Joint Lubrication with Artificial Lubricants

The joint lubricating properties, in vitro, in bovine metatarsal‐phalangeal joints, of silicone fluid, methyl cellulose and polyvinyl‐pyrrolidone were compared to buffer, serum and synovial fluid. As had been previously reported, synovial fluid was almost twice as good as serum and buffer, which are equivalent in their joint lubricating qualities. Of the three artificial lubricants tested, only polyvinyl‐pyrrolidone is superior to buffer or serum as a joint lubricant at 37 °C. At 55 °C both polyvinyl‐pyrrolidone and methyl cellulose had the same effect. At no time was any of the artificial lubricants tested as effective at reducing joint friction as was synovial fluid. Silicone fluid was consistently an inferior joint lubricant compared with buffer or serum. It was concluded that effective joint lubrication with artificial lubricants depends on their boundary and hydrophilic properties, rather than directly on their flow characteristics.