Cartilage In Knee Damage: Symptoms, Causes, Diagnosis, And Treatment
Why is Cartilage?
Cartilage is the body-wide, tough, flexible tissue. Cartilage is a shock absorber and mold that serves two principal functions. Cartilage covers the joining surface so that the bones flow over and reduce friction and prevent damage.
It supports you when moving, bending, extending and running. The tough, flexible cartilage tissue is perfect for the creation of uniquely shaped and curved body components which otherwise would not have bone support.
Unlike to other tissue types, cartilage has no blood supply of its own. Therefore damaged cartilage does not recover as rapidly as harmed skin or muscles, helping blood cells to repair damaged tissues.
Causes of Cartilage Damage
a man playing football, Credits: pixabay
Direct blow – if a joint receives a heavy impact, perhaps during a bad fall or an automobile accident, the cartilage may be damaged. Sportspeople have a higher risk of suffering from articular damage, especially those involved in high impact sports like American football, rugby, and wrestling.
Wear and tear – a joint that experiences a long period of stress can become damaged. Obese individuals are more likely to damage their knee over a 20-year period than a person of normal weight, simply because the body is under a much higher degree of physical stress. Inflammation, breakdown, and eventual loss of cartilage in the joints is known as osteoarthritis.
Lack of movement – the joints need to move regularly to remain healthy. Long periods of inactivity or immobility increase the risk of damage to the cartilage
symptoms of cartilage damage, Credits: pixabay
Patients with damage to the cartilage in a joint (articular cartilage damage) will experience:
Inflammation – the area swells, becomes warmer than other parts of the body, and is tender, sore, and painful.
Range limitation – the affected limb will not move so freely and easily.
The most common location for cartilage damage is in the knee joint. In some cases of knee joint damage, bleeding can occur inside the knee joint. This is known as haemarthrosis and can lead to skin around the joint swelling up. Dark red blotches similar to bruises may also develop on the skin.
MRI scan, Credits: pixabay
Diagnosing articular cartilage damage can be challenging because it cannot be confirmed through a physical examination. Also, the symptoms are often similar to other types of knee injures, such as a sprain or a damaged ligament.
Magnetic Resonance Imaging (MRI)
Magnetic resonance imaging (MRI) scans are often used for detecting cartilage damage. MRI scans use strong magnetic fields and radio waves to produce detailed images of the inside of your body.
However, access to MRI scans is limited in many primary care trusts (PCTs), and patients with life-threatening conditions are usually given priority. You may have to wait a considerable amount of time before you can have a MRI scan.
If you have articular cartilage damage, another option is to have an arthroscopy. This is a form of ‘keyhole surgery’ where the surgeon makes a small cut in your joint. They will then use an arthroscope (a small, flexible tube with a camera on the end) to look inside your joint.
Arthroscopies are often carried out under local anaesthetic where painkilling medication is used to numb the joint. This means that you may not have to spend the night in hospital.
Knee cartilage treatment, Credits: pixabay
Knee Cartilage Repair
A surgeon can use special tools to remove frayed and tattered cartilage and smooth the remaining cartilage surface. This contouring of cartilage reduces joint friction, which in turn can:
Reduce knee pain
Restore knee function
Slow down future cartilage degeneration
The medical term for surgery to reshape knee cartilage is knee chondroplasty—“Chondro” refers to cartilage and “plasty” means to form or mold. Chondroplasty may be performed on a knee’s articular cartilage, meniscus, or both.
Knee chondroplasty is often done in conjunction with debridement. During knee debridement the surgeon removes potential irritants to the joint, such as loose pieces of cartilage, and flushes the joint with a saline solution (lavage).
Knee Cartilage Regeneration
Cartilage tissue’s ability to repair itself is severely limited because it does not contain blood vessels, and bleeding is necessary for healing. A surgeon can encourage new cartilage growth by making small cuts or abrasions in the bone underneath the injured cartilage. The hope is that the blood from the damaged bone will facilitate new cartilage cell growth.
