Patient-specific computer models can help predicting fracture risk

12 July 2018

Patient-specific computer (finite element (FE)) models are a potential tool to improve clinical fracture risk predictions in patients with metastatic bone disease. That was concluded in a study by Eggermont et al., recently published in Bone and Joint Research.

Patients with cancer and bone metastases have an increased risk of pathological fractures, which severely affect the quality of life. Treatment of patients with bone metastases is based on the fracture risk: patients with a low fracture risk will be treated conservatively with local radiotherapy, while patient with a high fracture risk are considered for preventive stabilizing surgery. However, current clinical practice lacks an accurate tool to guide clinicians to the correct treatment decision. Therefore, researchers from the Orthopaedic Research Lab have been developing an FE model for fracture risk prediction, which was previously validated using cadaveric femurs. The next step was to evaluate the FE models in a multi-center prospective cohort study. A total of 39 patients with non-fractured femoral metastatic lesions who were treated with radiotherapy were included. All patients underwent CT scans, from which the patient-specific geometry and bone density were obtained, that functioned as input to the FE models. An axial load was simulated on the FE models and femoral failure load was calculated. Patients were followed for six months, during which nine pathological fractures occurred. FE-predicted failure loads were compared between fractured and non-fractured femurs. In addition, the FE-predictions were compared with fracture risk assessments by experienced clinicians.The FE model was more accurate at identifying patients with a high fracture risk compared with experienced clinicians, with a sensitivity of 89% versus 0% to 33% for clinical assessments. Specificity was 79% for the FE models versus 84% to 95% for clinical assessments. It was concluded that FE models can be a valuable tool to improve clinical fracture risk predictions in metastatic bone disease, mainly to prevent unnecessary surgeries.

Publication
Can patient-specific finite element models better predict fractures in metastatic bone disease than experienced clinicians? Towards computational modeling in daily clinical practice. 
F. Eggermont, L. C. Derikx, N. Verdonschot, I. C. M. van der Geest, M. A. A. de Jong, A. Snyers, Y. M. van der Linden, E. Tanck.

Florieke Eggermont is member of research theme Reconstructive and regenerative medicine.