Knee cartilage starts to wear away as we get older. Knee pain and swelling symptoms develop as the cartilage cushioning begins to fail. So what happens when you have no cartilage in your knee, and what can you do about it? We discuss treatment options for knee cartilage damage in this blog. 

Causes of no cartilage in the knee

The most common cause of knee cartilage damage is osteoarthritis. Knee cartilage loss can be due to an injury to the knee, such as a ligament tear, patellar dislocation, or meniscal tear. In addition, loss of knee cartilage can be triggered by lifestyle factors such as weight gain, diabetes, and high cholesterol. Also, inflammatory arthritis conditions such as rheumatoid arthritis can further damage knee cartilage. Knee osteoarthritis is not as simple as ‘wear and tear.’

A recent study suggested that osteoarthritis should be seen as a ‘total’ failure of the joint, including the cartilage, ligaments, and synovial lining.

Symptoms of knee cartilage damage

Generally, symptoms of worsening loss of knee cartilage include pain with activity, swelling of the joint, and reduced knee joint function. Simple tasks such as walking, housework, and standing from sitting become more difficult due to pain, swelling, and restriction. 

No cartilage in knee treatment

But all is not lost. A variety of treatments are used to treat cartilage loss in knee. Generally, treatments range from simple weight loss and exercise measures to more invasive treatments such as injections or surgery. Overall, we recommend simple treatments first for cartilage loss in knee.

Weight loss

In general, weight gain leads to worsening symptoms and progression of osteoarthritis. Increasing weight places more pressure on the knee joints, leading to more significant knee cartilage damage. It is well known that obese people develop osteoarthritis at an earlier age and have worse pain than healthy people. Secondly, increased fat cells in the body stimulate insulin production, leading to chronic inflammation. This type of inflammation leads to more significant cartilage degradation and worsening cartilage loss in knee.

Losing weight reduces pressure on the joints and body inflammation, improving symptoms. Studies suggest that a 10% reduction in weight leads to a 50% reduction in knee pain from cartilage loss – a vast improvement.

Exercise therapy 

knee strengthening for arthritis

Strength training and aerobic conditioning exercises improve symptoms of loss of cartilage in the knee. Symptom improvement occurs from lowering chronic inflammation in the body and weight loss and muscle strength gain. In addition, strengthening the muscles around the knee helps offload the knee and reduce pressure on the joint. Studies suggest that a combination of gym, pilates, yoga, and Tai Chi is the most effective for improving pain and function. Also, aquatic exercises such as swimming or aqua aerobics have significantly improved pain and function.

Generally, exercise works best for the following: 

  • Younger patients, although older patients, still benefit.
  • Knee arthritis. There are over 50 high-level studies showing exercise works in knee arthritis.
  • An exercise program that follows the American College of Sports Medicine guidelines. So, a combination of aerobic, resistance training, and balance exercises with the progression of strength training. Also, a supervised program with a personal trainer works best.

Are low-intensity workouts as good as high-intensity workouts for knee arthritis?

We think so. A recent study found that 20-30 minutes of exercise three times a week produced the same benefits on pain and function in knee arthritis compared to 90 minutes three times a week. However, those in the low-intensity group were likelier to stick to their exercise programme. These results suggest that an exercise program involving less time and fewer exercises can still offer benefits and may be easier for people to undertake and stick to than one involving more time and effort.

Can I run with knee arthritis?

There are no simple answers. An exercise program improves symptoms and general exercise tolerance, including running. We always say to people that running should be their goal if they enjoy it. However, some people might need to reduce their running depending on pain.

The good news in this study is that running at your own pace does not worsen cartilage loss in the knee on X-ray and may improve your pain.

Also, a recent survey of marathon runners found they were not at an increased risk of knee arthritis compared to the average population.

Couch to 5km is a good start for sedentary people who want some guidance for a gradual return to running.


An offloading brace can be effective when cartilage loss in the knee is confined to only one area of the knee. These offloading braces push the knee away from the side of no cartilage, reducing pressure and inflammation in that part of the knee. Generally, braces are OK at reducing pain and improving function in the knee. However, some people find them uncomfortable.

