Biomechanical comparison of a new minimally invasive technique versus conventional plating for the treatment of open book symphyseal injuries in osteoporotic human pelvises.

PURPOSE: Traumatic open book injuries of the pubic symphysis require stable fixation while minimizing surgical morbidity. Traditional symphyseal plating is associated with complications such as implant failure and infections. This study aims to evaluate the biomechanical performance of a novel minimally invasive technique using an internal fixator (IF) compared to conventional plating (symphyseal locking dynamic compression plate [SLDCP]) in human cadaveric pelvises.

METHODS

Ten human cadaveric pelvises were assigned to two groups (n = 5 each). After anatomical reduction, either SLDCP or IF stabilization was applied. Intrasymphyseal compression forces, contact area and interfragmentary motion were assessed using pressure-sensitive sensor films and an optical tracking system under incrementally applied axial loads up to 600 N. Bone density and symphyseal dimensions were measured and were comparable across both groups.

RESULTS

At key loading stages (400 and 600 N), the IF group demonstrated significantly higher intrasymphyseal compression forces (IF 61.78 ± 31.98 N vs. SLDCP 15.98 ± 8.2 N at 400 N and IF 42.82 ± 25.2 N vs. SLDCP 9.42 ± 5.81 N at 600 N) and larger contact areas (IF 453 ± 137.6 mm2 vs. SLDCP 216 ± 135 mm2 at 400 N and IF 337.6 ± 168.45 mm2 vs. SLDCP 154 ± 59.73 mm2 at 600 N), with more homogeneous segmental force and area distributions. Higher compression forces, particularly in the caudal symphyseal region (IF 23.68 ± 18.69 N vs. SLDCP 13.78 ± 10.1 N), were achieved. Three-dimensional analysis showed reduced fragment displacement in the IF group under load.

CONCLUSION

The proposed technique using an internal fixator provided superior biomechanical stability compared to standard plating, offering a promising minimally invasive alternative for managing open book injuries. The technique facilitates uniform force transmission and improved contact conditions, which may enhance healing and reduce complications.

LEVEL OF EVIDENCE: N/A.