Schumaier AP, et al. - In this retrospective comparative study, researchers investigated the predictors of blocking screw placement in the treatment of a distal femur fracture with retrograde nail fixation. They also determined if the use of blocking screws provided acceptable alignment and stability. Two groups were defined: the BLOCK group (n = 30) of those who did receive blocking screws and a NO BLOCK group (n = 54) of those who did not. A higher body mass index (BMI), larger radiographic apparent bone gaps (RABGs), more space available for the nail (SAFN), and shorter distal segments were seen in patients treated with blocking screws. These factors when taken together, in a multivariable logistic regression, showed significant predictive value for blocking screw placement with a large effect size. Distal segment length > ×2 bicondylar width (79%), BMI <25 kg/m² (77%), RABG <4 mm (76%), and SAFN <50 mm (71%) had negative predictive values for blocking screw placement. Both groups of patients did not differ in terms of postoperative alignment or stability.