[Diffusion of imipenem in synovial fluid]

Area of Science:

• Pharmacokinetics
• Orthopedic Surgery
• Infectious Disease

Background:

• Knee joint infections pose a significant risk in orthopedic surgery.
• Effective antibiotic prophylaxis is crucial for preventing surgical site infections.
• Understanding drug diffusion into the synovial fluid is key for optimizing treatment.

Purpose of the Study:

• To investigate the diffusion and concentration of imipenem (IMP) in human knee joint synovial fluid.
• To evaluate the pharmacokinetic profile of IMP in the knee joint after intravenous administration.
• To assess the potential of IMP for perioperative prophylaxis in knee surgery.

Main Methods:

• A single intravenous dose of 1g imipenem (Tienam) was administered over one hour to patients undergoing knee arthroscopy.
• Synovial fluid and blood samples were collected at 1, 2, and 3 hours post-injection.
• Imipenem concentrations were quantified using high-performance liquid chromatography (HPLC).

Main Results:

• Mean imipenem concentrations in synovial fluid were 20.4 mg/l at 1 hr, 13.0 mg/l at 2 hrs, and 7.9 mg/l at 3 hrs post-injection.
• Serum imipenem concentrations were higher, with values of 42.5 mg/l at T0, 20.1 mg/l at 1 hr, 9.3 mg/l at 2 hrs, and 5.7 mg/l at 3 hrs.
• The decline in imipenem concentration in synovial fluid was 1.5 times slower than in serum.

Conclusions:

• Imipenem demonstrates favorable diffusion into the knee joint's synovial fluid.
• The sustained concentrations suggest potential efficacy for infection prevention.
• Imipenem is a viable option for perioperative prophylaxis in knee joint surgery due to its broad-spectrum activity and pharmacokinetic profile.