Stress fractures of the femoral neck in adults: an observational study on epidemiology, treatment, and reoperations from the Swedish Fracture Register

Background and purpose - Stress fractures of the femoral neck (sFNFs) are uncommon injuries. Studies on sFNFs are rare. We describe the demographics, classification, treatment, reoperation rates, and mortality in a cohort of sFNF patients from the Swedish Fracture Register (SFR). Patients and methods - We included 146 patients = 18 years of age with an sFNF registered in the SFR between 2011 and 2020. The cohort was linked with the Swedish Arthroplasty Register and reviewed using medical records and radiographs. We assessed the presence of disorders of bone remodeling, duration of symptoms, fracture classification, treatment, reoperations, and mortality. Results - The mean age was 58 years (21-96), 75% were women and the median duration of symptoms was 23 days (1-266). 40% of patients had disorders of bone remodeling. 54% were undisplaced (uFNF), 30% displaced (dFNF), and 16% basicervical (bFNF). 14% of patients < 60 years were treated nonoperatively, by internal fixation (IF) in 77% and by arthroplasty in 10%. Patients >= 60 years were treated nonoperatively in 10%, IF in 40%, and arthroplasty in 49%. Nonoperative treatment was reserved for uFNFs or bFNFs, resulting in 35% receiving late surgery. The overall secondary or late surgery rate was 19%. Mortality was 2% at 90 days and increased to 3% at 1 year. Interpretation - sFNF has a biphasic age distribution. One-third of patients presented with a displaced FNF and those managed nonoperatively for an undisplaced sFNF were at risk of late surgery. The mortality rates for patients with these injuries was low.

Automated summary

Stress fractures of the femoral neck (sFNFs) are rare injuries and studies on this subject are limited. This study examined a cohort of 146 sFNF patients registered in the Swedish Fracture Register (SFR) between 2011 and 2020. The analysis included demographic information, fracture classification, treatment methods, reoperation rates, and mortality. The findings revealed that sFNF occurs more frequently in women with a mean age of 58 years. Nonoperative treatment, internal fixation, and arthroplasty were the main treatment approaches. Late surgery was often necessary for patients with undisplaced sFNF. The overall reoperation rate was low and the mortality rate was relatively low at 90 days and 1 year.