There are three common knee cartilage regeneration techniques that use bleeding to spur cartilage healing:
Knee microfracture, which requires the damaged cartilage to be cleared away completely. The surgeon then uses a sharpened tool called an awl to pierce the bone.
Knee drilling, which uses a drill or wire to make tiny holes the bone. There is some evidence that the heat from the drill can cause unnecessary injury to nearby tissue, which can eventually lead to bone cysts or other problems.
Knee abrasion arthroplasty, which requires the damaged cartilage to be completely cleared away. The surgeon then uses a special tool to scrape and roughen the affected bone’s surface.
These regeneration techniques are used to treat damaged articular cartilage. They cannot be used to treat a damaged knee meniscus.
Knee Cartilage Replacement
Most knee cartilage replacement surgeries are called OATs surgeries—either osteochondral autograft transplantation or osteochondral allograft transplantation surgeries. These procedures are described in more detail below.
arthroscopic lavage and debridement
allograft osteochondral transplantation
autologous chondrocyte implantation
Arthroscopic Lavage and Debridement
Arthroscopic lavage and debridement is a technique used when pieces of cartilage have become loose in the joint, causing the joint to lock.
The surgeon makes a cut in the joint before using an arthroscope (a flexible tube with a camera on the end) to assess the damage. They then ‘clean out’ the joint using a saline (salt) solution. Loose cartilage fragments are removed using a device known as a shaver, which works in a similar way to a vacuum cleaner.
Arthroscopic lavage and debridement cannot repair the damaged cartilage, but it can help reduce pain and increase mobility.
Marrow stimulation involves making tiny holes (microfractures) into the bone beneath the damaged cartilage using a small pointed instrument known as an awl. This releases the bone marrow from inside the bone and leads to a blood clot forming within the damaged cartilage.
The marrow cells then begin to stimulate production of new cartilage. The drawback to marrow stimulation is that the newly generated cartilage is fibrocartilage rather than hyaline cartilage. As fibrocartilage is not as supple as hyaline cartilage, there is a risk that after a few years it will wear away and further surgery may be needed.
Mosaicplasty is a technique where small rods of healthy cartilage from the non-weight-bearing areas of a joint, such as the side of the knee, are removed and used to replace the damaged cartilage.
Mosaicplasty seems to be successful in most people. However it is only suitable for treating relatively minor cartilage injury. This is because removing too much healthy cartilage could damage the section of the body from where the cartilage was taken.
Before having mosaicplasty, your surgeon should discuss the possible risks and benefits of the technique with you.
Allograft Osteochondral Transplantation (AOT)
If damage to your cartilage is thought too extensive to be treated with mosaicplasty an alternative procedure called allograft osteochondral transplantation (AOT) may be considered.
AOT is a similar procedure to mosaicplasty, but the cartilage is obtained from a recently deceased donor. The cartilage will be tested in a laboratory to make sure it is free from infection before being prepared for transplant.
Autologous Chondrocyte Implantation (ACI)
Autologous chondrocyte implantation (ACI) uses a two-stage technique. During the first stage the surgeon takes a small sample of cartilage cells from the edge of your knee during an arthroscopy.
The cells are sent to a laboratory and placed in an incubator where they are given nutrients to encourage them to divide and produce new cells. After a few weeks, the number of cartilage cells will have increased by 50 times. The new cartilage cells are used to replace the damaged cartilage.
The second stage involves placing these cells on a collagen patch, which is then sutured/glued onto the damaged area usually through a small incision.
Painkillers, Credits: pixabay
There are a number of non-surgical treatments that can help to relieve symptoms of damaged articular cartilage. They are described below.
Physiotherapy – exercises that strengthen the muscles surrounding or supporting your joint which may help reduce pressure on the joint and reduce pain.
Painkillers – non-steroidal anti-inflammatory drugs (NSAIDs), such as ibuprofen, can help reduce swelling and pain. However, avoid taking ibuprofen if you have, or have had, a stomach problem, such as a stomach ulcer.
Supportive devices – such as a cane or leg brace.
Lifestyle changes – such as reducing activity that involves the affected joint.
In more severe cases of articular cartilage damage, non-surgical treatment may only provide short-term relief and surgery may be required.