What are the issues with allograft?
Since allografts are purchased, and not harvested from the patient (causing further damage), it seems an easy decision to use them to reconstruct torn cruciate ligaments. But there are issues...
Firstly they have a cost. Secondly the tissue bank from which they are purchased needs to be extremely vigilant about making the tissue safe to transplant while not destroying its important properties.
"....The advantages of allografts are no donor site morbidity, a shorter operation and less painful initial recovery. The disadvantages are slower graft incorporation and concern about higher rupture rates in some young highly active groups, concern about disease transmission and increased cost....The concern about a higher re-rupture rate may not be warranted...."