A 20-year-old college football player sustained a knee injury following a tackle. In the ED, his knee is very swollen, and a proper examination is not possible due to pain. Plain X-rays of the knee are negative. He is discharged home with a knee brace and crutches. During follow-up 2 weeks later, the pain and swelling are significantly improved. Which of the following findings would be most consistent with a tear to the posterior cruciate ligament?
(A) The lower leg sags on passive flexion of the knee at 90 ° while the patient is supine
(B) The lower leg moves forward relative to the knee with forward traction
(C) The foot moves laterally when the knee is pushed medially
(D) The foot moves medially when the knee is pushed laterally
(E) A clicking sensation is appreciated when the knee is flexed and the leg is rotated externally