A new shoe insert called APOS therapy has recently gained NICE recommendations for treating severe knee arthritis. These particular shoes have unique rounded pods fitted to the undersurface of the shoe. We think APOS therapy reduces knee pain by changing the forces on the foot and knee and correcting abnormal walking patterns. NICE highlighted that clinical evidence from a high-quality trial improves knee pain and function compared to a sham device. The cost for the footwear and associated treatment from trained professionals is estimated at £875 per person.

NSAIDs for cartilage loss in the knee

Over-the-counter medications such as ibuprofen reduce pain associated with no cartilage. However, the effect is negligible. Generally, diclofenac or etoricoxib works best for arthritis. But, you must be aware of possible side effects such as gastritis, reduced kidney function, and increased blood pressure. Generally, those people with heart disease should avoid NSAIDs. One alternative to tablets is topical NSAID creams or ointments, which are effective in relieving the pain of hand and knee osteoarthritis. In addition, creams have significantly fewer side effects than tablets.

Cortisone injection for cartilage loss in the knee 

Cortisone is a powerful anti-inflammatory drug that reduces inflammation and pain.

Studies suggest short-term and mild improvement of knee pain for up to 8 weeks. However, recent studies show that cortisone is no different from a placebo for knee arthritis at six months. Also, there is concern about repeated cortisone injections causing more knee cartilage damage. Overall, we use cortisone injections less for longstanding cartilage loss in the knee and reserve these injections only for a severely swollen knee.

Knee gel injection for cartilage loss in knee 

A gel injection, or viscosupplementation, injects a naturally occurring substance called hyaluronic acid into the knee joint.

How these gel injections work is unknown, but we think they naturally lubricate the joint or control inflammation. Some examples of commonly used gel injections include Durolane, Ostenil Plus, or Synvisc 1. Previously, repeated injections every week were required. There is a high molecular weight, a longer-acting gel that only needs to be injected once. Overall, these injections can last 6-12 months.

Recent studies suggest that the high molecular weight non-animal product hyaluronic acid such as Durolane works best for arthritis of the knee and hip. Also, if the first injection works, repeat injections are likely to work up to about five repeat injections.

Gel injections work better if the knee is quiet with no knee fluid. So, your doctor may empty the knee joint with fluid before injecting the gel.

PRP injection knee for damaged knee cartilage 

Platelet-rich plasma injections - alternative to cortisone injection in shoulder

Platelet-rich plasma, also known as PRP, is a concentrated source of platelets. We obtain PRP from your whole blood. Then, the blood is spun in a centrifuge, separating the plasma from the white and red cells. This plasma contains concentrated platelets, which have many growth factors. Overall, we believe PRP works by allowing the growth factors to settle chronic inflammatory cells, leading to lower pain.

Recent studies suggest that PRP or platelet-rich plasma improves knee pain from losing cartilage in the knee for over 12 months compared to gel injections, cortisone, and other substances.

Currently, 23 randomised trials show that PRP is better for no cartilage knee than other injections such as cortisone and hyaluronic acid. Also, we think that a type of PRP called leucocyte-poor PRP (compared to leucocyte-rich) has a good effect with less risk of a flare.

Often, 2-3 injections are needed about two weeks apart.

Combining PRP with hyaluronic acid 

Recent evidence suggests combining PRP with hyaluronic acid might be better than PRP alone. This positive effect is seen at 3, 6, and 12 months. Also, we think adding hyaluronic acid reduces the risk of a flare after a PRP injection.

When combining treatment for knee cartilage damage, we recommend one high molecular weight hyaluronic acid and 2 PRP injections.

Nstride PRP

Nstride PRP is a second-generation PRP that concentrates the platelets and white cells.

The theory is that Nstride PRP will last longer than normal PRP. Some studies suggest the pain-relieving effect can last for a few years. But how genuinely effective is Nstride PRP? It seems that the evidence is not so convincing compared to placebo. Also, Nstride contains a higher concentration of leucocytes or white cells. Higher white cells may cause a significant flare after an injection.

