1. Concepts In Basic Sciences
Asif Alrawi
MRCS,FRCS (Orth)

2. • Key Definitions
• Concepts
• Biomaterials

3. • BIOMATERIAL
• Any substance or combination of substances
,synthetic or neutral ,that can be used for any
period of time to treat ,augment or replace
any tissue organ or function of the body.
• Exhibit viscoelasticity, creep and stress
relaxation.

4. • Definitions:
• Load: forces that act on the body
(tension,compression,shear,torsion)
• Deformation: a temporary (elastic) or permanent
(plastic) change in the shape of the body.
• Elasticity: ability to return to the resting length after
undergoing shortening or lengthening
• Energy: ability to perform work

5. • Force: A mechanical push or pull (load)
causing external (acceleration) or internal
(strain) effect.
• - compression force shrinks the body in the
direction of the force.
• - tensile force elongates the body

6. • Stress:
• - is the intensity of the internal force.
• Stress= force/area
• Is the internal resistance of a body to a load
• Stress= n/m” (pascals)
• Ultimate stress is the stress at failure from a
single loading cycle or pull.

7. • Strain:
• Is the measure of deformation of a body as a result
of loading
• Strain = change in length/original length
• Strain is proportional and has no units

25. Macroscopic structure of bone and
types
• Types
• Matrix
• Draw
• Function

26. Types of bone
Lamellar bone Cortical (80% Skeleton)
Cancellous (Lower E)
Woven bone Immature (# Callus, embryonic bone)
Pathological
______________________________________________
Function Mechanical
Haematological
Ca Homeostasis

27. Bone Matrix
• Organic (40%) Collagen Type 1 (90%)
(Holes and pores)
Proteoglycans
Matrix proteins
Growth factors, cytokines
• Inorganic (60%) Hydoxyapatite
Brushite

28. Macroscopic structure of bone

29. Microscopic structure of bone
• Cells

30. Microscopic structure of bone
• Osteoblast

31. Osteoclast

32. Bone remodelling
• Types
• Why does it occur ?
• How does it occur ?

33. Bone remodelling

34. Blood supply of bone
• 5 – 10% Cardiac output
• Endosteal (High pressure) Inner 2/3 (Centrifugal)
• Periosteal (Low pressure) Outer 1/3
• Metaphyseal
• Epiphyseal
• Venous (Centripetal)

35. Types of bone formation
• Enchondral Cartilage model
Embyonic, # callus, physis)
e.g Achondoplasia
• Intramembranous (Flat bones, dist osteogenesis)
e.g Cleidocranial dysostosis
• Appositional
e.g Pagets

36. Epiphyseal Injuries + Growth arrest

38. Epiphyseal Injuries + Growth arrest
• Trauma (80%)
• Infection
• Tumour
• DXT , Burns
• Distal femur – Prox Tibia – Distal radius
• SH I, II, III, 5%
• SH IV 85%
• SH V ???

39. Epiphyseal Injuries + Growth arrest
• Assessment (Harris Growth lines , MRI)
Peripheral, Linear, Central bar
• Rx Excision + Fat, silicone, cement
Epiphyseodesis
Limb lengthen / shorten

40. Osteoporosis
• Definition
• Types

41. • Primary osteoporosis is a metabolic bone
disease characterized by low bone mass and
microarchitectural deterioration of bone
tissue, leading to enhanced bone fragility and
increased fracture risk
– Type I postmenopausal
– Type II age related

42. Osteoporosis
• Investigation

43. • Normal bone: T-score better than -1
• Osteopenia: T-score between -1 and -2.5
• Osteoporosis: T-score less than -2.5
• Established osteoporosis includes the presence of a non-traumatic fracture.
The Z-score is the number of standard deviations below age-matched avereage.

45. Cartilage
• Types
• Constituents
• Microstructure (Draw)
• Hyaline cartilage and injury
• Age changes

46. Cartilage
• Hyaline cartilage
• Fibro-elastic cartilage (Meniscus)
• Fibro-cartilage (Lig and tendons)
• Elastic cartilage (Tragus, trachea)
• Physes

47. Cartilage
• Chondrocytes (5%)
• Extracellular matrix (95%)
• Water (75%)
• Collagen Type 2 (5%)
• Proteoglycans (20%)
• Adhesives (Fibronectin)
• Enzymes, growth factors etc

49. Hyaline cartilage

50. THANK YOU