Case: 24 year old male with no significant past medical history presents to local urgent care with chief complaint of left knee pain. The patient reports playing basketball just prior to arrival and reports landing on left knee and "jamming it." 

Vital Sigs:
Temperature: 97.9 F
Heart Rate: 68
Repiratory Rate: 14
SpO2: 98% RA
Blood Pressure: 136/78 mm Hg

Pertinent Physical Exam: Patient has decreased range of motion of the left knee. There is generalized swelling and small-moderate knee effusion. Patient has. tenderness-to-palpation of lateral joint line. The patient has no joint laxity. The patient cannot bear weight on knee. The patient has decreased sensation to the lateral lower leg extending to the first and second digits of the left foot. The patient has decreased stregth with dorsiflexion of the left foot.

Plain film imaging of this patient's left knee was obtained:

What is the Diagnosis?
ANSWER