Maleolo: What is it? Types, Clinical Significance, and Associated Injuries

It is the bony prominence on either side of the human ankle.

Each leg is supported by two bones, the tibia on the inner (medial) side of the leg and the fibula on the outer (lateral) side of the leg.

The medial malleolus is the prominence on the inner side of the ankle, formed by the lower end of the tibia. The lateral malleolus is the prominence on the outer side of the ankle, formed by the lower end of the fibula.

Maléolo medial

The medial malleolus is at the end of the tibia. The medial surface of the lower extremity of the tibia is prolonged downward to form a strong pyramidal process, flattened from the inside out:

  • The medial surface of this process is convex and subcutaneous.
  • The lateral or articular surface is smooth and slightly concave, and articulates with the talus.
  • The anterior border is rough, for the fixation of the anterior fibers of the deltoid ligament of the ankle joint.
  • The posterior border has a wide groove, the malleolar groove, directed obliquely downwards and medially, and occasionally double; this groove houses the posterior tibialis tendons and flexor digitorum longus.
  • The upper part of the medial malleolus is marked by a rough depression behind, for the attachment of the deltoid ligament.

Structures passing behind the deep medial malleolus to the flexor retinaculum:

  • Posterior tibial tendon.
  • Extensor digitorum longus.
  • Posterior tibial artery.
  • Posterior tibial vein.
  • Tibial nerve
  • Flexor hallucis longus.

Lateral malleolus

The lateral malleolus is located at the end of the fibula, it is pyramidal in shape and somewhat flattened from side to side; descends to a level lower than the medial malleolus:

  • The medial surface presents in front a smooth triangular surface, convex from above downwards, which articulates with a corresponding surface on the lateral side of the talus. Behind and below the articular surface there is a rough depression, which gives attachment to the posterior talofibular ligament.
  • The lateral surface is convex, subcutaneous and continuous with the triangular and subcutaneous surface on the lateral side of the body.
  • The anterior border is thick and rough, and is marked below by a depression for the attachment of the anterior talofibular ligament.
  • The posterior border is wide and presents the superficial ankle groove, for the passage of the tendons of Peronæi longus and brevis.
  • The top is rounded and gives fixation to the calcaneal-fibular ligament.

Clinical significance

Fracture 

A bimalleolar fracture is a  fracture of the ankle  that involves the lateral malleolus and the medial malleolus. Studies have shown that bimalleolar fractures are more common in women, people over 60 years of age, and patients with existing comorbidities.

A trileolar fracture is a fracture of the ankle that involves the lateral malleolus, the medial malleolus, and the distal posterior aspect of the tibia, which may be referred to as the posterior malleolus. The trauma is sometimes accompanied by damage and dislocation of the ligament.

Causes

A medial malleolus fracture often occurs in association with a coiled ankle particularly with significant weight-bearing forces. They can also occur due to an awkward landing from a jump, due to a fall, or after a direct hit to the front or inside of the leg or ankle.

Medial malleolus fractures occasionally occur in jumping and running sports that involve a change of direction, such as soccer, rugby, and basketball. A medial malleolus stress fracture can occur as a result of overuse often associated with a recent surge or high running volume.

Signs and symptoms

Patients with a medial malleolus fracture typically experience a sudden onset of sharp and severe inner ankle or lower leg pain at the time of injury. This often causes the patient to limp to protect the medial malleolus.

In severe cases, particularly involving a displaced medial malleolus fracture, weight bearing may be impossible.

The pain is usually felt in the front or inner ankle or lower leg and occasionally settles quickly with rest, leaving patients with pain at the site of injury that may be particularly prominent. at night or first thing in the morning.

Occasionally, patients may experience symptoms in the Achilles or calf region.

Patients with a medial malleolus fracture may also experience swelling, bruising, and pain when firmly touching the affected bone region. The pain may also increase during certain movements of the foot or ankle or when standing or walking or when trying to stand or walk.

In severe medial malleolus fractures, an obvious deformity may be noted. Occasionally, patients may also experience tingling or numbness in the lower leg, foot, or ankle.

Diagnosis

A thorough subjective and objective examination by a physical therapist is essential to assist with the diagnosis of a medial malleolus fracture.

An x-ray is usually required to confirm the diagnosis and assess the severity of the fracture. In some cases, additional investigations, such as an MRI, CT scan, or bone scan, may be required to help with the diagnosis and assess the severity of the injury.

Treatment

Treatment is basically based on weight-bearing activities for about 6 weeks. An ankle support can help protect and support the joint. If the injury has progressed to a complete fracture, surgery will likely be required.

After a period of rest, proper ankle strengthening and proprioception exercises should be performed to restore full strength and coordination in the ankle joint, preventing future injury.

It is also important to identify the cause of the stress fracture in the first place. This can be due to overtraining, poor technique, or poor foot biomechanics .

A podiatrist or sports injury professional can prescribe orthotics to correct any biomechanical foot problem. Specialist sports coaches should be consulted if training errors are suspected to have contributed to the injury.