It takes the weight of your entire body, so there’s plenty that can go wrong with this complicated area causing knee joint pain, says Dr Melanie Wynn-Jones
Our knees are hinge joints, designed to bend, straighten and support our weight. Strong, gristly ligaments stabilise them at the front, back and sides.
Two pieces of cartilage act as shock absorbers between our thigh and shin bones, and our kneecaps (patellae) provide extra support.
Walking, climbing, jumping, twisting and squatting take their toll, but only a third of people aged 50-plus with knee joint pain are formally diagnosed with osteoarthritis (OA) – the wearing or roughening of the slippery cartilage on bony surfaces. ‘Soft’ internal tissues, hip or foot problems are often to blame instead.
Tests you may need
You may need these immediately if you have severe or sudden knee joint pain or swelling and/or an injury. You may need X-rays (to check your bones), an ultrasound or MR scan (to check cartilages and ligaments), blood tests (for inflammation, gout or infection) and/or an arthroscopy (an internal telescope examination with a general anaesthetic to detect or repair cartilage damage).
Fluid can be removed with a fine needle and tested for infection or crystals (see under ‘Hot, swollen knee’).
Strains and sprains
These are caused by sudden, awkward movements and trauma. You’ll notice knee joint pain and possibly swelling. Bursitis, eg, ‘housemaid’s knee’, is a painful swelling caused by repeated trauma, such as kneeling.
To treat, rest or support your knee (stretched out along a couch). Take a painkiller such as paracetamol or ibuprofen – check with your pharmacist if you have other medical conditions or take other medicines – and apply ice (wrapped in a tea towel) for 15 minutes, four times a day, switching to heat (such as a hot-water bottle) after three days until it’s better.
A support bandage may help, but regularly and gently bend and straighten your knee. If your knee joint pain doesn’t settle, see your doctor. But seek medical advice quickly if symptoms are severe after a major injury or fall because you may have a fracture, dislocated kneecap, or a cartilage or ligament tear.
Hot, swollen knee
A hot, red and painful knee and/or feeling feverish or fluey may indicate an infection that could cause major damage. You’ll need prompt treatment with antibiotics.
Gout can affect knees, too, and is more common in women after the menopause. It’s caused by crystals of uric acid from the blood which attack joints, causing severe inflammation. You’ll need strong painkillers, and perhaps daily tablets (allopurinol) to prevent a recurrence.
Inflammation can also be due to many immune system disorders, including rheumatoid arthritis, lupus and even psoriasis. Other joints may be affected and you may have problems with your eyes, skin and other organs. You’ll need to see a rheumatologist and, perhaps, take powerful or effective disease-modifying or immunosuppressant drugs.
Ligament and cartilage damage
Direct blows, jumping and falls can stretch, sprain or partially or completely rupture a ligament. Women are more prone to rupture of the criss-cross anterior cruciate ligament (ACL), which sits behind the kneecap – you may hear a ‘pop’ when it goes.
Rupture can cause severe pain and swelling, difficulty in bending your knee or a feeling of instability or giving way. Cartilage tears often occur when we turn forcefully with our weight on one knee. As well as pain and swelling, your knee may ‘catch’ or even lock.
Physiotherapy and exercises are the best initial treatment for both types of injury. Ligaments can be surgically reconstructed (often less successfully in older people) while cartilage surgery may, but not always, relieve pain.
5 steps to healthy knees
1. Regular walking and stair climbing for muscle strength and balance.
2. Maintain a healthy weight to avoid overloading your knees.
3. Use poles when walking to relieve strain by 25%, and avoid falls.
4. Wear cushioned shoes and avoid high-impact exercise that can accelerate arthritis.
5. Strengthen muscles daily with squats (hold a chair back for support), straight-leg raising (lying or sitting) and step-ups (use the bottom stair).