Plugs could curtail total knee replacement surgery

To this end, Dr Melissa Grunlan, a professor in the Department of Biomedical Engineering at Texas A&M University, has received a grant from the US National Institute of Arthritis and Musculoskeletal and Skin Disease to develop the potential off-the-shelf surgical device to treat osteochondral defects (OCDs).

“Chronic knee pain and disability are caused by cartilage loss and OCDs stemming from arthritis, including osteoarthritis and post-traumatic arthritis causing individuals pain that limits comfort and mobility,” Dr Grunlan said in a statement. “This grant will allow us to maximise the potential of the CC-ROPs to heal OCDs, and to collect data demonstrating this efficacy.”

This technology could be an alternative to current treatment methods, such as autografting or total knee replacement.

Autografting requires small cylindrical specimens to be harvested from the non-damaged part of the patient’s knee and transferred into pre-drilled holes in the defect area. However, this method can be hindered by the patient’s age and the size of the defect.

If patients do not meet the autografting criteria, they are likely to need a total knee replacement. This is an extensive surgery where parts of the damaged knee joint are replaced by an artificial or prosthetic comprised of metal and plastic. Although a total knee replacement is sometimes a patient’s only option, the surgery can lead to post-operative complications.

In contrast, the proposed CC-ROPs are not restricted by age or the size of the defect while offering several other benefits. Firstly, they were designed to have the geometry of cylindrical autografts so they could be implanted with existing surgical tools and protocols. Additionally, it does not require pre-loading with cells or growth factors to induce healing, but instead leverages the features of the cap and scaffold base. Once implanted, the CC-ROP is said to provide immediate support for joint function, including knee articulation.

“Overall, this design represents a feasible approach for clinical translation,” said Grunlan.

CC-ROP consists of a cartilage cap and an osseous (bone) base. The cartilage cap is an ultra-strong hydrogel that mimics the mechanical properties of biological cartilage. The base is made of a porous, bioresorbable polymer. After implantation, the base is replaced by new bone tissue and continues to anchor the cartilage cap. The cylindrical implant stimulates the formation of new bone tissue and integration with host tissue while supplying synthetic cartilage necessary for joint function.

The grant will allow the research team to maximise the potential of the CC-ROPs to heal OCDs and perform necessary analyses to ensure the materials and devices are functional and ready for real-life applications. They will also evaluate the effectiveness of the device in pre-clinical studies.

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