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The reason articular cartilage has a poor regenerative capacity is due to its lack of blood flow. Articular cartilage is one of the only structures in the body that doesn’t have a direct blood supply. It is the oxygen and nutrients in our blood that help to repair and regenerate damaged tissue in other parts of the body. It can be associated with conditions like Knee Osteoarthritis, acute injury of the connective tissue and rheumatoid arthritis. Moreover, some patients may also report joint locking and clicking or grinding sensation on movement.
For cartilage repair and articular cartilage regeneration to take place, it relies on absorbing nutrients from the fluid in the knee, commonly known as ‘synovial fluid.’
The problem is, the levels of this fluid start to decline with age, causing articular cartilage to become brittle as the nutrient supply depletes. As you can imagine, a brittle structure struggles to absorb force as efficiently as a soft structure.
This means that over time, articular cartilage becomes vulnerable to tearing or wearing down, leading to joint pain and a diagnosis of knee cartilage damage or knee arthritis. It also leads to chronic inflammation in the affected limb and joint swelling.
Prolotherapy
Prolotherapy involves the injection of a dextrose solution. Dextrose has been shown to promote the growth of new tissue through boosting the body’s natural healing processes. One of Prolotherapy’s effects on the physiology of osteoarthritis is thought to be an enhancement of anabolic cytokines which stimulate cartilage regeneration.
Knee cartilage tissue is composed of specialized cells called chondrocytes that produce a large amount of collagenous extracellular matrix. Articular cartilage matrix has both proteoglycans and collagen fibers within it. It is an elastic, flexible structure that covers the ends of the bones. Its mechanical properties allow it to protect from shock during weight-bearing activities, such as walking and running. There are three types of human cartilage:
Knee articular cartilage is made up of fibrocartilage, as it is more durable and can withstand more weight than the other forms.
Age
Genetics
Repetitive impact
Previous injuries
Meniscus tear:
Ligament tear or sprain:
Muscle tear
Arthroscopic surgery
Obesity
Both an X-ray and MRI scan (magnetic resonance imaging) can help to identify articular cartilage damage. The added benefit of an MRI scan compared to an X-ray is that it can pick up specific characteristics of the cartilage injury and the underlying subchondral bone, such as subchondral bone bruising, osteophytes or other articular cartilage defects. A doctor or orthopaedic consultant will decide which scan is right for you.
Physiotherapy –
The aim of physiotherapy is to improve the health of the muscles around your knee. The stronger and more flexible they are, the better support they can provide for the knee cartilage and associated cartilage damage.
One of the main supportive muscles is the quadriceps, as they attach around the front of the knee. They help to stabilise the joint during movement and act as a shock absorber during weight-bearing activities to prevent cartilage damage.
A physical therapy program will involve an initial physical examination followed by combination of strengthening, stabilizing, and stretching exercises. Follow-up sessions with physical therapist, will also help other injured areas around the knee that the cartilage damage and degeneration may have had an influence on. It may also involve the use of a knee brace, which will prevent further injury and reduce pressure on the injured area. This may also be recommended for other causes of knee conditions.
Exercise and weight loss –
Gentle non-weight-bearing forms of exercise can be a great conservative treatment to maintain the health of the muscles around an arthritic knee and damaged cartilage.
Types of non-weight-bearing activities include cycling and swimming.
Exercise not only helps to keep your muscles strong but it also helps to flush inflammation out of the joint and reduce the pressure.
A great by-product of exercise is weight-loss. Since increased body weight is a common cause of knee conditions, losing weight can prove to be an effective way for prevention of cartilage loss and sports injury. It can also help to take the pressure off your knee cartilage during weight-bearing activities such as walking and climbing stairs.
Stem cell injection –
A stem cell injection procedure is a form of cell therapy that involves drilling into your bone marrow in your hip to extract stem cells to reinject into your knee joint. The aim is to stimulate chondrogenic cells, cartilage regeneration, tissue repair and reduce pain. The clinical term is the chondrogenesis of mesenchymal stem cells.
Platelet-rich Plasma (PRP) injection –
This procedure is another form of cell therapy and regenerative medicine. The aim of platelet-rich plasma is to promote tissue regeneration through stimulating chondrogenic cells. The procedure involves taking between 30-60mls of blood from the patient. It is then placed into a centrifuge that helps to separate the red blood cells from the platelet-rich plasma. The plasma, which is thought to contain growth factors, is then injected into the knee joint.
Clinical trials have shown it to have a positive effect on the health of cartilage.
Cartilage tissue engineering –
Cartilage tissue engineering is an advanced form of stem cell therapy used to repair tissue in the body and treat cartilage damage. It combines chondrogenic cells with biomaterials and growth factors in an attempt to stimulate chondrogenic cells and cartilage regeneration.
Fibrin scaffolds are another form of tissue engineering treatment is that is being used to help with articular cartilage repair.
