As longer life expectancy coincides with an increase in the aging population, traumatic hip fractures requiring fixation become more common. In 2000, 1.6 million new osteoporotic hip fractures occurred, according to the International Osteoporosis Foundation, a number that is expected to reach between 4.5 million and 6.3 million by 2050. Of those surgeries, there is about a 6% reoperation rate for those using screws to anchor the bone.
Dublin-based X-BOLT Orthopaedics seeks to address the problem of screw cut out with its technology that replaces the lag screw for femoral head fixation in either a hip nailing or plating construct. Rather than a screw-based technology that rotates into the bone without good rotational stability, X-BOLT does away with the screw bit altogether and provides rotational stability and better anchorage. Studies indicate that the system significantly reduces the reoperation rate.
The vast majority of patients who are undergoing hip fracture fixation surgery are elderly, many with osteoporosis and other health conditions.
“The average age of the [hip fracture] patients is the mid-80s,” said Brian Thornes, M.D., Chief Executive Officer of X-BOLT. “Hip fracture is a devastating injury for most of these patients who are very fragile. If they have to have a second surgery on top of their initial surgery, which tends to be a bigger surgery anyway—you have to take out all the metalwork before putting more in—it’s quite a huge undertaking for these patients.”
X-BOLT’s goal is to get it right the first time. A single operation not only significantly increases the quality of life and success rate for patients, but also saves hospitals from unnecessary costs.
“A typical hospital doing 200 hip fixations a year will needlessly spend more than $500,000 for failed hip fixations,” Dr. Thornes said.
As with many inventions, the idea for X-BOLT came to Dr. Thornes during a simple everyday task.
“I was putting an expanding bolt into the wall to hang a TV on the wall of my apartment. It was like a molly bolt; it expands into the wall,” he said. “And I thought that we needed to have something similar for orthopedics, for hip fixation, and that’s the genesis of how it all kicked off.”
He applied the concept to a hip fixation bolt that could expand within the bone. The X-BOLT can be made out of titanium or stainless steel, depending on the overall nailing or plating construct. The technique is similar to existing nailing or plating constructs, so no real learning curve is required for surgeons.
Typical technology using screws can be problematic within osteoporotic bone, and the screw’s rotational stability can also pose issues. The X-BOLT ‘s expanding bolt technology is a different concept. It compresses surrounding bone, increasing density and giving better anchorage within the hip bone and providing rotational stability with a single device.
X-BOLT is a simple, user-friendly instrument that is similar in technique and construct to a standard sliding hip screw, but with stronger anchorage. The expanding bolt looks similar to a Chinese lantern with a central drive shaft, which then can compress and expand to close the fracture without spinning, pushing or pulling the femoral head.
X-BOLT has an inner drive shaft featuring left-hand threads at the bottom and right-hand threads at the top. When the instrument is turned, it expands out like a carjack and can be closed just as easily.
“It’s designed to be reversible, so if there’s any problem, say if the implant got infected, you can take it out very easily,” Dr. Thornes said.
Dr. Thornes also happens to be the inventor of the ankle syndesmosis TightRope, which was licensed to Arthrex in 2003 and is now sold worldwide. Although he is experienced in creating innovative products, X-BOLT has gone through years of R&D, prototyping, bench testing, getting regulatory approval and running clinical trials since its inception in 2007.
“As a small company, a large part of your time is taken up by the regulatory side of things,” Dr. Thornes said. “Thankfully, we have our FDA clearance as of Q4 2018, having spent a long time trying to get through there.”
An initial trial, WHITE1, was a 100-patient, randomized, controlled trial published in 2016 that showed a 0% reoperation rate among patients using X-BOLT, compared to a 6% reoperation rate for those using a screw. Following WHITE1, a much larger trial was launched.
“I realized at the early stage with the X-BOLT device that we needed a big trial to change surgeon perception on using it,” Dr. Thornes said. “If you’re a big brand company, you can introduce a new product quite easily and surgeons will accept it because of your brand value. But as a small startup, you need to either have brand value, of which we had none, or have very good scientific evidence. And to get very good scientific evidence, we needed a big trial.”
The WHITE4 trial is the largest-ever clinical trial in hip fracture fixation, running from June 2016 to August 2018 in 10 centers in the U.K. One-year follow-up was completed on the 1,000th patient in January 2019. Preliminary study results presented at the British Orthopaedic Association Annual Congress in September 2019 demonstrated a cut-out rate of 0.8% in a population of 476 patients.
Using feedback gleaned from surgeons during the WHITE1 and WHITE4 trials, X-BOLT Orthopaedics plans to update the current X-BOLT design to improve its functionality. About 80%-90% of the X-BOLTs that have been used were implanted through the WHITE1 and WHITE4 trials. The surgeons provided feedback, and the enhanced Generation 2 X-BOLT will include improvements such as reduced tip apex distance, easier manufacturability and better fatigue characteristics at the hinges where X-BOLT opens and closes.
“The updated X-BOLT will be easier to insert for deeper placement, easier to manufacture and will have better fatigue characteristics,” Dr. Thornes said. “The next generation X-BOLT should be better again, and can be easily modified to fit any competitor’s hip nailing or plating system.”
X-BOLT Orthopaedics has patented instrumentation that would make hip fracture surgery faster and easier, particularly in obese patients. The Curved Jig and Flexible Drive are not on the market yet, but are in X-BOLT’s kit. These allow surgeons to operate around a corner, resulting in less soft tissue disruption.
“You can actuate all the instruments from outside the body rather than actually having to go into the patient wound,” Dr. Thornes said. “The big advantage in obese patients is you have less of a soft tissue path to traverse.”
X-BOLT is also looking into R&D for additional anatomical fractures.
“Anyone who has osteoporosis that needs fixation, the X-BOLT could work,” Dr. Thornes said. “So we’ve modified some parts of the X-BOLT so that it would be compatible with a spinal fixation like a pedicle screw, and it offers some advantages in that it would be easier to put in and less disruptive to breaking some of the cortical bone in the pedicles.”
As the second half of 2019 unfolds, X-BOLT seeks to partner with a device company to commercialize the technology.
“I think surgeons can be very open to using new technologies, and the newer companies tend to tap into those,” Dr. Thornes said. “So whether we go with a bigger company or a mid-sized company that looks to disrupt, we’re happy with either. I think it’s very exciting what the future might hold for us.”
Heather Tunstall is an ORTHOWORLD Contributor.