The aim of this paper is to describe the possibilities of the therapeutic use of hyaluronic acid (HA) in the treatment of osteoarthritis of knee cartilage. This work provides an overview of the literature relating to the structure of hyaluronic acid, its properties and important functions of the human body. Moreover, the construction of the articular cartilage in the knee joint, including events leading to its degeneration, is presented. Viscosupplementation is a treatment for osteoarthritis involving several intra-articular injections of HA at specific time intervals. This treatment results in an increased lubricity, viscosity and elasticity of articular cartilage. Since HA is found naturally in the human body, viscosupplementation improves the biomechanical conditions of the joint whilst minimizing the side-effects of treatment. Hyaluronic acid occurs naturally in a linear form, but for many applications, chemical modifications are necessary. Thanks to this property, it remains in the body long enough to produce the desired therapeutic effect. Modification processes, in particular the cross-linking of HA, increase the mechanical properties of knee cartilage. HA is an example of a new kind of tissue engineering scaffold that is bioactive in both full-length and degraded forms. In turn, hydrogel scaffolds with interpenetrating polymeric network (IPN) gels can simulate the structure of the native extracellular matrix of cartilage tissue.