Cartilage repair and tissue engineering. Flashcards
(24 cards)
The function of articular cartilage is…
distribution and transmission of load, minimisation of peak stress on subchondral bone, and resistance to low friction repeated movements.
The main type of collagen in articular cartilage is…
Type 2 Collagen
Articular cartilage contains which main components?
Chondrocytes, subchondral bone and an extra cellular matrix made up of collagen, proteoglycan and water.
Type 1 Collagen is found where?
In your bones!
The articular cartilage proteoglycan, agrican, has what function?
It uses its glycosaminoglycan chains to draw in water - it’s osmotically active.
Normal articular cartilage has three zones, what are they called?
Superficial Zone (nearest the surface, releases lubrication into the joint space) and the Deep Zone (formed of more organised columnar chondrocytes). Between these two there is the mid zone where the chondrocytes are more disorganised
Loss of joint space, sclerosis, subchondral cysts and osteophytes are X-ray characteristics of which pathology?
Osteoarthritis.
Why is articular cartilage so poor at repairing?
Avascular (no fibrin to clot and no chemotactic factors) and slow diffusion of nutrients and waste through the synovial fluid.
Cartilage focal lesions are most often the result of what?
Trauma, mainly in young adults as a result of sports and exercise. - either repetitive or traumatic impact.
Which type of focal lesion lies entirely within the cartilage and have no spontaneous repair?
Chondral focal lesions.
Which type of focal lesion penetrates through vascularised subchondral bone and demonstrates some spontaneous repair?
Osteochondral focal lesions - deeper.
Advanced osteoarthritis and large cartilage defects are treated with what?
TKA - total knee replacement.
What 5 treatments are used for small localised defects?
Debridement Microfracture Osteochondral grafting Cell-based therapies Ostotomy
Which small lesion treatment relies on stimulation of the healing response by inducing bleeding into the joint space?
Microfracture
Which focal lesion treatment is used to re-establish a normal gait pattern?
Osteotomy
What is an autograft?
Tissue obtained from a patient for grafting.
What is an allograft?
Tissue obtained from donor or cadaver tissue bank.
Which focal lesion treatment technique requires a periosteal patch?
ACI - autologous chondrocyte implantation - a privately available technique. Not suitable for OA.
What are fibrinogen and thrombin used for in the ACI procedure?
As a ‘glue’ to hold the periosteal patch in place.
What is the recovery time after an ACI procedure?
6months to low impact eg swimming
9-12 months to higher impact ie jogging and aerobics
12+months basketball football etc
Porcine collagen is used in which advanced ACI procedure?
Matrix induced autologous chondrocyte implantation.
Mesenchymal cells give rise to which other cell types?
Chondrocytes Lipoblasts fibroblasts osteoblasts myoblasts
Fibroblasts are the building blocks of what structures?
ligaments, tendons, joint capsules and general supporting tissues.
What structure in joints acts as a shock absorber in the joint space and compliments the action of the cartilage?
Meniscus
