Success stories
Bone Cap: Offering new possibilities for all lower-limb amputees
Most people with major lower limb amputations rely on prosthetic devices to regain mobility. However, their long-term outcomes depend on several factors, such as the level of the amputation (above or below the knee) and how the prosthesis is attached. The two main options are conventional socket prostheses, which fit over the residual limb, and direct skeletal fixation, where an implant extends through the skin to directly attach to the prosthesis. Both present a difficult trade-off. Sockets can lead to chronic pain, tissue damage and skin breakdown as it transfers body weight through soft tissues. Direct skeletal fixation avoids this, but introduces a high risk of superficial and deep infection where the implant passes through the skin.
Bone Cap is an implant surgically placed at the end of an amputated bone
Bone Cap, a new venture from an Imperial College London researcher, was inspired by the superior function of knee disarticulation (through-knee) amputations, which retain the naturally wide, rounded end of the femur. “This structure allows patients to bear weight directly through the residual bone, often resulting in less pain, greater prosthesis use and improved quality of life,” explains Dr Dylan Ashton, co-founder of Bone Cap. “Our goal was to replicate these benefits for people with above-knee (transfemoral) and below-knee (transtibial) amputations, without the safety risks of transcutaneous ‘through-skin’ implants.”
Bone Cap is an implant surgically placed at the end of an amputated bone, reshaping it to mimic the natural, load-bearing structure of a joint. By creating a larger, rounded surface, the implant distributes forces more evenly across the soft tissues. This reduces pressure points and soft-tissue damage, allowing a patient to comfortably bear weight through their limb while using a standard socket prosthesis. The ultimate aim is simple but profound: “The goal of Bone Cap is to help people with lower limb loss walk further, with less pain, and regain greater independence in daily life,” says Dr Ashton.
Now in the late pre-clinical stage, Bone Cap has successfully completed its laboratory proof-of-concept. Rigorous mechanical, biological and usability testing has verified the implant’s safety and performance, demonstrating strong integration with bone and meeting key strength requirements. A custom surgical tool has also been developed to ensure the implant can be fitted efficiently. Engagement with surgeons, prosthetists, and potential patients has confirmed a strong clinical need for the device, and early health economic modelling indicates it has the potential to reduce long-term healthcare costs.
This promising progress has been recognised with a prestigious Royal Academy of Engineering Enterprise Fellowship, awarded to Dr Ashton to support the technology’s journey to market.
The next 12 months are set to be transformative for the venture. The plan is to formally spin out the company and submit a clinical investigation application to the MHRA for a first-in-human trial. Fundraising efforts will focus on securing the capital needed to deliver this crucial trial and begin the commercial activities required to navigate the path to CE/UKCA and FDA approvals.
Dr Ashton credits the MedTech SuperConnector with being a key catalyst in this transition from research to commercialisation. “The MedTech SuperConnector program provided invaluable support in refining my pitch, preparing for investor engagement, and shaping our business model and commercial strategy,” he says. “It also strengthened my entrepreneurial skill set, helping me to start the transition from an academic founder to a commercially focused CEO.”
