The effect of joint position on juxta-articular bone marrow pressure. Relation to intra-articular pressure and joint effusion–an experimental study on horses.

This study investigates the effect of joint position on the pressure within adjacent bone marrow (juxta-articular bone marrow pressure) in horses, finding that increased joint flexion and saline injection into the joint both significantly raise intraosseous and intra-articular pressure.

Methodology

• The research was conducted on six metacarpo-phalangeal joints of adult horses.
• Measurements were taken in both the joint and the metacarpal bone while also monitoring systemic arterial blood pressure.

Findings

• This study found that joint position significantly impacts juxta-articular bone marrow pressure. Specifically, the act of increasing joint flexion was invariably followed by a rise in intraosseous pressure.
• The increase in pressure was significant when the joint was flexed beyond 60 degrees.
• An elevated intra-articular pressure achieved by injecting saline into the joint was also always followed by a slower rise in intraosseous pressure. This shows a clear correlation in the rise of the pressures in these two areas.
• Additionally, even a small amount of saline in the joint (as little as a few milliliters) trigged an increase in intra-articular pressure testament to the sensitive nature of this area.

Implications

• The results highlight that changes in joint position, as well as effusion (the presence of excess fluid) may obstruct the vessels that drain from the bone marrow as they pass through the joint.
• This can prevent normal functioning of the joint and cause discomfort or problems in movement.

Conclusion

• Overall, this research contributes significant new knowledge about how joint position influences pressure in adjacent bone marrow and within the joint itself.
• Further studies could apply these findings to designing strategies for managing or preventing joint related disorders in both animals and humans.