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8 Cards in this Set
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Which of the following molecules is associated with macrophage induced osteolysis surrounding orthopaedic implants? 1-BMP-7; 2-IL-10; 3-SOX-9; 4- Osteoprotegrin; 5-IL-1
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IL-1 is associated with macrophage induced osteolysis surrounding implants. Macrophages -> the inflammatory cascade associated with aseptic loosening of implants by secreting ->(PDGF), (PGE2), TNF-alpha, IL-1, and IL-6. the primary cells involved in the process of periprosthetic loosening =macrophage, osteoblast, fibroblast, and osteoclast. the chemical mediators that are responsible for the cellular interactions and effects on bone primarily include PGE2, TNF-alpha, IL-1, and IL-6.
Incorrect Answers 1: BMP-2,4,6, and 7 all exhibit osteoinductive activity but BMP-3 does not. 2: IL-10 inhibits osteoclast formation along with calcitonin 3: SOX-9 is a key transcription factor involved in the differentiation of cells towards the cartilage lineage 4: Osteoprotegrin binds to RANKL on the osteoblast, preventing RANK activation and inhibiting osteoclast activity.Ans5 |
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Which of the following variables is associated w elevated serum metal ion levels following metal-on-metal hip resurfacing arthroplasty? 1-Smaller implant diameter; 2-Smaller acetabular cup abduction angle; 3-Higher postop functional scores
4-Severe preop OA; 5-Anteversion of acetabular cup between 10 and 20 deg |
Smaller implant diameter is assoc with elevated serum metal ion levels with metal-on-metal hip resurfacing arthroplasty.
(MOM) hip resurfacing arthroplasty has the advantage of better wear properties (lower linear wear rate and volume of particles) than metal on polyethylene. However, elevated serum metal ion levels is one of the negatives which has received much attention recently. Studies have found smaller implant diameter and acetabular cup abduction angle >55 degrees are associated with elevated serum metal ion levels. Cup abduction angles of greater than 55 degrees lead to a more vertical cup and edge loading.Ans1 |
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A pt undergoes a primary THA w/ a highly cross-linked (UHMW) polyethylene acetabular liner. In comparison to a 28mm femoral head, a 32mm femoral head will provide which of the following? 1-> risk of dislocation; 2-< ROM; 3-> risk of osteolysis; 4-Equivalent wear rate of the polyethylene acetabular liner ; 5-> risk of periprosthetic fx
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Wear rates of highly cross-linked UHMW polyethylene liners are independent of femoral head size between 22 and 46 mm in diameter.
While the wear rates of old polyethylene liners increased with increasing femoral head size, wear rates of the new highly cross-linked UHMW polyethylene liners have shown to be independent of head size. This is extremely advantageous, as increasing the femoral head size improves range of motion and increases jump distance, thereby decreasing dislocation rates. 1: Increasing femoral head size decreases the risk of dislocation. 2: Increasing femoral head size increases range of motion. 3: Increasing femoral head size has not been shown to affect rates of osteolysis. 5: Increasing femoral head size has not been shown to increase the rate of periprosthetic fracture.Ans4 |
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A design surgeon has created a new polyethlyene acetabular liner for THA. Early clinical outcomes are comparable to conventional total hip arthroplasty. At 4 year f/u, 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? 1-Osteolysis and subsequent component loosening will be minimal if the wear rate continues; 2-Osteolysis and subsequent component loosening will be > than conventional hip arthroplasty if the wear rate continues; 3- Predicting osteolysis and subsequent component loosening is not possible with this data; 4-All THA should use this new polyethylene; 5-Pt satisfaction will be > at 10 yr f/u
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Polyethylene wear rates have shown association with osteolysis and subsequent component loosening. Wear rates above 0.1 mm per year are at significant risk of osteolysis. Dumbleton et al performed a meta-analysis of the literature concerning wear rates and osteolysis. They concluded that osteolysis was rarely observed when the wear rate was < 0.1 mm per year. Ans1
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Osteoprotegrin (OPG) binds to what structure to inhibit particle-induced osteolysis? 1-RANK
2-;RANK-ligand ; 3-OPG-receptor ; 4-CD7; 5-CD10 |
Osteoprotegrin (OPG) binds to RANK ligand (RANKL) to inhibit it from binding to RANK which are present on osteoclast-precursor cells. Normally, RANKL interacts with RANK to stimulate activation of osteoclasts. Jacobs et al present a nice review of the cellular and chemical mediators of osteolysis.
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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? 1->shelf age of polyethylene liner; 2-Younger age of pt; 3-Male gender; 4-PCL retaining knee design; 5-Use of a rough tibial baseplate
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Increasing shelf age, younger age, male gender, and a rough tibial baseplate are all risk factors for wear-related failure in total knee arthroplasty when using a polyethylene liner. Posterior cruciate retaining knee design is not a documented risk factor.Ans4
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A 68-year-old right handed male golfer presents with significant left knee pain which has not been amenable to conservative management. A radiograph is shown in Figure A. He is interested in pursuing total knee arthroplasty (TKA). What can this patient expect with regards to his golf game after undergoing this procedure? 1-A significant rise in his handicap; 2-No change in his drive distance; 3;Decreased pain compared to undergoing a right TKA ; 4-A significant chance of having severe pain during play; 5-Patients are required to use a cart while golfing
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Active golfers who undergo total knee arthroplasty (TKA) typically have a significant increase in their handicap when they return to the game.
Mallon et al studied 83 (80 of which were right handed) active golfers who underwent TKA and found that they invariably experienced a significant rise in their handicap (mean +4.6 strokes) and also a decrease in the length of their drives. Approximately 15% of the cohort experienced a mild ache while playing, and golfers with left TKA's had more difficulty with pain during and after play than did golfers with right TKA's. It also should be stated that statistically significant increased pain ratings occur in golfers with a TKA on the target-side knee. Finally, almost 90% of the patients in this study utilized a cart while playing post-operatively. Mallon et al also evaluated the effect of total hip arthroplasty (THA) on the game of avid golfers. They found that hybrid and uncemented primary THA's had lower rates of radiographic loosening in active golfers when compared to cemented THA's. However, symptoms of pain while playing or after playing did not differ among these groups.Ans1 |
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When discussing metal on metal hip resurfacing versus metal on polyethylene total hip replacement, the surgeon should inform the patient that all of the following are disadvantages of hip resurfacing EXCEPT? Topic Review Topic
QID: 842 1. Higher dislocation rate 2. Higher periprosthetic fracture rate 3. Increased serum metal ion levels 4. Higher rates of osteonecrosis 5. Larger incision and surgical dissection |
Hip resurfacing is associated with higher rates (compared to conventional THA) of AVN, higher serum levels of metal ions, and higher rates of early postoperative fractures, specifically femoral neck fractures. However, the dislocation rate is significantly lower with hip resurfacing due to the larger size of the femoral component and more accurate restoration of anatomic hip biomechanics. Shimmin et al report on hip resurfacing complications, and published dislocation rates are 0.75% at a mean of 3 years’ follow-up. Also, in order to prepare the acetabulum while preserving the femoral head, a more extensive surgical approach and soft tissues releases are required for a resurfacing procedure.Ans1
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