Hyaluronic acid injection-
Hyaluronic acid, also known as hyaluronan, is a part of synovial fluid. The role of Hyaluronan is to help to lubricate the knee joint and act as a shock absorber. It can’t stimulate new cartilage or cartilage damage repair but it can help to improve the mobility of the knee joint.
Steroid injection –
This treatment involves the injection of steroid medication to help reduce inflammation to in a damaged part of the body. It may also help reduce swelling, however the the effect is only temporary, and patients normally have to go back for a top-up. The negative effect of this is that multiple steroid injections have been shown in studies to weaken damaged cartilage and cause problems in the underlying bone. As a result, many sports medicine practitioners and orthopaedic surgeons are looking for alternative ways to treat patients with knee cartilage damage.
For that reason, a steroid injection should only be used as a last resort for cartilage damage if the other treatments mentioned above haven’t worked.
Oral Medication –
Medication can be either over-the-counter or prescribed, depending on the level of knee pain an individual is experiencing. Unfortunately, there are many side-effects associated with taking painkillers and non-steroidal anti-inflammatory drugs (NSAIDs) such as ibuprofen.
Short-term effects: Drowsiness, constipation, nausea.
Long-term effects: vomiting, diarrhoea, heartburn, stomach bleeding and ulcers.
Due to the risks and side effects of surgical techniques, it is important to try all non-surgical avenues for articular cartilage injuries first before you look into the below procedures.
Arthroscopic lavage and debridement
An arthroscopy procedure is used when a piece of cartilage has become loose within the joint. The keyhole operation involves an instrument called an arthroscope being used to examine the joint and then a saline solution helps to clean it out. The orthopaedic surgeon then removes the loose fragments with a shaver. The problem with an arthroscopy, or keyhole surgery is that it doesn’t repair the cartilage injury, it can only help with managing the pain.
Meniscus transplant
A meniscus transplant is only recommended if the meniscus has worn away or been removed. It is an arthroscopic procedure that involves a donor’s meniscus being stitched to the patient’s knee.
Bone marrow stimulation
The aim of bone marrow stimulation is to attempt to stimulate new cartilage by making small holes in the bone to release bone marrow. This causes a blood clot to form over the damaged cartilage surface, in the hope that it stimulates chondrogenic cells. The issue with this technique is that it may have a limited lifespan before the improvement of articular cartilage injuries and cartilage repair and is undone and starts to wear away again after few weeks.
Autologous Chondrocyte Implantation (ACI)
This is a two-week long process that starts with surgically removing healthy cartilage cells from a good part of the knee.
The next stage involves another surgical procedure called an arthrotomy, where the newly grown cells are implanted into the damaged part of the cartilage.
The issue with this procedure for articular cartilage injuries is that it can have a negative effect on the part of the knee that had cells taken from it. For this reason, it is only offered to younger people with knee cartilage damage.
ACI knee surgery is also known as Matrix-induced autologous chondrocyte implantation (MACI).
Mosiacplasty and allograft osteochondral transplantation
A form of knee surgery that helps to replace damaged cartilage and improve symptoms of articular cartilage injury by using small rods of healthy cartilage from a donor.
Microfracture
Microfracture is an arthroscopic procedure that involves small holes being made into the knee bone. The aim of making these holes is to promote bleeding and stimulate cartilage growth.
Artificial scaffold
The aim of this procedure is to stimulate cartilage growth through implanting an absorbable frame made up of collagen and proteins.
Osteochondral allograft
A similar procedure to mosaicplasty, it involves a graft being taken from a donor to implant into the knee cartilage damage. The graft is sterilized before the surgery and cut to the exact shape of the damage in the affected joint.
Abrasion Arthroplasty
This procedure involves rasping damaged areas to promote bleeding with the aim of promoting cartilage regeneration in the affected joint.
Knee replacement surgery
It is a type of surgery that involves replacing a damaged or degenerated knee joint with artificial material. The clinical name of the surgery is ‘arthroplasty.’ There are two types of knee joint replacements:
Statistics state that knee joint replacement surgery is much less successful than hip joint replacement surgery.
Complications of surgery
The main issue with surgery is that scar tissue can build up where the incisions are made. This scar tissue can lead to long-term stiffness and imbalances which can lead to knee pain. Surgery can also cause damage to local blood vessels. Surgery should always be a last resort option if conservative treatments haven’t worked. It is important that you seek medical advice from several different consultants before deciding which surgical road to go down.
Conclusion
Knee Cartilage damage should never be left untreated as it can lead to a number of complications. The good news is that there are several safer non-surgical solutions that can be explored for joint pain and minor cartilage damage before considering surgery. At our clinic, we offer a comprehensive approach to treating knee cartilage damage which combines both Prolozone Therapy and rehabilitation exercise.