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The articular cartilage has very limited capacity to heal in as it lacks blood supply and the cartilage cells have a very low turnover. Once it is damaged the defect will be permanent. Depending on the size and location it may cause pain, swelling and limited mobility. If you wish to maintain your level of activity and are unable because of your knee, surgery can be considered.

These operations can only work if you have cartilage damage in a relatively small isolated area and the rest of the knee is in reasonably good shape. It will not help you if you have established arthritis in your knee.​


Microfracture can be used to treat smaller cartilage defects. The damaged area is cleared and the bone is punctured with a special awl to create little holes that causes bleeding. The clot filling the defect will turn into so called fibro-cartilage. This process takes many months but the new tissue is firm enough to allow weight bearing after 6 weeks. Learn more.


In larger defects or if microfracture failed mosaicplasty can be used to fill the damaged area. Mosaicplasty involves taking small bone cylinders with their cartilage caps from non-weight bearing areas of the knee and transplant them into the defect. This has the advantage of a larger surface area being covered by normal cartilage and only the gaps are filled with fibro-cartilage. Weight bearing is usually possible after 6 weeks. Learn more.


  • Preparing for your operation

    • We need to make sure you are as fit and prepared as possible to minimise the risk of complications and to ensure a speedy and smooth recovery. You will have a pre-assessment to identify any correctable abnormalities. We advise that you stop smoking and try to loose weight if applicable. Your BMI tells you if you are overweight. 

  • Cartilage surgery is a day case procedure requiring a general anaesthetic. The consultant carrying this out will discuss the details with you on the day.

  • Recovery

    • You should be able to walk within a few hours after the procedure using crutches but will not be able to fully weight bear. We may also limit the range of movement in the knee to protect the repair. We will give you a personalised exercise program for home and our physiotherapists will assess your progress regularly.


  • Your pain should gradually ease and any giving way sensation or locking will cease. 

  • The range of movement returns to normal with a few weeks. The initial swelling should also settle down during this time. This may take longer if you had mosaicplasty.

  • Your knee should feel stronger so you can rely on it better when doing sports or heavy manual work.

  • You can return to sporting activity and manual work as directed when you feel comfortable and if the knee is not swollen. This can take a few months after surgery.


  • Residual pain. You may experience some pain for a few months or even longer. This may be caused by inflammation in the knee or because arthritis set in in the joint.

  • Infection is rare and may only need a course of antibiotics. In severe cases a second operation is necessary to clear it.

  • Significant bleeding or nerve injury is uncommon.

  • Blood clots can form in the deep veins of the leg or travel to the lungs and cause a blockage of the arteries of the lung. Rarely, this can be fatal. This is very unlikely to occur and we will give you blood thinners if you need to offload your knee to reduce this risk further.

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