Why is knee pain worse after sitting or in the morning?

Knee pain or stiffness that feels worse after sitting for a period of time or first thing in the morning is one of the most common symptoms I see in clinic. Many patients describe stiffness, tightness, or discomfort when they first stand up, which then eases once they start moving.

This pattern is commonly associated with early knee osteoarthritis, kneecap-related (patellofemoral) pain, and overuse-related knee problems. While it can be uncomfortable and frustrating, it is very common and often explainable.

In this article, I explain why knee pain and stiffness are worse after rest, how long stiffness would usually be expected to last, and when it is sensible to seek specialist advice.

Why knee pain and stiffness are often worse after rest

When the knee joint has been still for a period of time:

• Joint lubrication reduces
• The muscles that support the knee temporarily become less active

As a result, the knee can feel stiff, tight, or sore when you first start moving again.

Movement helps restore circulation of joint fluid and reactivates the muscles around the knee, which is why stiffness often improves after a few minutes of walking or gentle movement.

This pattern is particularly common in active adults, people who take part in sport or regular exercise, but it can occur in anyone.

How long should stiffness last before it becomes concerning?

Short-lived stiffness, especially if it settles within a few minutes of movement, is generally normal and not a cause for concern.

However, stiffness that:

• Lasts longer than around 20–30 minutes
• Feels progressively worse
• Does not improve with movement

may suggest an underlying joint issue, such as cartilage wear or early degenerative change.

If stiffness or pain starts to affect walking, stairs, exercise, sleep, or daily activities, it is sensible to have it assessed.

Does morning knee pain always mean arthritis?

Not necessarily.

Osteoarthritis commonly causes stiffness that is worse after rest and improves with activity, which is why morning stiffness is one of the patterns clinicians look out for. However, not everyone with morning knee stiffness has arthritis.

The important point is that, when identified early, many knee conditions can be managed without surgery. Approaches such as targeted exercises, physiotherapy, and activity modification can help manage symptoms, maintain mobility, and slow progression.

When should stiffness and pain after rest be checked by a specialist?

It is sensible to seek specialist assessment if knee pain or stiffness:

• Persists over time
• Worsens gradually
• Begins to affect confidence, mobility, work, sport, or everyday activities

Being assessed does not automatically mean scans or surgery. In many cases, assessment simply provides reassurance, a clear explanation, and a treatment plan to help keep the knee moving comfortably.

About the author

Mr Akash Patel is a Consultant Trauma and Orthopaedic Surgeon based at the Royal Free Hospital in London and an Associate Professor at UCL. He specialises in hip and knee disorders, including sports injuries, joint replacement, arthroscopy (keyhole surgery), and trauma. Alongside surgical care, he has expertise in non-operative treatments such as biologics (PRP) and bracing, and sees private patients in London.