Articular cartilage repair
Encyclopedia
The aim of an articular cartilage repair treatment is to restore the surface of an articular joint
's hyaline cartilage
. Over the last decades, surgeons and researchers have been working hard to elaborate surgical cartilage repair interventions. Though these solutions do not perfectly restore articular cartilage
, some of the latest technologies start to bring very promising results in repairing cartilage from traumatic injuries
or chondropathies. These treatments are especially targeted by patients who suffer from articular cartilage damage
. They provide pain relief while at the same time slowing down the progression of damage or considerably delaying joint replacement
(knee replacement
) surgery. Most importantly, articular cartilage repair treatments help patients to return to their original lifestyle; regaining mobility, going back to work and even practicing sports again.
is a "cleaning up" procedure of the knee joint. This short term solution is not considered an articular cartilage repair procedure but rather a palliative treatment to reduce pain, mechanical restriction and inflammation. Lavage focusses on removing degenerative articular cartilage flaps and fibrous tissue. The main target group are patients with very small defects of the articular cartilage.
is drilled or punched until the underlying bone is exposed. By doing this, the subchondral bone is perforated to generate a blood clot within the defect. Studies, however, have shown that marrow stimulation techniques often have insufficiently filled the chondral defect and the repair material is often fibrocartilage
(which is not as good mechanically as hyaline cartilage). The blood clot takes about 8 weeks to become fibrous tissue and it takes 4 months to become fibrocartilage. This has implications for the rehabilitation.
Further on, chances are high that after only 1 or 2 years of the surgery symptoms start to return as the fibrocartilage
wears away, forcing the patient to reengage in articular cartilage repair. This is not always the case and microfracture surgery
is therefore considered to be an intermediate step.
An evolvement of the microfracture technique is the implantation of a collagen membrane onto the site of the microfracture to protect and stabilize the blood clot and to enhances the chondrogenic differentiation
of the MSCs
. This technique is known as AMIC (Autologous Matrix-Induced Chondrogenesis
) and was first published in 2003.
(HA). PBPC’s are a blood product containing mesenchymal stem cells and is obtained by mobilizing the stem cells into the peripheral blood. Dr. Khay Yong Saw and his team propose that the microdrilling surgery creates a blood clot scaffold on which injected PBPC’s can be recruited and enhance chondrogenesis at the site of the contained lesion. They explain that the significance of this cartilage regeneration protocol is that it is successful in patients with historically difficult-to-treat grade IV bipolar or bone-on-bone osteochondral lesions.
Dr. Saw and his team are currently conducting a larger randomized trial and working towards beginning a multicenter study. The work of the Malaysian research team is gaining international attention.
. First, the damaged section of bone and cartilage is removed from the joint. Then a new healthy dowel of bone with its cartilage covering is punched out of the same joint and replanted into the hole left from removing the old damaged bone and cartilage. The healthy bone and cartilage are taken from areas of low stress in the joint so as to prevent weakening the joint. Depending on the severity and overall size of the damage multiple plugs or dowels may be required to adequately repair the joint, which becomes difficult for Osteochondral Autografts. For Osteochondral Allografts the plugs are taken from deceased donors. This has the advantage that more osteochondral tissue is available and larger damages can be repaired. There are, however, ethical considerations and worries on the histocompatibility.
(ACI) procedures are cell-based repairs that aim to achieve a repair consisting of healthy articular cartilage.
ACI articular cartilage repair procedures take place in three stages. First, cartilage cells
are extracted arthroscopically from the patient's healthy articular cartilage that is located in a non load-bearing area of either the intercondylar notch or the superior ridge of the femoral condyles. Then these extracted cells are transferred to an in vitro environment in specialised laboratories where they grow and replicate, for approximately four to six weeks, until their population has increased to a sufficient amount. Finally, the patient undergoes a second surgery where the in vitro chondrocytes are applied to the damaged area. In this procedure, chondrocytes are injected and applied to the damaged area in combination with either a membrane or a matrix structure. These transplanted cells thrive in their new environment, forming new articular cartilage.
