I had my testicular torsion (left 1)opperation 1.5 years ago it was saved well in time but now i feel its shrinking can this happen after this long ?

Unlikely: If you are having pain or feel a lump, get another testicular ultra sound. If not you are probably fine.

See your doctor: Let your doctor check you , after exam , will blood flow studies to the testis , some time unaffected side need to be fixed , as the other side also get twisted, ( bilaterally is common ).

Yes,...: Intraoperative decision to save or fix testis is not always accurate, largely based on surgeon's experience and judgment. A partially damaged testis but saved may take time to resolve and heal resulting in atrophic testis in a later day as described. So, the described scenario does happen.