Changes in compression and distances between tibial and femoral condyles during immobilization of rabbit knee.

The compression forces and the distances between tibial and femoral condyles were measured during the development of osteoarthritis produced by immobilizing rabbit knees. The compression was measured in both the immobilized and non-immobilized knees with a sub-miniature pressure sensor. Compression increased up to threefold during the four first weeks of immobilization and decreased thereafter to below the initial level. These results give one explantation why immobilization produced degenerative joint changes; they also support the hypothesis that capsular tissues can play a role in the pathogenesis of osteoarthritis.