A List of the 5 Most Common Types of Medial Malleolus Fractures

When you break the inner bone of your ankle, it is called a medial malleolus ankle fracture. The medial malleolus is an anatomical region of the tibia bone, which is the larger of the ankle bones. It bears 90 percent of the weight bearing load, so this is a common fracture.

Medial malleolar fractures involve the articular surface of the ankle joint. The break may occur by itself but it normally accompanies injuries to the outside of the ankle (fibula fractures). A majority of ankle fractures are the result of rotational forces that cause the ankle bones to break.

Identifying if fracture ankle surgery is necessary for medial malleolus ankle fractures is usually straightforward. Whether you will need surgery or just casting depends on the entire ankle injury.

The 5 Kinds Of Medial Malleolar Fractures

The variants of medial malleolar ankle fractures. Dr. Neal Blitz

It’s important to understand the anatomy of the ankle in order to understand how medial malleolar fractures impact ankle fractures.

  • The tibia bone and the fibula bone make up the ankle.
  • The tibia bone makes up the knee joint and the ankle joint.
  • The fibula originates just below the knee and extends to the outer part of the ankle. It also provides the outer support of the ankle joint.
  • A strong ligamentous membrane keeps the two leg bones bound together. It is supported by a strong ligamentous connection at the ankle level (called the ankle syndesmosis).

Medial malleolus fractures are classified by the actual orientation of the fracture line. The five kinds of fractures are:

  • Chip Fractures
  • Transverse Fractures
  • Oblique Fractures
  • Vertical Fractures
  • Comminuted Fractures

Chip Fractures of the Medial Malleolus

Ligaments ruptures that pull off bone may be part of an unstable ankle fracture. Dr. Neal Blitz

Chip fractures are the sign of ligament rupture on the inner side of the ankle.

Rather than the force of the injury causing a bone break, the ligaments pull off directly where they attach to the bone. Here, the ligament pulls off a small piece of bone as the ligament is ruptured.

This chip fracture is also known as an avulsion fracture and sometimes these may be simple ankle sprains. The presence of an avulsion fracture, however, may indicate a more severe injury.

When chip fractures occur and the ligament is fully ruptured, the ankle can splay open.

Transverse Fractures of the Medial Malleolus

Transverse medial malleolar ankle fractures usually involve a small piece of bone. Dr. Neal Blitz

The transverse fracture occurs in the same direction as the ankle joint line and is generally a small bone fragment. While these fractures extend into the ankle joint, they do not extend into the weight bearing portion.

Oblique Fractures of the Medial Malleolus

Oblique medial malleolar ankle fractures are the most common. Dr. Neal Blitz

The oblique medial malleolar fracture generally occurs along with a rotational injury that starts on the outside of the ankle. It is associated with an oblique fibular fracture and often occur at the corner of the ankle joint.

The presence of an oblique medial malleolar fracture often suggests an unstable fracture and ankle surgery may be indicated. 

Vertical Fractures of the Medial Malleolus

The vertical medial malleolus fracture can be fixed with screws or a plate with screws. Dr. Neal Blitz

The vertical fracture usually occurs when the force is oriented more in the leg bone. These fractures can extend into the ​weight bearing portion of the ankle joint.

Comminuted Fractures of the Medial Malleolus

Comminuted fractures are when the medial malleolus is broken up into several small bone fragments. Dr. Neal Blitz

Comminuted fractures of the medial malleolus are generally high-energy injuries that break the bone into multiple pieces.

When Is Ankle Surgery Necessary?

The medial malleolar fracture needs to be evaluated in the context of the entire ankle when considering the needs for surgery. This is because ankle fractures typically occur as rotational injuries and commonly occur along with fibular fractures. 

In general, medial malleolar fractures that require surgery are those which are displaced, angular, or gape open. The presence of instability of the fracture segment or the ankle also calls for surgery.

An important consideration is that these fractures extend into the ankle joint and malignment of the cartilage surface may result in arthritis. Therefore, this is also an indication for surgery.

Not all medial malleolar fractures require surgery. It’s important to recognize that the bone will heal with or without surgery and it typically takes 6 to 8 weeks for a bone to heal. The purpose of any surgery is to stabilize the bone in its proper position while the bone is healing.

How a Surgeon Will Fix Your Ankle

The surgical repair of the medial malleolus fracture is generally dictated by the orientation of the fracture pattern. Broken bones may be fixed with wires, screws, screws with a plate, or any combination of these.

  • Vertically oriented fractures lend themselves to plate and screw fixes.
  • Oblique fractures are commonly fixated with screws that hold the bones together.
  • Transverse fractures can be repaired with screws and/or wire fixation techniques.
  • Some fractures are repaired with arthroscopic assisted ankle fracture surgery.

Be sure to discuss your questions and concerns about ankle surgery with your physician.