Validation of the Nottingham Hip Fracture Score in Predicting Postoperative Outcomes Following Hip Fracture Surgery

Abstract

Objective: Although several prognostic models have been developed for patients who underwent hip fracture surgery, their preoperative performance was insufficiently validated. We aimed to verify the effectiveness of the Nottingham Hip Fracture Score (NHFS) for predicting postoperative outcomes following hip fracture surgery.

Methods: This was a single-center and retrospective analysis. A total of 702 elderly patients with hip fractures (age ≥ 65 years old) who received treatment in our hospital from June 2020 to August 2021 were selected as the research participants. They were divided into the survival group and the death group based on their survival 30 days after surgery. The multivariate logistic regression model was used to identify the independent risk factors for the 30-day mortality after surgery. The NHFS and American Society of Anaesthesiologists (ASA) grades were used to construct these models, and a receiver operating characteristic curve was plotted to assess their diagnostic significance. A correlation analysis was performed between NHFS and length of hospitalization and mobility 3 months after surgery.

Results: There were significant differences in the age, albumin level, NHFS, and ASA grade between both groups (p < 0.05). The length of hospitalization in the death group was longer than the survival group (p < 0.05). The perioperative blood transfusion and postoperative ICU transfer rates in the death group were higher than in the survival group (p < 0.05). The death group's incidence of pulmonary infections, urinary tract infections, cardiovascular events, pressure ulcers, stress ulcers with bleeding, and intestinal obstruction was higher than the survival group (p < 0.05). The NHFS and ASA III were independent risk factors for the 30-day mortality after surgery, regardless of age and albumin level (p < 0.05). The area under the curve (AUC) of the NHFS and ASA grade for predicting the 30-day mortality after surgery was 0.791 (95% confidence interval [CI] 0.709-0.873, p < 0.05) and 0.621 (95% CI 0.477-0.764, p > 0.05), respectively. The NHFS positively correlated with hospitalization length and mobility grade 3 months after surgery (p < 0.05).

Conclusion: The NHFS demonstrated a better predictive performance than the ASA score for the 30-day mortality after surgery and positively correlated with the hospitalization length and postoperative activity limitation in elderly patients with hip fractures.

Keywords: Elderly Patients; Hip Fracture; Nottingham Hip Fracture Score; Outcomes.

Figure 1

Representative images of three cases during different time points. (A) Case 1, male, 78 years old, was admitted to the hospital on August 5, 2021, with left hip pain caused by a fall for 10 days. Diagnosis: Fracture of the left femoral neck. Left artificial femoral head replacement was performed. (B) Case 2, a 76‐year‐old female, was admitted to the hospital on August 3, 2021, with right hip pain caused by a fall for one day. Diagnosis: Fracture of the right femoral neck. Right total hip replacement was performed. (C) Case 3, an 87‐year‐old female, was admitted to the hospital on August 5, 2021, with left hip pain caused by a fall injury for one day. Diagnosis: Left intertrochanteric fracture of femur. Open reduction and internal fixation with intramedullary nail were performed.

Figure 2

A ROC analysis of baseline ASA grade (A) and NHFS (B) in evaluating the effectiveness in the 30 days mortality after surgery.