The Influence of Fracture Defect Size on Treatment Outcomes in Distal Femur Fractures: A Comparative Study Between Lateral Locking Plate and Double Plate Fixation.

Objective: Double plate (DP) fixation does not significantly improve outcomes compared to lateral locking plate (LLP-only) fixation for distal femur fractures (DFFs). We hypothesize this is due to the absence of clear indications for the application of these two fixation methods. This study aims to clarify the impact of metaphyseal defect size on the outcomes of these two treatments, in order to optimize surgical efficacy and minimize complications.

Methods: We screened patients with distal femoral fractures treated with lateral locking plate or dual plate fixation at our hospital between January 2018 and June 2023 retrospectively. Information such as demographic data, fracture classification, operation details, metaphyseal bone defect size, pre-nd post-operative imaging data, and other medical records were compiled. Additionally, patients' recovery status was follow-up, including evaluation of knee joint function (Lysholm score), range of motion (ROM), and EQ-5D-3L health score. We used diverse statistical methods for further analysis, such as t-test, chi-square test, Pearson correlation coefficients, and binary logistic regression analysis.

Results: According to the specified criteria, 55 distal femur fracture cases were ultimately included, with 38 cases in the LLP-only group and 17 cases in the DP fixation group. In terms of surgical and follow-up information, there were no statistical differences in healing status, but there were statistically significant differences in average blood loss (p = 0.013), metaphyseal bone defect size (p < 0.001), Lysholm score (p = 0.003), and EQ-5D score (p = 0.010). Notably, compared to other parameters, the size of the fracture defect exhibited the highest correlation (0.69) with healing outcomes. In logistic regression analysis, the defect size (OR 1.052, 95% CI 1.008-1.098, p = 0.021) was independently associated with the healing outcome. Upon further analysis, non-healing cases in the LLP-only group were predominantly associated with A3, C2, and C3 type fractures, with 83.3% of these patients presenting metaphyseal defects exceeding 15 mm.

Conclusions: We carried out a comparative evaluation of LLP-only versus DP fixation in addressing DFFs. Our research outcomes revealed that LLP-only fixation yielded notably suboptimal results compared to DP fixation, especially in intricate fractures accompanied by defects, such as those classified under types A3, C2, and C3. Furthermore, the more significant the defect, the less effective the fixation of LLP-only will be. This observation underscores the pivotal role of the scope of metaphysical damage in determining the most suitable internal fixation techniques for DFFs.