Exploring the Mathematical Representation and Study of Squeeze Film Lubrication within the Hip Joint: An In-Depth Investigation Utilizing a Comprehensive Sphere-Plate Model

The hip joint is especially crucial for movement, as synovial joints serve as pivotal bearings in the body. Synovial fluid, which is essential for lubricating and reducing wear and tear during mobility, is present in these joints. Friction between cartilages is reduced when lubrication is effective. Hip joint lubrication is represented by a geometric model that analyses load capacity, film thickness, and pressure distribution while simulating a sphere approaching a flat plate. Furthermore, finite element stress analysis investigates the behavior of the bone-implant system under the assumption of micro-motion between the femur and stem. This work focuses on Newtonian fluid flow and examines the properties of squeeze-film lubrication, such as pressure distribution, squeeze time, and load-bearing capacity during compression, using a modified Reynolds equation. Squeeze duration is affected by articular cartilage thickness, but squeeze film pressure rises with increased articular cartilage velocity and synovial fluid compression. Changes in the composition or viscosity of synovial fluid might indicate illness, making these features important for the diagnosis of synovial joint illnesses such osteoarthritis and rheumatoid arthritis. Increased pressure levels could be a sign of joint problems, which would limit the range of motion in the hip joint. While diseases may reduce hip joint load-bearing ability, regular exercise can increase it.