Types of artificial joints and materials
The types of artificial hip joints include.
1. surface replacement of the femoral head.
2.Artificial femoral head replacement.
3, total hip artificial joint replacement.
Commonly used artificial joint implant materials are.
1.Metallic alloys.
2.Polymer materials.
3, ceramic materials. Commonly used metals can be divided into titanium-based (titanium and titanium alloys), cobalt-based (cobalt-chromium, cobalt-nickel alloy, cobalt-chromium-molybdenum, etc.) and iron-based (stainless steel) 3 categories. Polymer materials refer to ultra-high polymer polyethylene, which is mainly used to make acetabular cup prosthesis and acetabular cup prosthesis lining. Alumina and zirconia ceramics have good inert stability and can be used in artificial joints for the cephalic portion of the artificial total hip joint. In both in vivo and in vitro experiments, the abrasion and wear rates of the artificial joint surfaces of alumina and zirconia were significantly reduced.
Depending on the different materials of the artificial total hip joint cephalic socket, the components of the articular surfaces are.
1. metal-polyethylene.
2, ceramic-polyethylene.
3.Metal-metal.
4. ceramic-ceramic. The first two of these combinations are currently the commonly used approach. In recent years, the latter two combinations have been used more and more and are standing the test of time.
According to the different fixation methods of artificial total hip prosthesis, they are divided into.
1, non-cemented biological fixation.
2.Bone cement fixation.
The service life of the artificial joint is the most important concern for patients who are about to undergo artificial total hip arthroplasty.
Although artificial total hip replacement has been widely carried out in China in the past decade, and orthopedic surgeons are becoming more and more technically mature, there is a lack of more frequent follow-up results. According to the results of foreign multicenter, large sample and long time studies, the survival rate of artificial joint reaches 80% in 20 years and 64% in 30 years, that is, about 80% of patients’ artificial joints can still be used 20 years after artificial joint replacement, and 64% of patients after 30 years, and the prosthesis they use is designed in 1970s or 1980s. In the 21st century, the material selection and design of artificial total hip prosthesis are now more reasonable, and the surgical techniques are widely improved, so the service life of the prosthesis is expected to be longer and the efficacy is more optimistic. The choice of prosthetic material and the placement of the prosthesis (i.e., the orthopedic surgeon’s surgical technique) are the two main factors that affect the service life of an artificial joint prosthesis; in both cases, 60% of the service life of the prosthesis depends on the surgical technique and 40% on the prosthetic material.
Cemented prostheses and their applications.
The technique of using cemented total hip joints was first introduced by Carnley in 2007, and this technique has been continuously improved and has since evolved into the fourth generation of cemented technology, resulting in a significantly longer service life of the joint prosthesis. The cemented total hip joint is mainly used for patients with osteoporosis or patients with a straight barrel-like proximal femur.
Non-cemented artificial joints and their applications.
Its theoretical basis is that the porous metal surface of the prosthesis can undergo bone growth into and osseointegration after tight pressure fit between the prosthesis and the bone, thus achieving the purpose of biological fixation of the prosthesis.
Application of minimally invasive surgery in artificial joint replacement.
With the continuous development of artificial total hip replacement surgery technology, minimally invasive total hip arthroplasty (MISTHA) with small incisions has become possible. Its surgical incision length is within 10 cm, and the operation time is not prolonged or can even be shortened. This technique means more than simply a small incision; its technical focus is to reduce damage to ligaments, muscles and bone tissue, and to be safe, effective, repeatable and time-tested.
The advantages are.
1. small, aesthetically pleasing incisions (intracutaneous sutures may be used)
2.Less trauma to the soft tissues around the joint during the operation, less bleeding, less postoperative wound pain and fewer complications; 3.Early recovery of both daily life and function. Patients can walk on the third day after surgery with the help of crutches, which greatly reduces the complications in the perioperative period.
Application of navigation technology in artificial joint replacement.
Image-guided surgical navigation system is a new technology developed in the past 10 years and has been widely used in clinical practice. Since the angle of placement of the acetabular cup prosthesis is essential to prolong the life of the prosthesis, it is not very reliable when placed using mechanical guides. To increase the correct position of the acetabular cup, it is necessary to increase the surgical exposure, which is different from modern surgical concepts and increases the chance of intraoperative soft tissue trauma and postoperative complications. If a navigation system is used to place the acetabular cup, the error can be within 1% and the operative time will only increase by 5 minutes if the navigation is used skillfully during surgery.
Femoral head surface replacement.
Since there is no fundamental solution to osteolysis and prosthetic loosening due to polyethylene abrasion of the cup after total hip arthroplasty, a femoral head surface replacement was developed to preserve as much bone as possible in the hip joint and replace only the femoral head surface. This procedure is technically demanding and requires the training and clinical experience of an orthopaedic surgeon. It should be performed in strict accordance with the indications for surgery, is suitable for young patients, and is considered a transitional surgery, which some people call “a surgery that costs money for time and can postpone total hip artificial joint replacement surgery.
Common surgical complications include.
1, femoral neck fracture.
2, poor prosthesis mounting position.
3, loosening and dislocation of the prosthesis, etc.
Articular fusion.
Hip fusion begins with the treatment of severe joint destruction caused by tuberculous arthritis as well as significant joint instability and painful fibromuscular ankylosis. The advantages of an already fused hip were that it was painless, absolutely stable and long-lasting, but over time it tended to cause low back pain and symptoms in the ipsilateral knee and contralateral hip. Until the late 1970s, this procedure was seen as an alternative to osteotomy and arthroplasty, especially in young patients with unilateral hip disease and heavy workload. In recent years hip fusions have been decreasing each year.