About the Hip

Hip Replacement Fact

The most common form of arthritis — osteoarthritis — is a wear and tear condition that destroys joint cartilage, due to years of constant motion and pressure in the joints. Cartilage cannot be replaced once it is destroyed.

Metal-On-Metal Hip Replacement

The M²a-Magnum™ Metal-On-Metal Hip Replacement
People facing hip replacement often wonder if they will be able to resume an active lifestyle after surgery. An additional concern is whether their new hip components will be able to withstand the stress of a more active lifestyle. Since hip implants are subject to wear over time, it was necessary to develop implants that may withstand the higher demands of active lifestyles. This, coupled with the positive results of some early metal-on-metal implants and advances in manufacturing technology, led to the development of the M²a-Magnum™ metal-on-metal implant.

The M²a-Magnum™ hip is a metal-on-metal hip implant designed to provide long-term resistance to wear. Traditional hip replacement implants feature a metal ball that moves against a polyethylene (high durability plastic) cup. Metal-on-metal implants feature a metal ball that moves against a metal cup.

The benefit of a metal-on-metal implant is that metal is much harder than polyethylene. As metal moves against another material, it creates friction, and friction wears down the material against which it moves. The more active a person is, the more movement and friction are placed against their hip implants. Since metal resists wear better than polyethylene, the M²a-Magnum™ metal-on-metal hip implant is better able to resist wear. In fact, extensive testing has demonstrated that the M²a-Magnum™ metal-on-metal hip implant has up to 1/350 the wear of conventional metal-on-polyethylene implants.^1,2 This means that there is a strong possibility that the metal-on-metal hip can outlast traditional polyethylene, which is an important consideration for patients whose surgeons think premature wear may become an issue.

Another feature of the M²a-Magnum™ hip is its size. The implant’s diameter can be as large as 60 millimeters. Most hip replacements have a ball, or head, that is between 28 and 32 millimeters in diameter. The larger size of the M²a-Magnum™ hip means that there is less risk of dislocation and an even greater reduction in wear when compared to the smaller implant heads.^3,5

Would I Benefit From Metal-On-Metal Implants?
Because metal-on-metal implants in lab testing have been shown to reduce implant wear, it is possible that you would benefit from a longer-wearing implant.

Your surgeon will consider your activity level, health, and age before recommending a metal-on-metal implant. The M²a-Magnum™ metal-on-metal hip implant may be recommended if your surgeon feels that your situation is appropriate for a metal-on-metal implant. However, your surgeon will only recommend the M²a-Magnum™ metal-on-metal hip implant if he or she feels the implant will give you the most satisfactory results. Not everyone is a candidate for the M²a-Magnum™ metal-on-metal hip system.

Complications
While uncommon, complications can occur during and after surgery. Some complications include, but are not limited to, infection, blood clots, implant breakage, malalignment, dislocation, and premature wear, any of which may require additional surgery. Although implant surgery is extremely successful in most cases, some patients still experience pain and stiffness. No implant will last forever, and factors such as post-surgery activities and weight can affect longevity. Be sure to discuss these and other risks with your surgeon.

There are many things that your surgeon may do to minimize the potential for complications. Your surgeon may have you see a medical physician before surgery to obtain tests. You may also need to have your dental work up to date and may also be shown how to prepare your home to avoid falls.

Recovery
Diligent physical therapy, proper diet, and a willingness to follow all of your surgeon’s recommendations will contribute to a more successful recovery after surgery. Most patients are able to walk without support and drive three to six weeks after surgery. Activities such as golf, doubles tennis, and swimming can usually be resumed, but only after a thorough evaluation by your surgeon. Always follow your surgeon’s recommendations, as recovery time will vary for each patient.

Most patients are typically not allowed to participate in high-impact activities or contact sports. These types of activities place extreme amounts of pressure on the joints, which could lead to complications. Ask your surgeon which activities you should avoid after surgery.

Summary
We realize that the decision to have surgery is sometimes difficult. We hope this guide has helped you understand some of the basics of hip replacement surgery with Biomet’s M²a-Magnum™ hip technology so you can make the best decision for yourself. This guide is not intended to replace the experience and counsel of your orthopedic surgeon. If you have further questions, please speak with your orthopedic surgeon.

References
1. Data on file at Biomet Manufacturing Corp.
2. Note: Lab test results may not correlate with the actual performance in the body.
3. McKellop, et al.: In-Vive Wear of 3 Types of Metal-On-Metal Hip Prostheses During Two Decades of Use. CORR, 329, pp. 128-140, August, 2002.
4. Orthopedic Network News: "2003 Hip and Knee Implant Review." Volume 14, Number 3, July 2003.

Patient Education information provided by Biomet, Inc. - Advanced Science for Real Living™