What is a malunion fracture?

A malunion fracture occurs when a broken or fractured bone does not line up correctly during the healing process and as a result the bone heals in the wrong position. Malunions can present in various forms, but are usually described as rotated or crooked. They can also form in a way that means the bone is shorter than it was before.

Where do malunion fractures most commonly occur?

Most commonly, malunion fractures occur in:

• bones between the hand and the arm
• femoral neck (in the hip joint) 
• ankle
• bones in your foot

If malunion fractures form near a joint, arthritis can also develop as a complication because of the atypical shape of the bone and its unusual wear on the joint.

What causes malunion fractures?

Complex fractures are often more difficult to treat and as such, the chance is higher that the bone will not heal correctly. Breaking a bone into multiple pieces or fracturing it at an angle can be defined as complex fractures. Additionally, in some cases bones rotate as they break, leaving the bone parts out of alignment. In all of these cases, the difficulties posed in treating the break may mean the patient is more likely to form a malunion.

There can be other causes behind malunion fractures including:

• a delay in receiving treatment, meaning the body starts the healing process before the bones can be aligned
• an incorrect setting of the bones, where they are not correctly aligned
• after being set, the bones become unaligned
• osteomyelitis, a bone infection which can complicate the healing process

What risk factors make someone more likely to develop a malunion fracture?

Malunion fractures are more likely to develop in people affected by obesity, diabetes and also those who smoke. In such patients, bone density is compromised, slowing the body’s bone repairing process.

What are the symptoms of a malunion fracture?

After the bone fracture has healed, signs that a malunion has formed can include swelling, pain or tenderness in the area. Additionally, a visible malformation in the way the bone has healed and difficulty bearing weight on the affected area can also indicate the presence of a malunion fracture.

How are malunion fractures treated?

In nearly all cases, malunions require surgery to correctly reset the bone. For many patients, malunion fractures affect their daily life as they impede physical activity and cause discomfort. Therefore, surgical treatment can substantially improve patients’ quality of life. The procedure, known as an osteotomy, can also sometimes involve the insertion of metal plates or pins to hold the bone newly in place.

What type of doctor treats a malunion fracture?

Specialist general and orthopaedic surgeons treat malunion fractures. Rheumatologists also treat malunion fracture related arthritis.