Literature on the subject is varied, but just a rough summary... Success depends on a LOT of factors, including whether your issue is just the transplant or whether you have concomitant procedures, what type of allograft you have, what your alignment is, what your activity level is, even what you define as "success".
That being said...Medial transplants have a higher failure rate than lateral. Average survival rate varies, but 10 years is getting up there.
For example, one ten year follow up study (n=22) showed 25% of medial allografts and 50% of lateral allografts failed. The combined failure rate was 35%. 85% of those patients underwent subsequent procedures, 5 had total resection; 2 required partial allograft resection; 1 had a repair. (Hommen JP, Applegate GR, Del Pizzo W.)
In another study (n=100), average failure rate (combined) was around 20%; average lifespan was about 10 years. (forgot to grab a citiation)
Another (van Arkel ER, de Boer HH.; n=57) had cumulative survival rates of the lateral and medial allografts as 76% and 50%, respectively.
There's a lot of literature out there, but basically...it depends on what yoru criteria for success are. If all you want is pain reduction for a decade or two, your odds are not bad. If you want it to hold up through competitive, high impact athletics, and not to develop any further cartilage issues...welll, that's a tougher call, and there's a lot less research on it.