Axial Micromotion Locking Plate Construct Can Promote Faster and Stronger Bone Healing in an Ovine Osteotomy Model

Abstract

Fixing bone fractures with controlled axial interfragmentary micromotion improves bone healing; however, the optimal type of implant construct for this purpose is still lacking. The present study describes a novel axial micromotion locking plate (AMLP) construct that allows axial interfragmentary micromotion of 0.3 or 0.6 mm. We investigated whether the AMLP constructs enhance bone healing compared to an ordinary locking plate (LP) using an ovine osteotomy model. The stiffness of the constructs was tested under axial loading. We created a 3-mm osteotomy in the left hind leg tibia of sheep that was then stabilized with a 0.3- or 0.6-mm AMLP or LP construct (n = 6/group). Bone healing was monitored weekly by X-ray radiography starting from week 3 after surgery. At week 9, the specimens were collected and evaluated by computed tomography and torsional testing. We found that the AMLPs had a lower stiffness than the LP; in particular, the stiffness of the 0.6-mm AMLP construct was 86 and 41% lower than that of the LP construct for axial loads <200 and >200 N, respectively. In the in vivo experiments, tibial osteotomies treated with the 0.6-mm AMLP construct showed the earliest maximum callus formation (week 5) and the highest volume of bone callus (9.395 ± 1.561 cm3 at week 9). Specimens from this group also withstood a 27% greater torque until failure than those from the LP group (P = 0.0386), with 53% more energy required to induce failure (P = 0.0474). These results demonstrate that AMLP constructs promote faster and stronger bone healing than an overly rigid LP construct. Moreover, better bone healing was achieved with an axial micromotion of 0.6 mm as compared to 0.3 mm.

Locked Intramedullary Total Wrist Arthrodesis: A Report of Three Patients With Distal Screw Migration

“…This motion resolves once a fracture has healed or fusion is complete. Fixation constructs are designed to provide relative and not absolute stability as some degree or micromotion is desirable to achieve a bony union [ 6 ]. Too much motion, however, at a fracture or fusion site can lead to nonunion and subsequent implant failure.…”

Influence of different fixation modes on biomechanical conduction of 3D printed prostheses for treating critical diaphyseal defects of lower limbs: A finite element study

“…Local biomechanical environment is an important factor that affect the regeneration and remodeling of new bone ( 13 , 30 ). Additionally, studies have demonstrated that less rigid fixation and comparable motion improved bone healing, and interfragmentary micromotion was thought to be a prerequisite for healthy fracture union ( 31 , 32 ). The same notion applies to bone growth after prosthesis implantation inside a bone defect.…”

A Review of the Impacts of Implant Stiffness on Fracture Healing

“…Furthermore, biological bridge plating aids in preserving the blood supply, facilitating a functional reduction in complex fractures [31]. Some types of locking plates offer a comparatively stable fixation for fractures while allowing adjustments to reduce the stiffness [32,33]. Fracture treatment devices characterized by excessive stiffness have been reported to result in suboptimal outcomes, including delayed bone healing and failure of the healing process [17,34].…”