Objective: Distal femoral fractures are a common orthopedic problem. The most used treatment is the fixation by lateral locking plates. The long plates offer greater biomechanical advantages, but there are no studies that analyze the influence of the length of the plate in the consolidation of the fracture.
The aim of the study was to identify the ratio plate length/fracture height as a predictor of non-union risk in less invasive stabilization system (LISS). As secondary goals, we studied patient comorbidities, fracture pattern and construct characteristics, and its relationship with the need for reintervention, infection, and implant failure.
Material and methods: Single-center retrospective case-control study of 59 patients with 64 distal femur fractures treated with LISS plates between 2007-2017. Consolidation group n=49, non-consolidation group n=15. Patient demographics (age and gender), comorbidities (obesity, diabetes and smoke habit), injury (tipe and mechanism) and construct characteristics (plate length, proximal and distal screws, proximal and distal holes and working length) were obtained for all participants. We measured the ratio between plate length and fracture height in the same anteroposterior X-ray.
Results: No significant differences were found between the two groups in ratio plate length/fracture height. There were no statistically significant differences in demographic data, fracture pattern, plate length or working length. A relationship was found between no union and periprosthetic fractures (p=0.047) and number of proximal screws (p=0.045). Use of less than 5 or more than 6 proximal screws were found to be associated with proxima l plate failure and nonunion.
Conclusion: According to the results, the use of 5 or 6 proximal screws reduces the risk of no union. Use of less than 5 proximal screws may not provide the necessary fixation, while using more than 6 proximal screws may result in a too rigid construct.
On the other hand, periprosthetic fractures represent an independent risk factor for non-union.
Distal femoral fractures, No consolidation, Non-union, Locking plate, LISS