Combined electric and magnetic field therapy enhances bone repair and regeneration in two tibia osteotomy models in sheep.

Abstract

Background: Therapies using electromagnetic field technology show evidence of enhanced bone regeneration at the fracture site, potentially preventing delayed or non-unions. Methods: Combined electric and magnetic field (CEMF) treatment was evaluated in two standardized sheep tibia osteotomy models: a 3 mm non-critical size gap model and a 17 mm critical size defect model augmented with autologous bone grafts, both stabilized with locking compression plates. CEMF treatment was delivered across the fracture gap twice daily for 90 mins, starting 4 days post-operatively (post-OP) until sacrifice (9 or 12 weeks post-OP, respectively). Control groups received no CEMF treatment. Bone healing was evaluated radiographically, morphometrically (micro-CT), biomechanically and histologically. Results: In the 3 mm gap model, the CEMF group (n=6) exhibited higher callus mineral density compared to the Control group (n=6), two-fold higher biomechanical torsional rigidity and a histologically more advanced callus maturity (no statistically significant differences). In the 17 mm graft model, differences between the control (n=6) and CEMF group (n=6) were more pronounced. The CEMF group showed a radiologically more advanced callus, a higher callus volume (p=0.003) and a 2.6x higher biomechanical torsional rigidity (p=0.024), combined with a histologically more advanced callus maturity and healing. Conclusions: This study showed that CEMF therapy notably enhanced bone healing resulting in better new bone structure, callus morphology and superior biomechanical properties. This technology could transform a standard inert orthopedic implant into an active device stimulating bone tissue for accelerated healing and regeneration.