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Joint Replacements
• Causes:– Trauma– Osteoarthritis– Reumatoid Arthritis
• Indication for Surgery– Severe Pain– Severe Deformation (knee in particular)
• Risks:– Infection, – Mechanical Failure (loosening etc.)
Joint Replacements
• The Joint Surface Problem (tribology)• The lubrication problem
– Synovial fluid has to be the lubricant
• Artificial joint does not employ the same hydrodynamic mechanism
• How does a bearing work (hydrodynamics)• The wear debris and their consequences• The interface problem
Hip Mechanics and Standing Posture
Shock Absorption of the Joint
• Strictly essential in the lower limb joints, to protect the bone implant interface
• Cartilage + Hydrodynamics in the Biological joint
• Metal-UHMWPE (plastic)
Cartilage
Bone Morphology
Hip Mechano-Morphology
Bone Disease: Osteoporosis
Normal Bone Osteoporosis
Osteoporotic Femoral Head
Normal Hip Osteoporotic Hip
Hip Fractures
(From Howmedica)
Over 250,000 hip fractures occur in the United States annually. 90% of these are in patients over 50 years old. With the growing aging population, the number of hip fractures is expected to double in less than 50 years.
Types of hip fractures include: femoral neck fractures and fractures of the intertrochanteric and subtrochanteric regions. Femoral neck and intertrochanteric fractures occur with equal frequency and account for over 90% of all hip fractures. The remainder are subtrochanteric fractures. Treatment options range from internal fixation to total joint replacement.
Severity Based on Fracture Site
Subcapital v. Per-Trochanteric
Garden’s Classifications of Hip Fractures
Type I fractures have the best outcome. The bone ends are impacted into one another, which facilitates vascular re-growth.
HIP FRACTURE SOLUTIONS
The Complete System for Faster, Easier Surgery.
The Omega Plus CHS System includes such features as sideplates made of superstrong alloy material, improved instrumentation, and the unique 98o ergonomically designed Supracondylar Plate which conforms to distal condyles with minimal contouring. Omega Plus plates and lag screws are
available in sterile or non-sterile packaging for customer preference and convenience.
OMEGA PLUS COMPRESSION FEMORAL SCREW SYSTEM
The Austin Moore Hip Implant
Nailing the Head-Neck
Hip Replacement
If there is damage to the acetabulum the patient may require a Complete hip replacement.
Hip Joint Prosthesis
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The Bone-Prosthesis Interface
• Long stem in hip and elbow prostheses
• Short stem in knee
• Method of fixation– Acrylic bone cement– Simple contact (contour congruency)– Porous technology
Composite Beam (two materials)
• For the beam to bend as one it should transmit shear
• If one material is much more rigid it bears most of the stress
• Preference in prosthetics is to have materials with rigidity similar to bone
Criteria to be Observed
• Minimal bone removal
• Mechanical compatibility (adjustment of compliance, Young’s moduli etc.)
• Avoid stress concentration
• Avoid stress shielding
• Provide for easy extraction?? In case of revision surgery
Anything else??
Fracture Fixation Examples of Fractures
• Simple fracture• Displaced fracture• Comminuted fracture• Long bone fracture• Vertebral fracture• Rib fracture• Clavicular fracture
• Pelvic fracture• Radial fracture• Finger fracture
Bone-Plate Fixation
• Dynamic loading required• Double plating may produce
stress shielding• Care is needed with the
periosteum• In some cases, compression
plate is preferred
Bone Plates Cont.
• In the epiphyseal region more screw support is needed
• Nail-Plate combination
Intramedullary Nailing
• Femoral nail vs. plating
Intramedullary Nailing
http://www.smithnephew.com/orthopaedics/products.
