June 20, 2024

Stem cell engineering is used in many fields of medicine with useful outcomes and it has a vast utility in the field of orthopedics.

Tissue engineering

Multidisciplinary area aimed at the regeneration of tissue and restoration of function of organs by implantation of cells or tissue grown outside the body or stimulation of cells to grow into an implanted matrix.

Basic Steps of Stem Cell Harvesting

Harvesting tissues from the donor side

Implanting these cells into natural or synthetic support

Produce scaffold functionally, mechanically, and structure equal to part to be replaced

Stimulation towards cellular proliferation

Differentiation toward a correct phenotype

Ultimately transplantation of living tissue or organs in the patient

Stem Cells are the Basic of tissue engineering

Immature, undifferentiated cells, capable of producing identical daughter cells

Sources of stem Cells

  1. Embryonic Stem Cells ( from inner cell mass of blastocytes)
  2. Adult Stem Cell (eg. Bone marrow, cornea, retina, liver, pancreas, GI tract)

Classification of stem cells

  1. Totipotent ( capable of forming any tissue eg. Fertilized egg or zygote)
  2. Pluripotent (embryonic stem cells)
  3. Multipotent (capable of differentiating into one particularly cell linage eg. Bone marrow stroma, mesenchymal stem cell)

Mesenchymal Stem Cells

Adult stem cells (bone marrow, periosteum, fat, skin)

Can be differentiated into osteoblast, chondrocytes, myoblast, adipocytes lineage)

Can be used to repair large osseous defects by the fully vascular bone flap, of desired shape in-vivo.

Orthopedics Application of Stem Cell Technology

  1. Cartilage Repair
  2. Critical bone defect and Nonunion
  3. Spinal Cord Regeneration
  4. ACL reconstruction augumentation
  5. Muscular dystrophies
  6. Spinal Fusion
  7. Osteogenesis imperfecta
  8. Intervertebral disc degeneration
  9. Tendon and ligament Repair
The stem cell in orthopedics
The stem cell in orthopedics

Cartilage Repair

Aim to restore normal joint function by regenerating hyaline cartilage in the defect and complete integration of regenerated cartilage, surrounded cartilage, and underlying bone

Technique:

Autologous Chondrocytes Implantation (ACI)

Harvesting periosteal flap

Fixation of the flap to the cartilage defect

Securing a watertight seat with fibrin glue

Implanting the chondrocytes

Wound closure

ACI results in the formation of new cartilage very similar in characteristics to normal cartilage in terms of collagen and matrix.

Previously ACI was limited to small or medium size focal chondral and osteochondral defects of the weight-bearing surface of the femoral condyle and patella-femoral joint.

Extended now to the tibia, talar, glenohumeral and femoral head.

Normally 1 cm2-4 cm2 can be repaired but with ACI 8 cm2-9 cm2 (but may lead to donor site morbidity)

Cultured Mesenchymal cells help in the repair of the chondral defect in advanced OCD,

See also: Osteochondritis dissecans (Knee)

Retarding process of OA,

Growth plate injuries ( after excision of the bone bridge ) where growth arrest and deformity occurs