Low-Intensity Pulsed Ultrasound Accelerates and a Nonsteroidal Anti-inflammatory Drug Delays Knee Ligament Healing

• Published in: The American journal of sports medicine 2006-07, Vol.34 (7), p.1094-1102
• Main Authors: Warden, Stuart J., Avin, Keith G., Beck, Erin M., DeWolf, Marie E., Hagemeier, Molly A., Martin, Kristin M.
• Format: Article
• Language: English
• Subjects: Animals; Anti-Inflammatory Agents, Non-Steroidal - pharmacology; Biological and medical sciences; Biomechanical Phenomena; Biomechanics. Biorheology; Bones, joints and connective tissue. Antiinflammatory agents; Care and treatment; Celecoxib; Diseases of the osteoarticular system; Female; Fundamental and applied biological sciences. Psychology; Health aspects; Health risk assessment; Injuries; Knee; Knee injuries; Ligaments; Medial Collateral Ligament, Knee - diagnostic imaging; Medial Collateral Ligament, Knee - injuries; Medical sciences; Nonsteroidal anti-inflammatory drugs; Pharmacology. Drug treatments; Pyrazoles - pharmacology; Rats; Rats, Sprague-Dawley; Sports injuries; Sports medicine; Sulfonamides - pharmacology; Tissues, organs and organisms biophysics; Ultrasonic imaging; Ultrasonic therapy; Ultrasonic Therapy - methods; Ultrasonic waves; Ultrasonography; Wound Healing - drug effects
• ISSN: 0363-5465; 1552-3365
• DOI: 10.1177/0363546505286139

Background: Low-intensity pulsed ultrasound and nonsteroidal anti-inflammatory drugs are used to treat ligament injuries; however, their individual and combined effects are not established. Hypotheses: Low-intensity pulsed ultrasound accelerates ligament healing, a nonsteroidal anti-inflammatory drug delays healing, and the nonsteroidal anti-inflammatory drug inhibits the beneficial effect of low-intensity pulsed ultrasound. Study Design: Controlled laboratory study. Methods: Sixty adult rats underwent bilateral transection of their knee medial collateral ligaments. Animals were divided into 2 drug groups and treated 5 d/wk with celecoxib (5 mg/kg) mixed in a vehicle solution (NSAID group) or vehicle alone (VEH group). One to 3 hours after drug administration, all animals were treated with unilateral active low-intensity pulsed ultrasound and contralateral inactive low-intensity pulsed ultrasound. