What Causes Pain Behind Knee After Total Knee Replacement?

Still dealing with pain behind your knee after total knee replacement?

You’re not alone.

While some discomfort is expected as part of the healing process, ongoing or worsening pain behind the knee isn’t something you should ignore.

It’s often a sign that something deeper is going on.

Let’s break down the most common causes of pain behind the knee after total knee replacement, what to watch for, and how we at Orthobiologics Associates help patients find real relief, often without more surgery.

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Understanding What’s Behind the Pain

The back of your knee houses several key structures that play a role in movement and stability.

These include the popliteus tendon, the posterior joint capsule, a small bone called the fabella, important nerves like the tibial and common peroneal nerves, and the popliteal artery and vein.

If any of these are irritated, inflamed, or compressed during or after surgery, it can lead to lingering pain.

Why You Might Still Have Pain Behind the Knee After TKR

Let’s take a look at some of the common causes of pain after total knee replacement:

Soft Tissue Problems

One of the most common reasons for pain behind the knee after surgery is soft tissue irritation.

Here’s what that can include:

Popliteus tendonitis: The popliteus muscle and tendon help rotate and stabilize your knee. If this tendon becomes inflamed, it can cause sharp or aching pain in the back of the knee.
Hamstring tightness: Tight muscles behind the thigh can pull on the back of the knee and create discomfort.
IT band irritation: While this usually causes pain on the outer knee, it can sometimes affect the back of the joint.
Fabella syndrome: This involves a small bone (the fabella) behind the knee that can become irritated or compressed.

Nerve-Related Issues

Some knee pain is actually nerve pain in disguise.

Nerve irritation or regrowth: As nerves heal after surgery, they can become hypersensitive or misfire.
Neuromas: These are painful nerve endings that may form if a nerve was cut during surgery.
Referred pain: Sometimes, lower back issues or sciatic nerve irritation can cause pain that feels like it’s coming from the knee.
CRPS (Complex Regional Pain Syndrome): Though uncommon, this condition causes burning, throbbing pain that can last long after surgery.

Scar Tissue and Joint Tightness

Arthrofibrosis: This happens when scar tissue builds up inside the joint, limiting movement and causing pain.
Posterior capsule stiffness: The tissues in the back of the knee can become tight, especially if full extension isn’t regained during rehab.

Surgical or Mechanical Factors

Implant alignment issues: If the components of your knee replacement aren’t positioned just right, they can affect how your knee moves.
Overstuffed joint: A joint that feels too tight or bulky may put pressure on surrounding tissues.
Component impingement: When metal or plastic parts rub against soft tissue, it can cause pain and inflammation.

More Serious Conditions to Rule Out

Some causes of pain behind the knee after knee replacement need immediate attention:

Blood clots (DVT): Swelling, warmth, and tenderness in the calf or back of the knee could point to a clot.
Infection: Ongoing pain with redness, fever, or drainage could indicate an infection.
Vascular issues: Enlarged blood vessels or bleeding can cause pressure in the back of the knee.

Diagnosing the Cause of Your Pain

To get the right treatment, you need the right diagnosis.

That starts with a hands-on exam and a review of your surgical history.

Imaging such as X-rays, MRIs, or ultrasounds can show if something is out of place or inflamed.

In some cases, we use diagnostic injections or nerve studies to pinpoint the exact source of the pain.

How Long Should Pain Behind the Knee Last?

Most post-surgical pain improves within a couple of months.

But if you’re still having pain three months or more after surgery, especially pain that’s getting worse or interfering with your day-to-day life, it’s time to take a closer look.

Chronic pain behind the knee isn’t something you just have to accept.

What Can You Do About It?

Here are some options to treat pain after total knee replacement:

Start with Conservative Options

Physical therapy: A targeted PT plan can stretch tight tissues, improve mobility, and reduce pain.
Manual therapy: Techniques like myofascial release can ease pressure in the back of the knee.
Home stretches and strength work: Keeping your hamstrings, calves, and glutes flexible and strong can help reduce strain.

Injection-Based Therapies

Cortisone: These shots can calm down inflammation temporarily.
PRP (Platelet-Rich Plasma): PRP uses your own blood components to promote healing in irritated tendons or soft tissues. We use guided ultrasound to deliver PRP exactly where it’s needed.
Stem cell therapy: For some people, stem cell injections help reduce inflammation and repair damaged tissue.

