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Internal validation of modified Mirels' scoring system for pathologic femur fractures
Vishal S Desai1, Richard L Amendola1, Kenneth A Mann2
1Department of Orthopedic Surgery, SUNY Upstate Medical University, 750 East Adams Street, Syracuse, NY, 13210, USA.
Background:
The proximal femur is a common site of bone metastasis. The Mirels' score is a frequently utilized system to identify patients at risk for pathologic fracture and while it has consistently demonstrated strong sensitivity, specificity has been relatively poor. Our group previously developed a Modified Mirels' scoring system which demonstrated improved ability to predict cases at risk of fracture in this patient population through modification of the Mirels' location score. The purpose of the present study is to internally validate this newly developed scoring system on an independent patient series.
Methods:
Retrospective review was performed to identify patients who were evaluated for proximal femoral bone lesions. Patients were stratified into one of two groups: 1) those who went on to fracture within 4 months after initial evaluation (Fracture Group) and 2) those who did not fracture within 4 months of initial evaluation (No Fracture Group). Retrospective chart review was performed to assign an Original Mirels' (OM) Score and Modified Mirels' (MM) score to each patient at the time of initial evaluation. Descriptive statistics, logistic regression, receiver operating curve, and net benefit analyses were performed to determine the predictability of fractures when utilizing both scoring systems.
Results:
The use of the MM scoring improved fracture prediction over OM scoring for patients observed over a 4 month follow up based on logistic regression. Decision curve analysis showed that there was a net benefit using the MM score over the OM scoring for a full range of fracture threshold probabilities. Fracture prevalence was similar for current internal validation dataset when compared to the dataset of our index study with a comparable reduction in misclassification of fracture prediction when utilizing the modified scoring system versus the original.
Conclusions:
Use of MM scoring was found to improve fracture prediction over OM scoring when tested on an internal validation set of patients with disseminated metastatic lesions to the proximal femur. The improvement in fracture prediction demonstrated in the present study mirrored the results of our index study during which the MM system was developed.
Insights
The Modified Mirels' score improves prediction of pathologic proximal femur fractures compared to the original Mirels' score. This validated system aids in identifying patients at risk for fracture, enhancing clinical decision-making.
Area of Science:
- Orthopedic Oncology
- Bone Metastasis Research
- Medical Imaging and Diagnostics
Background:
- Proximal femur bone metastasis poses a significant fracture risk.
- The Mirels' score aids in fracture risk assessment but has limitations in specificity.
- A previously developed Modified Mirels' (MM) scoring system aimed to improve fracture prediction accuracy.
Purpose of the Study:
- To internally validate the efficacy of the Modified Mirels' (MM) scoring system.
- To compare the predictive accuracy of the MM score against the Original Mirels' (OM) score for pathologic proximal femur fractures.
Main Methods:
- Retrospective review of patients with proximal femoral bone lesions.
- Stratification into fracture (within 4 months) and no-fracture groups.
- Assignment of OM and MM scores; statistical analysis including logistic regression and ROC curves.
Main Results:
- The MM score demonstrated improved fracture prediction accuracy over the OM score.
- Decision curve analysis confirmed a net benefit of using the MM score across various fracture probabilities.
- Validation dataset showed comparable fracture prevalence and reduced misclassification with the MM system.
Conclusions:
- The Modified Mirels' (MM) scoring system effectively enhances prediction of pathologic fractures in patients with proximal femur metastases.
- Internal validation confirmed the MM system's improved performance, mirroring its initial development findings.
- The MM score offers a more reliable tool for assessing fracture risk in this patient population.
