Finding	Diagnosis
High-velocity collision	Fracture
Inability to immediately bear weight
“Pop” occurred with injury
Cut or pivot mechanism of injury	ACL tear
Knee “gave way”
Inability to continue participation
“Pop” felt or heard with injury
Blow to proximal tibia	PCL tear
Less instability than ACL tear
Squat/kneel associated with a twist	Meniscal tear
Clicking
Locking
Pain with rotational movement
Occupational or recreational repetitive movement	Overuse syndrome
Fever, chills	Infectious arthritis
Intravenous drug use
Lack of traumatic injury
Recent sexual encounter
History of abnormal joint
Night pain	Tumor
Fevers
Night sweats
Unintentional weight loss