The fibula is the smaller bone that runs parallel to the Tibia. It only carries about 10% of your body weight. The fibula usually fractures at the same time as the tibia. When only the fibula fractures, it is usually because of a direct blow to the side of the leg or an extreme sideways bend at the ankle or knee. The Fibula is important because it provides extra stability and support to the Tibia. When both the Tibia and Fibula are broken the Fibula, when brought out to length, actually helps reduce the Tibia fracture and keeps the leg from shortening during the healing process.

This type of injury is usually treated non-operatively or closed but there are some things to watch out for.

Indication for Closed Treatment:

- chief indication of closed treatment is enough overlap to initiate early wt bearing; at least 50% cortical overlap at the fracture site.

- more than 50% initial fracture displacement will significantly increase risk of loss of reduction and non-union, due to instability of fracture.

- unstable fractures of tibia/fibula may be treated by closed reduction & casting, however, malunion may occur. - initial shortening of more than 2 cm is a contra-indication for casting, since this amount of shortening would be expected with weight bearing (despite the success of the initial reduction); OM Bostman et. al. JBJS 68-B (3) 1986. p 462-466.

Prognosis for Fracture Healing:

- more than 50% cortical comminution or displacement more than 50% are significant risk factors for non-union. - With a stable fracture the average time for union is 4 to 5 months, with a range of 2 to 14 months. - 1-2 % refracture and 1-2 % require surgical bone grafting for union. - nonunion occurs in 2-5%, malalignment occurs in 3% to 8%, and shortening of more than 1 cm occurs in as many as 10% of patients.