Fixation Strategies for the Displaced Femoral Neck Fracture in Patients Ages 18-59: Which Strategy is Superior? A Mechanical Approach to Clinical Decision Making

Abstract

Research Question: In young to middle-aged patients (18-59 years old) undergoing surgical repair for a displaced femoral neck fracture, is there a superior surgical fixation device, or combinations of devices that significantly affects clinical outcomes?

Background, Significance, and Rationale for the Question: Femoral neck fractures vary according to a variety of factors including age and mechanism of injury. In older patients (>60 years old), lower energy fractures such as a ground level fall are far more common due to high relative incidence of bone degeneration and disease. Poor bone quality, the inability to limit weight bearing, along with comorbidities where secondary surgeries may not be tolerated, often limits the utility of fracture repair in favor of replacement. Mechanism of femoral neck fractures in the cohort of young to middle-aged patients (18-59 years old) is highly variable. These fractures can be high energy leading to atypical fracture angles and comminution. Additionally, bone quality and comorbidity impact become more variable. Regardless, these patients are usually treated with operative repair as outcomes of arthroplasty in young to middle-aged patients are not well-defined and early revision surgery is expected due to implant wear over time. Highly impactful decisions are made regarding the hardware and methodology used for augmentation and there is great need to for identification of the superior internal fixation strategies that promises better results.

Materials and Methods: This is a retrospective study of patients 18 to 59 years old with a displaced femoral neck fracture treated with surgical repair between 2005 and 2017 at 26 Level 1 trauma centers in North America. A database including approximately 1500 patients was evaluated for injury mechanism, internal fixation method implemented, and success of that intervention, in addition to a variety of patient demographics.

Results: 808 of 1500 individuals met study criteria with 552 individuals having a displaced femoral neck fracture that qualified for analysis. Amongst the entire cohort the two most used constructs included SHS+AR (34%) and CS Alone (44%) of which SHS+AR was statistically less likely to fail (p=<0.001). Overall, 251 individuals received some form of a FA device. 302 individuals underwent fixation via CS. All FA devices demonstrated a significantly greater rate of fixation success in comparison to the CS group (p=<0.001). Amongst FA construct devices the CN demonstrated the lowest incidence of failure (38%) (p=0.305).

Conclusions: This study served to demonstrate the clear statistical superiority of the fixed-angle device amongst the general population, with sliding hip screws paired with anti-rotation screws promising best results in a number of subdivided patient groups including, both males and females, both younger and older cohorts, those with fracture comminution, and those without associated femoral shaft fractures. The cephalic nail, while less frequently implemented also posed the lowest incidence of failure with significant advantages in all ages, females, and those without alcohol use, metabolic disease or fracture comminution. Overall, with consideration given to patient demographic and co-morbidity, FA constructs should represent the internal fixation standard of care in patients aged 18-59.