Hoffa's Fracture: Diagnosis, management & New Classification System by BAGARI...Vaibhav Bagaria
Hoffa's Fracture - coronal split fracture of distal femur, its diagnosis, management strategy, a new classification and tips and tricks of management. First described Hoffa, a new classification system by Bagaria et al helps plan the surgery for these tricky fracture. The most crucial step is not to miss these fractures in ER.
Hoffa's Fracture: Diagnosis, management & New Classification System by BAGARI...Vaibhav Bagaria
Hoffa's Fracture - coronal split fracture of distal femur, its diagnosis, management strategy, a new classification and tips and tricks of management. First described Hoffa, a new classification system by Bagaria et al helps plan the surgery for these tricky fracture. The most crucial step is not to miss these fractures in ER.
A slide show of the paper- Tribology of artificial joints, T D Stewart BSc PhD Lecturer in Medical Engineering, Institute of Medical and Biological Engineering, The University of Leeds, Leeds, UK, Journal- ORTHOPAEDICS AND TRAUMA 24:6
Clinical Evidence in the Surgical Treatment of Advanced Osteoarthritis Kneeorthoprinciples
Evidence on the use of Cruciate Retaining / substituting, patient specific instrumentation, drains, continuous passive motion, obesity as risk factor, use of tourniquet, computer navigation, tranexamic acid
Ahmed ibrahim razooqi...corrosion conduct of austenitic stainless steel 316 l...ahmed Ibrahim
Corrosion conduct of Austenitic stainless steel 316L subjected
to surface treatment.
Abstract. The influence of low temperature liquid nitriding as a surface heat treatment analogy
with laser peening treatment at the various of throbs on pitting corrosion of the “AISI 316L
Austenitic stainless steel” is investigated in this paper. According to typical ASTM (G71-31) a
number of corrosion examination samples are equipped with the measurements of (15 * 15 * 3)
mm which distributed into the many groups. Three sets were exposed to liquid nit riding
process at temperatures of (500, 400, 300) Co for one hour. The specimens (without coating)
were exposed to a number of the throbs (1,2,3) by laser peening. Microstructure varia tions,
compression residual stress, hardness, were inspected in this work. The corrosion and its
variables (potential cell, current density) were also evaluated using the potential stat
examination and applying the Tafel method using saltwater solution (3.5% NaCl). Tafle
equation was used to compute the corrosion degree. The results revealed that the liquid
nitriding participated to raise the corrosion rate at (500) Co, compared to the original metal
because of chromium nitride and also leaser peening participated to the increase in the
corrosion rate due to plastic deformation which led to the heterogeneity in the microstructure
but liquid nitriding at temperature (400) oC gave the best result where it was closer to the parent
metal’s, also laser peening at one throb showed the lower corrosion rate.
Dispersion Hardening:
Hard particles:
Mixed with matrix powder
Consolidated
Processed by powder metallurgy techniques
Second phase – Very little solubility (Even at elevated temp.)
No coherency
So thermally Stable at very high temp.
Resists :
Grain growth
Over aging
Recrystallization
Mobility of dislocation
Different from particle Metallic Composites (Volume Fraction is 3 to 4% max.) (Does not affect stiffness)
Examples : Al2O3 in Al or Cu, ThO2 in Ni
Experimental evaluations and performance of the aluminum silicon carbide par...IAEME Publication
Stresses induced due to thermal mismatch between the metal matrix and the ceramic reinforcement in metal matrix composite may impart plastic deformation to the matrix there by
resulting in a reduction of the residual stresses. Thermal mismatch strains also may quite often crack
the matrix resulting in a relaxation of the residual stresses. The interface in MMCs is a porous, noncrystalline portion in comparison with the matrix or the reinforcement (metal matrix and ceramic reinforcement in this case).
This topic includes various aspects regarding Corrosion prevention. It includes material of construction, how environment changes and its effect on corrosion, how can we properly design our equipment to avoid from corrosion. It also includes Cathodic protection and Anodic protection.
Mechanism of Fracture in Friction Stir Processed Aluminium AlloyDr. Amarjeet Singh
Aluminium alloys are used for important
applications in reducing the weight of the component and
structure particularly associated with transport, marine,
and aerospace fields. Grain refinement by scandium (Sc)
addition can eliminate the casting defects and increase the
resistance to hot tearing for high strength aluminium alloys.
FSP for cast aluminium alloys have been focused and it has
great advantages including solid state microstructural
evolution, altering mechanical properties by optimizing
process parameters. These parameters are tool rotational
speeds (720, and 1000 rpm), traverse speeds (80, and 70
mm/min), and axial compressive force at 15 kN, etc. The
mechanical properties had been evaluated on FSPed
aluminium alloy with different microstructural conditions.
Fracture properties of aluminium alloys are very important
for industrial applications. Tensile and fracture toughness
properties were correlated to microstructural and
fractographic features of the aluminium alloys need to
explore their essential failure mechanisms.
6. Judet brothers- heat curved acrylic femoral head
prosthesis-fragmentation of acrylic with wear- severe
tissue reaction-bone destruction
Thompson and Moore – metallic endoprosthesis with
medullary stems- erosion of bone on pelvic side
7. Metal on metal
Urist, Ring and McKee Farrar
Friction metal wear
High incidence of loosening and pain.
8. Sir John Charnley
-Low friction torque arthroplasty
-Surgical alteration of hip biomechanics
-Lubrication
-Material design
-Operating room environment
-PMMA
9. 1 st Charnley prosthesis
Moore prosthesis stainless steel femoral component
Thin polytetrafluroethylene shell for acetabulum
12. Adhesive wear
Adhesion during contact of opposing bearing
surfaces
Sliding breaks these contacts
Strength of adhesion exceeds strength of material
Particles are pulled from the material
44. Biologic effectsCoC MoM MoHCLUH
WPE
Cell
toxicity
No Yes No
Local
tissue
reaction
Low Low Low
Chromo.
changes
NR R NR
Hypersensi
tivity
NR R NR
Carcin. NR * NR
47. Next generation polyethylenes
1. Sequential irradiation and annealing
2. Irradiation and solid state deformation by extrusion
below melting temperature
3. Vit E antioxidant containing polyethylene
48. Metal on metal
Increase in femoral head size –greater sliding velocity
and increased probability of fluid film lubrication –
decrease in wear
Reduced risk of impingement and dislocation
32 mm and bigger
49. Ceramic on metal
Alumina head
Cobalt chromium alloy cup
Reduced wear rate 100 fold
Clinical studies underway
51. Take home message
There is no 100 % ideal bearing surface
Hard/hard and hard/soft
Tribology –friction, lubrication and wear
Wear causes osteolysis
52. Modern bearings: - all have low wear
Young and active patients Hard/hard bearings will
produce less wear debris but noise remains a
problem
53. For hard on hard bearings cup placement is
important to reduce risk of impingement, excessive
wear and fracture.
Metal on metal bearings release metal ions and
corrosion products and probably should not be
used for patients with impaired kidney function or
women of child bearing age.
