The fibula is a bone in the leg located between the knee and ankle joints that runs in parallel to the larger tibia, or shin bone. The fibula can be fractured near the knee, mid shaft, or at the ankle. Symptoms are generally located in close proximity to the fracture site, although the fibula can be fractured in conjunction with other injuries that cause additional symptoms in other locations. X-rays of the lower leg and ankle are the best ways for physicians to evaluate the fibula and other bones for fracture.
Pain and Tenderness
A fibula fracture can lead to pain and tenderness over any part of the fibula--from the base of the outside of the knee to the outside of the ankle--depending upon where the fracture is. When other bones and ligaments are injured, pain and tenderness can be in proximity to those injured structures.
Swelling can typically occur around the fracture site, which can be either near the knee, between the knee and ankle, or at the ankle. Some patients may have minimal swelling, while other patients have pronounced swelling.
Bruising is a common sign of fracture, but can also be seen with a variety of other injuries. Bruising may be located at the fracture site or further away from the fracture site depending upon how the fluid travels through the tissues surrounding the fracture.
Inability to Bear Weight
The Ottawa Ankle Rules are a set of guidelines that physicians often use to help determine when an ankle injury may need to be imaged by x-ray to evaluate the bones from fractures. Criteria include bone tenderness over the inside or outside of the ankle and the inability to bear weight. Patients usually cannot bear weight when there is a fibula fracture.
The site of the fracture can exhibit a variety of different deformities. A midshaft fibular fracture can lead to a deformity in the lower leg between the knee and the ankle. A fibula fracture closer to the ankle can lead to an abnormal appearance of the ankle. Open fracture is the term for the deformity caused by a bone penetrating through the skin. Any fracture that occurs along with an ankle dislocation will usually lead to an abnormally appearing ankle joint.
A consequence of a broken fibula can be injury to the nerves and blood vessels that travel in close proximity. Injury to the common peroneal nerve can be caused by the fracture or by the mechanism that caused the fracture. Injury to the common peroneal nerve can lead to numbness, tingling and weakness in the lower leg and foot. Any vascular injury can lead to bleeding or pooling of blood, which is known as a hematoma, in the lower leg.