Epidemiology, classification, treatment, and mortality of adult femoral neck and basicervical fractures: an observational study of 40,049 fractures from the Swedish Fracture Register

BACKGROUND: Although femoral neck fractures (FNFs) are common in orthopedic departments, optimal treatment methods remain in dispute. There are few large nationwide studies, including basicervical FNFs (bFNFs), on epidemiology, treatment, and mortality. This nationwide study aims to describe the epidemiology, fracture classification, current treatment regimens, and mortality of undisplaced and minimally displaced (Garden I-II, uFNF), displaced (Garden III-IV, dFNF) and bFNFs in adults. METHODS: All FNFs, including bFNFs with a registered injury date between 1 April 2012 and 31 December 2020, were included in this observational study from the Swedish Fracture Register (SFR). Data on age, sex, injury mechanism, fracture classification, primary treatment, and seasonal variation were analyzed. RESULTS: Some 40,049 FNFs were registered in the SFR. The mean age of the patients in the register was 80.3 (SD 11) years and 63.8% (25,567) were female. Of all FNFs, 25.0% (10,033) were uFNFs, 63.4% (25,383) dFNFs, and 11.6% (4,633) bFNFs. Non-surgical treatment was performed in 0.6% (261) of the patients. Internal fixation (IF) (84.7%) was the main treatment for uFNFs and arthroplasty (87.3%) for dFNFs. For bFNFs, IF (43.8%) and hip arthroplasty (45.9%) were performed equally often. Of the 33,105 patients with a 1-year follow-up mortality at 1-year was 20.6% for uFNF, 24.3% for dFNF, and 25.4% for bFNF. CONCLUSION: The main treatment of uFNFs is IF with screws or pins. Hip arthroplasty is the predominant treatment for dFNF. bFNF are more common than previously reported and treated with IF or arthroplasty, depending on patient age. These results may help health care providers, researchers and clinicians better understand the panorama of FNFs in Sweden. LEVEL OF EVIDENCE: IV, retrospective cohort study.