Clunking Knee after Knee Replacement
Some patients may experience a painful clunking of the knee on straightening the knee after a knee replacement. The symptom may be a sign of patellar clunk syndrome. Patellar clunk syndrome occurs as a result of the formation of a fibrous nodule on the undersurface of the lower end of thigh muscles. The symptom is associated with the use of older implants and is rare with the designs of modern implants.
During knee replacement surgery, the surgeon replaces the diseased/arthritic parts of the knee joint with prosthetic parts. The lower end of the thigh bone (femur) is replaced with a metallic component fixed with bone cement. Similarly, the upper part of the shin bone (tibia) is replaced with a metallic component fixed similarly with bone cement.
X-ray showing total knee replacement and the site of fibrous tissue in patellar clunk syndrome.
The undersurface of the kneecap (patella) is replaced with a high-grade plastic component. The femoral component has a groove on the upper surface for the patella to glide smoothing as the knee bends and straightens.
The thigh muscles (quadriceps) in front of the thigh are attached to the shin bone (tibia) with the patellar tendon. The quadriceps muscle is attached to the patella and the patellar tendon extends from the patella to the tibial tuberosity.
The exact cause of the formation of fibrous tissue underneath the quadriceps muscle near the patella is unknown. The scar formation has been hypothesized due to direct injury to the quadriceps muscle during patellar cutting and as a result of the small size of the patellar component.
The patellar clunk syndrome occurs exclusively in posterior stabilized implants as the fibrosis tissue is prone to get engaged in box shaped wedge of the femoral component.
Risk factors
Preoperative patient factors such as low lying patella, a history of prior knee surgery, scar tissue/fibrous prior to knee replacement, knock knee deformity before surgery, etc. are risk factors for the development of patellar clunk syndrome.
A smaller patellar component or low placement of the patellar component also increases the risk of patellar clunk syndrome.
Mal-position of the femoral component and large size of polyethylene insert may also increase the risk of patellar clunk syndrome.
Symptoms
The symptoms of patellar clunk syndrome are reported in the form of a painful clunk experience on straightening a bent knee. The patients may describe the clunk as a popping, snapping, or catching sensation. The patients typically present after a year of knee replacement surgery.
Diagnosis
If you suspect you have Patellar Clunk Syndrome, your doctor will likely conduct a physical examination of your knee and may order imaging tests such as X-rays or MRI scans. These tests help assess the alignment of the artificial joint and identify any abnormalities or rough surfaces that could be causing the patella to catch.
Treatment Options:
The good news is that Patellar Clunk Syndrome is usually treatable, and several options are available depending on the severity of your symptoms:
Physical Therapy: Your doctor may recommend specific exercises to strengthen the muscles around your knee and improve its stability. Physical therapy can also help improve your range of motion and reduce the likelihood of the patella catching on the joint.
Medications: Over-the-counter pain relievers such as ibuprofen or acetaminophen can help alleviate any discomfort associated with Patellar Clunk Syndrome. In some cases, your doctor may prescribe stronger pain medications or anti-inflammatory drugs to manage pain and swelling.
Corticosteroid Injections: If conservative measures fail to provide relief, your doctor may recommend corticosteroid injections directly into the knee joint to reduce inflammation and alleviate symptoms.
Surgical Intervention: In severe cases where conservative treatments are ineffective, surgical intervention may be necessary. This could involve arthroscopic surgery to remove any bony overgrowths or scar tissue causing the patella to catch, or even revision surgery to replace the artificial joint with a different design or positioning.
Prevention
While it’s not always possible to prevent Patellar Clunk Syndrome entirely, there are steps you can take to minimize your risk:
- Follow your doctor’s post-operative instructions carefully, including any prescribed exercises or physical therapy.
- Attend all follow-up appointments to monitor the healing process and address any concerns promptly.
- Inform your doctor if you experience any unusual symptoms such as persistent pain, swelling, or clicking noises in your knee.
Conclusion
Patellar Clunk Syndrome may sound intimidating, but with the right knowledge and treatment, you can manage its symptoms effectively. If you’re experiencing any unusual noises or sensations in your knee after a replacement surgery, don’t hesitate to consult your doctor. By working together, you can identify the cause of your symptoms and develop a personalized treatment plan to get you back on your feet comfortably.
Do you have more questions?
How common is Patellar Clunk Syndrome after knee replacement surgery?
Patellar Clunk Syndrome occurs in a small percentage of patients undergoing knee replacement surgery, estimated to be around 1% to 3%.
Can Patellar Clunk Syndrome occur immediately after surgery, or does it develop over time?
