Risk Analysis Index: Superior Predictor of Mortality in Distal Femur Fractures, Suggests Study

Distal femur fractures carry high mortality risks in elderly patients, but a significant clinical gap remains in comparing modern frailty indices to traditional anesthesia scores. Kush Modi and colleagues from the Georgetown University School of Medicine investigated whether the comprehensive Risk Analysis Index (RAI) provides superior predictive value over the 5-Item Modified Frailty Index (mFI-5) and ASA classification for 30-day mortality and failure to rescue—defined as death within 30 days of a major complication—following surgical fixation.

Therefore, the retrospective study analyzed 2,638 patients with isolated distal femur fractures from the ACS-NSQIP database to compare frailty indices (RAI and mFI-5) against traditional metrics like age and ASA scores. Using multivariate regression and AUROC analyses, researchers evaluated 30-day mortality and failure to rescue as primary clinical endpoints, alongside secondary outcomes such as readmission rates.

Key Clinical Findings of the Study Includes:

• Enhanced Mortality Accuracy: The study found the Risk Analysis Index yielded a superior C-statistic of 0.80 for 30-day mortality, significantly outperforming age (0.68) and the American Society of Anesthesiologists score (0.73).

• Improved Rescue Discrimination: The study observed that the Risk Analysis Index demonstrated a higher accuracy for predicting failure to rescue with a C-statistic of 0.75, compared to only 0.61 for the 5-Item Modified Frailty Index.

• Substantial Mortality Risk: Reported, patients identified as very frail by the Risk Analysis Index faced more than six times the odds of 30-day mortality (OR 6.36) compared to their non-frail peers.

• Increased Rescue Failure: Identified, very frail individuals possessed more than double the odds of experiencing failure to rescue (OR 2.57) and major complications (OR 2.40) following the surgical procedure.

• Heightened Readmission Frequency: Confirmed, increasing frailty scores were significantly associated with higher odds of 30-day readmission, with very frail patients nearly three times more likely to return to the hospital (OR 2.87).

The results suggest that the Risk Analysis Index provides a more holistic and accurate prediction of critical postoperative outcomes than traditional metrics, particularly given the overall 3.4% mortality and 1.9% failure to rescue rates observed in the 2,638-patient cohort. This superior accuracy stems from its 11-variable weighted assessment of physiologic reserve, incorporating cognitive function and nutritional status, which the 5-Item Modified Frailty Index lacks.

Thus, the study concludes clinicians might consider adopting the Risk Analysis Index as a standard bedside screening tool to identify high-risk patients early and implement targeted multidisciplinary optimization to improve surgical outcomes.

Although the study is restricted by its retrospective database nature and focus on 30-day outcomes, it highlights an important need for future research into how preoperative prehabilitation and specialized geriatric care might mitigate mortality risks in frail orthopedic populations.

Reference

Modi, K., Sbaih, O., Sasaki, J., Koltenyuk, V., Gupta, N., Patel, H., & Miller, J. D. (2025). Risk Analysis Index as a Predictor of Mortality and Failure to Rescue in Patients Undergoing Distal Femur Fracture Fixation. Indian Journal of Orthopaedics, 60, 987–994.