The aim of this article is to present an the theoretical analysis of the problem is presented through a mathematical model depended on the idea of a Hyaluronic acid (HA) in cartilage and synovial fluid surrounding the joints (hip, knee and ankle) where are a major component of synovial fluid modified Reynolds equation governing the fluid film pressure was derived and solved analytically, and closed form expressions for the squeeze film pressure and load carry capacity were presented. The influence of film thickness and sliding motion on the squeeze film Characteristics were discussed .It has been found that the effect of decreased film thickness tend to increased the load carry capacity , friction force and decreased flow rate, The effect of decreased sliding motion tend to increasing frication force and decreased flow rate and when additives Hyaluronic acid (HA) to bearing material (articular cartilage ) .The results indicate to increasing pressure distribution (P) and improve both load carry capacity (W), friction force (F) Compared to the disease synovial hip joint. Keywords: Hyaluronic acid , Hip joint, load carry capacity, friction force.
