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Osteolysis occurs because there is a histiocytic response by macrophages to wear debris. What size particles are implicated in osteolysis?
less than 1 micron (submicron)
approximately 10 microns
approximately 100 microns
approximately 1000 microns
approximately 5000 microns
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Which of the following is the primary mechanism of polyethylene wear in the hip?
Fatigue cracking and delamination
Adhesion and abrasion
A design surgeon has created a new polyethlyene acetabular liner for total hip arthroplasty. Early clinical outcomes are comparable to conventional total hip arthroplasty. At 4 year follow-up, radioisometric analysis reveals 0.05 mm of annual wear in the surgeon's trial patients. Which of the following statements can be made from this data?
Osteolysis and subsequent component loosening will be minimal if the wear rate continues
Osteolysis and subsequent component loosening will be greater than conventional hip arthroplasty if the wear rate continues
Component positioning should have no effect on wear rates of these bearings
All total hip arthroplasties should use this new polyethylene
Patient satisfaction will be greater at 10 year follow up
A 75-year-old man underwent total hip arthroplasty 10 years ago. He now reports mild groin pain which has been increasing lately. What is the most likely explanation for the finding in Figure A indicated with the arrows?
Galvanic corrosion of the modular components
Polyethlene wear particles tracking through the effective joint space
A 56-year-old man reports progressively worsening left knee pain after undergoing total knee arthroplasty 6 years ago. He was initially very happy with his progress, but 18 months after surgery he began to have knee pain. Radiographs are shown in Figures A and B. Laboratory values reveal a C-reactive protein of 0.1 mg/dL (normal 0.0-0.6 mg/dL) and an erythrocyte sedimentation rate of 3 mm/h (normal 0-15 mm/h). An aspiration of the knee reveals 157 leukocytes/ml with 18% polymorphonucleocytes. What is the most appropriate next step in management?
Irrigation and debridement with polyethylene spacer exchange
Antibiotic impregnated cement spacer placement
Broad-spectrum, empiric oral antibiotics
A 69-year-old female 16 years status post total knee arthroplasty complains of knee pain. A radiograph is provided in Figure A. Which of the following is true regarding the pathogenesis of the bony abnormality seen in the distal femur?
It is related to the toughness of the polyethylene liner
It is more likely to occur with highly cross-linked polyethylene compared to conventional polyethylene
It is caused by macrophage activation by polyethylene particles
It is most frequently caused by infection
It occurs more frequently in patients taking immunosuppressive medications.
A 72-year-old female underwent an uncomplicated primary total hip replacement 18 years ago. Current radiographs reveal the abnormality shown in Figure A. Which of the following cell types (Figures B-F) is implicated in the process shown by the arrow?
Osteoprotegrin (OPG) binds to what structure to inhibit particle-induced osteolysis?
Which of the following variables is associated with elevated serum metal ion levels following metal-on-metal hip resurfacing arthroplasty?
Smaller implant diameter
Smaller acetabular cup abduction angle
Higher postoperative functional scores
Severe preoperative osteoarthritis
Anteversion of acetabular cup between 10 and 20 degrees
A patient undergoes a primary total hip arthroplasty with a highly cross-linked ultra-high molecular weight (UHMW) polyethylene acetabular liner. In comparison to a 28mm femoral head, a 32mm femoral head will provide which of the following?
Increased risk of dislocation
Decreased range of motion
Decreased risk of osteolysis
Equivalent wear rate of the polyethylene acetabular liner
Increased risk of periprosthetic fracture
A new biomaterial has been designed for hard on soft bearings in total hip arthroplasty. The implant company claims this new material has a lower wear rate and greater toughness than highly cross linked polyethylene. Which of the following studies would most accurately evaluate wear between the two materials?
