Lower limb fractures constitute a high burden of trauma, where mortality is an important statistical means of the quality of healthcare received. Fractures around the hip and knee diaphyseal fractures of the femur and pelvis are significantly associated with postoperative mortality. Time to surgery, nature of the injury, patient factors including age, sex, comorbidities, American Society of Anesthesiologists (ASA) score and acute management of trauma are associated with mortality following fractures of the lower limb.¹

Delays to surgery after a hip fracture have been extensively studied in the Western population as a factor that affects patient survival.^2,3 Despite recent large cohort studies and older meta-analyses, uncertainty remains as to what benchmark should be utilized as a marker of quality of care to improve patient outcomes.⁴ Recent international guidelines have suggested that 24 or 36 hours may be more appropriate clinical benchmarks for the timing of surgery to improve patient outcomes. The evidence supporting these new recommendations for an earlier time for surgery is currently limited.⁵

Elderly patients who sustain a hip fracture and undergo a surgical procedure have a high risk for postoperative complications, including pneumonia, heart failure and death. Prior studies have identified older age, cardiovascular disease, respiratory disease and prior stroke as risk factors for postoperative complications.^6,7 In Scotland, just over 6,000 patients per year sustain a fracture of the hip of which 95% are treated surgically.⁸

Lower limb fractures are a significant healthcare problem in the elderly, affecting 1.5 million people per year worldwide. This number is expected to increase to 2.6 million by 2025 and 4.5 million by 2050 due to the aging population. The consequences of a hip fracture can be serious; one-third of the patients die within the first year postoperatively.⁹ The mortality rate is highest in the early postoperative period, reaching up to 13.3% within the first 30 days after surgery.¹⁰

Numerous risk factors for early mortality following hip fracture surgery have been reported, however, study designs are inconsistent and the selection and definition of variables vary.¹¹ Given how common hip fractures are, it is important to obtain knowledge about these risk factors to optimise the quality of care. Identification of patients at high risk for early mortality is beneficial, to inform the patient about the prognosis of hip fracture surgery and to customize care. A simple scoring system is essential for such a preoperative identification in daily clinical practice. Various risk models for early mortality following hip fracture surgery have been published.¹²

The Nottingham Hip Fracture Score (NHFS) shows the most promising results so far. However, there is still room for improvement. With the NHFS, more than 87% of the patients score a risk of 30-day mortality of 11.8% or lower.¹³ These poor differentiating percentages are insufficient for clinical decision-making. An appropriate cutoff point defining a high-risk group is useful but has never been validated. Besides that, external validation of the risk model outside the United Kingdom is limited.¹⁴