The medial malleolus is the bony bump on the inner side of the ankle. This is the end of the shin bone (tibia) and forms the support for the inner side of the ankle joint. The medial malleolus is also the attachment of the major ligament on the inner side of the ankle, called the deltoid ligament. Fractures of the medial malleolus are relatively uncommon and usually occur as part of a more complex pattern of ankle fractures, including bimalleolar and trimalleolar fractures.1 That said, isolated fractures of the medial malleolus do occur, though they are less common than other types of ankle fractures.
Medial Malleolus Fractures
An isolated fracture of the medial malleolus generally occurs when the foot is forcefully rolled inwards or outwards.2 When the foot rolls inwards, this causes a compression of the medial malleolus on the inner side of the ankle. When the foot rolls out, this pulls tension on the medial malleolus, which can also cause a fracture.
Medial malleolus fractures can also occur as a stress fracture.3 In these cases, there is no forceful injury, but rather the repetitive stress of an activity causes the bone to weaken. Stress fractures of the ankle are most often seen in endurance athletes or military recruits.
Fractures of the medial malleolus cause symptoms including:
Pain on the inner side of the ankle
Swelling and bruising of the foot and ankle
If these symptoms occur, you should be seen by a physician to determine the source of your pain. There are well-established criteria to determine if an x-ray is necessary. Most fractures are readily visible on X-rays without need for other tests.
As stated, whenever a medial malleolus fracture is seen, there are concerns about other damage to the bone and ligaments that may occur as part of the typical injury patterns. Any patient with a medial malleolus fracture should be carefully examined to ensure there is no other fracture or ligament damage surrounding the joint.
There are options to treat medial malleolus fractures both non-surgically and surgically.5
There have been several studies that have documented good healing of medial malleolus fractures treated without surgery.2 Most often these fractures are not out of position. Nonsurgical treatment is also often preferred if the fragment of bone is too small to negatively affect the overall stability of alignment of the joint. In general, most doctors recommend surgery for fractures that can affect the stability or the alignment of the joint.
For fractures that are not well-positioned, a surgical procedure to line up and stabilize the bone is often recommended.6 The bone is usually held in position with metal screws, although there are several other options that can be considered based on the particular fracture pattern.
Complications of Treatment
If surgery is performed, the greatest concerns are infection and healing problems. The ankle joint is especially treated with caution after surgery because there is little to protect the bone, with just a layer of skin covering the surgical repair. Appropriate wound healing and avoiding infection of the surgical site is a significant concern. Because of this, most doctors either perform surgery immediately (before any swelling has developed) or wait days or even weeks to allow the swelling to subside, to allow the soft tissues to be healthy with minimal swelling at the time of surgery.
The other major concern with any ankle fracture injury is that while the bone generally tends to heal well, there may be cartilage damage inside the ankle joint from the injury itself. This cartilage damage can lead to early ankle arthritis. Depending on the type of fracture, your surgeon may be able to visually inspect the cartilage, and some surgeons may opt to perform an ankle arthroscopy at the time of repair to better see the cartilage. Even after surgery to restore proper alignment and stability of the joint, the risk of developing ankle arthritis later in life may be increased after sustaining an ankle fracture.