Incidence of medical and surgical complications, and subsequent mortality, after hip fracture surgery

Aims Hip fracture patients are at high risk of complications affecting their treatment, recovery, and survival. Previous studies report considerable variation in complication rates, and comprehensive data are limited. We examined the cumulative incidences of 20 medical and surgical complications after hip fracture surgery and their association with mortality. Methods Using Danish nationwide registries, we identified 72,693 hip fracture patients aged ≥ 65 years who underwent surgery (2010 to 2021). Primary outcome was 30-day cumulative incidence of hospital-treated registered complications. The analysis was conducted overall and stratified by age, sex, and comorbidity. Secondary outcome was mortality within 31 to 60 days after surgery in patients with and without each specific complication. Results The cumulative incidence of any medical complication was 23% (n = 14,404), while the incidence of any surgical complication was 4% (n = 2,708). The most frequent medical complications were pneumonia (6%; n = 4,364), urinary tract infection (5%; n = 3,943), gastrointestinal complication (3%; n = 1,893), delirium (2%; n = 1,454), and dehydration (2%; n = 1,301), and the most common surgical complications were major reoperations (2%; n = 1,655) and prosthesis dislocation (2%; n = 1,053). The cumulative incidence of any medical complication was higher in patients aged > 85 years compared with those aged 65 to 75 years (27% (n = 7,140) vs 18% (n = 3,221)), for males compared with females (26% (n = 5,931) vs 21% (n = 10,475)), and in patients with compared with without comorbidities (24% (n = 13,417) vs 18% (n = 3,022). Overall crude mortality was 3% (n = 1,667) for patients without any complication, compared with 11% (n = 1,584) after any medical or 11% (n = 298) after any surgical complication. Conclusion Medical and surgical complications occurred in 23% and 4% of hip fracture patients, with infections being most common. Mortality was threefold higher among patients who experienced a complication. Early detection of complications to improve personalized clinical pathways and treatment is essential to reducing the associated high mortality. Cite this article: Bone Joint J 2026;108-B(7):961–970.