early arthritis of the elbow joint.

Surgical Treatment

People with chronic elbow instability may require surgical treatment to return to full use of their arm and elbow.

• Ligament reconstruction. Most ligament tears cannot be sutured (stitched) back together. To surgically repair the injury and restore elbow strength and stability, your doctor may need to reconstruct the ligament. During the procedure, the doctor replaces the torn ligament with a tissue graft, which serves as a new ligament. In most cases, the ligament can be reconstructed using one of the patient's own tendons, but sometimes the doctor will use an allograft (cadaver graft).
• Ligament repair. In some cases, when the ligament injury is relatively fresh or the remaining soft tissues are healthy, your surgeon may recommend repairing the ligament with sutures.

The injured lateral collateral ligament is replaced with a tendon graft. The ligament capsule surrounding the elbow is plicated (tightened) and reattached to the bone.

Reproduced and adapted with permission from Yadao MA, Savoie FH, Field LD: Posterolateral rotatory instability of the elbow. Instructional Course Lectures 2004; 53:607-614.

• Fracture fixation. Patients with unstable elbows with significant associated fractures require treatment to repair both the broken coronoid bone and the torn ligament. During the operation, the broken bone fragments are repositioned into normal alignment, then held together with special screws and, sometimes, a metal plate.

This X-ray, taken from the front of a straightened elbow, shows a coronoid fracture fixed with a metal plate and screws.

Reproduced with permission from Steinmann SP: Coronoid process fracture. J Am Acad Orthop Surg 2008; 16: 519-529.

During the first week after surgery, you will most likely wear a splint to protect your elbow as it begins healing.

Rehabilitation typically begins in the second week after surgery. The splint will be replaced with a brace that limits how far you can bend or straighten your elbow but allows you to begin exercises to improve range of motion. With a commitment to rehabilitation, you may regain full range of motion by 6 to 10 weeks after surgery.

Physical therapists will often prescribe strengthening exercises 3 months after the procedure, and most patients return to full activities by 6 to 12 months after surgery.

Throwing athletes may require up to a year of rehabilitation before returning to competitive sports.

Recurrent elbow instability is a relatively new concept. Future research will provide a better understanding of the interaction between the muscles, ligaments, and bones. Newer techniques are always evolving for reconstructing the ligaments. Research will lead to better ways to diagnose, treat, and recover from these complex injuries.