Crossing sign (knee)

The crossing sign is seen on true lateral plain radiographs of the knee when the line of the trochlear groove crosses the anterior border of one of the condyle trochlea. It is a predictor of trochlear dysplasia. Trochlear dysplasia has been linked to recurrent patellar dislocation 1,2,4. The crossing sign is sensitive but not specific in diagnosing trochlear dysplasia, and has a sensitivity of 94% and a specificity of 56% 3,4.

Knee pathology

The knee is a complex synovial joint that can be affected by a range of pathologies:

Article information

rID: 22116
Section: Signs
Tag: cases, cases
Synonyms or Alternate Spellings:
  • The crossing sign
  • The crossing sign of trochlear dysplasia
  • Crossing sign of trochlear dysplasia
  • Crossing sign - patella
  • Crossing sign - knee

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