Cartilage wear (Arthritis)

What is knee cartilage?

The knee joints are lined by extremely smooth tissue called “articular cartilage.”

The articular cartilage of the knee coats 

• the end of the femur (thigh bone),
• the top surface of the tibia (shin bone) and 
• the back surface of the patella (kneecap)

It serves as a protective cushion, allowing smooth, low-friction movement of the joints as one bone end moves on the other. Cartilage tissue covers the adjacent bone surfaces of the knee.

Causes of cartilage wear

Because the cartilage is subjected to life long wear it tends to be an ageing disorder. 

Injury may damage articular (joint lining) cartilage also.

With time, the cartilage wears away, allowing the rough edges of bone to rub against each other. This generalised wearing out of cartilage is termed “osteoarthritis (OA)” however any damage to cartilage represents part of the osteoarthritis process.

Symptoms of cartilage wear

If the cartilage gets damaged by disease or injury, the tissues around the joint become inflamed, causing:

• pain
• swelling, 
• stiffness, 
• locking and 
• limited movement

Cartilage damage diagnosis

We will need to diagnose the specific nature of your cartilage damage or the extent of any osteoarthritis in the knee joint.

Often, cartilage damage can be identified during a physical examination.

During this consultation we will:

• take a medical history
• perform a physical examination 
• assess the joint’s range of motion
• review X ray imaging scans for loss of the joint space or bone spur formation.
• review any MRI scan that create detailed images of both hard and soft tissues within your knee. An MRI can produce cross-sectional images of internal structures required if the diagnosis is unclear or if other soft tissue injuries are suspected such ligament injuries or articular cartilage injuries.

Imaging tests:

In order to clearly understand the nature of any loss of the joint space or bone spur formation imaging scans are required:

• X-rays do not show cartilage but are often normal as they can help rule out other problems with the knee that may have similar symptoms like fractures (broken bone) or ACL injury.
• MRI can create detailed images of both hard and soft tissues within your knee. An MRI can produce cross-sectional images of internal structures required if the diagnosis is unclear or if other soft tissue injuries are suspected such ligament injuries or articular cartilage injuries.

While not all of these tests are required to confirm the diagnosis, this diagnostic process will also allow us to review any possible risks or existing conditions that could interfere with the surgery or its outcome.

Who is suitable for cartilage surgery?

Most candidates for cartilage repair are young adults with a single injury, or lesion. The size and location of the lesion and the status of other knee structures will help determine whether surgery is possible for you.

To improve the chance of success additional procedures could be recommended, these could include:

• knee realignment (osteotomy) and 
• ligament reconstructions 

Older patients, or those with many lesions in one joint, are less likely to benefit from the surgery, as this process is more representative of osteoarthritis.

Treatments for cartilage wear

As cartilage has minimal capacity to repair itself, surgical techniques have been developed to stimulate the growth of new cartilage.

While the treatments do not completely restore the cartilage to the original structure, these procedures can relieve pain and allow better function. 

Current techniques can

• stimulate cartilage growth
• delay or prevent the onset of arthritis

Surgical techniques to repair damaged cartilage are evolving and we are experienced in these approaches.

Cartilage procedures

The most common procedures for damaged cartilage are:

• Chondroplasty
• Microfracture

Chondroplasty

This procedure involves

• smoothing the roughened areas, 
• removing any loose fragments 

In many cases, patients who have joint injuries, such as meniscal or ligament tears, will also have cartilage damage. 

This involves smoothing out any unstable areas of cartilage by using fine mechanical shavers and thermal devices to stabilise loose areas of cartilage.

Benefits of chondroplasty are that it is not invasive with quick recovery, but it does not stimulate cartilage regeneration.

Microfracture 

The goal of microfracture is to stimulate the growth of fibrocartilage by creating a new blood supply. As with Chondroplasty this procedure involves

• smoothing the roughened areas, 
• removing any loose fragments and 
• scraping any exposed bone to stimulate cartilage recovery.

