“…The injection of very high-molecular-weight HA, and especially of partially cross-linked HA, may allow recovery of desirable viscoelastic behavior (especially elastic contribution) [7,36,37]. Other biologic roles for exogenous HA in OA include an analgesic effect by interaction with pain receptors [23], promotion of endogenous HA production [4,38], and various antiinflammatory effects [10,15,24,34,42,43,56]. Nevertheless, the biologic effects of VS last much longer than its presence in SF, leading to the concept of ''viscoinduction'' effects extending beyond the effects of viscosupplementation.…”