Rapid Decrease in Dextrose Concentration After Intra-Articular Knee Injection: Implications for Mechanism of Action...

Area of Science:

• Biomedical Engineering
• Orthopedics
• Pharmacology

Background:

• Dextrose prolotherapy (DPT) uses high-concentration dextrose injections for pain therapy, with growing clinical trial support.
• The precise mechanism of action for DPT remains unclear, hindering further research.
• A prevailing theory suggests hyperosmotic dextrose induces inflammation, initiating a healing cascade, but in vitro models lack data on in-vivo dextrose clearance rates.

Purpose of the Study:

• To determine the rate of dextrose concentration decrease in human knees following intra-articular injection.
• To understand the duration of tissue exposure to high dextrose concentrations after DPT.

Main Methods:

• An N-of-1 study involved a 70-year-old male self-injecting his knees with 12,500 mg% dextrose on three occasions.
• Serial synovial fluid aspirations were performed from 7 to 360 minutes post-injection to measure dextrose concentration.
• Dextrose clearance kinetics were analyzed using Minitab and GraphPad Prism software.

Main Results:

• Dextrose concentration decreased rapidly in all trials, following a steep, near-exponential curve.
• A third-order chemical reaction pattern was observed, indicating factors beyond simple dilution or transporter activity.
• Rapid diffusion across the synovial membrane is suggested as a contributor to the swift dextrose clearance.

Conclusions:

• Intra-articular injection of 30 mL of 12,500 mg% dextrose results in rapid concentration diminution in the knee.
• Intra-articular cells and tissues are exposed to high dextrose concentrations for a limited duration.
• These findings have implications for understanding the mechanism of action of DPT and refining in vitro study designs.