The Knee Goes BadRadical Solution: Tibio-
Femoral Fusion
Knee Arthrodesis
Anatomical Constraints
Total Knee Arthroplasty
Bone Preparation for Total Knee Arthroplasty
Procedure of Total Knee Arthroplasty
Cemented versus Cementless Total Knee Arthroplasty
Radiographic Imaging of Total Knee Arthroplasty
Prosthetic Knee
Hinge Knee Joint
Artificial Knee
Knee
Hoffman External Fixator
http://www.howmedica.com/
Based on the long-standing tradition of the original Hoffmann Fixator, the new Hoffmann II design provides today's surgeon with advanced technology and ease of application. The new spring loaded snap fit mechanism allows the easy connection of 8mm connecting rods or pins providing versatile intraoperative frame management and excellent stability. The system allows independent pin placement of 4 or 5mm Apex Pins and is ideally suited for proximally or distally located fractures. The system is designed with versatile and simple instruments with a single wrench that fits all screws. A multi pin clamp is designed to accept the same pin placement as the original Hoffmann with single or bi-lateral torx connections allowing 12 angular positions for a compact frame design.
External Fixator
Monotube External Fixator
http://www.howmedica.com/
Fracture Fixation
http://www.howmedica.com/
Bone Lengthening
Arm Fractures Fixation
Radial Fracture Bridging
http://www.howmedica.com/
Pelvic Fracture
External Fixation
Ligament Rupture
Bioresorbable MaterialsStimulan™, medical grade calcium sulfate dihydrate and stearic acid, is an osteoconductive material used to fill bone voids in non weight bearing applications that resorbs and is replaced with bone during the healing process. Stimulan is indicated for uses in cases where there is a bony defect or void in the boneTraumaSpinal fusions Revision SurgeryInfected JointsCore DecompressionsOsteoporosis
Advantages of Stimulan: Predictable, consistent resorption ratesEliminates need for second surgical site and added pain for patient that occurs with traditional autograft techniqueCost and time savings per procedure over autograftOsteoconductive material that acts as scaffolding for new bone to formEliminates risk of disease transmission and availability of quality bone present with traditional allograft techniqueProven dissolution rates
Bioabsorbable ACL Cross Pin
Bioabsorbable Screws
Femoral Neck Fracture FixationProximal Femur
The Shoulder Bones
Acromion
Humerus
Glenoid Cavity
Coracoid Process
Scapula
Clavical
Ligaments of the Shoulder
Acromioclavicular Joint / Coracoclavicular Ligaments
ClavicleAcromion
Muscles (Posterior | Anterior)
Deltoid
Infraspinatus
Supraspinatus
Teres Minor
Teres Major
Deltoid
Lattisimus Dorsi
Subscapularis
Teres Major
Supraspinatus
Subclavius
Noel PinsInter Trochanteric Nail
Supracondilar Plate
Proximal Tibia
Carpal and Finger Plates
The Spinal Segment
Harrington Rod
Spine Posterior
Spinal Implants
Isobar® TTL Posterior Spinal System
System allows the use of either "U" Screws or Hemispherical Screws with Offset Clamps Unique Claw Hooks provide firm and secure fixation The Monobloc Clamps allow the screws to be positioned according to the anatomy Screws are available in multiple sizes to accommodate all patient anatomy Rigid and Semi-Rigid Rod options are available to cover a wide variety of surgical indications A unique instrument prevents cross threading of the Blocker Nut when applied on the "U" Screws or Hook
http://www.encoreortho.com/products.html
Spinal Implants
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are needed to see this picture.
Intervertebral Cage
CC Lumbar Intervertebral Cage System
The material, PEEK, has a modulus of elasticity close to that of bone, improving the biomechanical interface The radiolucent design allows direct visualization of the osteogenesisThe superior and inferior surfaces of the device are notched to achieve stabilization of the implants within the vertebral endplatesThe cages are available in straight and lordotic designs in order to replicate the normal anatomic lordosis of the lumbar spineCages are available in five thicknesses to accommodate a wide range of anatomy
This product is not yet approved to sell in the United States.
http://www.encoreortho.com/products.html
Spinal Interbody Fusion
Zigomatic Fracture Fixation
Distal Tibia
Proximal Radius-Ulna Fracture Plates
Distal Radius and Distal Ulna
Distal Humerus
See you next time