Wearing out of Total Hip Replacement
Hip replacement components may wear out over their lifespan that may require revision surgery. Hip replacement surgeries are highly successful with most implants lasting 20-25 years or more. However, the implant components may wear out with time that may result in the loosening of the components which is known as aseptic loosening.
The hip replacement components may wear out due to a number of different reasons besides natural wear and tear. The implants are more likely to wear out in men and in patients aged 50 or less. The implants wearing out in younger patients and men, in general, may be linked to higher activity levels.
Similarly, patients who may be obese or overweight, or more physically active also are at an increased risk of hip implants being worn out. Other factors such as implant positioning during the surgery may also be linked with increased wear and tear of the implant.
X-ray showing aseptic loosening of the hip replacement.
Aseptic loosening
Hip replacement implants consist of a prosthetic head of the femur made of metal alloy/or ceramic placed over a metal alloy femoral stem. The stem is usually press-fitted inside the femoral canal so there may be bone in-growth at the implant-bone interface.
The acetabulum prosthetic shell is similarly made of metal alloy parts and is press-fitted in the acetabulum shell. The shell is additionally secured with screws so the implant stays in place as the bone in-growth occurs.
The shell is covered inside with a highly cross-linked polyethylene plastic that allows smooth gliding of the prosthetic head inside the socket. The fixation of the prosthetic stem may also be done by the use of bone cement. However, the majority of the hip replacements done today are uncemented.
The aseptic loosening means loosening of the implants inside the bone without any evidence of infection. The loosening occurs as a result of the formation of particle debris. The debris may form as a result of:
- Adhesion wear occurs as the implant surface microscopically attaches to the polyethylene spacer and pulls off the debris.
- Microscopic abrasion of the metal prosthesis with the polyethylene spacer may lead to the formation of debris.
- As the debris collects in the space between the polyethylene and the metal surface, the debris acts as a third body that may lead to the formation of even more debris.
The debris mainly consists of polyethylene (PE) but may also consist of cobalt-chromium metal ions and bone cement. While metal on polyethylene has the maximum rates of formation of debris, ceramic on ceramic has the least amount of debris formation. However, ceramic on ceramic and metal on metal implants are associated with other side effects, therefore, are not commonly used in hip replacement surgery.
The debris attracts inflammatory cells such as macrophages that try to clear the debris. The macrophages in turn get activated and may lead to the release of inflammatory mediators. The inflammation may cause local swelling due to an increased influx of fluids.
The inflammation leads to activation of cells known as osteoclast that result in cutting of the bone surrounding the implant. The cutting/decrease of the bone surrounding the implant leads to micromotion of the implant. The micromotion of the implant leads to more particulate debris formation. Ultimately, the implant loosens and may present with symptoms suggestive of aseptic loosening.
Symptoms
Patients with aseptic loosening of hip replacement often complain of instability and pain. The pain is usually located in the groin region and is aggravated with weight-bearing. If the prosthetic femoral stem subsides inside the canal, patients may complain of instability with motion which may lead to the partial popping of the head out of the socket (subluxation) or a complete popping of the head out of the socket (dislocation).
Diagnosis
The diagnosis of aseptic loosening is made after a physical examination and radiological studies that suggest the aseptic loosening of the implants. The physical examination may reveal a clunking motion, instability, and may elicit tenderness.
The radiological studies in the form of an X-ray may reveal thinning of the bone surrounding the implant and in severe cases, the implants may move out of place. Blood investigations and joint fluid aspiration studies may be done to rule out any infection of the prosthetic joint.
Extracted head of femur and the femoral component during revision surgery.
Management
Aseptic loosening of the hip joint is managed surgically by a revision hip replacement. The revision surgery may involve extracting and replacing all the components of a total hip or may involve the replacement of only the loose stem or the acetabulum shell. The revision hip replacement surgery is more complex than primary surgery and is best performed by a surgeon with experience in revision surgeries.
Do you have more questions?Â
Can wearing out of a total hip replacement cause pain or discomfort?
Yes, wearing out of a total hip replacement can lead to pain, discomfort, and decreased mobility as the implant components degrade over time.
How common is wearing out of a total hip replacement?
Wearing out of a total hip replacement is relatively common, especially in individuals who have had the implant for many years or are highly active.
Are there specific activities that increase the risk of wearing out a total hip replacement?
Activities that place repetitive stress on the hip joint, such as high-impact sports or heavy lifting, can increase the risk of wearing out a total hip replacement.
