Viscosupplementation is the intra-articular (IA) injection of hyaluronic acid (HA, aka hyaluronans, sodium hyaluronans, or hyaluronates) into synovial joints for the relief of osteoarthritic pain. HAs are only FDA approved for the treatment of pain associated with knee osteoarthritis (OA). In contrast, outside the US, HAs are generally approved for the treatment of pain of OA in all joints. Because evidence is accumulating to support the use of HAs in joints in addition to the knee, FDA approval for use in other joints, particularly the hips, may be forthcoming.