Artificial hip replacement is a relatively mature operation. According to statistics, the success rate is more than 95%. Although patients all hope for 100%, there are still a few patients who have loosening, dislocation or infection of the prosthesis after the operation. Looseness in the first two years after the operation does not rule out the possibility of infection. The main causes of these problems are the following three factors:
Patient factors
There are 4 types of people who are at higher risk.
htmlThe failure rate of is higher in male patients under 550 years old. Most of these patients are not degenerative osteoarthritis of the elderly, but osteoarthritis secondary to trauma or avascular necrosis of the femoral head. Many people have a large amount of daily activities, resume sports or heavy physical labor after surgery, and are prone to aseptic loosening of the prosthesis. According to statistics, among men under the age of 50, the survival rate of the prosthesis is 80-85% within 18 years after replacement, which means that 15-20% have loosened.
Female patients with rheumatoid arthritis under the age of 55 are another high-risk group, with a 25% failure rate within 15 years. Changes in the bioactivity of the patient's bones and the amount of bleeding during surgery may be the reasons for loosening of the prosthesis. Although the exact cause is unknown, rheumatoid arthritis is relatively complex.
Patients with other diseases are prone to infection. Deep infection occurs in about 0.5-2% of total hip replacements, accounting for about 7.5% of secondary surgeries (revisions). Infections are more common in inflammatory arthritis. For example, psoriatic arthritis , patients taking corticosteroid therapy, chronic renal failure , diabetes , high-risk surgical patients, and patients with malnutrition and frailty.
Patients with improper postoperative recovery are prone to dislocation. Dislocation refers to the artificial femoral head protruding out of the joint socket. The risk is greatest in the first few months after the operation. At this time, the prosthesis has not yet become firm. Some patients are careless in their movements, crossing their legs, raising their legs high, sleeping in incorrect postures, and squatting. Defecation, accidental fall, may cause dislocation. Female patients over 70 years old, weak in constitution, with various comorbidities, and ligament laxity are at the highest risk of dislocation. After dislocation, manual reduction is usually performed first, or anesthesia is used to relieve muscle spasm for reduction. If the dislocation still fails, a second operation will be performed.
Factors of the prosthesis
The first is the design of the prosthesis, including the design of the femoral head and the femoral stem . The ratio between them determines the angle of activity during abduction. There is also an eccentricity design, which is very important for rebuilding the length of the lower limbs and the abductor muscle arm. Excessive eccentricity will cause high soft tissue tension, causing pain and greater trochanter bursitis. Small eccentricity will affect gait and make walking easy to fatigue. Accelerates lining wear. Another problem is the use of bone cement. Although some people now believe that bone cement may cause loosening, for patients over 65 years old, with poor bone mass, osteoporosis, and bone defects, it is still recommended to use bone cement for fixation. Young patients may consider not using bone cement.
Doctor’s Factors
Currently, there are many types of artificial hip prostheses, and surgical plans vary from person to person. Choosing a doctor is actually more important than choosing a prosthesis. The location, direction, and angle of the installation during surgery will all affect the service life and survival rate of the artificial joint.. The doctor's experience plays a vital role in it, because artificial hip replacement is a tailor-made surgery. The doctor must formulate the most appropriate surgical plan based on the patient's actual situation. For example, young patients are more suitable for all-ceramic joints, which have the longest service life. However, if they are heavy manual workers, the possibility of physical strain and collision is high, the characteristics of ceramic joints must be considered. Although there are few cases of breakage, ceramics are not as strong as metal after all.
In short, the more surgeons have performed replacement surgeries, the lower the dislocation loosening rate and the possibility of complications. Patients will have smaller wounds, less bleeding, faster recovery, longer service life of artificial joints, and higher success rates of surgeries.
Medical science, for reference only.
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