Mild pain
Swelling over lower pole of patella that may result in restricted ROM
May be so severe that must differentiate from a joint effusion
May be so severe that must differentiate from a joint effusion
Prepatellar bursitis 
Knee dislocation
Hip bursitis
Knee fractures
Pes anserine bursitis
Patella fracture
Calcaneal bursitis
Segond fracture