There are published reports documenting survivorship of total hip and knee replacement of approximately 90% at 15 years in the elderly individual. Joint replacements do however fail, both in the young and the old. There are two spikes in the failure rates. The first spike is within the first few years and this is typically related to surgical technique that lead to instability or mechanical failure of the joint. The second spike is down the road 10 to 15 years and is related to wear of the implant surfaces. Traditionally, implants have been made of cobalt chrome and polyethelene, a type of plastic. These bearing surfaces with more than one million cycles per year can wear out over time. New bearing surfaces have been introduced including, metal-on-metal, ceramic-on-ceramic and new types of polyethelene that will hopefully be more durable and lead to better results down the road.
There are two factors that influence the wear rate of total hip and knee replacements. These are body weight and activity. Most total hip and knee replacements are designed to withstand moderate physical activity. However, they are not designed to withstand high impact physical activity. Several factors influence the durability of your joint replacement. These include, surgical technique, surgeon experience, design of the implant, and the material utilized. You should discuss these with your surgeon prior to joint replacement to ensure that both you and your surgeon do their best to ensure the most durable outcome.
