Why is micromotion so valuable in fracture healing?
It is widely recognized that micromotion contributes to fracture healing by stimulating the formation of bridging callus. Studies of dynamic plating and flexible external fixation devices in large animals and humans have demonstrated an improved time structural bone healing response when a small amount of micromotion was enabled alongside torsional stability.
To assess clinical opinions regarding the science of micromotion in fracture fixation, a survey of fellowship-trained orthopaedic trauma surgeons was conducted in the United States.* Universally, these surgeons concurred that micromotion is a strong determining factor in fracture healing. Micromotion was understood by the surgeons to be critical to healing under conditions of relative stability. However, the survey revealed a problematic lack of available information on how much micromotion is produced by intramedullary nailing constructs under typical post-operative loading conditions.
Figure 1 – The value of controlled axial micromotion from the device itself, to patient outcomes, to the healthcare systems and to the trauma surgeons implanting the Apex Tibial Nailing System in Micromotion Locking Mode.
Surveyed surgeons expressed a desire for an intramedullary nail that solves current clinical challenges, notably the persistent problem of nonunion in tibial shaft fractures. Reducing the burden of revision surgery benefits the patient, the healthcare system, and society. See Figure 1.
Survey respondents also indicated a strong preference for the use of a tibial intramedullary nail with micromotion for their high-risk fracture cases, including open injuries, comminuted fractures, and patients with pre-existing comorbidities that placed them into the high-risk category, such as cigarette smoking, diabetes, and alcohol or substance abuse.
Figure 2 – Micromotion locking with the Apex Tibial Nailing System allows 1 mm of controlled cyclic axial compression during weightbearing by means of a preassembled proximal stem insert.
The Apex Tibial Nailing System combines the benefits of micromotion with the biomechanical and procedural advantages of intramedullary nailing. The gliding proximal stem insert allows 1mm of controlled axial micromotion with unparalleled torsional stability (see Figure 2). The Apex Tibial Nail is the first and only implant to target optimized fracture fixation biomechanics in the early healing period through this combination of axial micromotion and torsional stability. The Apex Tibial Nail has CE Mark Certification in Europe and FDA 510(k) clearance in the United States. The system is in clinical use with new suprapatellar instrumentation and is available for surgeons in both markets and is intended for use in a wide variety of tibial shaft fractures.
*25 Fellowship Trained Orthopaedic Surgeons interviews and analysis conducted by Strategy Inc. Disclosure an honorarium of $500 was paid per physician for participation.