Title: Restore healthy biomechanics after early intervention orthopaedic surgery
Funder: Department of Health and Social Care

Abstract: Background Osteoarthritis is one of the leading causes for disability worldwide. The most established treatments are designed to treat end stage disease, but early intervention procedures to prevent or delay the disease progression are getting popular. This research aims to improve these treatments by better recreating healthy biomechanics post-surgery. Aims & Objectives The proposed research aims to restore healthy biomechanics after early intervention orthopaedic surgery. Specific objectives are to: (1) Assess the efficacy of different joint preserving surgical techniques and propose modified techniques that better restore healthy biomechanics. (2) Create a method to manufacture implant materials that control bone strain (which drives bone mechanoresponse). (3) Design prototype implants for hip, knee and spine applications. Methods The joint preserving surgical techniques will be performed on cadaver specimens, and the biomechanics tested in a robot that makes the specimens perform physiological activities. Using this system, we will investigate surgery for femoroacetabular impingement and developmental dysplasia of the hip (DDH), and measure synovial fluid pressures, joint loads, cartilage contact pressures, ligament strains and joint kinematics for different activities. Then we will propose modified surgical techniques related to incision and repair of structures that may improve the biomechanics post-intervention and increase efficacy of the procedures. We will also investigate how muscles that span multiple joints at the hip and knee influence the loading within those joints. Implantable technology will be created that can generate a desired strain gradient in the bone to invoke a desired mechanoresponse. This will be achieved by manufacturing lattice Titanium structures in a range of stiffness that can increase, reduce or maintain the bone strain and thus cause bone formation, loss or maintain homeostasis. Prototypes will be manufactured for different early intervention procedures in the hip and knee, and also a lumbar spine application. Timelines for delivery 20 months: Femoroacetabular impingement study complete, prototype compartmental knee implant validated in cadaver model. 40 months: DDH study of shelf surgery complete, prototype shelf implant and low profile implant fixation surfaces validated in cadaver model. 60 months: DDH study of periacetabular osteotomy complete, prototype spine and osteotomy fixation plate implants validated in cadaver model. Study into multi-segment-spanning muscle loading complete. Anticipated impact and dissemination The impact will be improved early intervention orthopaedic surgery, better patient function at reduced cost to the tax-payer. Dissemination will be via the conventional route of journal publications and conference presentations, but also via unconventional routes including Twitter, Pint of Science, Imperial festival, Patient Public Involvement meetings and other outreach activities that I now routinely use to disseminate research news. Translation to clinical practice will be through surgeon collaborations (the surgical techniques) and industry partnerships (the implant technology).

Lay abstract: Osteoarthritis (OA) is the one of the most common reasons for disability worldwide. The disease is managed over a patient's life using non-surgical intervention like anti-inflammatories and activity modification, followed by surgical procedures of increasing invasiveness: joint preserving surgery, partial joint replacement, total joint replacement and, if necessary, repairing the total joint replacement. This research will attempt to improve the two earliest surgical stages (joint preserving surgery and partial replacement) to delay the need for more drastic surgery like total joint replacement. The research will improve these surgical treatments by better restoring healthy biomechanics of the joint. Restoring healthy biomechanics means maintaining the integrity of ligaments so they can function properly. It means maintaining or reducing the contact pressure on the cartilage surfaces so they do not wear out. If the surfaces are already worn out and need replacing, it means creating implants that do not alter the load transmission within the bone. The research will achieve these things by making human cadaver joint specimens perform physiological activities in the laboratory using robot manipulators. As the research is laboratory based, we can instrument the cadaver specimens with a full set of sensors to measure how different surgical procedures change the biomechanics in all the different structures of the joint. Then we can experiment with modified surgical techniques and implant designs that restore healthy biomechanics better than current treatment.Achieving these research goals will improve early intervention surgery and leave the joint in the best possible condition for later interventions. The research will be translated to clinical practice in the short and long term. In the short term (0-5 years), improvements to surgical technique can be implemented immediately to improve joint preserving surgery. In the longer term (5-10 years), partial joint replacement implants will enter clinical use. These take longer due to the regulations around implants, but our group have the necessary skills and track record to achieve this. The research will be disseminated through conventional channels like journal papers and conference presentations, but key findings will also be posted on our Twitter feed @ICbiomechanics, which is viewed about 7,000 times a month. We will also present research updates at our quarterly Patient Public Involvement Group. The research will also be disseminated through outreach activities like Pint of Science (to a London pub audience) and the Great Exhibition Road Festival (predicted to attract 100,000 visitors in 2019). We will also use the research to encourage the next generation of orthopaedic researchers - we have previously demonstrated testing on CBBC's 'Operation Ouch' children's TV show, which we will seek to repeat. We will also include research findings in our scheduled talks at local secondary schools.

Research activity codes: 6.4 SURGERY
Health categories: MUSCULOSKELETAL