A tool makes multiple holes in the joint surface to promote a healing response. Stem cells from the underlying bone marrow create new fibrocartilage tissue. 

This procedure is best for young patients with:

• a single lesion
• lesions under 2cm
• healthy subchondral bone

The recovery is usually slower than a chondroplasty as specific rehabilitation protocols are required to allow the new fibrocartilage to regenerate.

Outcomes of cartilage repair

Typically, cartilage repair patients report:

• significant improvement in symptoms and 
• are able to return to most activities. 

Cartilage damage prevention

The best way to keep your knee joint healthy is to:

• keep a low body weight 
• perform regular low impact exercises (bike riding, swimming, gym exercises)
• build core muscles by exercise or pilates

Complications

Some patients find no improvement in their symptoms following cartilage repair surgery. The quality of the cartilage tissue that regenerates can vary between patients and affect the result of surgery. 

Sometimes, the cartilage repair becomes too thick (hypertrophy) and requires further surgery to perform a chondroplasty and reduce symptoms. 

Less commonly, the cartilage repair can fail completely. Other symptoms that may arise include swelling and clicking (crepitus).

Preparing for knee cartilage surgery

Once we decide that surgery is required, preparation is necessary to achieve the best results and a quick problem free recovery.

Preparing mentally and physically for surgery is an important step toward a successful result. 

• We will create a treatment plan and 
• patients will also need to understand the process and their role in it 

We will also need to:

• discuss any medications being taken with your doctor or physician to see which ones should be stopped before surgery
• do not eat or drink anything, including water, for 6 hours before surgery
• stop taking aspirin, warfarin, anti-inflammatory medications or drugs that increase the risk of bleeding one week before surgery to minimise bleeding
• review blood replacement options (including banking blood) with your doctor
• consider alternate medical interventions and other treatments
• eat a well-balanced diet, supplemented by a daily multivitamin with iron.
• consider losing weight (if overweight) before surgery to help decrease the stress on the new joint. However, dieting one month before surgery.
• stop or cut down smoking to reduce your surgery risks and improve your recovery
• treat any tooth, gum, bladder or bowel problems before surgery to reduce the risk of infection

Report any infections to us prior to surgery as the procedure cannot be performed until all infections have cleared up.

After your operation

Some patients need one night in hospital, although it is possible to leave hospital the day of surgery. 

After your operation you will have pain medication and antibiotics. 

The wounds take 7-10 days to heal. Most patients improve dramatically in the first 2 weeks. 

Occasionally, there are periods where the knee may become sore and then settle again. This is part of the normal healing process. If a meniscal repair was performed, it can take 3 months for it to heal fully.

If any postoperative problems arise with your knee, such as redness, increasing pain or fevers, do not hesitate to contact us. If unavailable, seek advice from the hospital or your doctor.

When can I drive after cartilage surgery?

Driving a car is discouraged for 48 hours after an anaesthetic. After 48 hours, your ability to drive will depend on the side you had your operation, left or right, and the type of vehicle you drive, manual or automatic. You can drive whenever you feel comfortable.

Return to work after cartilage surgery

Return to work will vary depending on the procedure performed and type of work you do. Most patients can return to office work within 1 week. Labour intensive work however, may require up to 6 weeks before returning to full duties.

During these period patients are not fit to perform work duties that involve:

• prolonged standing, 
• heavy lifting, 
• bending or 
• excessive stair climbing 

Return to sport after cartilage surgery

As the knee joint cartilage has been damaged, activities such as long distance running are not recommended as this can result in rapid deterioration of the knee joint cartilage. 

It is best to delay leisure activities or sports for 6 weeks to allow the meniscus time to heal and repair. Discussions with us regarding these time frames is suggested.

Pain management

Often there is little pain they have after surgery. This is because local anaesthetic is injected around the wound during the procedure and it is performed arthroscopically (ie. minimally invasive keyhole surgery).