Posterior Malleolus Fracture: Causes, Symptoms, Diagnosis, Treatment, Recovery Time, Complications

Ankle fractures are common as they are prone to twisting and pressure due to body weight. ^{(1, 2)} The specific part of the ankle that gets injured may differ and can be a single or a combined injury. Posterior malleolus is the backside of the long bone of the leg, forming the ankle joint. Let us know about the causes, symptoms, diagnosis, treatment and recovery time of posterior malleolus fracture.

Ankle is one of the important joint, which bears the weight of the body. Ankle fractures are a common event, which occur due to various causes, ranging from accidents to sport injuries.⁽³⁾ Depending on the type of injury and the number of parts in which the bone breaks during an ankle fracture, it is classified into important types.

The ankle joint is formed of two lower leg bones, tibia on the inner side and fibula on the outer side. Both the bones end with a bump on inner and outer side, which form a part of the ankle. The bump or prominence on the inner side of ankle, which is the lowermost part of tibia is called medial malleolus; while the bump on the outer side is called the lateral malleolus. The lower end of the tibia also forms a small portion at the back, called the posterior malleolus, which too is a part of the ankle joint.

Ankle fractures can be medial malleolus fracture, lateral malleolus fracture, bimalleolar ankle fracture (both medial and lateral malleolus fracture), posterior malleolus fracture or trimalleolar fracture, where all the three parts, medial, lateral and posterior malleolus are fractured.^{(4, 5)}

Here, we look at posterior malleolus fracture, its causes, symptoms, diagnosis, treatment and recovery time.

Posterior malleolus fracture is not common, but it does occur in some cases.⁽⁶⁾ It may be difficult to manage posterior malleolus fracture, as the pattern of injury is often irregular and may be associated with other fractures as well. Also, considering the location and thin skin fold over it, a posterior malleolus fracture can easily damage the skin and result in an open fracture.

A posterior malleolus fracture rarely occurs as a single fracture and is mostly a part of trimalleolar fracture, in which other two malleolus are also injured and may also have other ligament and soft tissue injuries.⁽⁷⁾ If there are multiple cracks or associated injuries, a posterior malleolus fracture may be complicated to treat.

It is often noted that isolated posterior malleolus fractures are rare and they are mostly seen with other ankle injuries. The causes of posterior malleolus fracture include: twisting the ankle joint, falls, accidents or injuries to the leg; including sports injuries.⁽³⁾ Sports that involve sudden twisting and turning, which can easily injure the ankle are one of the commonest causes of ankle fractures, posterior malleolus fracture and trimalleolar fractures.⁽⁷⁾ Rolling that results from irregular or improper placing of the foot or landing on an uneven surface, too can be one of the causes of posterior malleolus fracture.⁽⁷⁾ Falls, tripping over too can cause posterior malleolus fracture and trimalleolar fracture.

Some of the causes of posterior malleolus fracture also include a direct blow to the ankle or sudden, forceful impact on the ankle, as during vehicular accidents. Sometimes, repeated injuries to the soft tissues, ligament tear or weakening of the supporting structures in elderly people or those with joint problems too can result in trimalleolar ankle fractures and posterior malleolus fracture.

Symptoms of posterior malleolus fracture include pain at the posterior side of the ankle. ⁽⁴⁾ Pain may also be present on the inner and outer malleolus, if the posterior malleolus fracture is associated with fracture of other malleolus as well.⁽⁴⁾ Pain is often worse on moving the ankle, turning the ankle inwards or outwards with difficulty in standing or walking. Tenderness is noted in the injured region, which aggravates on applying pressure.

Following an injury, severe pain and swelling of the area is the commonest symptom of posterior malleolus fracture. Bruising or signs of local injury may be noted. Usually, as it is a part of trimalleolar fracture, the entire ankle is swollen, painful and bruised. In severe fractures, the injured or displaced bones may be noticeable.

Symptoms of posterior malleolus fracture caused due to weak ligaments may cause pain along with ligament instability. Another common symptom is the inability to bear weight on the ankle, stand or walk. Pain may worsen and may be present even after low impact activities like walking and eventually even at rest. Some may also experience ankle stiffness and swelling around the injured area. Other symptoms of posterior malleolus fracture include: limited range of movements, pain on moving or turning the ankle and difficulty in standing and walking.

Diagnosis of posterior malleolus fracture and associated injuries can be made based on the history, clinical examination and x-ray.⁽⁴⁾ The history often reveals an accident, fall or sports injury, as the complaints begin soon following the injury. Examination of the ankle joint reveals pain, tenderness and swelling, based on which a possibility of multiple fractures and soft tissue injury can be assessed.

In general, if there is pain and tenderness at the medial and lateral malleolus or if the person is unable to walk due to severe ankle pain and swelling, a fracture is suspected and x-ray is advisable.

The diagnosis of posterior malleolus fracture can be confirmed by x-rays and other scanning investigations.

