What is Pilon Fracture?
“Pilon”, which comes from the French word for a tool known as a ‘pestle’, is a term first used by a person named Etienne Destot in 1911. He used it to describe the way the lower part of the shinbone (known as the distal tibia) works on the ankle bone (or talus). In medical terms, we also use this word to describe fractures of the lower shinbone. These fractures happen when there’s a lot of pressure from the shinbone acting like a pestle, pushing straight down into the ankle bone. These types of fractures make up about 1% to 10% of all lower leg or shinbone fractures. They often come with serious bone shattering and tissue damage. Pilon fractures might also stretch into the wide part at the end of bones (we call this metaphyseal extension) and can involve a break in the other lower leg bone (the fibula).
The lower part of your shinbone is shaped in a four-sided way. This, along with the fibula (the other bone in your lower leg), ligaments (bands of tissue connecting bones), and capsule (part of the joint structure), helps to form what we call the ‘ankle mortise’. The design of this structure is meant to increase the joint surface area with the top part of your ankle bone and reduce the stress placed on your ankle joint. The shinbone and fibula are connected by a membrane, as well as some ligaments. The lower part of the shinbone gets its blood supply from branches of the anterior tibial, posterior tibial, and peroneal arteries.
To describe and understand pilon fractures better, doctors often use two main classification systems: the Ruedi-Allgower classification and the AO/OTA classification. The Ruedi-Allgower classification has three categories. A Type I fracture is when the shinbone isn’t displaced or moved out of place and are often treated well with non-surgical methods.The Type II fracture involves a simple displacement (or shift) without shattering the joint surface, while Type III fractures involve substantial shattering, often accompanied with harm to the wide part at the end of the bone. Type III fractures are quite common and make up about 25% to 71% of all pilon fractures.
The AO/OTA classification system has its own categories for pilon fractures. They are classified as being outside of the joint, partial joint, and inside the joint, categorized depending on the degree of shattering. Besides classifying the fracture, doctors have to consider the extent of tissue damage. They use the Gustilo-Anderson classification for open fractures or the Tscherne classification for closed fractures.
What Causes Pilon Fracture?
Pilon fractures usually happen due to high-energy events, like car accidents or falls from significant heights. These incidents cause a direct and strong downward force, which crushes the lower part of the shinbone, also known as the tibial plafond.
Less commonly, pilon fractures can occur from low-energy events. In a study by Ruedi and Allgower, they found that most of their patients got pilon fractures from skiing injuries. These injuries were believed to happen because of twisting forces on the lower shinbone, which caused fewer breakages, less movement of the broken bone pieces, and less damage to the surrounding soft tissue than high-energy events.
Additionally, older women with osteoporosis, a condition that weakens bones, are at high risk of suffering from low-energy pilon fractures.
Risk Factors and Frequency for Pilon Fracture
Pilon fractures tend to happen more often in men, with 57% to 65% of all cases occurring in males. They usually show up in two main age groups — at 25 years old and at 50 years old. This pattern is known as a bimodal distribution.
Signs and Symptoms of Pilon Fracture
People who suffer from high-energy pilon fractures often have other severe injuries as well. The first response to such an injury should follow established guidelines to stabilize the patient. This includes an initial focus on the patient’s airways, breathing, and circulation. Once the patient’s condition is stable, medical personnel need to get more information about the injury and examine the patient for other possible injuries.
A careful look at the patient’s lower legs can provide more insight into the potential level of soft tissue damage. In high-energy injuries, there may be clear deformities and exposed wounds. However, detection can be tougher with lower-energy injuries that twist the tissues rather than directly impact them. Signs to watch out for include inability to put weight on the leg, significant bruising, swelling, and blisters around the ankle. These could point to an acute fracture with accompanying soft tissue damage.
Especially severe injuries to the limbs often occur as open fractures accompanied by serious skin removal or as crush injuries. The Tscherne classification system grades soft tissue injuries in closed fractures as follows:
- Grade 0 refers to minimal tissue damage associated with simple fracture patterns
- Grade 1 involves superficial skin or muscle damage
- Grade 2 involves deep skin or muscle damage
- Grade 3 presents with extensive skin and muscle damage, skin removal, and/or compartment syndrome
The Gustillo-Anderson system is used for classifying open pilon fractures.
It is crucial to do a detailed examination of nerve and blood vessel function and to check the compartments of the lower leg for compartment syndrome when assessing pilon fractures. The nerve and blood vessel examination involves checking specific pulse points, evaluating sensation in various areas, and assessing active movements of the ankle and big toe. However, pain may limit movement.
