Name This Injury

got this email from a friend:

“I was playing soccer last night and heard a loud pop in my leg. I
think something is torn above the achilies and below the end of the
calf, on the right leg. A guy who was 10 yards away from me ran up to
me and said he heard a bad pop.
I’m ok now. Just lying in bed, and taking Ibuprofin. I called my
doctor, and of all days, this is the day they are moving to new
offices. What do you think it is?”

anybody have any ideas what this could be?

Classically, an ACL tear.

Other things on the differential include PCL, LCL, or MCL tear; fracture; patellar subluxation.