Cutting Edge Orthopedics - Issue 3

8 • CUTTING EDGE - ORTHOPEDICS Hypertrophic and stiff nonunions require only stability to promote union [11, 16]. Stable constructs minimize motion, allow compression, and minimize shearing at the fracture site. A stable fracture construct, made up of the patients bone and the fixation device, allows stable vas- cular ingrowth and the progression of fracture healing. This may involve the addition of blocking screws to improve the stability of a nailing construct in the distal tibial metaphysis, plate fixation, or compression with an external fixator. Atrophic Nonunions Atrophic and oligotrophic nonunions require both stability and biology. Patients with bone loss and infection fall into this category as well (Fig. 2). These fractures require the most preopera- tive planning, often involving several stages, as the physiological environment is inadequate to promote healing. Medical problems must be treated, while vascular surgery and plastic surgery consults may be necessary to correct soft tissue problems. These fractures must be opened and the bone ends debrided back to healthy viable tissue. All nonviable scar tissue must be removed, and the endosteal canal of the bone must be opened, either with a curette or a drill bit. Atrophic fractures also require the addition of boney stimulus in the form of bone grafting [17– 21]. Though the gold standard remains autogenous cancellous bone from the iliac crest, there are many other methods available to the orthopedic surgeon. Autogenous graft may come in the form of local bone from the proximal tibia or calcaneus and endosteal bone harvested from the femur or the tibia with a reamer-irrigator-aspirator or with other patient-derived material such as bone marrow aspirate. There are many commercially available bone graft substitutes in the mar- ketplace from osteoconductive ceramics to osteoinductive growth factors, each with a specific use. Some patients will require more of an osteoconductive scaffold, while others will require a true osteogenic graft substitute. The challenge to the surgeon is to cut through the extensive marketing noise and to select the product, combination of products, or method that will solve unique clinical needs of each specific patient. Table 2: Treatment strategy: distal tibia and ankle nonunions. Treatment method Clinical indication Plate and screw fixation Metaphyseal, malleolar, or articular nonunion, no infection, adequate soft tissue Intramedullary nail Metaphyseal location, may require polar screws for stability, no infection Multiplanar external fixation Larger deformity, leg length deficiency, infection, bone defect, poor soft tissue, joint subluxation Acute correction Small or no deformity, no lengthening, adequate soft tissues, nonunion requires open approach Gradual correction Larger deformity, leg length deficiency, infection, bone defect, poor soft tissue, joint subluxation