How We Help at Orthobiologics Associates With Knee Pain

We specialize in helping people with persistent pain after total knee replacement—especially when traditional treatments haven’t worked.

Our non-surgical approach is focused on real healing, not just symptom relief.

We offer:

PRP and regenerative therapies to treat tendon injuries, soft tissue inflammation, and scar tissue buildup
Stem cell options to encourage tissue repair and joint support
Genicular Artery Embolization (GAE): GAE for knee pain is a minimally invasive procedure reduces blood flow to inflamed parts of the knee. For patients with ongoing inflammation after TKR, GAE has benefits that make it an effective way to relieve pain without needing another surgery.

We create a personalized plan based on your symptoms, imaging, and goals—so you can get back to walking, moving, and living without constant pain.

When Other Options Are Needed

If biologic treatments or therapy haven’t resolved the issue, you may need:

Nerve ablation: Helps with chronic nerve pain that doesn’t respond to other treatments.
Arthroscopic debridement: A procedure to remove excess scar tissue.
Revision surgery: Only considered when implant issues are confirmed.

When to Reach Out to Us

You should consider contacting us at Orthobiologics Associates if:

You still have pain behind your knee 3 months after surgery
You’re noticing new swelling, heat, or tightness in the back of your leg
Physical therapy and cortisone haven’t helped
You want to explore non-surgical options before considering revision surgery

We’re here to help you understand what’s going on and create a clear plan to move forward.

Final Thoughts: What Causes Pain Behind the Knee After Total Knee Replacement

Pain behind the knee after total knee replacement isn’t something you just have to live with.

Whether it’s soft tissue irritation, a nerve issue, or inflammation that won’t settle down, there are effective treatment options.

At Orthobiologics Associates, we use advanced regenerative therapies like PRP and GAE to target the root of the pain and help you heal naturally.

If you’re tired of being told to “just wait it out,” let’s talk.

We’re ready when you are.

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FAQs: What Causes Pain Behind Knee After Total Knee Replacement

How do you get rid of knee pain behind the knee?
Getting rid of pain behind the knee starts with identifying the root cause. Treatments may include physical therapy, stretching, manual therapy, or targeted injections like PRP. If soft tissue or nerve issues are involved, regenerative treatments or procedures like Genicular Artery Embolization (GAE) may offer relief.

How long does it take for nerves to heal after total knee replacement?
Nerves can take several weeks to several months to heal after total knee replacement. In some cases, mild nerve irritation may resolve on its own, but more persistent nerve pain could require additional therapies such as nerve blocks or regenerative treatments.

Is walking good for pain behind the knee?
Gentle walking is usually beneficial and can improve circulation and joint function, but overdoing it can aggravate soft tissue or nerve-related pain. If walking increases your discomfort, it’s a sign to reassess your activity level or seek a clinical evaluation.

Why does the back of my knee hurt after knee replacement?
Pain behind the knee after replacement can be caused by several things, including popliteus tendon irritation, scar tissue (arthrofibrosis), nerve issues, or implant-related mechanics. It’s important to have the pain properly evaluated to determine the exact cause.

Should I keep my knee straight or bent?
A healthy balance is key. Keeping the knee too straight can lead to stiffness, while keeping it bent for long periods can cause tightness and strain. Regular movement through your full range of motion—along with guided rehab—is usually the best approach.

What is GAE?
Genicular Artery Embolization, or GAE, is a non-surgical procedure that reduces blood flow to inflamed areas in the knee. It helps decrease chronic pain by targeting the small arteries that contribute to ongoing inflammation, especially in patients with persistent knee pain.

What are the side effects of GAE?
GAE is generally well-tolerated, but some people may experience temporary bruising, mild discomfort, or inflammation near the treatment area. Serious side effects are rare but should be discussed with your provider before the procedure.

Does GAE help with failed knee replacement?
Yes, GAE can be a helpful option for patients experiencing pain after knee replacement, especially when inflammation or overactive blood vessels are contributing to the discomfort. It offers a non-surgical alternative for those not ready—or not eligible—for revision surgery.