Treatment Failure After Repair of Displaced Femoral Neck Fractures in Young and Middle-aged Adults: An Analysis of 555 Cases Treated at 27 Level One Trauma Centers

Abstract

Research Question: In middle-aged adults (ages 50 to 59 years), what factors contribute to the failure of operative repair in the treatment of displaced femoral neck fractures (FNFs) as compared to similar treatments in young adult patients (ages 18 to 49 years)? Further, does the likelihood of a successful reparative outcome vary with increasing age by decade of life?

Background and Significance: Displaced FNFs in elderly patients (e.g. = 60 years) are typically treated with arthroplasty (surgical replacement) given that these procedures generally have predictable, positive results in this age group. Young adult patients are usually treated with operative repair because outcomes of arthroplasty in this population have not been favorable and revision surgeries are required. These polarized findings have created a grey area within which an under-studied “middle-aged” group resides. The primary focus of our research has been to compare clinical results in this middle-aged cohort to a recent database consisting of the outcomes of similar injuries in patient populations stratified by decade of life. As such, we attempt to identify risk factors that could predict which patients might fail reparative treatment and be better suited to undergo replacement.

Materials and Methods: A retrospective study of patients 18 to 59 years old treated for a displaced femoral neck fracture (FNF) with surgical repair between 2005 and 2017 at 27 different Level 1 trauma centers in North America was conducted. A database of 555 patients was sorted by decade of life and patients cohorts were evaluated for demographics, pre-existing medical problems, injury mechanism and pattern, treatment methods, follow-up, and overall outcomes.

Results: Overall treatment failure was observed in 48% of hips. Complications and the need for major secondary surgeries increased exponentially with age by decade of life (P=0.004). FNFs resulting in nonunion/failed fixation were most affected by age (4th vs 5th vs 6th decade groups had nonunion/failed fixation in 38%, 48%, and 57% of hips, respectively; P<0.001). The rates of osteonecrosis were also increased in older patients (4th, 5th, and 6th decade groups had ON in 9%, 20%, and 27% of hips, P<0.001). The 6th decade group and their injuries were similar to the younger groups for most variables evaluated; however, treatments varied widely between the 6th decade group and the younger groups, including reduction type (open vs. closed), reduction quality, and construct type (cannulated screws (CS) vs. fixed angle devices (FADs)).

Conclusion: Displaced FNFs in young and middle-aged adults are a challenging clinical problem with a high rate of treatment failure. Major complications and the need for complex reconstructive surgery increased exponentially by decade of life, with the patients in their 6th decade experiencing failed fixation/nonunion and osteonecrosis at the highest rate seen among patients in the decades studied. Interestingly, treatments provided to the 6th decade group studied were quite different compared to those provided to the younger patients. Above all, we expect the results from this study to assist with surgical decision making and improve outcomes in patients presenting with displaced FNFs.