What Is Inflammatory Arthritis?

Inflammatory arthritis refers to autoimmune conditions where the immune system drives ongoing inflammation in the joints.
Common examples include:

• Rheumatoid arthritis

• Psoriatic arthritis

• Systemic Lupus Erythematosus (SLE)

• Other connective tissue diseases

These conditions behave differently from osteoarthritis and can influence both pain and recovery after a knee replacement.

Why Inflammatory Arthritis Matters After Knee Replacement

1. Sensitisation is very common

People with inflammatory arthritis experience sensitisation more frequently than those without inflammatory disease.
This includes:

• Peripheral sensitisation from inflamed joints

• Central sensitisation from long-term pain

Both can increase pain after knee replacement even when the prosthesis itself is functioning normally.

2. Inflammation may persist longer

In people without inflammatory arthritis, postoperative inflammation generally settles within 6 to 12 weeks.
In inflammatory arthritis, inflammation may:

• Persist beyond this timeframe

• Fluctuate over time

• Affect multiple joints at once

• Maintain higher levels of sensitivity

This means that pain after knee replacement may behave differently and may require a different clinical approach.

Pain After Knee Replacement in Inflammatory Arthritis

Even when the knee replacement is functioning well, people with inflammatory arthritis may still experience pain due to:

• Ongoing inflammation in the joint

• Systemic disease activity

• Sensitisation (peripheral or central)

• Muscle weakness or movement limitation

• Fatigue and whole-body pain typical of inflammatory conditions

This means that pain does not always indicate a problem with the prosthesis.

Modern Treatments Can Control Inflammation — But Pain May Still Persist

Medications such as:

• Prednisolone

• Methotrexate

• Sulphasalazine

• Leflunomide

• Biological therapies (e.g., etanercept)

can lead to complete resolution of inflammation when prescribed appropriately.

However, even when inflammation resolves, pain can continue due to sensitisation and other factors described in the Kneed program.

In other words:
Pain can exist without active inflammation — and this is very common in inflammatory arthritis.

How to Manage Knee Pain After Replacement if You Have Inflammatory Arthritis

The key is to determine whether your inflammatory arthritis is active or inactive.

1. If Your Inflammatory Arthritis Is Active

Signs may include:

• Red, swollen joints

• Heat around the joint

• Multiple joints affected at once

• Elevated CRP or ESR

• General flare symptoms

If inflammation is active:

• Speak with your doctor about appropriate medication

• Ice or cold packs may help

• Avoid overloading inflamed joints

• Use pain as a guide for exercise levels

Rehabilitation should be modified until the inflammatory activity settles.

2. If Your Inflammatory Arthritis Is Not Active

Once inflammation is controlled:

• Rehabilitation principles from Kneed can be used

• Exercise can progress gradually

• Normalise movement patterns

In clinical practice, people with controlled inflammatory arthritis follow the same approach as those recovering from osteoarthritis-related knee replacement pain.

3. If You Have a Knee Replacement and Inflammatory Arthritis

It is important to:

• Look for signs of local inflammation

• Ensure that the knee replacement is free of infection

• Have reassurance from your surgeon or GP regarding the status of the prosthesis

• Modify rehabilitation during flares

• Progress activity when falres have settled

People taking immunosuppressive medications may have an altered risk profile, so medical guidance is essential.