Central (interior) osteophytes of the distal femur. Imaging and pathologic findings.
OBJECTIVE
To characterize central osteophytes (COs) of the distal femur, imaging features that enable their differentiation from intra-articular bodies were identified, and the frequency of overlying articular cartilage abnormalities was determined.


METHODS
The authors inspected 133 distal femoral specimens and retrospectively reviewed knee radiographs of 48 symptomatic patients and magnetic resonance images of 60 symptomatic patients for presence of COs. The location and imaging features of COs, and their association with marginal osteophytes (MOs), were recorded. Articular cartilage abnormalities, if any, were documented in patients who underwent magnetic resonance imaging.


RESULTS
Specimen analysis showed a 41% prevalence of COs, 95% association of COs with MOs, and predominance of large COs in the medial femoral condyle (81%). Radiographic analysis revealed a 9.8% prevalence of COs in the distal femur. Magnetic resonance images demonstrated a 14.3% prevalence of COs, with the majority (73%) accompanied by an overlying cartilage that had abnormal signal intensity or morphology, or both.


CONCLUSIONS
Central osteophytes are a common finding in the distal femur. Based on their location and cortical continuity with the underlying bone, most COs can be differentiated from intra-articular bodies.
Abrahim-Zadeh
R
R
Department of Radiology, New York Medical College, Valhalla.
Yu
J S
JS
Resnick
D
D
D000328:Adult; D000368:Aged; D002357:Cartilage Diseases / Q000000981:diagnostic imaging / Q000473:pathology; D002358:Cartilage, Articular / Q000000981:diagnostic imaging / Q000473:pathology; D005096:Exostoses / Q000000981:diagnostic imaging / Q000473:pathology; D005260:Female; D005269:Femur / Q000000981:diagnostic imaging* / Q000473:pathology*; D006801:Humans; D007592:Joint Diseases / Q000000981:diagnostic imaging / Q000473:pathology; D007719:Knee Joint / Q000000981:diagnostic imaging / Q000473:pathology; D008279:Magnetic Resonance Imaging; D008297:Male; D008875:Middle Aged; D010003:Osteoarthritis / Q000000981:diagnostic imaging* / Q000473:pathology*; D011859:Radiography; D012189:Retrospective Studies