The Future of Knee Replacements

Kenton Reynolds, Writer
@uxconnections

A Newly discovered hydrogel could be the perfect substitute for knee cartilage, saving huge amounts of time and money for healthcare services.

Duke University’s Professor of Chemisry, Ben Wiley – who specialises in nanomaterials – has worked alongside Ken Gall – Professor in the Department of Mechanical Engineering and Materials Science – to investigate the creation of a hydrogel with the mechanical properties of cartilage.

Cartilage is a strong yet flexible connective tissue. Water can account for up to 80% of cartilage with remainder being a substance called the ‘matrix’ made up of various specialised proteins.  The water and matrix form a gel-like substance that can be malleable when it needs it to be to allow for movement and flexibility but also providing support and dealing with high amount of pressure in joints like the knees. A single 10p coin-sized disc of this substance can hold a 100 lbs. kettlebell which is important as cartilage absorbs a huge amount of force with every step that you take.

Your cartilage covers the end of bones in order for them to glide smoothly over one another. Damage to the cartilage – most commonly occurring in knees, hips, ankles and elbows – leads to symptoms of joint pain, swelling, stiffness and a clicking or grinding sensation. It can be a very painful condition and can result in loss of movement and further damage to the surrounding area. 

Knee cartilage concerns often lead to intrusive surgery with a common result of a serious tear being a knee replacement. The vital and difficult to mimic cartilage cannot be replaced alone and the entire knee must be removed and replaced, and this injury contributes to the 600,000 knee replacements that take place in the US every year. The high force that the knee faces means that a knee replacement has to be redone around every 15 years too.

As a result, the research done by Wiley and Gall will be a huge advancement in medicine and science. They have discovered a hydrogel that is suitable to replace cartilage. The substance, consisting of a series of three polymers that combine to achieve the desired properties, was the only one that matched the squish-and-stretch ability of cartilage when compared to other similar materials.

The polymer has been tested rigorously. It proved as strong as porous titanium when it faced a cycle of 100,000 repeat pulls which is what is used for bone implants. The material was also rubbed a million times against natural cartilage and its self-lubricating properties meant that it was as wear resistant as the real thing and four times more wear resistant than the synthetics currently used for big toes.

There are still more tests to be carried out and more medical approval required before the hydrogel is used. However, this could revolutionise knee surgery.