Types

Fractures of the lower end of the humerus include:

Fractures not involving the joint surface. These injuries have a good prognosis because the joint surface is still intact. There is less likelihood of long term wear and tear of the joint.

Supracondylar fractures. These injuries affect the area shaped like an inverted Y just above the joint. Severe bending forces, over-extension (over straightening) forces, or impact can break the bone in this area. Accurate reduction of the fracture is important otherwise the mechanics of the elbow will be affected. It is also difficult to keep these fractures in a good position in a cast. For this reason it is common for this injury to be treated by surgery to put the pieces back in a good position (Open Reduction) and hold them with pins or plates (Internal Fixation) until they are healed. This operation is often referred to as ORIF. Fractures in the supracondylar region are much more common in children. Major trauma such as a motor vehicle accident is probably the most common cause of this type of fracture in an adult.

Avulsion of the medial epicondyle. The medial epicondyle is the site of orgin of the strong medial collateral ligament of the elbow and the flexor muscles of the forearm. A force that bends the elbow outwards may dislocate it and disrupt the ligaments on the inner side of the elbow. This may result in an avulsion (pull-off) fracture of the medial epicondyle. The fragment of bone is pulled off by the medial collateral ligament. Because the elbow may be opened up widely in such an injury, the piece of bone broken off may end up trapped inside the joint. In that case it is necessary to do an operation to extract the bone fragment from the joint and fix it back in place.More commonly the avulsed piece of bone is still close to its correct position and the injury can be treated non-operatively. Avulsion of the medial epicondyle as a result of muscle pull is rare. This injury can usually be treated without surgery.

Avulsion of the lateral epicondyle. This region of bone is the site of origin of the lateral ligament of the elbow and the extensor muscles of the forearm. A force that bends the elbow inwards may tear the ligaments or pull off the epicondyle. This is a rare injury which occurs most often in combination with other more severe injuries to the elbow. Avulsion fracture of the epicondyle in which the muscles pull off a piece of bone is also very uncommon.

Fractures affecting the joint surface

Breaks of the humerus extending into the region of the bone covered by joint surface are called intraarticular fractures. They carry with them a more serious prognosis because irregular joint surface will promote post traumatic arthritis in the long term. The aim of management is to restore smoothness to the joint surface where that is possible.

Fracture of the Capitellum. This is the rounded end of the humerus on the outer side. It forms a joint with the radial head and is important for the stability of the joint. A piece of capitellum can be broken off when the elbow is dislocated or when force is transmitted up the radius as a result of a fall on the outstretched hand. The floating piece may jam in the joint, limiting movement. The irregular joint surface may cause long term wear. It is often necessary to operate on the elbow to retrieve loose pieces following this fracture and it is sometimes possible to fix them back in position.

T or Y Fractures. The lower part of the humerus divides into two columns which support the joint. If you sustain a blow on the elbow, a common fracture pattern is for the columns to be broken and the fracture to extend into the trochlear region of the joint forming a T or Y pattern.

This type of injury is unstable as the columns themselves are small. Once disrupted the fracture fragments are likely to separate and leave a big gap in the joint. If possible, it is best to treat these fractures surgically (ORIF).

Smash Fracture. More severe forces on the elbow may cause multiple fractures of the end of the humerus. The joint surface may be in many pieces and some of the bone fragments may lose their blood supply. This is a difficult situation to manage but the best results come from open reduction and internal fixation (ORIF), restoring the joint surface, and fixing it rigidly to allow early movement of the joint.

Fractures of the Proximal Ulna

Olecranon and coronoid process fractures are two common patterns of injury which result in isolated fracture of the proximal ulna; both may be considered avulsion fractures. The Monteggia fracture is a combination injury with dislocation of elbow and fracture of the ulna. The ulna is often involved in combination injuries that involve dislocations or more than one bone at the elbow.

