Joint Replacement

Michael Eckhoff, MD

Content Contributor

Evolution of Joint Replacement

Joint replacement of the hand has continuously advanced as better implant materials have been developed. Metal hinge joints were initially developed, but were wrought with complications. Joint replacement today has two main categories: silicone and PyroCarbon implants.

Silicone implants are a single rubber piece that bridges the joint after removing the destroyed cartilage ends of the bone that is able to bend. This is beneficial because it has intrinsic stability because it is a single piece. However, risks are associated with increased stability such as implant fracture or loosening from too much force occurring on the implant-bone interface. This has long been the standard of care. Another more recent type of joint replacement is PyroCarbon implants.

PyroCarbon is a graphite-derived substance that has been shown to have excellent durability and compatibility within the human body. Additionally, it has similar strength characteristics to the bone, which helps in preventing abnormal forces between the bone-PyroCarbon interface. This results in improved longevity of the implants.

Studies have also shown that PyroCarbon that articulates with PyroCarbon has essentially no wear effect, even after 10 million cycles less than 1000th of an inch of wear was measured in the prosthesis. These implants, however, are not connected and rely on the body’s natural soft tissues to provide stability after replacement.

Technology Spotlight

Integra Ascension MCP Joint Replacement™

Integra Ascension MCP Joint Replacement™ is a PyroCarbon based joint replacement that takes advantage of exceptional wear characteristics and bio- compatibility of PyroCarbon for the replacement of the MCPJ. The system uses two articulating implants with high-congruence and the body’s natural ligaments and joint capsules to recreate the MCPJ.

This can be done through an S-shaped or straight longitudinal incision over the knuckle. This implant allows for maintenance of more natural motion at the joint and often significant pain relief to restore function to a painful hand.