nothing can be done to strengthen ligaments. over time they do become stronger because of use and as adaptation to progressively heavier weights but there is nothing that can repair or build tendons directly due to poor blood circulation not allowing for recovery at the same pace as muscle tissue. this is what leads to muscle/tendon imbalances and then compounding the injury by continued training in a threshold too high for the tendons making the injuries worse.
if the injuries come after cycles, deca isnt really an option. you might want to look into alternative training methods for pct times and a few after.