TKR is an abbreviation of 'total knee replacement'.

In a total knee replacement the joint surfaces of tibia, femur, and often the patella too, are replaced with metal and plastic.
Synonyms:
total knee replacement
TKA
total knee arthroplasty
-
-
FORUM DISCUSSIONS
Normality after TKR - How long?
CLINICAL PUBLICATIONS
Estimating the Burden of Total Knee Replacement in the United States. Weinstein AM et al. J Bone Joint Surg Am. 2013 Mar 6; 95(5): 385–392.