Our knees are a marvel of engineering. They take quite a battering over the course of a lifetime, especially an active one; knees bear our full weight when we’re standing, with extra force when we run, jump, twist, go up and down stairs, kick a ball or cavort around a tennis court or down a ski slope. Little wonder knees are susceptible to short-term (acute) injuries and long-term (chronic) problems such as osteoarthritis (“wear and tear”). Most acute knee problems get better without specific treatment, and the best initial treatment for chronic knee pain is exercise and weight loss. Other options include simple painkillers, physiotherapy, steroid injections, cartilage and ligament repair, and total knee replacement. Claims are made for dietary supplements and spices such as fish oils, turmeric and glucosamine. Newer therapies being investigated include injecting the knee with hyaluronic acid, stem cells or platelet-rich plasma.

Does it matter if my knees pop or crack when I squat?

A popping or cracking noise does not matter if there’s no pain, swelling or difficulty moving your knee. The alarming sound can be caused by air bubbles popping in the joint fluid or ligaments and tendons snapping back into place after moving or catching on bits of bone or cartilage. If you also get pain, swelling or find the knee catches in certain positions, you may have a small cartilage tear. Most minor tears get better without specific treatment within six weeks; if not, see your GP.

I have heard people talk about ACL and meniscal tears. What’s the difference?

It helps to visualise the whole knee. The joint between the femur (thigh bone) and tibia (shin bone) is helped by the patella (kneecap) and stabilised by four powerful ligaments, which are fibrous bands between the bones (anterior and posterior cruciate – ACL and PCL – which cross the joint space, and lateral and medial collateral – LCL and MCL – which run down either side of the joint). The strong quadriceps (thigh muscles) are attached to the patella via a tendon and are key to the smooth movement and stability of the joint; strong quadriceps make for strong knees. Cartilage lines the surfaces of femur and tibia to prevent bone grinding on bone, and two cushions of cartilage (menisci) sit in the joint as shock absorbers. Most cartilage and ligament tears get better on their own within a few weeks, but surgical repair is sometimes needed. An ACL tear is a common sports injury that makes the knee painful and unstable. It particularly affects skiers, footballers and rugby players who stop or change direction suddenly or get a direct blow to the knee during a tackle.

I’ve got patellofemoral pain syndrome; should I give up my gym membership?

Patellofemoral pain syndrome often affects young, sporty women and is a fancy name for the dull ache and crunching sound you get at the front of both knees around the kneecap. It can be worse after sitting for a long time, pounding up and down stairs, kneeling or doing squats. Ice packs and anti-inflammatory gel or tablets help in the short-term, and exercises to strengthen the muscles around the knee may solve the problem. You may have to change your exercise regime; walking and cycling in place of running and jumping. Giving up the gym is your call but you would be advised to stay active for your physical and mental wellbeing.

My knees are dodgy; should I avoid running?

Not necessarily. Elite athletes, runners and footballers certainly get knee injuries as an occupational hazard. But for the rest of us, the evidence suggests that even long-distance running doesn’t increase the chances of developing osteoarthritis. Older runners with mild osteoarthritis don’t seem to make it worse if they keep on running.

I’ve been told that my knee pain is osteoarthritis and there’s nothing I can do. Is that really true?

No, there’s lots you can do, but it’s not about heroics or headline-grabbing new therapies. Leading orthopaedic surgeon Fares Haddad of University College hospital, London, says it’s essential to keep exercising and lose weight. “If people lose weight, their knee pain improves, and if they need surgery, they do better.” Haddad encourages people to take a low dose of mild painkillers if they need something to keep active, but he is concerned about the rise in the use of opiates (strong and addictive painkillers such as morphine), which is a huge problem in the US and is increasing in the UK. Steroid injections help some people in the short-term, but injections of platelet-rich plasma, stem cells or hyaluronic acid haven’t been shown to work.

I get occasional knee pain and my X-ray shows severe osteoarthritis; should I have a knee replacement? I would pay for it myself if I need to.

Bart Ferket of Mount Sinai Health System, New York, says it’s best to treat the person, not the X-ray. X-ray and MRI findings don’t correlate well with symptoms; you can have an awful-looking X-ray but not suffer much pain or stiffness, and vice versa. He has carried out a study in the US to look at the cost-effectiveness of knee replacements. Most people with knee symptoms do report an improvement in symptoms after this major operation but, unsurprisingly, the worse you are before the op, the bigger the improvement. In the NHS, no one will offer you a knee replacement until your symptoms are severe and you have tried other options such as exercise regimes, weight-loss and painkillers. Haddad says that developments in robotics mean that partial and full knee replacements are likely to become even safer, more effective and long lasting in the coming years.

Ever since I Googled “knee osteoarthritis” I have been bombarded by things to buy and try. How do I know what works and what doesn’t?

Look at evidence and price. Does it work? Does it cause any harm? Is it worth the money? The trial evidence to date is that acupuncture doesn’t work, but it’s safe and may help some individuals. There’s a lack of evidence for the effectiveness of a Tens machine, but is cheap and safe. Lateral wedge insoles can be bought online and put in shoes to take pressure off the knee; evidence is weak, but they’re cheap, safe and sometimes effective. Glucosamine and chondroitin supplements are popular, but there’s no evidence to recommend their use. The yellow pigment in the spice turmeric contains chemicals that are said to be beneficial in osteoarthritis, but it’s likely you would have to eat a ton of it for any significant effect, says Haddad.

What about a steroid injection?

Steroid injections into the knee joint can provide rapid relief from pain, swelling and stiffness. The effect lasts up to three months or more. But the evidence is inconclusive; 44% of people given a steroid injection reported an improvement in pain compared with 31% given a placebo injection. Some 36% said they noticed improved function, compared with 26% given a placebo.

The waiting list for NHS physio in my area is more than six months. What should I do?

Stay on the waiting list, but meanwhile walk every day and do exercises on your own to strengthen and stabilise the knee. There’s no good evidence that physiotherapy or other manual therapies are much more effective than exercising on your own, so long as you can motivate yourself.

When do I need to go to the doctor?

See your GP if you’ve got a red, swollen, painful or stiff knee and don’t know the cause. This is particularly urgent if you have a fever, are unwell, can’t stand on the leg, have had recent knee surgery or an impaired immune system or have other painful joints. If your knee swells up and is painful after trauma or a fall, you may need to go straight to A&E. Children with painful knees should see a GP and not be dismissed as having “growing pains”. Any child or adult that starts limping suddenly with no clear cause (such as a sprained ankle) should see a doctor urgently to rule out an infected joint.