Iplants In Orthopedics Flashcards
are devices or tissues that are placed inside or
on the surface of the body.
●
Are prosthetics, intended to replace
missing body parts.
Implants
it is the resistance of a structure to
deformation.
STIFFNESS
it is used in context of fracture fixation
describes an implant or of a bone- implant construct
physical property of resisting deformation under load
RIGIDITY
it is the ability of a material to recover its
original shape after deformation.
ELASTICITY
the ability of a material to be formed to a new shape without fracture and retain that shape after load removal.
PLASTICITY
the ability of solid material is to be deformed under tensile stress and to be stretched into a wire without fracture. It also bestows capacity to be shaped eg.
DUCTILITY
With the advent of antiseptic surgery b/w 1860s and 1870s by___________ and anaesthesia by_________
1860s and 1870s by LORD JOSEPH LISTER and anaesthesia by MORTON (ETHER) and SIMPSON
A further impetus to internal fixation was given by
discovery of_________
X –RAYS BY ROENTGEN in 1896.
________) the surgery developed rapidly.
CHLOROFORM
LAVERT in animal experiment found_________ was the most inert metal but, gold and silver and too soft for clinical use.
Platinum
LISTER himself was one of the first to successfully wire a ___________
fractured patella using a silver wire.
_____) was one of the early person to fix a fracture with PLATE AND SCRE
HANSMANN(1866
He was the early pioneer, who placed plate and screw fixation on sound footing.
He devised his form of plates.
SIR WILLIAM ARBUTHNOT LANE (BRITISH
SURGEON & PHYSICIAN )
He devised “NO TOUCH” technique , to prevent wound
infections and his own results bear testimony of his great
skills.
SIR WILLIAM ARBUTHNOT LANE (BRITISH
It was made of “STOUT STEEL” a high carbon steel of fairly
high percentage of carbon.
SIR WILLIAM ARBUTHNOT LANE
He improved the design of LANE’S plate to make it stronger. His implants were made of “VANADIUM
STEEL”, an alloy containing much less carbon and 0.1-0.15%
of vanadium along with small amounts of chromium and
molybdenum.
SHERMAN(1912).
in 1908 introduced pins for
fixation of “small fragments” at the intra articular level.
VON BAYER
in 1893 stressed the value of rigid fixation and showed that movement at the fracture site encouraged corrosion and break up of the fixation device.
He was the 1st to try fixing fractures of the femoral neck by round pins introduced through the trochanter , as well as the use of round intramedullary rods for the fractures of
the shaft of long bones.
EARNEST HEY GROVES
The story of stainless steel, it is said , started in SIBERIA with discovery of a new mineral “_______” way back in 1776.
CHROMITE
The_____ was the 1st stainless steel to give satisfactorily as an SURGICAL IMPLANT.
Its corrosion resistance is high and it is one of the best form of steel available.
18-8 SMo
In last 30 years another metal which came into use is_______ because of its total inertness(chemically inactive) in the body.
TITANIUM
___________, __________ have the fabrication(invention)versatility and strength of stainless steel and excellent compatibilty in the body.
TITANIUM,VITALLIUM h
Implants can be tested under following categories
• Physical
2)• Chemical
3)• Structural
4)• Biological.
Specification directs that the implants should be free from cracks, draw marks, pits, burrs and surface contamination.
They should be polished bright .
Appearance : Physical Test
Screws of identical diameter, geometry and length should weigh same, pr
Weight: physical tst
The austenitic(primary phase) stainless steel (ISI 316) is nonmagnetic.
A magnet is applied to the implant and tested for its magnetism.
A small implant can be lifted up by the magnet ,
A large implant when suspended will be found to zoom(move) with the magnet.
Magnetism
It is the ability to resist plastic deformation under identical load.
Hardness
To scale 30T is used to comply with nondestructive testing and to check even the small components as well.
Rockwell superficial hardness testing
This test involves a load of 30 kg and an indentor of 1/16 inch diameter ball. Two readings are taken and the mean is calculated.
Rockwell superficial hardness testing
with an elevated standard pendulum, the implant is struck and the energy absorbed in the fracture is measured.
IMPACT TEST”
Molybdenum has a characteristic spark profile.
•The implant is abraded on a standard grinding wheel, and spark trajectories are noted for the characteristics.
Spark Test
Chemical Test
A.Molybdenum detection test
B.• Molybdenum percentage estimation
C.• Corrosion test.
A drop of the electrolyte is placed on the stainless steel under test, and the electrodes are placed against the electrolyte solution. to turn pink or rosy red. If molybdenum is present, the drop will retain its hue and if not, the hue will fade rapidly
Molybdenum Detection Test
“Mini-Moly Detector”
This can be carried out by various metal testing laboratories in all major cities
It contains hydrochloric acid and nitric acid in the proportion of 3:1, and it is a strong solvent.
If the implants are of identical alloys, they should dissolve identically. The percentage loss is estimated and compared with the standard one.
Corrosion Test (Aqua Regia)