See also Autologous Mesenchymal Stem Cell Transplant for Cartilage Growth
concluded that routinely practised knee surgery is ineffective at reducing joint pain or improving joint function in people with osteoarthritis. The researchers did however find that arthroscopic surgery did help a minority of patients with milder symptoms, large tears or other damage to the meniscus)
— cartilage pads that improve the congruence between femur and tibia bones.
Joint
A joint is the location at which two or more bones make contact. They are constructed to allow movement and provide mechanical support, and are classified structurally and functionally.-Classification:...
's hyaline cartilage
Hyaline cartilage
Hyaline cartilage consists of a slimy mass, pearly bluish in colour with firm consistency and considerable collagen. It contains no nerves or blood vessels, and its structure is relatively simple....
. Over the last decades, surgeons and researchers have been working hard to elaborate surgical cartilage repair interventions. Though these solutions do not perfectly restore articular cartilage
Cartilage
Cartilage is a flexible connective tissue found in many areas in the bodies of humans and other animals, including the joints between bones, the rib cage, the ear, the nose, the elbow, the knee, the ankle, the bronchial tubes and the intervertebral discs...
, some of the latest technologies start to bring very promising results in repairing cartilage from traumatic injuries
Articular cartilage injuries
Cartilage structures and functions can relatively easily be harmed, often resulting in damage. Such damage can result from a variety of causes, resulting from a bad fall or sport-accident , previous knee injuries or wear and tear over time...
or chondropathies. These treatments are especially targeted by patients who suffer from articular cartilage damage
Articular cartilage damage
Cartilage structures and functions can be damaged. Such damage can result from a variety of causes, such as a bad fall or traumatic sport-accident, previous knee injuries or wear and tear over time...
. They provide pain relief while at the same time slowing down the progression of damage or considerably delaying joint replacement
Joint replacement
Replacement arthroplasty [from Greek arthron, joint, limb, articulate, + -plassein, to form, mould, forge, feign, make an image of], or joint replacement surgery, is a procedure of orthopedic surgery in which the arthritic or dysfunctional joint surface is replaced with an orthopaedic prosthesis...
(knee replacement
Knee replacement
Knee replacement, or knee arthroplasty, is a surgical procedure to replace the weight-bearing surfaces of the knee joint to relieve the pain and disability of osteoarthritis. It may be performed for other knee diseases such as rheumatoid arthritis and psoriatic arthritis...
) surgery. Most importantly, articular cartilage repair treatments help patients to return to their original lifestyle; regaining mobility, going back to work and even practicing sports again.
Different articular cartilage repair procedures
Though the different articular cartilage procedures differ in the used technologies and surgical techniques, they all share the aim to repair articular cartilage whilst keeping options open for alternative treatments in the future. Broadly taken, there are five major types of articular cartilage repair:Arthroscopic Lavage / Debridement
Arthroscopic lavageArthroscopic lavage
"Lavage" means 'washing'. To lavage a joint means to wash out any blood, fluid or loose debris from inside the joint space.Arthroscopic lavage is generally combined with arthroscopic debridement, where fronds of joint material or degenerative tissue are removed using a combination of injected fluid...
is a "cleaning up" procedure of the knee joint. This short term solution is not considered an articular cartilage repair procedure but rather a palliative treatment to reduce pain, mechanical restriction and inflammation. Lavage focusses on removing degenerative articular cartilage flaps and fibrous tissue. The main target group are patients with very small defects of the articular cartilage.
Marrow Stimulation Techniques (Microfracture Surgery and others)
Marrow stimulating techniques attempt to solve articular cartilage damage through an arthroscopic procedure. Firstly, damaged cartilageCartilage
Cartilage is a flexible connective tissue found in many areas in the bodies of humans and other animals, including the joints between bones, the rib cage, the ear, the nose, the elbow, the knee, the ankle, the bronchial tubes and the intervertebral discs...
is drilled or punched until the underlying bone is exposed. By doing this, the subchondral bone is perforated to generate a blood clot within the defect. Studies, however, have shown that marrow stimulation techniques often have insufficiently filled the chondral defect and the repair material is often fibrocartilage
Fibrocartilage
White fibrocartilage consists of a mixture of white fibrous tissue and cartilaginous tissue in various proportions. It owes its flexibility and toughness to the former of these constituents, and its elasticity to the latter...
