An audible pop at the time of injury.
Hemarthrosis with fat globules.
Delayed onset of pain.
A history of “locking” on flexion or extension
Positive anterior drawer sign.
A joint effusion may develop with a meniscal injury. Hemarthrosis with fat globules indicates a fracture involving marrow. Solitary hemarthrosis may result form skeletal, ligamentous, or cartilaginous injuries. If the cartilage interposes in the intercondylar notch, the joint will lock.