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If you are experiencing pain after a partial knee replacement, it is important to determine the cause of that pain. There can be many reasons for discomfort after surgery, and some may require revision knee replacement surgery to correct. In this blog post, we will discuss the most common causes of pain following partial knee replacement surgery and what you can do if you are experiencing problems.

A partial knee replacement is a type of joint replacement surgery where only a portion of the knee is replaced with metal and plastic. The most common reason for this type of surgery is to relieve pain from arthritis. Arthritis is a condition that causes the cartilage in your joints to break down, which can lead to pain, stiffness, and swelling. Although partial knee replacement surgery can be very effective in relieving these symptoms, some patients may still experience pain after the surgery.

Complete recovery following a partial knee replacement can take up to a year after surgery. Not every patient recovers at the same rate. While most patients achieve 80% of their recovery within 2 – 3 months, some patients may take several months longer than expected to recover. Appropriate pain medication with multimodal pain management, ice, and physical therapy are the keys to successful recovery.

Worsening pain or persistent pain after surgery that is not improving may be signs that your partial knee replacement has failed. There are many reasons why partial knee replacement surgery may fail. Some of the most common reasons include:

Poor Indications for Partial Knee Replacement:

In some cases, partial knee replacement surgery is not the best treatment option for a patient. This can be due to several factors such as advanced arthritis, ACL tear, severe deformity, significant flexion contracture, or inflammatory arthritis.

Advanced Arthritis at the Time of Initial Surgery

Patients with arthritis in more than one compartment may be unsuitable for knee replacements. This may lead to rapid deterioration of the partial knee replacement. Some patients will notice that they never seemed to have much improvement from their partial knee replacements. Similarly, patients with inflammatory arthritis such as rheumatoid arthritis have disease in all of the compartments of their knee.

Ligament Instability

The ligaments around the knee are very important to the stability of the knee. An injury to one of the ligaments, especially the Anterior Cruciate Ligament (ACL) is generally considered a reason not to have a partial knee replacement. An unstable knee in the setting of a partial knee replacement may lead to persistent feelings of instability or pain.


Partial knee replacements are not designed to correct knee deformity. Patients with a severe deformity or significant flexion contracture who undergo partial knee replacement will not see the resolution of problems stemming from their deformity. This may lead to decreased satisfaction with a partial knee replacement.


An infected partial knee replacement can present with pain. You may notice the pain developing later on after recovery that doesn’t seem to improve. Laboratory tests and aspiration with a needle are usually required to confirm the diagnosis.

Implant misalignment

Placing the partial knee replacement in the wrong position can lead to edge loading of the plastic component of the knee replacement and early failure. Placing the components too tightly can lead to the progression of arthritis. Placing the components with too much laxity can lead to instability of the knee. It is important to have a surgeon who has experience placing partial knee replacements to lower the chance of failure.

Loose implants

Loose knee replacements are a common cause of revision surgery after partial knee replacement. As the components wear out, the components can begin to toggle. It is the motion of these implants within bone that cause pain. Failed implants require revision to total knee replacements in order to improve pain.

Progression of arthritis

Sometimes patients develop arthritis in other parts of the knee. While many partial knee replacements can last a lifetime, patients may continue to wear out the other compartments in their knee with regular wear and tear. As this happens, many patients will notice pain in areas of their knee where they didn’t feel it before.


Fracture around a partial knee replacement can occur when the cuts made for the implants are too deep into the bone. This is more likely to occur in smaller patients as there is less bone to work with. Often when this occurs, revision to total knee replacement is required early in the recovery.


If you are experiencing persistent pain after partial knee replacement, it is important to seek medical attention. There are many potential causes of your pain, and only a trained medical professional will be able to properly diagnose and treat your condition. Revision knee replacement surgery may be required in some cases in order to improve symptoms. Be sure to discuss all of your treatment options with your doctor in order to make the best decision for your individual situation.

If you have any questions or would like to learn more about partial knee replacement, please contact our office. We would be happy to help you schedule a consultation with Dr. Morton.