Nail Dynamization for Delayed Union and Nonunion in Femur and Tibia Fractures

Femoral and tibial shaft fractures are common injuries in the United States. Since their introduction, reamed intramedullary nails have become the treatment of choice for most of these fractures. However, delayed union and nonunion can complicate treatment in up to 10% of patients. Removal of interlocking screws, or dynamization, can promote fracture healing in cases of delayed union or nonunion. The efficacy of nail dynamization has been reported to range from 19% to 82%. This study was conducted to evaluate the efficacy of dynamization, identify the factors associated with its success or failure, and analyze the cost compared with exchange nailing. The authors retrospectively reviewed charts from 2011 to 2014 and searched billing records for Current Procedural Terminology codes 27506 and 27759, for intramedullary nailing of femoral and tibial shaft fractures, and code 20680, for removal of deep hardware. This search identified 34 patients with 35 fractures treated with dynamization for delayed union or nonunion. Dynamization was effective in creating union in 54% of patients. The factor that best correlated with the success of dynamization was the diameter of the fracture callus at the time of dynamization. Direct costs associated with dynamization were nearly $10,000 less than those associated with exchange nailing. Dynamization can be an effective first-line treatment for delayed union and nonunion of femoral and tibial shaft fractures. The union rate in the current study is similar to previously published rates, and cost data suggest that dynamization is a viable alternative to exchange nailing for some patients with delayed union or nonunion. [Orthopedics. 2016; 39(6):e1117-e1123.].