Implant-related infection and tendon healing challenges in orthopaedics

We’re living longer and staying more active later in life, but that’s creating new challenges for surgeons, says orthopaedic registrar Dr Scott Bolam, who’s completing his PhD in bone and tendon regenerative medicine.

“One of the best things about orthopaedics is that it not only combines theoretical clinical knowledge with practical skills, but also has a strong interface with emerging technologies and research,” says Scott who’s taken time out from clinical training to engage in high-quality research.

“Being part of a research team means bringing together people with many different backgrounds and skill sets. My research involves clinicians, biologists, bioengineers, physiotherapists, veterinary technicians and statisticians. This collaboration means everyone has a unique perspective on the project.”

He’s involved in several interesting projects. One is designed to enhance healing of rotator cuff tears post-surgery by applying a novel combination of growth factors at the bone-tendon repair site. “We hope these growth factors can modulate the healing process to improve the strength and function of the rotator cuff. We’ve had promising results in vitro and hope ongoing research will eventually lead to us to pre-clinical human trials,” says Scott.

He’s also looking at how obesity affects tendon healing. “There’ve been numerous studies in the last decade looking at how increased weight, usually measured as BMI, leads to increased risk of rotator cuff tendon injury. We want to better understand how increased fat mass affects tendon cells to help develop future therapies.”

More people aged 85-plus are having joint replacement surgery with a consequent higher risk of implant-related infections. “We’re looking at applying lactoferrin, an antimicrobial protein from milk, to help remove bacterial biofilm (which is effectively a dense layer of “slime”) tightly adhered to the implant surface which is notoriously difficult to treat.”

Infection is the leading cause of failure in joint replacement surgery and Scott says any progress in this area will have a worldwide impact. “Despite all the advances of the past few decades, implant-related infection rates continue to rise. While this is partly because we’re operating on patients who are older and have other medical problems, it’s also because we’re also entering an age of more virulent bacteria and increasing resistance to antibiotics.

“Infection is a devastating complication after orthopaedic surgeries and involves multiple further surgeries, long hospital treatments and high healthcare costs. Technologies that aims to prevent and treat these types of infections needs to continue to be a major focus.”

Tendon healing is another area where Scott says technology could deliver huge benefits. “I think this is an area that has been somewhat neglected. Tendon injuries are difficult to treat because of the tendon tissue’s relatively poor blood supply and the forces transmitted through it. As a crude estimate, there’s over one million published articles on bone, but less than 100,000 relating to tendon.”

As we age, our risk of rotator cuff injuries increases and after the age of 60 over 50 per cent of us will have a rotator cuff injury. Scott says up to 70 per cent of rotator cuff repairs fail because of ineffective tendon healing after surgery and we need new treatments that will deliver significant gains.”

For Scott, combining clinical acumen with emerging technology is hugely exciting with the potential for combining knowledge and expertise across the orthopaedic field into world-leading research.

By Prue Scott