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Technique guide are not considered high yield topics for orthopaedic standardized exams including the ABOS, EBOT and RC.
Which of the following is a characteristic change in cartilage involved in moderate osteoarthritis?
Decreased thickness of subchondral bone
Decreased chondrocyte activity
Increased proteoglycan quantity
Increased water content
Increased collagen quantity
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The changes observed in articular cartilage affected by osteoarthritis include: increased water content (as a result of the disruption in architecture of the matrix molecules), decreased quantity of proteoglycans, decreased quantity of collagen with decreases in cross-linking and stiffness associated with degradation, increased thickness of subchondral bone, and increased chondrocyte activity and proliferation of chondrocytes.
This is different than the the changes seen during the natural aging process which include: decreased water content, decreased proteoglycan content and size (decreased length of protein core and GAG chains), normal quantity of collagen, increased collagen stiffness and cross-linking, unchanged chondrocyte activity/proliferation, unchanged thickness of subchondral bone, and decreased ratio of chondroitin sulfate to total glycosaminoglycans.
Hunziker reviewed the literature and found the existence of many novel and very promising biologically-based approaches for the induction of articular cartilage repair, the vast majority of which are still at an experimental phase of development.
Answer 1: Subchondral bone thickness is increased in osteoarthritis.
Answer 2: Chondrocyte activity is increased in moderate osteoarthritis.
Answer 3: Proteoglycan content is decreased in both osteoarthritis and the normal aging process.
Answer 5: Collagen quantity is decreased in severe osteoarthritis and remains unchanged in the normal aging process.
Osteoarthritis Cartilage. 2002 Jun;10(6):432-63. PMID: 12056848 (Link to Abstract)
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Which of the following characteristics of stromelysin is incorrect?
Belongs to the family of proteolytic enzymes called metalloproteinases
Secreted by chondrocytes
Inhibited by Tissue Inhibitor of Metalloproteinase
Inhibited by plasmin
Degrades cartilage and is thought to play a role in degenerative joint disease
Stromelysin is not inhibited by plasmin.
Metalloproteinases (MMPs) are a family of proteolytic enzymes which utilizes a metal during the catalytic process. Stromelysin and plasmin are two examples of metalloproteinases, both secreted by chondrocytes, which have degradative action against cartilage. It is believed that these metalloproteinases play a role in articular degeneration and degenerative joint disease. Tissue inhibitor of metalloproteinase inhibits the degradative action of stromelysin. Tissue inhibitor of metalloproteinase (TIMPs) counteract the proteolytic enzymes produced by chondrocytes.
Tetlow et al performed an experiment on the superficial zone of cartilage in in osteoarthritis specimens. They found cells that immunostain for IL-1beta, TNFalpha, and 6 different MMP's which support the concept that cytokine-MMP associations reflect a modified chondrocyte phenotype and an intrinsic process of cartilage degradation in OA.
Tetlow LC, Adlam DJ, Woolley DE
Arthritis Rheum.. 2001 Mar;44(3):585-94. PMID: 11263773 (Link to Abstract)
Tetlow, A 2001
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Histology of Osteoarthritis
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How would you treat this patient?
HPI - Traumatic paraplegia at T4 level (ASIA A) 12 years ago with progressive spasticity and difficulty with hygiene since the injury.
HPI - Valgus deformity of right knee, corrected with distal femoral varus osteotomy. Postoperative x-rays showed good correction with intact medial hidge. 50 days later, during physical therapy, patient felt acute pain and x-rays revealed fractured medial hidge and loss of correction
How would you treat the patient at this time (Postoperative P1 images below)?
HPI - c/o on off pain over lt hip, diff in cross leg sitting & squatting. H/o pain for 3 yrs treated by anti TB drugs for 8 months now pain reduced taken biopsy 2 yrs back
Assuming serum labs and joint aspiration confirm eradication of infection, how would you treat this patient?