Review Question - QID 3243

If a hypertrophic nonunion is present, it is most likley a mechanical issue. Tibial diaphyseal hypertrophic nonunions (Illustration A) have approximately an 85-90% incidence of union with exchange reamed nailing. A nonunion that has bone loss or appears atrophic (Illustration B) will usually require improved mechanical stability as well as biological stimulation in the form of either autograft or an osteoinductive substance like BMP. A bone defect of up to 5-6cm in length can usually achieve union with bone grafting. In the presence of an infected nonunion, the infectious process needs to be addressed prior to the introduction of any revision hardware. If a patient does not show radiographic signs of tibial fracture union for 9 months and does not have progression toward healing for 3 consecutive months, then revision surgery would be indicated.

Tempelman et al looked at 71 tibial shaft fractures treated with nonlocked or dynamically locked IM nails and found a loss of alignment in 11% of the fractures that were not transverse in nature. They concluded that these nailing techniques should not be used in the treatment of spiral or oblique tibial shaft fractures.

Incorrect Answers:
1-A 4cm bone defect could not be corrected with exchanged nailing alone, and would either need extensive grafting or bone transport
2-An infected tibial shaft nonunion would require infection clearance prior to exchanged nailing
4-Atrophic nonunions typically need biologic stimulation in the form of acute grafting or insertion of a BMP type substance
5-Hypertrophic metadiaphyseal distal tibial nonunions can be treated with isolated exchanged nailing, however this does not have the same success as diaphyseal injuries. It is difficult to acheive appropriate stability to allow for fracture healing in the metadiaphyseal region, and other modalities such as plating need to be considered.