Ever since I had bilateral cartilage removal my knees were going downhill. That was 10 years ago. I went to an excellent knee surgeon and he said yes, soon, I will need TKR. I went to Mayo for a second opinion. They told me yes your knees are shot but you are a good candidate for a PKR since only the medial side was shot on both knees. My ligaments were good and the arthritis was mostly confined to the medial side. I went ahead with the PKR spaced 2 years apart. Result? Better than I expected. My left knee is 95% of what it used to be and my right knee which was only done 6 months ago is 90% and still improving. Day 3 to 5 after surgery was "hell" but then it slowly got better. Today I can barely tell that knee #1 was even operated upon because it feels like the original, and knee #2 is rapidly improving as well, it has only been about 6 months. Bottom line: it comes down to whether you are a candidate or not for the PKR. I "was" a candidate but I would not have known that if I did not seek out the 2nd opinion from Mayo. Partial knee replacement is a difficult surgery (as is a TKR) but under certain circumstances it can be a viable alternative to TKR, IMO.