Cutting Edge Orthopedics - Issue 3

Distal Tibia and Ankle Nonunions • 3  and greater psychological stress for the patient. As soon as slow healing is identified, there should be a frank discussion with the patient about the possibility of nonunion and the need for further future treatment. Most patients will opt for early intervention if it means an earlier return to work or recreational activities. The causes of nonunion are multiple, and if identified should be addressed during treatment [4–8]. An inappropriate fracture treatment construct, whether unstable or too stiff, malpositioned or distracted, will lead to poor results. The injury itself may result in comminution, bone loss, soft tissue injury, or stripping and avascularity. Infection can result in bone death with formation of a sequestrum, as well as osteolysis with loosening of implants and eventual instability at the frac- ture site. Host factors such as age, nutritional status, metabolic abnormalities [9], chronic disease, medicines, and smoking all play a role. In some patients, the cause is not identifiable, and thus idiopathic. Classification of Nonunions Unlike acute fractures, there is no single definitive classification system for nonunions. Nonunions can be classified on the basis of their anatomy, the presence or absence of infection, their biologi- cal potential, or their stiffness. Often more than one method of describing the nonunion will be helpful in determining a treatment plan. Nonunions can be classified by their anatomic location. Diaphyseal nonunions have rela- tively less biological potential as they involve cortical bone, but are amenable to a wide variety of treatment methods, including nails, compression plating, and external fixation. The goal in this instance is to restore length and axial alignment while achieving fracture union. As the nonun- ion reaches the metaphyseal region, the goals remain the same. The potential for bone growth improves in the metaphysis, but the options for fixation are more limited. Fractures of the meta- diaphyseal region of the tibia are particularly problematic. Peri-articular nonunions may also be associated with stiff, contracted, or arthritic joints that must be accounted for in the preoperative plan. Nonunions of the malleoli, with their ligamentous attachments, can lead to joint instability. Nonunions of the articular surface are particularly challenging. Defining the extent of the non- united segment may require multiple radiographs and computed tomography scans. Step-offs, gaps, and injury to the joint surface may lead to local or global articular arthritis. In the ankle, treatment may consist of open reduction and rigid fixation or arthrodesis. Nonunions may be aseptic or infected. Though many authors have shown that bone con- structs with adequate stability can heal in the face of infection, the general goal is to convert an infected nonunion into a non-infected nonunion, and then proceed with treatment of the frac- ture. Though many infected nonunions will have skin breakdown, open wounds, and drainage, the diagnosis is not always obvious. Laboratory studies can be helpful, as can nuclear medicine studies. The patient should be counseled that treatment might take several staged procedures for hardware removal, debridement of dead bone, soft tissue coverage, and stabilization. A period of intravenous antibiotics-based thorough deep cultures is followed by definitive reconstruction. Depending on the extent of the infection and the amount of bone resected, this may require a