Corin Group PLC


The original metal-on-metal Resurfacing Hip system was pioneered and developed by Corin, a British company based in Cirencester, Gloucestershire. The device has been in use since 1991 with only minor modifications, and is now called the Cormet Resurfacing Hip System. Other manufacturers have now introduced similar devices, and most orthopaedic companies now produce Hip Resurfacing devices. The implant is made of high carbon Cobalt Chromium, a metal alloy consisting primarily of the elements cobalt, chromium but nickel and molybdenum. It is used for its strength, resistance to wear, and its biocompatibility, which means that it does not normally create adverse effects inside the body.

Just as important to the long-term wear properties of these implants are the way in which they are manufactured. The surface finish (the smoothness of the shiny metal surfaces) is controlled to around five microns. One micron is one thousandth of a millimetre or 0.00004 of an inch. The average width of a human hair is about 100 microns, so the smoothness of the resurfacing bearing surface is controlled to about 1/20th the width of a human hair. The sphericity (or “roundness”) of the bearing surfaces is also critical, as is the deliberate mismatch between the diameters of the head and cup bearing surfaces, allowing body fluid to enter the bearing and lubricate it, just as in the normal hip joint. Every single Corin Resurfacing implant is individually quality controlled to ensure that they are each manufactured to the most exacting standards.