Biomechanical effects of osteoplasty with or without Kirschner wire augmentation on long bone diaphyses undergoing bending stress: implications for percutaneous imaging-guided consolidation in cancer patients.

Background: Osteoplasty has been discouraged in long bones. However, despite a substantial lack of pre-clinical biomechanical tests, multiple clinical studies have implemented a wide range of techniques to optimise long bone osteoplasty. The aim of the present study is to evaluate the biomechanical properties of osteoplasty alone and in combination with Kirschner wires (K-wires) in a cadaveric human diaphyseal model undergoing 3-point bending stress.

Methods: Thirty unpaired human cadaveric hemi-tibia specimens were randomly assigned to receive no consolidation (group 1, n = 10), osteoplasty alone (group 2, n = 10), or K-wires augmented osteoplasty (group 3, n = 10). Specimens were tested on a dedicated servo-hydraulic machine using a 3-point bending test. Fracture load was calculated for each specimen; two-sample Wilcoxon rank-sum tests were used to assess differences between groups.

Results: Median volume of polymethyl methacrylate injected was 18 mL for group 2 (25th-50th percentile 15-21 mL) and 19 mL for group 3 (25th-50th percentile 17-21). There were no significant differences in fracture load between groups 1 and 2 (z = - 0.793; p = 0.430), between groups 1 and 3 (z = - 0.944; p = 0.347), and between groups 2 and 3 (z = - 0.454; p = 0.650). Fractures through the cement occurred in 4 of 30 cases (13.3%); there were no K-wires fractures.

Conclusions: Osteoplasty with or without K-wires augmentation does not improve the resistance of diaphyseal bone to bending stresses.