watch the dermabond. I personally think its useless I had a finger dermabonded. Kept coming open doctor said would leave less of a scar. whos cares about scars I wanted it to stay closed so I could work. I work with the public doesnt look good when you start bleeding in front of them. On a knee moving I would worry it could come open easier than the tip of a finger. Glad he is ok. Sounds like something my hubby would do.