IN BRIEF

Better Bone Healing by Reversing Current Techniques?

April 10, 2020

Bones may heal denser and stronger when given room for controlled micro-movement at first, followed by rigid stabilization — a complete flip-flop of the standard of care.

A combination of biology and mechanical influence determines how well a bone heals, for better or worse. For half a century, physicians have believed that complete bone immobilization after a fracture, followed by a gradual increase in movement and weight-bearing, is the optimal way to spur new bone growth and effective healing. Now, research in large and small animal models suggests the reverse approach (called reverse dynamization) may be more effective.

“Biologically, it makes sense that dynamization may not be the best solution, since it’s like trying to glue two pieces of wood together while you move them back and forth,” says Christopher Iobst, MD, director of the Center for Limb Lengthening and Reconstruction at Nationwide Children’s Hospital. “The glue doesn’t set well.”

The underlying concept of reverse dynamization is that, after the body begins to make new bone — a process that happens the fastest immediately after the break and when there is some mobility allowed — fixation should allow the bone to mature and fully heal. Dr. Iobst was searching for possible ways to improve bone healing and patient experience when he first discovered promising work on reverse dynamization in rats by Vaida Glatt, PhD, director of basic science research at University of Texas Health – San Antonio. Dr. Iobst and collaborators Mikhail Samchukov, MD, and Alexander Cherkashin, MD, co-directors of the Center for Excellence in Limb Lengthening and Reconstruction at Texas Scottish Rite Hospital, reached out to Dr. Glatt to develop a study using a large animal model.

The study team used three fracture treatment models: complete immobilization, dynamization (micromovement the entire time), and reverse dynamization (micromovement for 3 weeks, followed by 5 weeks of rigid fixation). The fracture sites were examined for bone callus, bone volume, bone density — a better indicator of quality than volume — and strength under stress.

Fractures undergoing reverse dynamization healed stronger and with greater bone density than either other treatment method, and the differences were statistically significant. Dr. Iobst presented the group’s research at the 2019 Limb Lengthening and Reconstruction Society’s Annual Meeting, where it received the award for Best Basic Science Research.

“If these results in animals are confirmed by early human studies, it could really change the fields of limb reconstruction and orthopedic trauma,” says Dr. Iobst.

 

Reference:

Glatt V, Samchukov M, Cherkashin A, Singh S, Iobst C. “Reverse dynamization accelerated bone healing in a large animal osteotomy model.” Presentation at the Limb Lengthening and Reconstruction Society 28th Annual Scientific Meeting; Jun 2019. Boston, MA.

Image credit: Adobe Stock