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Challenge of the Unknowns—Unknown 5

Radiographic Findings and Differential Diagnosis

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Plain film radiographs of the left knee dated 10-25-96 did not reveal gross alteration in alignment. Minimal degenerative joint disease at the medial compartment of the left knee is noted with minimal osteophyte formation at the tibial spines and the proximal portion of the posterosuperior surface of the patella. Bone density is at least minimally diminished consistent with postmenopausal osteoporosis. Atherosclerotic plaquing of the femoral artery is also noted.

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July of 1997


Multiple sagittal, coronal, and axial scans of the left knee were obtained with T1 and T2 weighted, proton density, and STIR images acquired. Coronal proton density and sagittal T1 weighted meniscal windows were also obtained.

  • Irregularity and disruption of the subchondral bone of the medial femoral condyle is noted with a small separate fragment lying in situ within the larger defect in the medial femoral condyle. There is fluid noted surrounding this fragment. Adjacent to the defect is bone marrow signal alteration consistent with bone marrow edema.
  • There is also globular intrasubstance increased signal in the posterior horn of the medial meniscus consistent with mucoid degeneration with question of linear signal extending to the articular surface on the sagittal meniscal window images consistent with a meniscal tear.
  • A suprapatellar moderate joint effusion is also noted.
  • Anterior and posterior cruciate ligaments and both collateral ligaments are intact.

"A radiologic viewpoint"

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Also July of 1997

AP upright bilateral knee views obtained on 7-1-97 reveal moderate joint space narrowing at the medial compartments bilaterally with mild osteophyte formation consistent with at least moderate degenerative joint disease. There is a lucent defect in the weight bearing portion of the medial femoral condyle with quite prominent surrounding sclerosis. There is also a question of subtle sclerosis adjacent to the defect in the medial tibial plateau. These findings confirm the MRI study information and combined with the patient's unique history and clinical findings, leads to our discussion on differential diagnosis. At this point you have to opportunity to put the information together and make a diagnosis. Have fun!!


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Introduction to Unknown Cases

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