Proteoglycan 4 (PRG4) is a glycoprotein in synovial fluid (SF) and on the articular cartilage surface, where it acts as a boundary lubricant. Hyaluronan (HA) is another SF constituent that acts as a boundary lubricant at the cartilage-cartilage biointerface and interacts with PRG4 to synergistically lower friction. The meniscus is a fibrocartilaginous pad in the knee, on which PRG4 exists, that is critical for joint health. This thesis aimed to develop an in vitro lubrication test to determine the boundary lubricating ability of PRG4 and HA, alone and in combination, at the cartilage-meniscus biointerface, and assess the surface adsorption of recombinant human PRG4 (rhPRG4). A novel cartilage-meniscus test demonstrated that (rh)PRG4 and HA, alone and in combination, act as effective boundary lubricants at this biointerface. rhPRG4 adsorbed to the meniscal surface. This work contributes to the understanding of meniscus lubrication and potential development of osteoarthritis biotherapeutic treatments.