The lateral malleolus is a bony prominence on the fibula, one of the long bones that makes up the lower leg. The fibula is the narrowest of the long bones, situated on the outside of the leg, with this prominence creating the distinctive bump on the outside of the ankle. It is frequently involved in ankle fractures.
At birth, the ends of the fibula are actually cartilaginous, eventually ossifying and turning into solid bone as people get older. The lateral malleolus articulates with the talus, one of the bones in the ankle, creating the ankle joint. This structure is partially responsible for stabilizing the joint and transferring weight from the upper body to the ankle.
When people experience ankle fractures, this part of the bone is often involved. A piece of the bone may chip off, or the lateral malleolus may fracture, destabilizing the joint. This will be clearly visible in X-ray images taken of the ankle. An orthopedic physician can examine the X-rays to determine how serious the break is and to recommend the best form of treatment.
In some cases, casting and wearing a support boot can be enough to keep the ankle still and stable while the fracture heels. The patient may also need to use crutches or a wheelchair to avoid placing weight on the ankle in the early weeks of healing to give the bones a chance to heal without stress. A follow-up X-ray can be used to determine whether or not this course of treatment is working for the patient.
In other instances, it may be necessary to perform surgery to pin the joint. Pinning is done when the bones cannot knit on their own or when they need some extra support. Once they have healed, the pins may be removed, or left in, depending on the preference of patient and healthcare professional. Surgery is performed by a foot and ankle surgeon or a general orthopedic surgeon.
Some people have noted that the lateral malleolus sometimes ends up bruised or calloused, thanks to the fact that it projects from the ankle. Bruising is not uncommon, and may leave the area looking black and blue as well as sore for a few days. If people experience extreme pain, instability of the joint, or trouble walking when they think that the bone is bruised, it may actually be broken, and it can be a good idea to see a medical profesisonal to get the site examined. If it is broken, it is important to get timely treatment.