What are the symptoms of wearing out of a total hip replacement?
Symptoms may include increased hip pain, stiffness, decreased range of motion, swelling around the hip joint, and difficulty walking or bearing weight on the affected side.
How is wearing out of a total hip replacement diagnosed?
Diagnosis typically involves a combination of clinical evaluation, imaging studies such as X-rays or MRI scans, and assessment of symptoms and functional limitations.
Can wearing out of a total hip replacement be prevented?
While wearing out of a total hip replacement cannot always be prevented, certain measures such as maintaining a healthy weight, avoiding excessive stress on the hip joint, and following post-operative care guidelines can help prolong the lifespan of the implant.
What are the treatment options for wearing out of a total hip replacement?
Treatment options may include conservative measures such as pain management, physical therapy, and activity modification, as well as surgical interventions such as revision hip replacement to replace the worn-out components.
How long does recovery take after revision hip replacement surgery for wearing out of a total hip replacement?
Recovery time after revision hip replacement surgery varies depending on factors such as the extent of the procedure, individual patient factors, and adherence to post-operative rehabilitation protocols.
What are the risks associated with revision hip replacement surgery for wearing out of a total hip replacement?
Risks of revision hip replacement surgery include infection, bleeding, blood clots, implant loosening or failure, nerve or blood vessel injury, and complications related to anesthesia.
Are there any factors that increase the risk of wearing out of a total hip replacement, such as patient age or implant materials?
Factors that may increase the risk of wearing out of a total hip replacement include patient age, implant materials, activity level, implant positioning, and surgical technique.
Can wearing out of a total hip replacement affect other parts of the body, such as the spine or knees?
Yes, wearing out of a total hip replacement can alter gait mechanics and place increased stress on other joints such as the spine or knees, potentially leading to secondary complications over time.
How often should individuals with a total hip replacement undergo follow-up appointments to monitor for signs of wearing out?
Individuals with a total hip replacement should undergo regular follow-up appointments with their orthopedic surgeon to monitor for signs of wearing out and assess implant function and integrity.
Can wearing out of a total hip replacement lead to complications such as metallosis or adverse tissue reactions?
Yes, wearing out of a total hip replacement can lead to complications such as metallosis (metal poisoning) or adverse tissue reactions due to the release of metal ions from the implant components.
Are there any dietary or lifestyle modifications that can help slow down the wearing out of a total hip replacement?
While there are no specific dietary or lifestyle modifications proven to prevent wearing out of a total hip replacement, maintaining a healthy weight, staying physically active within recommended limits, and avoiding smoking may help optimize overall joint health.
Can individuals with a total hip replacement safely participate in physical activities such as sports or exercise classes?
In general, individuals with a total hip replacement can safely participate in low-impact activities such as swimming, cycling, or walking. However, high-impact sports or activities that place excessive stress on the hip joint should be avoided to minimize the risk of wearing out the implant.
How does the type of implant material used in a total hip replacement affect the risk of wearing out?
The type of implant material used in a total hip replacement, such as metal-on-metal, metal-on-polyethylene, ceramic-on-ceramic, or ceramic-on-polyethylene, can influence the risk of wearing out and the longevity of the implant.
Can individuals with a total hip replacement experience symptoms of wearing out even if the implant appears intact on imaging studies?
Yes, individuals with a total hip replacement can experience symptoms of wearing out even if the implant appears intact on imaging studies, as wear-related changes may not always be visible on imaging and can manifest clinically.
Are there any alternative treatments or therapies available for individuals experiencing symptoms of wearing out of a total hip replacement?
Alternative treatments or therapies for symptoms of wearing out of a total hip replacement may include non-invasive modalities such as acupuncture, chiropractic care, or physical therapy to manage pain and improve joint function.
Can wearing out of a total hip replacement affect the stability or alignment of the hip joint?
Yes, wearing out of a total hip replacement can lead to changes in implant position, joint stability, and alignment, which may contribute to symptoms such as pain, stiffness, and decreased mobility. Regular monitoring and timely intervention may be necessary to address these issues and prevent further complications.
Dr. Suhirad Khokhar
My name is Dr. Suhirad Khokhar, and am an orthopaedic surgeon. I completed my MBBS (Bachelor of Medicine & Bachelor of Surgery) at Govt. Medical College, Patiala, India.
I specialize in musculoskeletal disorders and their management, and have personally approved of and written this content.
My profile page has all of my educational information, work experience, and all the pages on this site that I've contributed to.