(which is not as good mechanically as hyaline cartilage). The blood clot takes about 8 weeks to become fibrous tissue and it takes 4 months to become fibrocartilage. This has implications for the rehabilitation.
Further on, chances are high that after only 1 or 2 years of the surgery symptoms start to return as the fibrocartilage
Fibrocartilage
White fibrocartilage consists of a mixture of white fibrous tissue and cartilaginous tissue in various proportions. It owes its flexibility and toughness to the former of these constituents, and its elasticity to the latter...
wears away, forcing the patient to reengage in articular cartilage repair. This is not always the case and microfracture surgery
Microfracture surgery
Microfracture surgery is one of the articular cartilage repair surgical techniques that works by creating tiny fractures in the underlying bone. This causes new cartilage to develop from a so-called super-clot...
is therefore considered to be an intermediate step.
An evolvement of the microfracture technique is the implantation of a collagen membrane onto the site of the microfracture to protect and stabilize the blood clot and to enhances the chondrogenic differentiation
Chondrogenesis
-Cartilage in fetal development:In embryogenesis, the skeletal system is derived from the mesoderm germ layer. Chondrification is the process by which cartilage is formed from condensed mesenchyme tissue, which differentiates into chondrocytes and begins secreting the molecules that form the...
of the MSCs
Mesenchymal stem cell
Mesenchymal stem cells, or MSCs, are multipotent stem cells that can differentiate into a variety of cell types, including: osteoblasts , chondrocytes and adipocytes...
. This technique is known as AMIC (Autologous Matrix-Induced Chondrogenesis
Autologous matrix-induced chondrogenesis
Autologous Matrix-Induced Chondrogenesis is a biological treatment option which repairs articular cartilage damage. It combines microfracture surgery with the application of a bi-layer collagen I/III membrane....
) and was first published in 2003.
Marrow Stimulation augmented with Peripheral Blood Stem Cells
A 2011 study reports histologically confirmed hyaline cartilage regrowth in a 5 patient case-series, 2 with grade IV bipolar or kissing lesions in the knee. The successful protocol involves arthroscopic microdrilling/ microfracture surgery followed by postoperative injections of autologous peripheral blood progenitor cells(PBPC's) and hyaluronic acidSodium hyaluronate
Sodium hyaluronate is the sodium salt of hyaluronan. The name hyaluronic acid is derived from the Greek word ύαλος meaning vitreous, and uronic acid as it was first isolated from the vitreous humour in the eye and possesses a high uronic acid content. The term hyaluronate also refers to the...
(HA). PBPC’s are a blood product containing mesenchymal stem cells and is obtained by mobilizing the stem cells into the peripheral blood. Dr. Khay Yong Saw and his team propose that the microdrilling surgery creates a blood clot scaffold on which injected PBPC’s can be recruited and enhance chondrogenesis at the site of the contained lesion. They explain that the significance of this cartilage regeneration protocol is that it is successful in patients with historically difficult-to-treat grade IV bipolar or bone-on-bone osteochondral lesions.
Dr. Saw and his team are currently conducting a larger randomized trial and working towards beginning a multicenter study. The work of the Malaysian research team is gaining international attention.
Osteochondral Autografts and Allografts
This technique/repair requires transplant sections of bone and cartilageCartilage
Cartilage is a flexible connective tissue found in many areas in the bodies of humans and other animals, including the joints between bones, the rib cage, the ear, the nose, the elbow, the knee, the ankle, the bronchial tubes and the intervertebral discs...
