The term pilon fracture (also known as a hammer) fracture occurs when one bone is driven into another bone with force. The bone may be broken into more than one piece. This is a comminuted pilon fracture. Pilon fractures can affect the spine and either bone in the lower leg (tibia or fibula).
The most common pilon fracture affects the lower end of the tibia. The break occurs across the entire bone and into the ankle joint. It results from a high-energy, loading injury from the foot up into the bone. Car accidents, skiing injuries, and falls during horseback riding are the most commonly reported cause of pilon fracture.
Pilon fractures are difficult to manage. There is often damage to the joint surface, soft tissue complications, and poor outcomes. It often requires one or more operations to repair the damage. In 10 percent of cases, fusion of the joint is needed.
But advances in surgical management are ongoing and in this article, orthopedic surgeons from the University of Missouri bring us up-to-date on this problem. Using X-rays, MRIs, illustrations, and written descriptions, the reader gets a clear picture of all that goes into the treatment of these fractures.
Surgical management begins with careful preoperative planning. Preoperative planning often requires assessing patient risks for success or failure of surgical management. For example, malnutrition, diabetes, tobacco use, osteoporosis (brittle bones), and alcohol abuse are key risk factors that can contribute to extra complications and poor results.
The surgeon also examines the fracture from every angle trying to see where all the damage has occurred and preparing a plan of action. It may be helpful to trace the X-rays and create an overlay that can be used to plan out the surgical approach.
Surgical fixation will be needed. This requires the use of pins, screws, wires, cages, and/or plates to hold the bones together until healing takes place. Strategic placement of fixation devices may improve the results. Bone graft may be used to prevent bone collapse and help stimulate bone growth around the fracture sites. Special surgical struts are often used to buttress metal plates and prevent deformities such as bone angulation and bone rotation.
Two key changes in today’s surgical routine are mentioned for pilon fractures. The first is the timing of the surgery. Timing also directly impacts the second factor and that is the amount of soft tissue injury that accompanies these high-energy injuries.
Surgery that is done too soon may compromise underlying soft tissue injuries that are not recognized in advance. Studies show that surgery performed too soon to fix the bone fractures actually results in much higher rates of complications with wound infections and poor wound healing. Amputation from nonunion of the fractures and deep infection are additional serious complications.
Unless the surgeon is able to bring the joint surfaces back together and match them up evenly, the risk of joint arthritis is much greater. Likewise, if the alignment of the ankle joint isn’t normal, there may be a loss of stability, uneven wear, inability to walk without a limp, and early development of osteoarthritis.
How long should the surgeon wait then before attempting to repair the fractures? These authors recommend the following:
All of these guidelines are made even more difficult to gauge and follow when the smaller bone in the lower leg (the fibula) along the outside of the leg is also broken. If that occurs, then the surgeon must identify the optimum surgical timing and approach to repair both areas. Limb length depends on having both bones in the lower leg (fibula and tibia) lined up and working together.
That brings us to the next decision moment for the surgeon: what surgical approach to take? Should the surgeon make the incision in the front (anterior) or back (posterior) aspect of the joint? Or should the first cut be made halfway between and on which side (inside or outside of the ankle)?
Each approach has its own pros and cons, advantages and disadvantages. The location and severity of the fractures and presence and type of soft tissue damage will also affect the decisions made. The surgeon also takes into consideration the type of fixation that will be used. For example, metal plates take a different angle and approach than screws or pins.
The more complex the problem, the more likely the surgeon will have to plan multiple surgical steps that may involve more than one approach. There has to be enough skin to cover the surgical site so that’s another consideration. And the health of the surrounding soft tissues can make a big difference in the surgical planning.
On the plus side are the new and improved options for fixation. Locking plates that are preshaped to conform to the curve of the bones are now available. Another advance in surgery for pilon fractures is the ability to place some plates using a minimally invasive approach. The surgeon can actually slip the plate through the skin and put it in place with tiny incisions that don’t disturb already damaged soft tissues.
Surgeons who are interested in details of outcomes reported with each surgical approach and fixation type will find the last section of this article of interest. Treatment comparisons and outcomes from studies already published are reviewed and summarized. The information is helpful but doesn’t provide a one-approach-fits-all guideline. Most of the studies have a small number of patients and final results are often measured differently from one study to the next.
In general, there is a consensus from these studies that the final results of treatment for pilon fractures (regardless of the surgical approach used) vary greatly from patient-to-patient. It isn’t easy to predict who should have what type of surgery or to predict complications and outcomes. And surgeons are finding that having a perfectly lined up joint doesn’t always mean a pain free, full return-to-function result.
Further studies to find ways to reduce complications and improve results are clearly needed. Surgeons can expect to see continued reports of new treatment strategies (or at least comparison of results for current surgical approaches). Having updated information will be helpful when dealing with the technically demanding nature of these injuries and need to consider so many different patient, injury, and surgery factors.