No abstract

The influence of chronic synovial inflammation and effusion on the juxta-articular bone haemodynamics in the juvenile knee was studied in 12 immature dogs with Carragheenin-induced unilateral arthritis. Using a fluid filled electromanometric pressure recording system simultaneous pressure measurements were taken from the distal femoral metaphysis, juxta-articular epiphyses and knee joint cavity in general anaesthesia followed by intraosseous phlebographies. During resting conditions the intraosseous pressure of the distal femoral epiphysis and the intra-articular pressure was significantly elevated. The phlebographies showed increased accumulation of contrast in arthritic femoral epiphyses with decreased contrast clearance rate. During increasing intra-articular pressure an augmented vulnerability of the blood supply of the arthritic femoral epiphyses was demonstrated. The results suggests that joint effusion may play an important role in the bone changes in juvenile degenerative arthritis of the knee.

The relationships between intraosseous pressure and regional blood flow in the juxta-articular epiphyses were determined in the knees of immature dogs. Intraosseous pressures were continuously registered in one knee. Regional blood flow rates were simultaneously determined by the microsphere technique before and after venous tamponade of both knee joint capsules. During complete venous tamponade the intraosseous pressure of the distal femoral epiphyses rose 268%, while flow increased 122%. A concurrent 20-fold flow increase of the knee capsule and 3-4-fold flow increase of the proximal femoral bone was observed. Evacuation of the knee joints resulted in an immediate drop of the intraosseous pressure of the distal femoral epiphyses, whereas hyperaemia prevailed for at least half an hour and was most pronounced in the distal femoral epiphyses and knee joint capsule. Intraosseous pressure registration did not significantly influence regional blood flow. It is suggested that the changes of intraosseous pressures during knee joint tamponade reflect changes in the venous outlet resistance. The results demonstrate the significance of intra-articular pressure increase on the hemodynamics of the juxta-articular tissues of the knee and proximal femoral bone. These findings may be of importance in the pathogenesis of growth disturbances observed in juvenile degenerative arthritis.