Arthrosamid injeciton for damaged knee cartilage


Hydrogel injection

Arthrosamid is a unique hydrogel of water molecules attached to a polyacrylamide backbone. The injectable is non-degradable, meaning the body does not break it down.

It works by coating the lining of the synovium of the knee joint, reducing inflammation, and providing lubrication.

Recent studies show improvement in pain scores lasting for up to 2 years. In addition, compared to hyaluronic acid, it works better in younger and slimmer patients.

Comparing injectables, Durolane, PRP or Arthrosamid: Which drug is more effective?

According to studies published on each injectable for knee arthritis, we think the effectiveness for the treatment of knee arthritis in percentage terms is as follows:

Durolane: 65-70%

PRP: 60-70%

Arthrosamid 73% (although long-term data for Arthrosamid is lacking as it’s a relatively new drug). Patients less than 70 years old do better (80-95%)

Surgery for damaged knee cartilage: what are the options? 

Surgical options for bone-on-bone cartilage loss in the knee are limited.

Firstly, keyhole surgery for knee cartilage loss is ineffective and could accelerate knee damage. Therefore, the only indication for keyhole surgery is when you have actual mechanical symptoms such as locking or giving way due to a loose body or a meniscal flap.

High tibial knee osteotomy can reduce pressure on the knee joint if there is a malalignment problem. However, the evidence for effectiveness is not strong, and the risks are real. In addition, recovery is prolonged (greater than six months), and there is currently debate as to whether osteotomy is better than a knee replacement.

Finally, knee replacement surgery effectively reduces pain and improves function compared to physiotherapy. Still, the sting in the tail is that 16% of people have problems after this surgery – some of these are serious. The bottom line is that surgery should only be done once your pain and activity levels become unacceptable.

Knee cartilage repair without surgery: Is it possible? 

So, overall, no current non-surgical treatment will repair or regenerate cartilage in the knee. Even surgery for cartilage replacement is problematic. Injections such as PRP, hyaluronic acid, and stem cells have not demonstrated cartilage regeneration in arthritis. Procedures injecting stem cells into knee joints have not shown better results than any other injection, including a placebo.

Other commonly asked questions about knee cartilage damage: 

Will my knee arthritis get worse? 

Not necessarily. Your chances of knee replacement are only 30% in your lifetime. Generally, the best way to prevent the progression of knee cartilage damage is to maintain a healthy lifestyle: exercise, lose weight, and stop smoking. If you gain weight, your chances increase from 30% to 35%.

What causes pain with knee arthritis?

Contrary to popular opinion, cartilage damage does not cause pain. Instead, pain comes from swelling of the bone under the damaged cartilage (subchondral bone) or the inflamed synovium.

Does arthroscopic surgery help knee arthritis? 

No. Some studies suggest it may worsen cartilage loss in the knee. However, keyhole surgery may also contribute to mechanical symptoms such as locking or giving way due to a loose body or flap.

When to have knee surgery for arthritis? 

Every person is different, but we suggest a knee replacement if you need to reduce your step count to 7000 or less daily due to pain. The good news is that most people (85%) get back to their chosen sport five months after a knee replacement. These activities include walking, skiing, and even running.

Which injection is best for knee arthritis? 

Overall, we think Arthrosamid injection has a slightly better effect than other injectables, such as PRP or hyaluronic acid. Studies suggest that 73% of patients experience a meaningful reduction in knee pain and improved function compared to 60-70% who have PRP and 65-70% who have hyaluronic acid. However, Arthrosamid is considerably more expensive. 

Final word from sportdoctorlondon about knee cartilage damage

Loss of cartilage in the knee is expected as we get older. Weight loss and exercise are the best medicines to reduce pain and improve activity. Only use injections sparingly to help with lifestyle factors with a preference for knee gel and PRP. Avoid any expensive treatments like stem cells that promise regeneration. Finally, consider a knee replacement if all other treatments fail and your ability to exercise drops.

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Dr. Masci is a specialist sport doctor in London. 

He specialises in muscle, tendon and joint injuries.