Non-operative treatment for impacted femoral neck fractures is a now rarely used strategy whose indications are controversial. No outcome predictors have been convincingly identified, in part due to the small sizes of available studies. We conducted a large retrospective study with the following objectives: (1) to evaluate the percentage of patients older than 65 years of age with non-operatively treated Garden I femoral neck fractures who experience secondary displacement, (2) to identify predictors of secondary displacement, and (3) to determine the frequency of non-operative treatment failure due to any cause and requiring joint replacement surgery.

Non-operative treatment is reliable in patients older than 65 years of age with Garden I femoral neck fractures.

Approval was obtained from the French data protection authority to conduct a retrospective observational study of information in the Marseille university hospitals database. Consecutive patients who were older than 65 years of age at traumatology department admission for Garden I femoral neck fractures managed non-operatively between January 2007 and December 2017 were included. Non-operative treatment consisted in a walking test on day 1 followed by radiographs on days 2, 7, 14, 21, and 45 and after 3 and 12 months. Patients with secondary displacement underwent hip arthroplasty. Demographic data, cognitive performance, and radiological parameters were collected for each patient. We evaluated the rates of secondary displacement avascular necrosis, and non-union.

We included 298 patients with a mean age of 82 years (range, 65–101). Mean follow-up was 5±3 years. Secondary displacement occurred in 91 (30%) patients, at a mean of 16 days (range 2–45 days) after the fracture. Avascular necrosis of the femoral head developed in 13 (4.3%) patients and non-union in 11 (3.7%) patients. Secondary displacement was significantly associated with hypnotic treatment (OR, 4.1; 95%CI, 2.2–7.5; p=0.039), institutionalisation (OR, 6.7; 95%CI, 3.1–14.8; p=0.028), a history of repeated falls (OR, 13.5; 95%CI, 6.3–8.4; p<0.0001), having three or more comorbidities (OR, 3.2; 95%CI, 1.7–5.8; p=0.046), and having dementia (OR, 3.5; 95%CI, 1.7–6.9; p=0.0003). Secondary displacement occurred in 18 (12%) of the 151 community-dwelling patients with normal cognition and no history of repeated falls compared to 37 (75%) of the 50 institutionalised patients with dementia.

Non-operative treatment was effective in 196 (66%) of 298 patients with Garden I femoral neck fractures. Significant risk factors for secondary displacement were dementia, institutionalisation, hypnotic treatment, multiple comorbidities, and a history of repeated falls. Of 151 community-dwelling patients with normal cognition and no repeated falls, 133 (88%) achieved a full recovery with non-operative treatment alone.

IV, retrospective cohort study.