Do the Number, Size, and Position of Partially Threaded Screws Affect the Radiological Healing of Surgically Treated Displaced Femoral Neck Fractures? A Review of 136 Children

Background and Objectives: The quantity, size, and position of implants might affect the fracture healing process of surgically treated displaced pediatric femoral neck fractures (PFNFs). The aim of this retrospective multicenter study was to evaluate the correlation between the time needed to achieve radiological union and the number, size, and location of the partially threaded cannulated screws (PTCSs) in children with displaced PFNFs. Materials and Methods: A retrospective review of 136 children (mean age: 10.6 ± 3.8 years) with displaced PFNFs treated by two (n = 103) or three (n = 33) PTCSs was carried out. Student's t-tests, one-way ANOVA, Cox regression analysis, and multiple linear regression analyses were performed to investigate the variables affecting the time needed to achieve radiological fracture healing according to the number, size, and position of PTCSs, as assessed on plain radiographs. Results: A total of 132 hips achieved union at an average of 3.2 ± 1.6 months after the initial surgery. The time needed to achieve union in the patients treated with two or three PTCSs was comparable (p = 0.36). Among the fractures treated by two PTCSs, the time needed to achieve union did not correlate with the size of the implant (p = 0.122), or with the angulation between the PTCSs on anterior-posterior (p = 0.257) and lateral radiographs (p = 0.547). The time needed to achieve union in the fractures that were fully compressed by the implants was similar to the partially compressed fractures (p = 0.08). Conclusions: The number, size, and position of the PTCSs do not affect the radiological healing in the children with displaced PFNFs treated surgically.