Yes, we don't know whether the injury to

Yes, we don't know whether the injury to Paul's knee (the right one) was just a one-off accident during jogging (rough track surface? kerbing?) or due to a congenital knee weakness in his family tree affecting both knees. Another unknown that has an important bearing is the size of his stomach - attorneys are famously accustomed to dining well and in order to counterbalance what would otherwise be a dangerous asymmetric stress loading they need a corresponding enlargement of the buttocks in order to retain upright stability. Fortunately lawyering is a largely sedentary occupation so large buttocks tend to be the rule. But any imbalance between stomach and buttocks weight could well result in undue stress on the knees with catastrophic results.

The best advice that can be given to Paul is when he "takes a knee" he should lower himself very slowly and gently onto the good (i.e. undamaged) knee and wear a knee pad to cushion the pressure. I have never seen anyone taking a knee go down onto a cushion placed there for the purpose so apparently it is considered bad form to do that (it would be overdoing it and might add an unwanted comical appearance to the performance). It would also be advisable for him to have one of his staff on hand to help him rise again from the stooped position.