Intraosseous pressure during loading and with vascular occlusion in an animal model

Abstract

ObjectivesWe studied subchondral intraosseous pressure (IOP) in an animal model during loading, and with vascular occlusion. We explored bone compartmentalization by saline injection.Materials and MethodsNeedles were placed in the femoral condyle and proximal tibia of five anaesthetized rabbits and connected to pressure recorders. The limb was loaded with and without proximal vascular occlusion. An additional subject had simultaneous triple recordings at the femoral head, femoral condyle and proximal tibia. In a further subject, saline injections at three sites were carried out in turn.ResultsLoading alone caused a rise in subchondral IOP from 11.7 mmHg (sd 7.1) to 17.9 mmHg (sd 8.1; p < 0.0002). During arterial occlusion, IOP fell to 5.3 mmHg (sd 4.1), then with loading there was a small rise to 7.6 mmHg (sd 4.5; p < 0.002). During venous occlusion, IOP rose to 20.2 mmHg (sd 5.8), and with loading there was a further rise to 26.3 mmHg (sd 6.3; p < 0.003). The effects were present at three different sites along the limb simultaneously. Saline injections showed pressure transmitted throughout the length of the femur but not across the knee joint.ConclusionThis is the first study to report changes in IOP in vivo during loading and with combinations of vascular occlusion and loading. Intraosseous pressure is not a constant. It is reduced during proximal arterial occlusion and increased with proximal venous occlusion. Whatever the perfusion state, in vivo load is transferred partly by hydraulic pressure. We propose that joints act as hydraulic pressure barriers. An understanding of subchondral physiology may be important in understanding osteoarthritis and other bone diseases.Cite this article: M. Beverly, S. Mellon, J. A. Kennedy, D. W. Murray. Intraosseous pressure during loading and with vascular occlusion in an animal model. Bone Joint Res 2018;7:511–516. DOI: 10.1302/2046-3758.78.BJR-2017-0343.R2.

An interpretation of intraosseous perfusion physiology and the effect of steroids

“…We were interested in the effect of steroids on IOP in a model which had previously been developed to explore perfusion physiology and the effects of loading on IOP [16]. The present study confirmed that steroid treatment raised IOP, as most previous authors have found [17].…”

Combined computational analysis and cytology show limited depth osteogenic effect on bone defects in negative pressure wound therapy

“…Bone structure, as well as the nourishing vessels, the lymphatic vessels, soft tissue are damaged when open fractures occur. Bone nourishing vessels and lymphangion connect to the circulatory system and thus fluid enters the bone marrow compartment ( Beverly et al, 2018 ; Beverly and Murray, 2018 ; Chang et al, 2021 ; St-Pierre et al, 2022 ); furthermore, intraosseous pressure (pressure inside the bone marrow compartment) can up to tens of mmHg, allowing NPWT work. The results for shear stress (up to 100Pa) and velocity (up to 4 m/s) imply a flow rate of tens of liters per hour, which seems to reflect the unrealistic boundary conditions in this study, but there are two clinical scenarios need to be highlighted: ①In the case of large amounts of fluid (tens of milliliters) present in some severe fracture wounds, the calculated flow rate is reasonable but may only be valid for a short time because the amount of fluid is always limited and the broken capillaries, lymphatic vessels and damaged soft tissue (from which the fluid is coming) will gradually heal and close; ②When the substantial liquid was drained, or the liquid only exude at a low level, the vacuum pump can still generate negative pressure but there is not enough liquid to form a clear flow, resulting in a draw volume of a few milliliters per hour.…”

Changes in bone density, intraosseous pressure of distal femoral articular cartilage and subchondral bone after proximal femoral medullary cavity cement filling in rabbits

“…IOP is the pressure produced by the blood flow of the phalanx in the intramedullary cavity or the interosseous space and is the most reliable index to gauge intraosseous hemodynamics and the state of intraosseous circulation (20). Porsch et al (21) used modern bone cement implantation technology to set up pressure measuring devices in different positions of femur.…”