SLR - January 2020 - Tiffany Chin
Reference: Bohl DD, Idarraga AJ, Holmes GB Jr, Hamid KS, Lin J, Lee S. Validated Risk-Stratification System for Prediction of Early Adverse Events Following Open Reduction and Internal Fixation of Closed Ankle Fractures. J Bone Joint Surg Am. 2019 Oct 2;101(19):1768-1774.Reviewed By: Tiffany Chin, DPM
Residency Program: Cedars-Sinai Medical Center – Los Angeles, CA
Podiatric Relevance: Foot and ankle surgeons have various criteria for operative versus non-operative management for closed ankle fractures. Regardless of the type of ankle fracture, every surgeon has their own impression on what is deemed higher risk for early adverse outcomes whether it be BMI, compliance, or comorbidities which guide surgical planning. This study reviews 12,845 patients and introduces a point-based risk-stratification system for adverse event risk.
Methods: This is a level IV retrospective cohort study of patients undergoing open reduction internal fixation for ankle fractures between 2006 and 2017. A total of 7,582 patients were followed for 30 days postoperatively. Patients were randomly divided in a development cohort and a validation cohort. Multivariate Cox proportional hazards modeling was used for the development of cohort followed by a nomogram analysis to create point values for each risk factor. This point-based risk-stratification system was then applied to the validation cohort. Then both cohorts were combined for a final analysis of the risks associated with the point system.
Results: Of the 7,582 patients in the development cohort, 455 had adverse events (6 percent risk). Of the 5,263 patients in the validate cohort, 334 had adverse events (6.3 percent risk). Points were assigned to patients with various risk factors: +1 point for ages of 40 to 59 years or the female sex, +2 points for chronic obstructive pulmonary disease , +2 points for insulin-dependent diabetes, +3 points for ages 60 to 79 years, +3 points for anemia, +4 points for end-stage renal disease, 5+ points for age of >80 years. A risk of 1.9 percent for a patient with zero points to 68.7 percent for a patient with 17 points was determined after analyzing the combined cohort.
Conclusions: Of note, risk factors like smoking, bi- and tri-malleolar ankle fractures and obesity showed no association with early risk which was surprising. These risk factors are known to contribute to venous thromboembolism as well as wound and bone healing complications. Limitations of this study includes follow up duration, certain post-operative complications not analyzed by the registry (loss of reduction and hardware removal), and other associated anatomic deformities (congenital, acquired, or from previous lower extremity surgeries) of the operated ankles. Overall, it is helpful to have a point-based systematic approach in determining early adverse events for open reduction and internal fixation of closed ankle fractures.