A Comparative Analysis of 80 Femoral Neck Fractures in Young Adult Patients with Ipsilateral Neck-Shaft Fractures Treated at 26 North American Trauma Centers

Abstract

Research Question: In patients less than 50 years old who were treated for a femoral neck fracture (FNF) at 1 of 26 Level-1 North American Trauma Centers, how do the patients, surgical factors, and subsequent outcomes of surgical management differ between patients who sustained an isolated FNF to those who sustained a FNF with an ipsilateral femoral shaft fracture.

Background, Significance and Rationale: In young adults, FNFs are at high risk for treatment failure. Specifically, these injuries carry high rates of nonunion, symptomatic malunion, and osteonecrosis. Femoral neck fractures associated with an ipsilateral femoral shaft fracture (associated FNFs) may be even more difficult to treat due to the complexity of the additional injury and its often high-energy mechanism. Numerous studies have analyzed the different fixation constructs to treat ipsilateral femoral neck–shaft fractures, yet no strategy has been proven superior. There is a mounting need to understand the implications of associated injuries and how they can impact the healing of a FNF to prevent the significant morbidity associated with treatment failure after a FNF in young adults.

Materials and Methods: This is a retrospective, multicenter, cohort series that analyzed 492 patients less than 50 years of age who were treated for a FNF at 1 of 26 North American Level-1 Trauma Centers. Patients with FNFs were separated into comparative cohorts for analysis based on the presence of an associated ipsilateral femoral shaft fracture (associated FNFs) or an isolated FNF. The primary outcome measurement is major treatment failure, defined as nonunion, malunion with shortening of 15mm, avascular necrosis, or the need for subsequent major revision surgery.

Results: Overall, 80 patients sustained an associated FNF, and 412 patients had isolated FNFs. The associated FNF cohort was younger, had a greater BMI, and lower incidence of ESRD. The associated FNFs were more frequently displaced (95% vs. 73%), vertically oriented (60.3° vs. 51°), and reduced open (74% vs. 46) (P < 0.001 for all). Treatment failure was less common in associated FNFs (20% vs. 48%), specifically they had lower rates of non-union and malunion. Odds of major failure (OR = 0.27, 95% CI = 0.15-0.48) and nonunion (OR = 0.24, 95% CI = 0.10-0.57) was lower for the associated FNFs. In associated FNFs, no significant association was found between the outcome of the FNF and the number of fixation constructs (i.e., 1 vs. 2 surgical devices) used to address both fractures (P > 0.05).

Conclusions: Associated FNFs, in adults < 50 years old, are fundamentally different in their patient and fracture characteristics compared to isolated FNFs, and also have a superior prognosis.