Background: The primary aim of this study was to determine and compare the biomechanical properties of a fractured or intact rib after implant fixation on an embalmed thorax. Methods: Five systems were fixated on the bilateral fractured or intact (randomly allocated) 6th to 10th rib of five post-mortem embalmed human specimens. Each rib underwent a four-point bending test to determine the bending structural stiffness (Newton per m²), load to failure (Newton), failure mode, and the relative difference in bending structural stiffness and load to failure as compared to a non-fixated intact rib. Findings: As compared to a non-fixated intact rib, the relative difference in stiffness of a fixated intact rib ranged from −0.14 (standard deviation [SD], 0.10) to 0.53 (SD 0.35) and for a fixated fractured rib from −0.88 (SD 0.08) to 0.17 (SD 0.50). The most common failure mode was a new fracture at the most anterior drill hole for the plate and screw systems and a new fracture within the anterior portion of the implant for the clamping systems. Interpretation: The current fixation systems differ in their design, mode of action, and biomechanical properties. Differences in biomechanical properties such as stiffness and load to failure especially apply to fractured ribs. Insight in the differences between the systems might guide more specific implant selection and increase the surgeon's awareness for localizing hardware complaints or failure.

Objectives: During osteosynthesis of a fracture patients are exposed to the primary radiation of an X-ray image and scattered (secondary) radiation. The primary objective was to measure the amount of scattered radiation at the thyroid, breast tissue, and gonads of patients undergoing primary osteosynthesis of acute fractures. The secondary objective was to calculate the effective dose caused by scattered radiation. Methods: In this multicenter prospective observational case series patients undergoing a primary osteosynthesis of an acute fracture of hand/wrist, shoulder, ankle, knee, or hip were included. Three dosimeters were attached to the patient at the level of the thyroid, breast and gonads. Scattered radiation doses were corrected for the average background radiation per hospital per day. Results: A total of 205 patients were included between March 6, 2017 and June 18, 2018; 49 (24%) had a hand/wrist fracture, 37 (18%) a shoulder fracture, 47 (23%) an ankle fracture, 35 (17%) a knee fracture, and 37 (18%) a hip fracture. In 32–39% of all patients undergoing primary osteosynthesis effective scattered doses was detected. The highest measured median effective dose was 60.43 µSv (P₂₅–P₇₅ 33.84–100.76) at the gonads during hip osteosynthesis. Conclusions: The results of this study show that scattered radiation is detectable in a third of patients undergoing an osteosynthesis. However, both effective doses due to direct radiation and scattered radiation are low. Advances in knowledge: This is the first study that presents that no radiation protection for patients undergoing an osteosynthesis is necessary.