Testing for Pilon Fracture
If you’ve taken a serious fall and may have injured your ankle, your doctor will likely take different x-ray images of your ankle to assess the injury from various angles. The x-ray images can also check your tibia (the larger bone in your lower leg) for other possible fractures and to check that it is aligned and rotated correctly. If your fall was from a significant height, additional x-rays may be taken of your spine, pelvis, foot, and the lower limb on the other side of your body to check for any other injuries, especially to your spinal column or heel bone.
Your doctor may also run some blood tests to check your overall health and how well your blood is clotting, test your urine, and possibly check for any drugs or toxins in your system, especially if you’ve been involved in a bigger accident with multiple injuries.
To get a better understanding of how severe the injury to your ankle is (known as a “pilon fracture”), your doctor might suggest a computed tomography (CT) scan. This advanced imaging test can provide a lot of detail and even a 3D reconstruction of the fracture, which can help your doctor determine the best treatment plan. One study found that CT scans added additional helpful information to the treatment plan in more than 80% of cases with a pilon fracture, and it changed the treatment approach in almost 65% of cases. Usually, the CT scan is done after the fracture has been temporarily set and stabilized, often using a device called an external fixator.
Treatment Options for Pilon Fracture
Some pilon fractures, which are breaks that occur at the bottom of the shinbone near the ankle, may not require surgery if the bone fragments haven’t moved out of place or affected the joint. In such cases, the patient may simply wear a cast and be asked to not put weight on the injured leg. This conservative approach may also be taken with patients who aren’t able to walk prior to the injury or are medically unfit for surgery. However, one downside to this method is that it can be challenging to assess how the tissues around the fracture are healing.
In the past, it was often challenging to properly treat pilon fractures due to difficulty in achieving bone union and the high chance of complications. Because of this, many patients suffering from pilon fractures ended up with lasting pain, movement issues, and disability. Years ago, the common thinking among surgeons was that pilon fractures were generally not suitable for operating on. Not undergoing surgery often resulted in the joint displacement and poor recovery outcomes.
However, there was a significant change in approach to managing pilon fractures following a publication by Ruedi and Allgower in 1968. They proposed a four-stage surgical treatment that aimed to restore the proper alignment and stability of pilon fractures. The steps involved restoring the length of the fibula (a bone in the lower leg), reconstructing the surface of the broken bone, filling the bone defects with bone graft, and using a buttress plate for additional support.
Initial attempts at this surgical approach led to high rates of wound complications and infections, due to the compromised condition of the tissues around the fracture. This led to a shift towards a two-step procedure where an external fixator is first used to hold the fracture in place and later replaced with a permanent internal fixture after the surrounding tissues have healed.
Advanced imaging techniques are now used to help in assessing the fractures and in surgical planning. The surgeon can choose the best surgical approach based on the specific fracture pattern. Post-surgery, patients are advised to refraining from bearing weight on the operated leg for 6 to 12 weeks and keeping the leg elevated to reduce swelling.
What to expect with Pilon Fracture
Despite improvements in things like x-ray imaging, surgical tools, and our understanding of how to properly handle soft tissues, pilon fractures (breaks in the lower part of the shin bone) remain difficult to treat. The severity of the fracture and the quality of the repair can impact how well a patient recovers.
Interestingly, a study from Spain found that people with pilon fractures scored lower on the Short Form-36 Health Survey (SF36). The SF36 is a widely used patient survey that asks about both physical and mental health. The pilon fracture patients scored lower than what you’d expect from people in the general population of similar gender and age. Specifically, patients with more complex fractures and those with a lower level of education reported poorer physical health. Additionally, mental health tended to decline in patients who were over 55 years old. Being divorced, having larger portions of misplaced joint, and limited ankle movement were identified as risk factors for both worse physical and mental health.
After surgical treatment, there are possible complications including issues like wounds not healing properly, infections, joint stiffness, and developing arthritis as a result of the trauma. Only about 28% of patients in one study reported being able to walk without pain after treatment.
However, there are treatment options available for those who develop painful arthritis after the fracture. It can initially be treated with changes in daily activities and anti-inflammatory drugs. If the pain doesn’t go away despite these efforts, surgical fusion of the ankle joint may offer relief. It’s crucial for patients to understand the potential outcomes and what to expect after the treatment for pilon fractures.