A new scoring system for predicting cut-out risk in patients with intertrochanteric femur fractures treated with proximal femoral nail anti-rotation.

Objective: The objectives of this study were to: (1) determine all the potential risk factors defined in the literature for cut-out after proximal femoral nail anti-rotation in managing intertrochanteric fractures and (2) make a reliable prediction about the likelihood of cut-out by developing a quantitative scoring system.

Methods: Four hundred eighty patients who were operated on for an intertrochanteric femur fracture were included in the study. The patients were evaluated retrospectively. Radiological parameters known to affect cut-out, including tip apex distance (TAD), calcarreferenced TAD (CalTAD), and reduction quality, were also used to evaluate the patients. Additionally, the classification of the fracture according to the cortical thickness index for osteoporosis, the Charlson comorbidity index for additional comorbidities, and the Arbeitsgemeinschaft Für Osteosynthesefragen classification were evaluated.

Results: The cut-out rate among all patients was 7.2%. Cut-out risk could be predicted by gender, TAD, CalTAD, and reduction quality. Female gender, TAD > 29.45, CalTAD > 31.75, and acceptable or poor reduction quality significantly increased the cut-out risk. Based on the chi-square analysis, it was determined that there was a significant relationship between the cut-out risk and the variables of TAD, CalTAD, reduction quality, gender, and fracture type (P=.000, P=.000, P=.000, P=.008, P=.016, respectively). Logistic regression analysis showed a strong correlation between the newly developed scoring system and the risk of cut-out. The risk of cut-out increased 8.1 times in individuals with a score of more than 2 (P < .001).

Conclusion: Female gender, TAD > 29.45, CalTAD > 31.75, and acceptable or poor reduction quality are the parameters found to be significant in determining the cut-out risk. With the newly developed scoring system, risks can be calculated for all situations that may occur according to the scores obtained by the patients. The cut-out risk increases significantly in patients with a score above 2 points.

Level of evidence: Level III, Diagnostic Study.