What are injection options for knees that won't further deteriorate the joint? Trying to prolong total knee replacement but am in immense pain

Viscosupplementation. If it is from an early degenerative phenomena, then viscosupplementation can be used in which the injected material is somewhat similar to normal synovial fluid is another option beyond steroid injections.
Injection . There ar several injections available. See your orthopedist. He can give you the best advice .