Can patient-specific finite element models better predict fractures in metastatic bone disease than experienced clinicians?

Abstract

ObjectivesIn this prospective cohort study, we investigated whether patient-specific finite element (FE) models can identify patients at risk of a pathological femoral fracture resulting from metastatic bone disease, and compared these FE predictions with clinical assessments by experienced clinicians.MethodsA total of 39 patients with non-fractured femoral metastatic lesions who were irradiated for pain were included from three radiotherapy institutes. During follow-up, nine pathological fractures occurred in seven patients. Quantitative CT-based FE models were generated for all patients. Femoral failure load was calculated and compared between the fractured and non-fractured femurs. Due to inter-scanner differences, patients were analyzed separately for the three institutes. In addition, the FE-based predictions were compared with fracture risk assessments by experienced clinicians.ResultsIn institute 1, median failure load was significantly lower for patients who sustained a fracture than for patients with no fractures. In institutes 2 and 3, the number of patients with a fracture was too low to make a clear distinction. Fracture locations were well predicted by the FE model when compared with post-fracture radiographs. The FE model was more accurate in 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.ConclusionFE models can be a valuable tool to improve clinical fracture risk predictions in metastatic bone disease. Future work in a larger patient population should confirm the higher predictive power of FE models compared with current clinical guidelines.Cite this article: 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. Can patient-specific finite element models better predict fractures in metastatic bone disease than experienced clinicians? Towards computational modelling in daily clinical practice. Bone Joint Res 2018;7:430–439. DOI: 10.1302/2046-3758.76.BJR-2017-0325.R2.

Effect of different CT scanners and settings on femoral failure loads calculated by finite element models

“…However, to what extent the simulations were affected by the air artifact remains unclear, as the change in position in the gantry also played a role. In our previous patient study, we noted that air gaps induced a visibly larger artifact in the calibration phantom compared to the current results. Additionally, this artifact was only seen in scans made on a relatively old CT scanner (AcQSim CT, Philips Medical Systems, Eindhoven, The Netherlands).…”

“…The subject‐specific geometry and BMD are used as input for the FE models. Recently, studies using FE models showed promising results in discriminating patients with a low fracture risk from patients with a high fracture risk …”

Modeling the Human Bone–Tumor Niche: Reducing and Replacing the Need for Animal Data

“…(48,49) This approach might also be applied to the context of cancer-induced bone disease, as demonstrated by Eggermont and colleagues who incorporated patient-specific finite-element analysis to predict fracture risk in individuals with bone metastasis. (50) The bone-remodeling process, involving bone formation and destruction by osteoblasts and osteoclasts, respectively, has been abstracted in mathematical models. The basic multicellular unit, which consists of models of these cells, has been studied in a normal context as well as in disease.…”

“…Similarly, attempts to assess bone mathematically have resulted in models describing alterations in physical properties such as bone strength, trabecular structure, permeability, and bone healing . This approach might also be applied to the context of cancer‐induced bone disease, as demonstrated by Eggermont and colleagues who incorporated patient‐specific finite‐element analysis to predict fracture risk in individuals with bone metastasis . The bone‐remodeling process, involving bone formation and destruction by osteoblasts and osteoclasts, respectively, has been abstracted in mathematical models.…”

Distinguishing fact from fiction in finite element analysis

“…This is often not practical in terms of computational effort and thus proxies are often used. For bone and implant materials this has included regions where strain concentrates excessively [17,18]; or the volume of elements within a defined region experiencing strain above the yield point for that material [4,6].…”