Biomechanical Variability and Usability of a Novel Customizable Fracture Fixation Technique

Abstract

A novel in situ customizable osteosynthesis technique, Bonevolent™ AdhFix, demonstrates promising biomechanical properties under the expertise of a single trained operator. This study assesses inter- and intra-surgeon biomechanical variability and usability of the AdhFix osteosynthesis platform. Six surgeons conducted ten osteosyntheses on a synthetic bone fracture model after reviewing an instruction manual and completing one supervised osteosynthesis. Samples underwent 4-point bending tests at a quasi-static loading rate, and the maximum bending moment (BM), bending stiffness (BS), and AdhFix cross-sectional area (CSA: mm²) were evaluated. All constructs exhibited a consistent appearance and were suitable for biomechanical testing. The mean BM was 2.64 ± 0.57 Nm, and the mean BS was 4.35 ± 0.44 Nm/mm. Statistically significant differences were observed among the six surgeons in BM (p < 0.001) and BS (p = 0.004). Throughout ten trials, only one surgeon demonstrated a significant improvement in BM (p < 0.025), and another showed a significant improvement in BS (p < 0.01). A larger CSA corresponded to a statistically significantly higher value for BM (p < 0.001) but not for BS (p = 0.594). In conclusion, this study found consistent biomechanical stability both across and within the surgeons included, suggesting that the AdhFix osteosynthesis platform can be learned and applied with minimal training and, therefore, might be a clinically viable fracture fixation technique. The variability in BM and BS observed is not expected to have a clinical impact, but future clinical studies are warranted.

Keywords: in situ customizable osteosynthesis; patient-specific osteosynthesis; surgical skills; usability; variability.

Figure 1

Illustration of the stepwise application of the AdhFix-technique.

Figure 2

Illustration of the synthetic bone model (one fragment shown).

Figure 3

Illustration of the four-point bending fixture and example of AdhFix fixation on the synthetic bone fracture model.

Figure 4

Example of samples after four-point bending to failure.

Figure 5

Boxplot of max bending moment (Nm) for each of the six surgeons included in the study (S1–S6). One outlier illustrated in S2.

Figure 6

Boxplot of bending stiffness (Nm/mm) for each of the six surgeons included in the study (S1–S6).

Figure 7

Linear model of max bending moment (Nm) for all surgeons (S1–S6) across 10 consecutive trials (1–10).

Figure 8

Linear model of bending stiffness (Nm/mm) for all surgeons (S1–S6) across 10 consecutive trials (1–10).