In reply to Iamgregp:
As you might expect your issue is different to mine which involves bending the knee under stress more than a given number of degrees. The main categories of treatment were:
Four degree shoe insert to correct pronation (my running shoes are already corrected).
Wall squats
Step up and step over exercises
Ice at least a couple of times a day.
And also balance and core strength exercises (mostly for a dodgy ankle which she noticed).
My untutored impression is that the wall squats and the ice were the main contributors; it seemed to be a question of reducing inflammation and fluid in the joint, plus strengthening the support muscles around it to prevent a recurrence.
I'm currently moving house, and so am up and downstairs with 25k boxes a fair bit, so far no issues
HTH