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A 53-year-old male laborer presents to his primary care physician with complaints of acute onset of left knee pain. He has had mild episodes of knee pain in the past and is two years status post a left partial medial meniscectomy. He has had mild relief with the use of anti-inflammatories. His past medical history is significant only for hyperparathyroidism and mild hypertension. He denies any fevers or chills. His exam reveals a moderate knee effusion and diffuse pain and tenderness with palpation and range of motion. Weightbearing radiographs are shown below. The most likely etiology of the patient's knee pain is characterized by which finding?
Deposits of monosodium urate crystals
Deposits of calcium pyrophosphate-dihydrate crystals
Destructive pannus formation
Empty osteocyte lacunae
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The patient has chondrocalcinosis, or pseudogout. This disease is characterized by radiographs that show deposits of calcium pyrophosphate-dihydrate crystals in the articular cartilage and menisci. Aspiration typically yields a moderate WBC count (<50,000) and weakly positive birefringent rhomboid-shaped crystals as shown in Illustration A.
Fisseler-Eckhoff and Muller examined over 3,000 menisci from arthroscopic retrieval for evidence of chondrocalcinosis followed by acquisition of clinical data to evaluate for a possible association with prior surgery or trauma. Their results revealed a positive correlation between prior surgery or traumatic knee injuries and the presence of chondrocalcinosis in 68.6% of patients.
Hough and Webber discussed multiple pathologies affecting the menisci, including chondrocalcinosis. They report on the high association of chondrocalcinosis with the presence of OA within the knee, but conclude that the exact relationship of these two pathologies has yet to be fully elucidated.
Answer 1: Refers to gout which can display punched out periarticular erosions on radiographs and strongly negative birefringent needle-shaped crystals, as shown in Illustration B.
Answer 3: Characteristic of rheumatoid arthritis, which is associated with symmetric joint space narrowing, osteopenia and periarticular erosions
Answer 4: Consistent with osteonecrosis, which is not apparent on the radiograph
Answer 5: Suggests hemophilia. Typical presentation includes a history of bleeding events and radiographs that show a widened intercondylar notch and enlarged femoral condyles
Fisseler-Eckhoff A, Müller KM.
Arthroscopy. 1992;8(1):98-104. PMID: 1550657 (Link to Abstract)
Hough AJ Jr, Webber RJ.
Clin Orthop Relat Res. 1990 Mar;(252):32-40. PMID: 2406071 (Link to Abstract)
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