Does postoperative alignment affect union in distal femoral fractures?

Abstract

Background: Distal femoral shaft fractures can be hard to treat. Recently, a meta-analysis concluded that healing rates of distal femoral fractures are suboptimal, and further research is needed. The purpose of our study was to evaluate if postoperative alignment affected union rates of distal femoral fractures. Methods: Eighty-nine distal femoral fractures from the University of Louisville met inclusion and exclusion criteria. We used the Fracture and Dislocation Classification Compendium-2018 to classify fractures. Radiographs were evaluated for fracture location, alignment, and for healing. All statistical tests had a level of significance of 0.05. Statistical tests included a chi squared analysis, a t-test for two independent samples for proportions, and Fisher’s exact tests. Results: Chi squared analysis showed a statistically significant difference in healing of fractures with anatomic alignment versus those with nonanatomic alignment (χ2=18.241, P<0.001). The t-test of two independent samples for proportions showed that the 51% increase in healing of fractures with anatomic alignment was statistically significant (P<0.002, 95% CI 0.22, 0.80). Fisher’s exact test for specific fracture types also showed statistical significance (P<0.01). Conclusions: Proper anatomical alignment during surgical fixation of infraisthmal and supracondylar fractures is strongly associated with increased rates of fracture healing. Likewise, there is a strong association between nonanatomic alignment and nonunion. A prospective study examining the effect of alignment on union, regardless of fixation method, is reasonable and recommended.