Functional and Radiological Outcome Analyses Following Dynamic Hip Screw With Anti-Rotational Screw Fixation in Young Adults With Femoral Neck Fractures

Introduction: Femoral neck fractures in young adults pose a great challenge to the orthopedic surgeon because of the high rate of non-union and high risk of avascular necrosis (AVN) of the femoral head. Anatomical reduction is the most important factor for union success. Fixed Angle devices can resist shear and torsion forces across the fracture helping the union. The aim of the study is to assess the functional and radiological outcome following fixed angle fixation of a femoral neck fracture. Patients and methods: A prospective study including 40 patients for fixation of femoral neck fracture utilizing fixed angle device in the form of dynamic hip screw and anti-rotational screw. Results: The study included 40 cases, 34 males (85%) and 6 females (15%). The mean age of the patients was 32.2 years (range 18–50 years). The mean follow-up period was 12.5 months (range 12–14 months). The mean tip-apex distance was 18.85 mm (range 10–30 mm). Time to union was 13.8 weeks (range 12–36 weeks) with three fractures of delayed union and 1 case on non-union. Discussion: In the current thesis, all cases had anatomical reduction with a failure rate of 2.5%. No cases of AVN were encountered in comparison to Gautam et al. who had three cases of AVN (12%). Also, Protzman and Burkhalter showed a very high incidence of AVN with an incidence of (87%). In a meta-analysis done by Lang et al. comparing DHS against multiple cannulated screws, the incidence of non-union was 8.6% with DHS and 8% with multiple cannulated screws. By performing a sensitive analysis, they found that the incidence of AVN in patients fixed with multiple cannulated screws was significantly lower than in cases fixed with DHS. Conclusion: Dynamic hip screw with anti-rotational screw is a successful method of fixation of femoral neck fractures in the young adult population. Anatomical reduction of the femoral neck fracture can decrease the incidence of non-union and AVN in the presence of posterior comminution of the femoral neck. Closed methods of reduction can achieve proper reduction if used properly.