What is Micromotion? OrthoXel’s patented gliding insert explained

February 28th, 2024

This month, we are providing an insight into our unique patented micromotion technology, with particular focus on its use in our Apex Tibial Nailing System. We will recall how the success of the Apex Tibial Clinical Study led to the further development of our Apex Femoral Nailing Systems.

In 2009, Prof. Harty (CMO) highlighted the severity of complications associated with lower limb fracture nonunions to Pat (CEO), Hannah (CSO), and Charles (CTO). Together they began developing the concept of a nail with a moving part allowing for controlled axial micromotion, based on evidence of faster fracture healing in external fixators with micromotion. Following successful early concept testing, cadaver studies, and a large animal study, the micromotion-enabled Apex Tibial Nail became a reality in 2014.

What is Micromotion Technology?

OrthoXel’s patented Micromotion gliding insert facilitates 1mm controlled axial micromotion, creating a biomechanically optimal construct to stimulate bone callus formation. This movement initiates the cellular process that converts mechanical loads into chemical signals, ultimately accelerating and improving fracture repair and fixation. It also generates best-in-class torsional stability via the insert design which prevents rotation of the bone fragments.

Simply put, the insert creates a straight-line motion within the nail, triggering a biological response that assists with faster fracture healing.

Micromotion Fixation in IM Nailing: An Unmet Need

Following a long bone shaft fracture, approximately 1 in 4 patients encounter complications with their bone healing, resulting in delayed union or nonunion.

Apex Nailing Systems address this unmet need. Based on data from tibial fractures treated in North American Level I Trauma Centres, U.S. Managed Care Claims Data, as well as data from the UK and Europe, the incidence of tibial nonunions ranged between 7%19% (refs 1,2,3). Patients with nonunion fractures often require multiple revision surgeries over extended periods of time, typically facing more pain which therefore leads to prolonged use of opioids compared to patients with normal healing.

This causes higher rates of depression requiring treatment and longer periods of disability, resulting in greater loss of earned income. Less than 60% of patients with tibial fracture nonunion can return to work within one year. OrthoXel developed the Apex Nailing Systems to accelerate fracture healing and alleviate these clinical challenges associated with delayed healing and nonunion.

Apex Nailing Systems

The Apex Nailing Systems are the first and only micromotion-enabled IM nailing systems that are specifically designed to stimulate bone healing. Our portfolio consists of Tibial, Femoral Antegrade and Femoral Retrograde systems. Click the image here to review our full range.

Clinical Evidence

OrthoXel conducted a clinical study in Cork, Ireland (2018-2021) that evaluated the success of the Apex Tibial Nailing system with micromotion fixation against traditional intramedullary nailing. The study in CUH was conducted over a 2-and-a-half-year period with patients being treated in a single level 1 trauma center in Cork, Ireland. The 3 items it focused on were:

  • Healing Speed: Assessing the time required for clinical union.
  • Incidence of Complications: Including delayed healing and nonunion.
  • Early Mechanical Integrity of New Bone: Evaluating the strength of newly formed bone.

There were 2 patient groups: the micromotion group implanted with OrthoXel’s Apex Tibial Nails with micromotion fixation and a group implanted with benchmark intramedullary nails (control). The comparison between these two groups was centered around the analysis of the three items above whilst also focusing on the primary fixation mode: either micromotion or standard-of-care static locking mode.

The Apex implants generated beneficial passive motion during the early healing period while a patient goes about their normal activities of daily living. The control group static locking means that the implant did not generate passive micromotion. These patients in the clinical study were enrolled at the time of their implant surgery and followed for 1-year post-surgery. The patient cases included in the study encompassed a variety of fracture types, incorporating both open and closed injuries, with a blend of high- and low-energy impact orthopaedic traumas.

Clinical Study Results

The findings of the study revealed superior clinical outcomes of OrthoXel’s Apex Tibial Nailing System with controlled micromotion across all key clinical measures.

“All micromotion patients united without additional interventions (i.e. there were zero nonunions). By comparison, the 11% nonunion rate in the control group is consistent with expectations for the current standard of care from the clinical literature.” Bone & Joint Open (2021)

Moreover, patients undergoing micromotion treatment experienced faster healing compared to those treated with static locking, resulting in fewer instances of delayed union. CT scans showed that micromotion significantly enhanced bone formation, particularly among patients with co-morbidities or underlying health condition such as smoking and diabetes.

In summary, the findings from this study suggest that Apex micromotion nailing holds promise in reducing the occurrence of delayed healing and nonunion, while also accelerating the healing process for all patients. The key takeaways from this study are as follows:

Compared to the current standard of care, tibial fractures treated with Apex Micromotion fixation had:

  • Significantly faster healing
  • Zero nonunions
  • Significantly reduced incidence of delayed healing
  • Significantly more new bone in high-risk patients

Have a look at our Apex Tibial Clinical data presentation that was given by our CSO, Professor Hannah Dailey: Apex Tibial Clinical Data Presentation

Spotlight on Professor Hannah Dailey

OrthoXel’s Chief Scientific Officer

Hannah Dailey is an Assistant Professor of Mechanical Engineering and Mechanics at Lehigh University (Pennsylvania, USA) and one of the co-founders of OrthoXel. Prof. Dailey has played a pivotal role in the development of the Apex Nailing Systems, leading the research and development of micromotion technology.

Prof. Dailey remarked,

I am very proud of our innovative technology, which optimizes the biomechanics of fracture fixation to achieve faster healing. For the last 30 years, intramedullary nails have increasingly focused on features to enhance stability and clinical outcomes have plateaued. Apex nails are different because they provide axial motion without sacrificing rotational stability. Patients get all benefits of mechanical stimulation to kickstart healing through passive limb loading immediately after surgery. We are excited about the performance of the Apex products and to see additional clinical studies beginning in the US in 2024.

Prof. Dailey recently attended the Orthopedic Research Society (ORS) Annual Meeting this year in Long Beach, California. She participated in the judging panel of this year’d Business Innovation Competition. Check out the LinkedIn post here: ORS 2024