Experimental Osteoarthritis in the Rabbit

Abstract

The earliest sign of osteoarthritis is acute synovitis with joint effusion and elevated intraarticular pressure, which causes compression of the intracapsular vein segments draining the epiphyseal bone compartment. The increased outflow resistance may cause a fall in the regional blood flow and thereby lead to a state of tissue hypoxia. The acute osteoarthritis may also affect the transfer of oxygen to the cartilage across synovial membrane because of the extensive inflammation with hypercellularity and edema.

In the present study we have investigated the subchondral P₀₂ and P_c02 in acute osteoarthritis. There was no significant difference between these gas tensions in the normal and osteoarthritic bone. We have also investigated the oxygen consumption and diffusion capacity in the synovial membrane. The latter was decreased by a factor of 4 in the osteoarthritic joints whilst the oxygen consumption was increased by a factor of 3.

Sammendrag

I de tidlige stadier af osteoartritis er der som følge af ledeffusion og øget intraartikulært tryk en øget udløbsmodstand fra det subchondrale knoglekompartment. Dette kan medføre et fald i det regionale blood flow og dermed føre til subchondral hypoxi. Desuden er Synovialmembranen inflammeret i de tidlige stadier med hypercellularitet og ødem, hvilket vil kunne nedsætte iltoverførslen fra kapillærerne til synovi.

I nærværende arbejde har vi ikke kunnet påvise ændringer i de subchondrale gastensioner i det akutte stadium men synovialmembranens metabolisme var øget med en faktor 3 og diffusionskapaciteten nedsat med en faktor 4.