. First, the damaged section of bone and cartilage is removed from the joint. Then a new healthy dowel of bone with its cartilage covering is punched out of the same joint and replanted into the hole left from removing the old damaged bone and cartilage. The healthy bone and cartilage are taken from areas of low stress in the joint so as to prevent weakening the joint. Depending on the severity and overall size of the damage multiple plugs or dowels may be required to adequately repair the joint, which becomes difficult for Osteochondral Autografts. For Osteochondral Allografts the plugs are taken from deceased donors. This has the advantage that more osteochondral tissue is available and larger damages can be repaired. There are, however, ethical considerations and worries on the histocompatibility.
Cell Based Repairs
Aiming to obtain the best possible results, scientists have striven to replace damaged articular cartilage with healthy articular cartilage. Previous repair procedures, however, always generated fibrocartilage or, at best, a combination of hyaline and fibrocartilage repair tissue. Autologous chondrocyte implantationAutologous chondrocyte implantation
Autologous chondrocyte implantation is a biomedical treatment that repairs damages in articular cartilage. ACI provides pain relief while at the same time slowing down the progression or considerably delaying partial or total joint replacement surgery...
(ACI) procedures are cell-based repairs that aim to achieve a repair consisting of healthy articular cartilage.
ACI articular cartilage repair procedures take place in three stages. First, cartilage cells
Chondrocyte
Chondrocytes are the only cells found in cartilage. They produce and maintain the cartilaginous matrix, which consists mainly of collagen and proteoglycans...
are extracted arthroscopically from the patient's healthy articular cartilage that is located in a non load-bearing area of either the intercondylar notch or the superior ridge of the femoral condyles. Then these extracted cells are transferred to an in vitro environment in specialised laboratories where they grow and replicate, for approximately four to six weeks, until their population has increased to a sufficient amount. Finally, the patient undergoes a second surgery where the in vitro chondrocytes are applied to the damaged area. In this procedure, chondrocytes are injected and applied to the damaged area in combination with either a membrane or a matrix structure. These transplanted cells thrive in their new environment, forming new articular cartilage.
Autologous Mesenchymal Stem Cell Transplant
For years, the concept of harvesting stem cells and re-implanting them into one's own body to regenerate organs and tissues has been embraced and researched in animal models. In particular, mesenchymal stem cells have been shown in animal models to regenerate cartilage[1]. Recently, there has been a published case report of decrease in knee pain in a single individual using autologous mesenchymal stem cells.[2]An advantage to this approach is that a person's own stem cells are used, avoiding transmission of genetic diseases. It is also minimally invasive, minimally painful and has a very short recovery period. This alternative to the current available treatments was shown not to cause cancer in patients who were followed for 3 years after the procedure.See also Autologous Mesenchymal Stem Cell Transplant for Cartilage Growth
The importance of rehabilitation in articular cartilage repair
Rehabilitation following any articular cartilage repair procedure is paramount for the success of any articular cartilage resurfacing technique. The rehabilitation is often long and demanding. The main reason is that it takes a long time for the cartilage cells to adapt and mature into repair tissue. Cartilage is a slow adapting substance. Where a muscle takes approximately 35 weeks to fully adapt itself, cartilage only undergoes 75% adaptation in 2 years. If the rehabilitation period is too short, the cartilage repair might be put under too much stress, causing the repair to fail.Concerns
New research by Dr. Robert Litchfield, September 2008, of the University of Western OntarioUniversity of Western Ontario
The University of Western Ontario is a public research university located in London, Ontario, Canada. The university's main campus covers of land, with the Thames River cutting through the eastern portion of the main campus. Western administers its programs through 12 different faculties and...
concluded that routinely practised knee surgery is ineffective at reducing joint pain or improving joint function in people with osteoarthritis. The researchers did however find that arthroscopic surgery did help a minority of patients with milder symptoms, large tears or other damage to the meniscus)
Meniscus (anatomy)
In anatomy, a meniscus is a crescent-shaped fibrocartilaginous structure that, in contrast to articular disks, only partly divides a joint cavity. In humans it is present in the knee, acromioclavicular, sternoclavicular, and temporomandibular joints; in other organisms they may be present in other...
— cartilage pads that improve the congruence between femur and tibia bones.