Retrospective review of each material with immediate post-operative radiographs compared to annual follow-up radiographs
Prospective trial comparing each material with radiostereometric analysis
Prospective trial comparing each material with annual CT scans
Prospective trial comparing each material with computer-assisted edge-detection radiographs
Retrospective trial comparing each material with computer-assisted edge-detection radiographs
Which of the following molecules is associated with macrophage induced osteolysis surrounding orthopaedic implants?
Which of the following is indicative of type 1 collagen breakdown and can be utilized as a marker of bone turnover?
Increased urinary N-telopeptide
Increased urinary cAMP and phosphate
Increased urinary phosphoethanolamine
Increased urinary Bence Jones proteins
Increased serum bone sialoprotein
When comparing conventional polyethylene liners to the newer highly cross-linked polyethylene liners, all of the following are true EXCEPT for one. Which of these statements about conventional poly liners is incorrect?
Higher steady-state femoral head penetration rate
More susceptible to adhesive wear
Generate smaller wear particle size
Increased fracture toughness
Increased tensile strength
Which type of inflammatory cell is thought to be involved in the activation of the biological response to metal-on-metal particulate debris?
A 45-year-old male, with a history of avascular necrosis, undergoes a total hip arthroplasty using a metal-on-metal bearing. Which of the following statements regarding the use of metal-on-metal bearings is true?
Produce lower serum metal ion concentrations than metal-on-cross linked polyethylene bearings
Have a decreased volumetric wear rate compared to metal-on-ceramic bearings
Have smaller wear particles compared to metal-on-cross linked polyethylene bearings
Have a higher incidence of early soft-tissue sarcoma compared to all other bearing surfaces.
The wear rate significantly increases after the first year of use.
All of the following are risk factors for wear-related failure in total knee arthroplasty when using a polyethylene liner that underwent sterilization via gamma irradiation in air EXCEPT?
Increasing shelf age of polyethylene liner
Younger age of patient
Posterior cruciate retaining knee design
Use of a rough tibial baseplate
Figure A shows a ceramic head removed during a total hip revision. The component shows damage to the femoral head which was most likely caused by which of the following?
Third body debris
Impingement of the femoral stem neck on the acetabular socket
Lift-off separation of the femoral head during hip range of motion
Insertion of the head on the femoral stem at time of initial surgery
Ultra-high-molecular-weight polyethylene (UHMWPE) particles have been associated with osteoclastogenesis, a key component of osteolysis in total joint replacement. Which of the following accurately describes the expression of vascular endothelial growth factor (VEGF) and receptor activator of nuclear factor kappa-B ligand (RANKL) during UHWMPE induced osteolysis?
RANKL expression is increased and VEGF is unchanged or mildly decreased
VEGF expression is increased and RANKL is decreased
VEGF expression is increased and RANKL expression is unchanged
Expression of both VEGF and RANKL is increased
Expression of both VEGF and RANKL is decreased
Which of the following interventions reduces osteolysis around distal portion of the femoral stem when performing a total hip arthroplasty?
Use of an extended offset femoral neck component
Use of a proximal circumferentially coated ingrowth stem
Use of a collared stem
Use of a long femoral stem
Ensuring that the stem fills the diaphysis of the femur
Figure A is a photograph of a femoral head removed during revision of a ceramic on ceramic total hip arthroplasty. Which of the following is the most likely indication for this revision total hip arthroplasty?
Leg length discrepancy
Ceramic bearing fracture
Aseptic lymphocytic-vasculitis-associated lesion (ALVAL)
Highly cross-linked ultra-high-molecular-weight polyethylene (UHMWPE) liners used in total hip arthroplasty have which of the following characteristics compared to conventional UHMWPE liners?
Increased average wear particle size
Increased resistance to abrasive wear
Increased number of wear particles generated
Increased resistance to fatigue crack propogation
Highly cross-linked ultra high molecular weight polyethylene has which of the following characteristics as compared to conventional polyethylene?
Increases the elongation to break
Improved resistance to crack propagation
Improved wear resistance