Thanx for the revert, Michele... much appreciated.
Even I had been rounding on the two codes you suggested as the exact code was not found. And of those two, R29.898 seems more close as the other is too general.
There isn't other diagnoses... Patient came for consultation status post knee surgery, and doctor has written "Postop knee weakness" as diagnosis on the claims form
Am also wondering if we can we use the code for knee pain M25.56 for this diagnosis (well, not sure if terms 'weakness' and 'pain' can be used interchangeably)