Subluxation refers to partial dislocation. This is comparatively better than having a complete shoulder dislocation and may be treated by a closed reduction. May need surgical intervention if recurrent.
Subluxation of the shoulder is the dislocation of the upper arm from the shoulder that may require surgery if the tissue and structures of the shoulder are torn.
It is incomplete or partial dislocation of a joint or organ. It needs medical attention to relocate or reduce the joint. It depends on the damage of a joint or organ if you will need a surgery.
Simply put, subluxation is a displacement within the surfaces of a joint. Differing from a "dislocation" the joints MAY simply be in need of a realignment. A consult with a physical therapist/chiropractor would serve you well. Surgery may not be your only option.