Knee Pain

The common causes by age

• Teens and twenties: patellofemoral pain, patellar tendinopathy, Osgood-Schlatter in growing adolescents
• Twenties to forties: patellofemoral pain, sporting ligament and meniscal injuries, iliotibial band syndrome
• Over 45: osteoarthritis, degenerative meniscal tears, Baker's cysts

What increases the risk

• A change in activity — new running programme, new job on your feet, a house move. Almost always "too much, too soon"
• Excess weight — which loads the knee several times over with each step
• Previous knee injury or surgery — the strongest predictor of later osteoarthritis
• Weak thigh and hip muscles
• Kneeling occupations — flooring, plumbing, carpet fitting
• Family history

Two beliefs that cause real harm

"Exercise wears the knee out." It does not. Cartilage depends on movement and loading for its nutrition, and muscle is what protects the joint. Inactivity accelerates arthritis; appropriate exercise slows it and reduces pain. This is one of the most damaging myths in musculoskeletal medicine.

"My scan showed bone on bone, so nothing can be done." X-ray appearance correlates poorly with pain — plenty of people with severe changes have little pain, and plenty with mild changes have a great deal. Hearing "bone on bone" reliably makes people stop moving, which makes everything worse.

Meniscal tears with age

Degenerative meniscal tears are found on the scans of a large proportion of people over 50 with no knee pain at all. Finding one on an MRI does not mean it is the cause of your symptoms — which is precisely why keyhole surgery for them has been shown not to help.

Knee problems are diagnosed largely from age, mechanism and location of pain — and a video consultation works well because you can show us the movement and point to exactly where it hurts.

What we ask

• Where precisely — front, inner, outer, or behind
• Age, and whether there was a specific injury
• Was there a pop, and did it swell within hours? — which suggests a significant structural injury
• Does it lock, catch or give way
• How long morning stiffness lasts — under or over 30 minutes
• Stairs, sitting, squatting, kneeling
• What changed in the weeks before it started
• Other joints involved
• In a child or teenager: hip symptoms and limp, always

Imaging — when it helps and when it misleads

• X-rays are not needed to diagnose osteoarthritis, which is a clinical diagnosis in someone over 45 with activity-related pain and short-lived morning stiffness. They are useful before considering joint replacement
• MRI is rarely helpful for degenerative knee pain — it finds meniscal tears that are present in large numbers of pain-free people and leads to surgery that does not work
• MRI is appropriate after significant injury with locking, instability or a suspected ligament rupture

Blood tests

Inflammatory markers and full blood count where inflammatory arthritis or infection is possible; HbA1c and urate where gout is a consideration.

What needs same-day in-person assessment

• A hot, red, swollen knee with fever — septic arthritis
• Inability to weight-bear after injury, or deformity
• A locked knee
• Calf swelling, warmth and pain — possible DVT
• A limping child or adolescent

The belief worth abandoning

Using your knee does not wear it out. Cartilage is nourished by movement and loading, and strong muscles protect the joint. Avoiding activity to "save" the knee produces weaker muscles, more stiffness and more pain — exactly the opposite of the intention.

Some discomfort during exercise is acceptable if it settles within 24 hours. That is the rule to work to.

Exercises that matter most

• Straight leg raises — lying down, leg straight, lift and hold. Simple, safe even in a painful knee
• Sit-to-stands from a chair, slowly, without using your hands
• Hip strengthening — side-lying leg raises and glute bridges. Hip weakness is one of the biggest contributors to knee pain and almost nobody addresses it
• Wall squats, going only as far as comfortable
• Little and often; consistency beats intensity

Day to day

• Build activity gradually — roughly 10% a week
• Cycling and swimming when walking is sore — keep moving something
• Supportive footwear; replace worn trainers
• Use a handrail on stairs; lead with the good leg going up, the painful one going down
• Kneeling pads for work
• Lose excess weight where relevant — the return per kilo is large at the knee

Supplements, honestly

Glucosamine and chondroitin have been studied extensively and perform no better than placebo. They are harmless, and a good deal of money is spent on them. Turmeric and collagen have weak, inconsistent evidence at best.

The money is better spent on a few physiotherapy sessions, which have real evidence behind them.

If you have been told "bone on bone"

Worth putting in context. X-ray appearance correlates poorly with pain — many people with severe changes have modest symptoms, and vice versa. It does not mean nothing can be done, and it does not mean you should stop moving. Strengthening still works, and knee replacement remains available when quality of life warrants it.

A note about children

Any child or teenager with knee pain needs their hip examined. Hip conditions in children very commonly present as knee pain, and missing them has lasting consequences. Do not accept knee pain in a limping child without the hip being checked.

Will exercise wear my knee out?

No — and this is the most important thing on the page. Cartilage is nourished by movement and loading, and strong muscles protect the joint. Exercise is the single most effective treatment for knee osteoarthritis, and avoiding activity to protect the knee produces weaker muscles, more stiffness and more pain.

I was told I'm "bone on bone". Does that mean surgery is the only option?

No. X-ray appearance correlates poorly with pain — plenty of people with severe changes have modest symptoms, and plenty with mild changes have a great deal of pain. Strengthening still works. Knee replacement is highly effective when quality of life genuinely warrants it, but "bone on bone" is not a reason to stop moving in the meantime.

Should I have keyhole surgery for my meniscal tear?

For an age-related degenerative tear, almost certainly not. Arthroscopy for degenerative tears and wear and tear performed no better than placebo surgery or exercise in high-quality trials, and is no longer recommended. Surgery has a clear role for genuine locking, and for significant injuries in younger people.

Do I need a scan?

Usually not. MRI finds meniscal tears in a large proportion of people over 50 with no pain at all, so a tear on a scan does not prove it is your problem — and it often leads to surgery that will not help. Imaging is worthwhile after a significant injury with locking or instability, and before considering joint replacement.

What should I take for the pain?

A topical anti-inflammatory gel is first-line for knee osteoarthritis — effective and safer than tablets. Oral anti-inflammatories short-term if needed. Interestingly, paracetamol alone is not recommended for knee osteoarthritis: the evidence simply does not support it, which catches people out.

Are glucosamine supplements worth it?

No. Glucosamine and chondroitin have been studied extensively and perform no better than placebo. They are harmless, but a great deal of money goes into them. The same money spent on a few physiotherapy sessions buys something that actually works.

Which exercises should I actually do?

Start with straight leg raises, slow sit-to-stands, and hip strengthening — side-lying leg raises and glute bridges. Hip weakness is one of the biggest contributors to knee pain and is very often overlooked. Little and often, and give it three months before judging it.

My child has knee pain. Does that need checking?

Yes, and specifically the hip. Hip problems in children and adolescents very commonly present as knee pain — including conditions where delay causes lasting damage. Any limping child, or a child with persistent knee pain, should have their hip examined rather than the knee alone.