Early resistance rehabilitation improves functional regeneration following segmental bone defect injury

Many studies have explored different loading and rehabilitation strategies, yet rehabilitation intensity and its impact on the local strain environment and bone healing have largely not been investigated. This study combined implantable strain sensors and subject-specific finite element models in a 2 mm rodent segmental bone defect model. After injury animals were underwent high or low intensity rehabilitation. High intensity rehabilitation increased local strains within the regenerative niche by an average of 44% compared to the low intensity rehabilitation. Finite element modeling demonstrated that resistance rehabilitation significantly increased compressive strain by a factor of 2.0 at week 2 and 4.45 after 4 weeks of rehabilitation. Animals that underwent resistance running had the greatest bone volume and improved functional recovery with regenerated femurs that matched intact failure torque and torsional stiffness values. These results demonstrate the potential for early resistance rehabilitation to improve bone healing.