X-ray confirms a break in the bone; in this case, it could be posterior and sometimes even medial and lateral malleolus (inner and outer side of the ankle).⁽⁴⁾ X-ray also gives an idea about the type and severity of posterior malleolus fracture. If other soft tissue damage, ligament injuries or other fractures are suspected, additional scans like CT scan and MRI may be needed.

The treatment of posterior malleolus fracture, in case of injury to the ankle joint, needs immediate treatment, which includes the following.

Resting the joint and elevating the leg is often advisable for posterior malleolus fracture.

Icing can be done for pain and swelling resulting from posterior malleolus fracture, but is best avoided if there is a severe injury or if a complicated fracture is associated with dislocation or displacement.

In case of displacement of bones, the treatment of posterior malleolus fracture would require joint reduction, in which the displaced bones are brought to their original position. This often needs emergency medical assistance.

The possibility of nerve injury and other soft tissue injury must be evaluated to plan appropriate investigations and treatment.

Treatment of posterior malleolus fracture, like any other type of ankle fracture includes conservative (non-surgical) and surgical approach. Treatment selection depends on the type and severity of the fracture and the condition of the patient. In this, conservative methods of treatment are used, which include medicines, braces, rest and physical therapy, allowing time for the fracture to heal on its own.

Usually, conservative treatment of posterior malleolus fracture, is recommended for less severe and uncomplicated injuries. Fractures that are often not out of place and in patients who are not active, can be managed well with conservative or non-surgical treatment. Conservative treatment may also be advised when the fractured pieces of bones are too small to be repaired surgically. However, for treatment of posterior malleolus fracture with dislocation or when more than 25% of malleolus is involved, surgical treatment is needed. The treatment of posterior malleolus fracture is crucial, as the cartilage may be injured, which increases the risk of developing arthritis later.

Conservative treatment of posterior malleolus fracture is similar to other ankle fractures. It includes the use of removable braces or short leg cast. The healing usually takes up to 6 weeks, during which, the fractured ankle is supported by the cast or braces. Depending on the condition, the person may be allowed to bear weight or restricted from bearing weight on the injured leg. Usually, weight bearing on the fractured leg is to be avoided for at least 6 weeks, post which, it depends on the healing of the fracture.

Regular monitoring and repeated X-rays are taken to check the healing and to detect any change of position of the posterior malleolus fracture.

Treatment of posterior malleolus fracture also includes the use of non-steroidal anti-inflammatory drugs (NSAIDs) for pain management. Any additional medicines and supplements may also be considered, if appropriate. For people with nutritional deficiencies, diabetes, circulatory problems and elderly adults, appropriate medications need to be given to ensure proper healing.

Depending on the severity and complications of the injury, the treatment of posterior malleolus fracture may include surgical correction. Surgery is often performed to align and stabilize the bones, limit ligament damage and speed up the recovery process. While the type of surgery depends on injury and bone fragments, most surgical corrections are done using screws, plates and wiring options.

Possible complications of surgery of posterior malleolus fracture include: the risk of infections and delayed healing. Another important risk of posterior malleolus fracture is the cartilage damage, which increases the risk of ankle arthritis. People with diabetes, elderly adults and those who smoke may be at greater risk of complications, as the wound healing may be slow in such cases. However, with appropriate timely treatment and effective management, the complications can be minimized and proper healing can be expected.

Rehabilitation: Rehabilitation plays an important role in the treatment of posterior malleolus fracture. Whether the fracture is treated with conservative or surgical treatment, appropriate rehabilitation programs promotes better healing and reduces the risk of long term pain and complications. For surgical treatment of posterior malleolus fracture, early postoperative physical therapy is often advised.

Physical Therapy: Physical therapy treatment of posterior malleolus fracture aims to improve the movement of ankle joint and progress through weight bearing and then standing and walking. Exercises help to strengthen the supporting muscles, prevent injuries and promote better healing.

Exercises: Weight training is progressively done so that the healing of the ankle fracture is assessed and it gains the strength to bear weight, so that partial and then complete weight bearing can be done. This is done over a span of 3 to 4 months, post which most posterior malleolus fracture can get healed.

Recovery time in posterior malleolus fracture varies from person to person and depends on the type and severity of the injury and the overall health of the person.⁽⁴⁾ On an average the recovery time is approximately 6 weeks, while a lot depends on the rehabilitation.⁽⁴⁾ If with posterior malleolus, all three malleolus are involved, like in trimalleolar fracture, the recovery time may be more.

In cases that need surgery, recovery time for posterior malleolus fracture is longer, around 3 to 4 months. However, in some cases, the recovery time may be even longer while it may take time to return to sports. But with timely treatment and effective rehabilitation, good healing and recovery of posterior malleolus fracture can be expected.

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Also Read:

• Compound Ankle Fracture: Causes, Symptoms, Treatment, Recovery
• Ankle Fracture Surgery-ORIF
• What is Bimalleolar Ankle Fracture: Causes, Symptoms, Treatment, Recovery Time, Surgery