There are indeed many different kinds of artificial hip joints, and as you can see on the Internet, the price varies from product to product, and the types of products that are suitable for different ages are not exactly the same. The following are answers to the most important questions about the choice of artificial joints.
What are the main components of an artificial joint?
The metal parts are mainly made of titanium and titanium alloys, which are not only corrosion resistant, but also easy to grow with the bones of the human body. The metal material is responsible for growing with the bone. The metal parts of the pelvic bone side of the artificial joint and the metal parts of the thigh are padded with a wear-resistant material, and the two wear-resistant materials rub against each other to form the joint surface.
The wear-resistant material can be polymer polyethylene plastic to metal or ceramic friction, or metal-to-metal friction or ceramic-to-ceramic friction. Metal and ceramic have better resistance to friction, especially ceramic, which has less toxic side effects and has emerged in recent years and is increasingly used in the field of artificial joints.
Are there any differences between the various friction surfaces?
Of course there are differences. Metal to polyethylene plastic is the most common friction surface used, with 150-200 microns of wear per year, while ceramic to plastic is relatively slow to wear, with nearly 90 microns per year, and metal to metal or ceramic to ceramic is very slow to wear, with less than 5 microns per year.
What kind of patients are these different types of friction surface matching suitable for?
The general rule of thumb is that the younger the patient, the more likely he or she is to prefer a ceramic-to-ceramic or metal-to-metal friction surface, e.g., patients under 60 years of age, who are expected to live more than 30 years in the future, should use a slow-wearing joint friction surface. Patients over the age of 70 will have the rest of their lives covered with a metal to plastic friction surface since their expected survival is generally less than 30 years.
Will ceramic prostheses shatter?
Ceramic tableware can break accidentally, and ceramic artificial joint prostheses have this problem, but ceramic joints are much stronger than tableware, and the chance of breakage during normal use is about 1 in 1,000 to 1 in 10,000, which is much less than other complications of surgery, so there is basically no need to worry about ceramic breakage.
What is the difference between the third and fourth generation ceramic joint prosthesis?
This is an improvement in the manufacturing process. The IV ceramic is more wear resistant and less likely to shatter than the III ceramic, but of course it is also more expensive.
Metal to metal does not have the problem of shattering, and wear-resistant, is not better?
Metal does not shatter, this is true, but the materials used to make the metal friction surface are heavy metals, wear down the heavy metal ions will not cause harm to the human body has not yet been finalized, for women of childbearing age who will be pregnant with a baby, heavy metal ions may have an impact on fetal development, because heavy metal ions are mainly excreted through the kidneys, so patients with renal insufficiency should not be used.
How can there be a difference in size of the head of the prosthesis of the replacement femur?
This is mainly for metal and ceramic friction surface prostheses, the larger the head the less likely it is to dislocate after surgery. The prerequisite for using a prosthesis with a large head is that the patient’s pelvis is large enough.
What are the current approximate price points for each material?
Generally speaking, there is some variation in the price of each company’s products, but the difference is not too great. A set of prosthesis with a four-generation ceramic friction surface is usually around 60,000, a set of prosthesis with a three-generation ceramic friction surface is around 35,000, a set of prosthesis with a metal-to-metal match is mostly around 40,000, a set of prosthesis with a ceramic-to-polyethylene plastic match is close to 30,000, and a set of prosthesis with a metal-to-polyethylene match is close to 25,000 round. However, the price may vary from city to city. The price is not set by the hospital, but by the government bidding pricing, and most large hospitals sell to patients at a lower price than the government pricing.
When is bone cement used?
The purpose of bone cement is to line the space between the metal prosthesis and the bone, allowing for an even distribution of force between the two. It is used less and less these days, mainly in older and severely osteoporotic patients.
What principles does the surgeon follow when selecting a prosthesis for a patient?
The first consideration is the outcome of the surgery, not only for the immediate future, but also for the lifetime benefit of the patient who is fitted with an artificial joint. Therefore, in general, the surgeon will estimate the patient’s future life expectancy and daily activity and choose different materials for the prosthesis accordingly. Secondly, the doctor will consider the patient’s economic conditions to choose different prices of the prosthesis, to ensure that the patient can get the most benefit for the least amount of money.
For example, the patient Guo is 50 years old, it is estimated that he still has about 40 years of life to go, for him to choose a more wear-resistant prosthesis. Guo’s family is not very wealthy, but not overstretched, so the doctor chose a third-generation ceramic friction surface artificial joint for him.