KNEE PAIN – Why Does My Total Knee Replacement Still Hurt So Much
Persistent Knee Pain After Total Knee Replacement Surgery
Pain is a highly complex human experience that cannot be easily explained by mechanical problems.
It is possible to have scar tissue without pain. It is possible to have limited range of motion without pain. It is even possible to have redness and swelling without pain.
But many of the patients I work with in my physical therapy clinic who are experiencing persistent pain after total knee replacement are experiencing all of these impairments AND pain.
What percent of total knee replacements are successful?
By several accounts nearly 20% of patients are not happy with the outcome of their total knee replacement. 
Why does my total knee replacement still hurt?
One of my favorite clinical studies reviewing different aspects of pain following a total knee replacement is The painful knee after total knee arthroplasty: evaluation and management. 
A list of the most common causes of pain:
- Mechanical Instability
- Loosening of the component
- Periprosthetic fracture
- Anterior knee pain
- Non-Joint Causes:
- Soft tissue irritation
- Neuropathic pain
- Complex regional pain syndrome
In future updates to this article, I will be providing more details on the above conditions.
What is considered normal knee pain?
Many of the patients I work with in my physical therapy clinic will ask “Is this normal?”
There is something calming about knowing the pain you feel is normal or common.
Normal Knee Pain After Joint Replacement Surgery
Normal knee pain would be characterized by soreness throughout the knee, thigh, and calf. It is often described as a 4 out of 10 increasing to a 7 out of 10 at the most.
Patients will report the first 24 hours after surgery feeling lower pain levels than compared to the next 48 to 72-hour. After 72 hours the pain levels should reduce to a more comfortable level.
Normal pain may increase with activity and normalize with rest. Normal pain often responds well to pain medication, icing, or moist heat.
What are Abnormal Pain Levels
Abnormal pain would be characterized by pain that increases throughout the day and doesn’t relent with pain medication, icing, or moist heat. High pain levels cause increased respiration rates, sweating, and signs of stress.
Abnormal pain may cause loss of appetite, nausea, and anxiety.
In these cases, it is important that the patient contact the surgical team for a possible change in pain medication or further medical assessment.
Infection After Total Knee Replacement
While it is true that an infection may also cause pain after a total knee replacement, an infection may also be present without pain. Some classic warning signs to watch for infection include:
- Excessive and worsening redness
- Seepage, drainage, or oozing
- Redness that progressively extends away from the knee
- Increased warmth at the knee
- Increased body temperature
If you or your therapist have reasons to suspect a possible infection, it is important that you contact your surgical team or go to your local emergency room for further medical assessment.
There have been reported cases in which the prosthesis implanted during a total knee replacement surgery becomes unstable or the ligaments surrounding the knee become ruptured.
Mechanically instability is often associated with an unsafe feeling while walking to stepping on the surgical leg, but it isn’t often associated with pain in the knee joint.
A knee that has become mechanically unstable is loose and therefore patients do not feel the pain associated with knee stiffness.
Citations and Reference:
 Wylde V, Beswick A, Bruce J, Blom A, Howells N, Gooberman-Hill R. Chronic pain after total knee arthroplasty. EFORT Open Rev. 2018;3(8):461-470. Published 2018 Aug 16. doi:10.1302/2058-5241.3.180004
 Momoli A, Giarretta S, Modena M, Micheloni GM. The painful knee after total knee arthroplasty: evaluation and management. Acta Biomed. 2017;88(2S):60-67. Published 2017 Jun 7. doi:10.23750/abm.v88i2-S.6515
More Blog Posts …
What is the worst day after knee replacement? I am a physical therapist who specializes in treating patients after a total knee replacement. In my experience, the worst day after knee replacement is the third day. I will explain why in this article and share some...
Introduction to Joint Replacement Surgeries Joint replacement surgery is a common and highly effective treatment option for severe pain and functional limitations associated with a variety of joint disorders. This surgical procedure involves replacing a damaged joint...
I have been a physical therapist since 2006 and a certified strength coach since 2001. If there is one thing I have learned over the past 22 years it is that pain does not always mean danger or damage. A simple rule of thumb for guiding your decision to stop an...
Best Surgery Clothes for Before, During, and After your Knee Surgery I have been a licensed physical therapist since 2006 and have worked with hundreds of patients who underwent total knee replacement surgery over the past 16 years. One thing nobody prepares for are...
Understanding and Treating Muscle Spasms in the Shoulder Muscle spasms in the shoulder can be incredibly uncomfortable and can significantly limit your range of motion and daily activities. Whether it's a sudden, involuntary contraction or a persistent tightening of...
Unraveling the World of Can TENS Unit Cause Heart Attack? Transcutaneous Electrical Nerve Stimulation (TENS) units are specialized devices widely used in the medical and physical therapy fields. These handy gadgets function by sending low-voltage electrical currents...
Table of Contents TENS Unit for Knee Pain Contraindications for using TENS on Knee Pain Indication for Using TENS on Knee Pain TENS Unit for Knee Pain Transcutaneous Electrical Nerve Stimulation (TENS) is a non-invasive and drug-free method for pain relief that is...
Foot swelling after total knee replacement surgery is a common concern among patients. This comprehensive guide will explore the causes of swelling, how to manage and reduce it, and steps to prevent it from occurring. Read on to learn more about foot swelling after...
Rooster comb injections have become so popular in my area over the past 10 years. Since I am mostly treating patients after a total knee replacement surgery, I see the patients who were not helped by hyaluronic acid injections. In this article I want to share my...
In this article, we'll explore some strategies to help you walk without a limp and manage swelling following a total knee replacement (TKR) surgery. We'll also provide motivational quotes to keep you inspired and hopeful throughout your recovery journey. Motivational...