It can happen either immediately after surgery or develop gradually over time as scar tissue forms around the joint.
Is Patellar Clunk Syndrome more common in certain types of knee replacement surgeries or implant designs?
Yes, certain factors like implant design, surgical technique, and patient-specific anatomy can influence the likelihood of developing Patellar Clunk Syndrome.
How long after knee replacement surgery does Patellar Clunk Syndrome typically develop?
It can vary from patient to patient, but symptoms typically arise within the first few months to a year after surgery.
Are there any specific risk factors that predispose someone to develop Patellar Clunk Syndrome?
Factors such as a history of knee trauma, previous surgeries, or underlying conditions like rheumatoid arthritis may increase the risk.
Can Patellar Clunk Syndrome lead to complications or further damage to the knee joint?
While it’s uncommon, severe cases of Patellar Clunk Syndrome can potentially lead to complications such as implant wear or instability if left untreated.
Is Patellar Clunk Syndrome more common in younger or older patients?
There’s no definitive age correlation, but younger patients with more active lifestyles may be at a slightly higher risk due to increased knee joint stress.
Are there any lifestyle modifications or activities that patients with Patellar Clunk Syndrome should avoid?
It’s generally advisable to avoid activities that exacerbate symptoms, such as high-impact sports or activities that involve repetitive knee bending.
Corticosteroid injections are generally safe but carry a small risk of complications such as infection, bleeding, or damage to surrounding tissues. Your doctor will discuss these risks with you before administering the injection.
Conservative treatments can be very effective, especially when combined with lifestyle modifications and medications. However, their success depends on the individual patient’s condition and response to treatment.
: What are the potential risks or side effects associated with corticosteroid injections for Patellar Clunk Syndrome?
Corticosteroid injections are generally safe but carry a small risk of complications such as infection, bleeding, or damage to surrounding tissues. Your doctor will discuss these risks with you before administering the injection.
Are there any alternative treatments or complementary therapies that can help manage Patellar Clunk Syndrome?
Some patients find relief from complementary therapies such as acupuncture, chiropractic care, or herbal supplements. However, the effectiveness of these treatments can vary, and it’s essential to discuss them with your doctor before trying them.
How long does it take to recover from surgical interventions for Patellar Clunk Syndrome?
Recovery time varies depending on the type of surgery performed and the individual patient’s healing process. In general, patients can expect several weeks to months of rehabilitation and recovery.
Are there any long-term implications of Patellar Clunk Syndrome on knee function or mobility?
With proper treatment and management, most patients can regain full function and mobility in their knees. However, some individuals may experience persistent symptoms or limitations, especially if complications develop.
Can Patellar Clunk Syndrome recur after successful treatment?
While recurrence is uncommon, it’s possible for symptoms to return if the underlying cause is not adequately addressed or if new issues arise.
Are there any specific exercises or stretches that can help prevent Patellar Clunk Syndrome from recurring?
Yes, your physical therapist can recommend specific exercises to strengthen the muscles around your knee and improve joint stability, reducing the risk of recurrence.
How often should patients with a history of Patellar Clunk Syndrome follow up with their healthcare provider?
It’s essential for patients to attend regular follow-up appointments with their doctor to monitor their knee health and address any concerns promptly.
Are there any dietary or nutritional recommendations that can help manage Patellar Clunk Syndrome?
While there are no specific dietary guidelines for Patellar Clunk Syndrome, maintaining a healthy weight and eating a balanced diet can support overall joint health and recovery.
Can Patellar Clunk Syndrome affect other activities of daily living, such as walking or climbing stairs?
Yes, depending on the severity of symptoms, Patellar Clunk Syndrome can impact various activities of daily living. Physical therapy and lifestyle modifications can help minimize these effects.
Are there any assistive devices or braces that can help alleviate symptoms of Patellar Clunk Syndrome?
In some cases, a knee brace or orthotic device may provide additional support and stability, reducing the likelihood of the patella catching on the joint.
How soon after knee replacement surgery can patients resume normal activities like driving or returning to work?
The timeline for returning to normal activities varies depending on the individual patient’s recovery process and the type of surgery performed. Your doctor will provide specific guidelines based on your unique situation.
Are there any advancements in surgical techniques or implant designs that can reduce the risk of Patellar Clunk Syndrome?
Yes, ongoing research and advancements in orthopedic surgery continue to improve implant designs and surgical techniques, reducing the incidence of complications like Patellar Clunk Syndrome.
What should patients do if they experience a sudden increase in pain or swelling in their knee after surgery?
Sudden increases in pain or swelling should be promptly evaluated by a healthcare provider to rule out complications such as infection or implant failure.
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.