Olecranon Process Fracture.The triceps muscle straightens the elbow by pulling on the olecranon. When you fall the muscle may be contracting to straighten the elbow but a force can be applied which is great enough to make the elbow bend anyway; something must give way. Often it is the bone of the olecranon process. A transverse fracture into the joint is the common pattern. If there is also an impact on the point of the elbow the fracture may be more complex with multiple pieces.

The injury is significant in that the joint surface is involved. The usual treatment is surgery (ORIF) to line up the fragments exactly, make the joint smooth again and fix the fracture fragments until they heal. Olecranon fractures are quite often seen in combination with other elbow injuries.

Coronoid Process Fracture. The bracialis muscle acts to bend the elbow and attaches to the coronoid process the front of the ulna. When the flexed elbow is suddenly loaded this muscle may pull so hard that it pulls off the coronoid process. If this is an isolated injury and the fragment is not displaced it may be treated nonoperatively even though the fracture goes into the joint. When this injury is combined with elbow dislocation and radial head fracture it has a poor prognosis.

Monteggia Fracture. This fracture pattern involves dislocation of the radial head combined with fracture of the shaft of the ulna. The mechanism of injury can be a fall with the elbow straight or a bending force on the upper part of the forearm. The shaft of the ulna breaks near the joint. There is a spectrum of damage to the radial head ranging from ligament damage only, through joint surface damage, to fracture of the neck of the radius. Restoring the ulna to its correct length and orientation is the critical element in treating this injury and making the elbow stable again. For this reason an open reduction and internal fixation (ORIF) operation on the ulna is usually undertaken in adults. The treatment of the radial part of the injury depends on its extent.

Fractures of the Proximal Radius

Fractures of the shaft of the Radius are considered in A Patient's Guide to Fractures of the Forearm. Here we are concerned with radial fractures that directly affect the elbow joint.

Radial Neck Fractures. Longitudinal compression forces such as a fall, may cause a transverse fracture of the radial neck just below the head with variable amount of compression and angulation. A direct impact on the elbow may also cause this fracture. Because of the importance of the radial head in the function of the forearm, angulation as a result of this injury may limit forearm rotation. Because most of the radial head is covered by articular cartilage a fracture through the neck region may deprive the radial head of its blood supply.

Radial Head Fractures. These injuries are caused by axial forces compressing the radial head against the capitellum. This may happen with a fall, especially with the elbow slightly bent. The result is a fracture with a depressed segment of the radial head. The broken segment is most likely deprived of its blood supply. Treatment depends on the extent of the injury and the degree of displacement and angulation. The more severely displaced fractures may be treated by surgery.

Combination Fractures

Many of the more severe elbow fractures involve more than one of the bones. Combinations of capitellum fractures with radial head or neck fractures are common. So are combinations of intra-articular fractures of the distal humerus with fractures of the ulna. In general these combination injuries make the prognosis worse and increase the likelihood that the best treatment for the fracture will be surgery.

Open Fractures

The bones of the elbow are near the skin. High energy injuries to the elbow joint quite often result in the broken bone ends tearing through the skin. This means that the bone and probably the joint is contaminated and there is a high risk of infection. Regardless of the fracture pattern, these injuries are treated by surgery (debridement) to wash the dirty tissue and remove anything that is contaminated or dead . This type of surgery may be followed by reduction and fixation of the fracture fragments (ORIF) but avoiding infection is the first consideration and some surgeons prefer not to disturb the blood supply of the area by further surgery. Others feel that there is less likelihood of infection if the fracture fragments are immobilized.

Fractures with Bone Loss

Some open fractures are so severe that part of the bone is lost. This is typical of gunshot wounds or blast injuries. There is a real risk of losing the arm in these types of injuries as they may be accompanied by damage to nerves and blood vessels and heavily contaminated. Saving the arm by restoring the blood supply and careful removal of all dead tissue including bone and joint fragments is the first priority. Reconstructing the elbow after the risk of infection has passed is a difficult problem which will be approached on a case-by-case basis. The options are to accept the damaged joint, to fuse the joint so it is painless, or to plan for an artificial joint.