Orthopedic bone cement is a medical material widely used in orthopedic surgery. It is mainly used to fix artificial joint prostheses, fill bone defect cavities, and provide support and fixation in fracture treatment. It fills the gap between artificial joints and bone tissue, reduces wear and disperses stress, and enhances the effect of joint replacement surgery.
The main uses of bone cement nails are:
1. Repair fractures: Bone cement can be used to fill and fix fracture sites.
2. Orthopedic surgery: In orthopedic surgery, bone cement is used to repair and reconstruct joint surfaces.
3. Bone defect repair: Bone cement can fill bone defects and promote bone tissue regeneration.
Ideally, bone cement should have the following characteristics: (1) adequate injectability, programmable properties, cohesion, and radiopacity for optimal handling properties; (2) adequate mechanical strength for immediate reinforcement; (3) adequate porosity to allow fluid circulation, cell migration, and new bone ingrowth; (4) good osteoconductivity and osteoinductivity to promote new bone formation; (5) moderate biodegradability to match the resorption of the bone cement material with new bone formation; and (6) efficient drug delivery capabilities.
In the 1970s, bone cement had been used for joint prosthesis fixation, and it can also be used as tissue filling and repair materials in orthopedics and dentistry. At present, the most widely used and researched bone cements include polymethyl methacrylate (PMMA) bone cement, calcium phosphate bone cement and calcium sulfate bone cement. Currently, the commonly used bone cement varieties include polymethyl methacrylate (PMMA) bone cement, calcium phosphate bone cement and calcium sulfate bone cement, among which PMMA bone cement and calcium phosphate bone cement are the most commonly used. However, calcium sulfate bone cement has poor biological activity and cannot form chemical bonds between calcium sulfate grafts and bone tissue, and will degrade rapidly. Calcium sulfate bone cement can be completely absorbed within six weeks after implantation in the body. This rapid degradation does not match the bone formation process. Therefore, compared with calcium phosphate bone cement, the development and clinical application of calcium sulfate bone cement are relatively limited. PMMA bone cement is an acrylic polymer formed by mixing two components: liquid methyl methacrylate monomer and dynamic methyl methacrylate-styrene copolymer. It has low monomer residue, low fatigue resistance and stress cracking, and can induce new bone formation and reduce the incidence of adverse reactions caused by fractures with extremely high tensile strength and plasticity. The main component of its powder is polymethyl methacrylate or methyl methacrylate-styrene copolymer, and the main component of the liquid is methyl methacrylate monomer.
PMMA bone cement has high tensile strength and plasticity, and solidifies quickly, so patients can get out of bed and perform rehabilitation activities early after surgery. It has excellent shape plasticity, and the operator can perform any plasticity before the bone cement solidifies. The material has good safety performance, and it is not degraded or absorbed by the human body after forming in the body. The chemical structure is stable, and the mechanical properties are recognized.
However, it still has some disadvantages, such as occasionally causing high pressure in the bone marrow cavity during filling, causing fat droplets to enter the blood vessels and cause embolism. Unlike human bones, artificial joints may still become loose over time. PMMA monomers release heat during polymerization, which may cause damage to surrounding tissues or cells. The materials that make up bone cement have certain cytotoxicity, etc.
The ingredients in bone cement may cause allergic reactions, such as rash, urticaria, dyspnea and other symptoms, and in severe cases, anaphylactic shock may occur. Allergy testing should be performed before use to avoid allergic reactions. Adverse reactions to bone cement include bone cement allergic reaction, bone cement leakage, bone cement loosening and dislocation. Bone cement leakage may cause tissue inflammation and toxic reactions, and may even damage nerves and blood vessels, leading to complications. Bone cement fixation is quite reliable and can last for more than ten years, or even more than twenty years.
Bone cement surgery is a typical minimally invasive surgery, and its scientific name is vertebroplasty. Bone cement is a polymer material with good fluidity before solidification. It can easily enter the vertebrae through the puncture needle, and then diffuse along the loose internal fracture cracks of the vertebrae; bone cement solidifies in about 10 minutes, sticking the cracks in the bones, and the hard bone cement can play a supporting role inside the bones, making the vertebrae stronger. The entire treatment process only takes 20-30 minutes.
In order to avoid diffusion after bone cement injection, a new type of surgical device has been manufactured, namely the vertebroplasty device. It makes a small incision on the patient's back and uses a special puncture needle to puncture the vertebral body through the skin under X-ray monitoring to establish a working channel. Then a balloon is inserted to shape the compressed fractured vertebral body, and then bone cement is injected into the vertebral body to restore the appearance of the fractured vertebral body. The cancellous bone in the vertebral body is compacted by balloon expansion to form a barrier to prevent bone cement leakage, while reducing the pressure during bone cement injection, thereby greatly reducing bone cement leakage. It can reduce the incidence of complications related to fracture bed rest, such as pneumonia, pressure sores, urinary tract infections, etc., and avoid the vicious cycle of osteoporosis caused by bone loss due to long-term bed rest.
If PKP surgery is performed, the patient should usually rest in bed within 2 hours after the surgery, and can turn over on the axis. During this period, if there is any abnormal sensation or the pain continues to worsen, the doctor should be informed in time.
Note:
① Avoid large-scale waist rotation and bending activities;
② Avoid sitting or standing for long periods of time;
③ Avoid carrying weight or bending over to pick up objects on the ground;
④ Avoid sitting on a low stool;
⑤ Prevent falls and recurrence of fractures.
Post time: Nov-25-2024
