(P 240) IDENTIFYING PATIENTS AT HIGH RISK OF HIP FRACTURE DUE TO BONE TUMORS BY COMPUTATIONAL BIOMECHANICS: A RANDOMIZED PROSPECTIVE CLINICAL STUDY

Objective: The low sensitivity of Mirels' score poses challenges in predicting fracture risk in patients with metastatic tumors in the femur. However, there is a promising quantitative patient-specific decision support tool called Simfini-TUMOR, which is an autonomous CT-based finite element analysis system (CTFEA) [2,3]. This study evaluates the clinical performance of CTFEA in a prospective randomized trial.

Methods: Patients with femoral metastatic tumors who were referred to the orthopedic oncology department were included in the study. Two orthopedic oncology surgeons assessed the need for prophylactic surgery, and CTFEA analysis was conducted to evaluate the fracture risk. In the study group, the surgeons were provided with the CTFEA analysis report containing a quantified fracture risk to aid their final decision-making. In the control group, the surgeons were unaware of the CTFEA results, and patients received treatment based on the initial surgeons' recommendation. The randomization ratio between the study and control groups was 2:1. All patients were followed up for a duration of four months. The study flowchart can be found in Figure 1. A total of 110 patients were enrolled in the study between 2017 and 2023, and a statistical analysis was conducted. Each femur underwent a simulated stance position loading CTFEA with a force of 2.5 times the body weight applied at the femur's head to determine the fracture risk.

Results: 98 CTFEAs were successfully completed. 12 CTs were excluded due to either implants in the other femur or those who did undergo a surgery but could not be followed for 4 months (died).
The study group contains 64 patients (37 Females, 27 males), ages 31-89, mean 64, STD 13.4. The control group contains 34 patients (17 females, 17 males), ages 36-83, mean 64. STD 11.8. Most common tumors types were breast (26%) and prostate (13%).
The CTFEA was completed successfully in 90% of the cases.
In the study group, 34 surgeries (53%) were performed whereas in the control group 19 surgeries (56%)
In 95% of the cases where the CTFEA predicted low risk of fracture (and thus recommended not to perform surgery), the patient did not fracture the femur during the following 4 months.
In the study group there were two fractures (3%) – one month and two and a half months after the CT scan, in both cases the analysis predicted high risk of fracture in the fractured regions. In the control group there was one fracture (3%) 6 months after the CT scan, caused by a fall.

Conclusion: The preliminary results show that CTFEA is a valuable tool in the clinical decision making process, and is able to assist the surgeon in making the best treatment choice for the patient. In two recorded cases of fractures CTFEA suggested a high risk of fracture in the correct regions.
In the study group the surgeons decided not to perform a prophylactic surgery, whereas the CTFEA indicated a high risk of fracture. Following CTFEA results a new X-ray showed a crack initiation in femur’s neck, the patient underwent immediately a fixation procedure, avoiding a complicated fracture to occur.
In many cases CTFEA results strengthens the clinical decision.

References
[1] Yosibash Z, Myers K, Trabelsi N, Sternheim A, "Autonomous FEs (AFE) - A stride toward personalized medicine", Comp. Math. Appl., 80(11), pp. 2417-2432, 2020.
[2] Sternheim A, Giladi O, Gortzak Y, Drexler M, Salai M, Trabelsi N, Milgrom C and Yosibash Z, “Pathological fracture risk assessment in patients with femoral metastases using CT-based finite element methods. A retrospective clinical study”, Bone, 110, pp. 215-220, 2018.
[3] Sternheim A, Traub F, Trabelsi N, Gortzak Y, Dadia S, Snir N, Gorfine M and Yosibash Z., “When and where do patients with bone metastases actually break their femur? A CT-based finite element analysis of patients”, Bone & Joint Jour., 102-B, No. 5, pp. 638-645, 2020.