10 Common Causes of Knee Pain

Written by: James Gill BOst GOsC 6039. Registered Osteopath, Founder & Clinic Director

Medically Reviewed: Yannick Gracia, M.Ost GOsC 10475. Registered Lead Osteopath

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Knees tend to be taken for granted – until they start hurting. Whether you’re glued to a desk or running marathons, knee pain has a way of sneaking in, sometimes with no clear cause at all. That’s why it helps to get familiar with the most common knee pain causes.

Some are activity-related, others come from wear and tear, and a few might surprise you. The goal here isn’t to guess or self-diagnose, but to understand what might be going on. So, let’s look at ten of the most frequent causes of knee pain, explained in plain English.

Osteoarthritis of the Knee

This is one of the most well-known knee pain causes – and while it’s often linked to older adults, it’s showing up in younger people, too.

Osteoarthritis is a long-term joint condition where the protective cartilage wears away, leading to pain and stiffness. You might notice it more after movement or at the end of the day. Swelling, clicking, and reduced flexibility are all common knee injury symptoms here. It’s not something you can reverse, but it can be managed. If it’s bothering you regularly, physiotherapy treatments may help ease the pressure and improve mobility.

Rheumatoid Arthritis

Unlike osteoarthritis, this isn’t about wear and tear – rheumatoid arthritis is an autoimmune condition where your immune system mistakenly attacks your joints. It tends to affect both knees at once and can cause swelling, warmth, and pain that feels worse in the morning. It’s usually a longer-term issue that develops over time, and it does need medical oversight.

If your symptoms are persistent and seem symmetrical, it’s probably time to chat with your NHS GP before considering any hands-on treatment.

Meniscus Tears

Twisting your knee too fast – that’s often all it takes. A torn meniscus is usually caused by sudden movement or impact, especially during sport or exercise. Inside the knee, the meniscus acts like a shock absorber, so when it’s damaged, you might feel pain, swelling, or even a catching or locking sensation. The pain often sticks around after the injury, especially when trying to squat or turn.

In some cases, osteopathy services may support recovery, especially when movement feels limited but surgery isn’t necessary.

Ligament Injuries (ACL, MCL, PCL, LCL)

Ligaments hold the knee steady, but when one gets overstretched or torn – usually in sports or accidents – things can go wrong fast. Different ligaments lead to different symptoms, but most involve sudden pain, swelling, and a sense of instability. An ACL injury, for instance, might make the knee feel like it’s about to give way. These types of knee injury symptoms often come on immediately and don’t go away easily.

If your knee feels wobbly or won’t bear weight, it’s worth seeking professional assessment, particularly if you’re dealing with a suspected ligament injury in the knee.

Patellar Tendinitis (Jumper’s Knee)

This one tends to show up in people who run or jump a lot – think basketball, tennis, or weightlifting. Patellar tendinitis happens when the tendon connecting the kneecap to the shinbone becomes irritated. The pain usually sits just below the kneecap and might flare up when going up stairs, squatting, or getting up from a chair. It can get worse without rest or support, so it’s not something to push through.

For those dealing with it repeatedly, our sports massage options may ease the strain and support patellar tendinitis treatment.

Bursitis

Bursae are tiny fluid-filled sacs that help cushion your knee. When one of them becomes inflamed – from a fall, prolonged kneeling, or even repeated stress – you get knee bursitis. Relief is often possible with rest and hands-on therapies, but knowing what triggered it can stop it from returning.

Look out for swelling just below or above the kneecap, warmth, and tenderness. It can feel like a deep ache that just doesn’t go away. If the swelling increases or movement feels restricted, get it checked – it might be more than just irritation.

Runner’s Knee (Patellofemoral Pain Syndrome)

Despite the name, you don’t have to be a runner to develop this. Patellofemoral pain syndrome often crops up in people who squat, cycle, or do a lot of stair climbing. It tends to feel like a dull ache around or behind the kneecap, especially when going down stairs or sitting for long periods.

The pain is usually activity-related and might ease with rest, but it’s a sign your knee isn’t tracking properly. If you’re noticing runner’s knee symptoms regularly, early intervention can help you keep moving without making things worse.

Dislocated Kneecap

This one usually happens fast – a fall, a sharp twist, or sudden impact can knock the kneecap out of place. You’ll know something’s off right away: the pain is sharp, the knee looks deformed or out of line, and it often swells up quickly. This isn’t a wait-and-see situation. Emergency care comes first, but follow-up support is just as important.

Once the kneecap is back where it belongs, rehab helps strengthen the area and prevent repeat dislocations.

Fractures Around the Knee

Breaks and cracks in the bones around the knee – the kneecap, femur, or tibia – are serious and usually caused by trauma like a fall or accident. Symptoms often include sudden swelling, intense pain, bruising, and not being able to put weight on the leg. It might even be visibly out of place. Immediate medical help is non-negotiable, but the story doesn’t end there.

Once healing begins, physiotherapy treatments can play a big part in regaining strength and range of motion.

Iliotibial Band Syndrome (ITBS)

The iliotibial band runs along the outer thigh and helps stabilise your knee. But with overuse, especially in runners and cyclists, it can become irritated and rub against the bone. The pain often builds slowly and shows up on the outside of the knee, worsening with activity. ITBS tends to be stubborn and doesn’t always respond to rest alone.

Targeted support, like massage or stretching therapies, can form part of iliotibial band syndrome treatment, especially if you’re trying to stay active without triggering more pain.

Knee pain can be anything from a minor irritation to a daily struggle – but either way, guessing what’s going on won’t do you any favours. The truth is, there are lots of possible causes of knee pain, and most of them share overlapping symptoms. That’s why it helps to get a clearer picture from someone who knows what to look for.

Whether you’ve been dealing with stiffness for a while or something’s flared up after a run, there’s no harm in checking in. A proper assessment could make all the difference in how quickly you feel better and how likely it is to come back.

Book a knee pain consultation with our team at Bodytonic Clinic today and take the guesswork out of feeling better.