By definition, a prosthesis is an artificial substitute for a part of the body that is missing
Whether it be an eye, leg, arm, or tooth, a prosthesis is inserted—or implanted—in order to serve a function or cosmetic purpose.
Prosthetics or implants involve the drawing, manufacturing, and fitting of custom-made artificial appendages or other helpful physical devices for patients. This is a very detailed process that requires advanced technology and know-how.
When Does a Patient need Prosthetics?
Prosthetics are needed when a patient has undergone a traumatic injury, cancer, disease (vascular or diabetes), or congenital disorders. A prosthesis can give them back not only the appearance of a missing limb but full or partial functionality.
Typically, prosthetics are needed for the following body parts:
- Hip prosthesis – A prosthesis used when part of the hip has been amputated.
- Knee prosthesis – A prosthesis is used when an amputation goes through the knee.
What are the Knee Prosthesis Options?
Every year, new and more sophisticated implants and prostheses are made available to patients. For example, there are over 150 knee replacement designs on the market these days. The most popular type is a Fixed-Bearing prosthetic (a polyethylene plastic is attached to a metal prosthetic).
Others include the Cruciate-Retaining and the Posterior-Stabilized prostheses (shaped and acts as a ligament). Unicompartmental Implants are used when a complete knee replacement is needed. Both ends of the femur and tibia are resurfaced with the implant.
For an above the knee amputee, there are several types of knee prosthesis options:
- Polycentric – A simple mechanical based on friction
- Hydraulic – A fluid mechanical option
- Electronic – An elaborate microprocessor that is fluid and mechanical
In addition, recent designs make it possible for implants to be specific to a patient’s gender.
If a woman needs a knee prosthesis, which is shaped more delicately than a man’s, she can receive an appropriate prosthetic that fits the shape and proportion of her body.
What Kinds of Hip Prosthesis Implants Exist?
Implants can be made from numerous materials, but metal and plastic implants are the most popular.
Titanium, stainless steel, and cobalt chrome make up the metal prosthesis and come with a plastic spacer. The implant is secured to the bone either with specialized bone cement or a press-fit method that allows new bone growth to secure it into place. Metal and plastic implants wear out at a rate of 0.1 mm per year.
If you need an implant that is presumed to last, a metal-on-metal choice is needed. Without the plastic spreader, these implants wear at a rate of approximately 0.01 mm per year. However, there are downsides to this prosthetic. Debris in the joint can build up, and metal ions can be released into the bloodstream. At this point, it is uncertain if these ions cause cancer or disease.
Another option is a ceramic-on-ceramic implant that is resistant to scratches and is super smooth, lasting longer than the metal-on-metal option. The downside is that they could break inside of the patient’s body.
The final option is metal and highly cross-linked polyethylene. It is a popular choice, resistant to wear. This prosthetic technology is relatively new so its performance rate is yet to be determined.
What are the Most Commonly Used Implants?
Hip replacements are one of the most common orthopedic procedures which use an artificial ball-and-socket implant. Depending on the patient’s age, activity level, and surgeon, an implant may be selected from a variety of options.
How Can I Find the Right Fit?
Your physician and specialist will help you find what you need, but it’s always a good idea to learn as much as you can about implants and prosthetics.
The brand of choice really comes down to what it has to offer in the way of design, your personal needs (age, size, health and activity level), the remaining surface area on your existing body part, your doctor’s experience, cost and the performance record of the implant.