Elbow injuries in the form of fracture and dislocation are a common cause of sore elbow, and can occur after a fall on the elbow or a bike accident. Children are especially susceptible to these injuries as elbows are more accessible to injury while playing. Moreover, the elbow of a child is not well developed and contains mainly cartilaginous tissue, which is not as hard as bones. Elbow movements are quite complex, occurring in different planes, like bending of the elbow as well as forearm rotation in screwing movements. Elbow anatomy deals with the unique arrangement of elbow bones to provide all these movements.
The elbow joint is formed by the lower end of the arm bone humerus, and the upper ends of forearm bones radius and ulna. The upper end of ulna is called olecrenon, and upper end of radius is called radial head. Thus, it is a combination of ulno-humeral, radio-humeral, and radio-ulnar joint. Each of this joint is of a different type and contributes to a particular movement.
- Ulno-humeral joint is a hinge joint and provides the bending movement.
- Radio-humeral joint is a ball and socket joint and helps in forearm rotation as well as bending.
- Radio-ulnar joint is a pivot joint that brings about forearm rotation.
In order to support these movements, the symmetry and alignment of the bones have to be maintained. Even a slight change in the arrangement of the bones leads to restrictions in elbow movement and later on elbow arthritis.
Picture 1: Normal Elbow on X-ray
(Source: Wikimedia Commons)
These are commonly due to a fall on the elbow or a forcible twisting of the forearm. In children, the bones are not fully formed, but ligaments are stronger than bones. Hence, they are more prone to elbow fracture than dislocation. In adults, the bones are fully developed and more stronger than ligaments. Thus, elbow dislocation is more common in adults than in children. However, both forms of injury are possible at any age group, and so they have to be carefully differentiated. A sore elbow is present in both, but elbow dislocation is associated with pronounced elbow stiffness, whereas elbow fracture causes severe pain with a relatively mobile elbow. This distinction is only possible after treatment with an injectable analgesic, as severe pain can prevent a person from moving the elbow, giving the false impression of stiffness. The first thing to be done after a suspected elbow injury, is to put that hand in a sling. This restricts further elbow movements and prevents additional damage to the elbow. Urgent visit to an ER with investigations like X-rays are needed for rapid diagnosis and institution of treatment.
Elbow Fracture or Broken Elbow
This can be a fracture of lower end of humerus (arm bone), or the olecrenon or radial head.
Fracture of the lower end of humerus is a complex injury considering the characteristic shape and angulations of this part. Even a simple 2 part fracture has to be surgically treated to restore the alignment of the elbow. In the presence of multiple small pieces which cannot be reconstructed surgically, one has to go ahead with elbow replacement (very expensive). Many important nerves of the hand pass closely along this part and are at risk to injury during surgical repair of the fracture. The friction of nerves and muscles with the metallic parts implanted in the elbow can cause damage even months to years after the initial injury. Hence, this type of elbow fracture generally follows a complicated course of recovery.
Fracture of olecrenon is a relatively simple injury as the bone is superficial. Thus, it can be manipulated and brought in normal alignment even without a surgery. Elbow surgery is specifically needed only if there are more than 2 parts, or for concurrent fracture of the radius or humerus.
Fracture of radial head is relatively less common due to its deep seated location. However, its treatment is also difficult for the same reason. Many times removal of the broken radial head is chosen over trying to put it back in place. This is because, more than 6 hours after injury, a radial head, which has lost its blood supply, becomes non-viable (dead). Even after its removal elbow function is fully retained without any restrictions.
Picture 2: Elbow Fracture Surgery
(Source: Wikimedia Commons)
Elbow surgery for fractures of the elbow involves a meticulous rearrangement of the displaced bone fragments and securing them with the help of bone screws and metallic wires (Picture 2). The pre-operative evaluation of a patient consists of a 3d-CT scan, which tells us about the exact position of the broken pieces of the elbow bones, so that one can carefully plan the approach for the surgery as well as the types of screws or wires that are needed. Even the duration of the surgery is quite long and appropriate anesthesia fitness has to be taken.
Elbow dislocation (Picture 3)mainly consists of displacement of the olecrenon from its corresponding socket (olecrenon fossa) on the lower end of humerus. On rare occasions, it may also include displacement of radial head from its socket. The strong pull of the triceps muscle on the olecrenon prevents it from coming back into the olecrenon fossa. In the event of such an injury, one must carefully support the forearm in a comfortable position and seek prompt medical care. Forcible bending or straightening of the elbow should not be attempted as it aggravates the injury to neighboring blood vessels and nerves. Confirmation of the presence of dislocation with an X-ray and manipulation by a trained orthopedist are all that is needed to treat this condition. However, one has to keep the forearm in an elbow pouch for 6 weeks, to allow the damaged ligaments and soft tissues of the elbow to heal. Physical therapy is essential after this immobilization to regain full elbow function and overcome the ensuing elbow stiffness.
Picture 3: Elbow dislocation on X-ray
(Source: Wikimedia Commons)
Complications of Elbow Injuries
Elbow injuries are frequently complicated by concurrent injury to the ulnar or radial nerves, either from primary injury or during surgical treatment. These are noticed in the form of tingling and numbness in hand or fingers, or weakness in wrist and finger movements. Nerve conduction studies are needed to document these injuries and predict their outcome.
Myositis ossificans commonly occurs as a late consequence of elbow injury and is largely preventable by use of the NSAID Indomethacin, which is the analgesic of choice in elbow injuries.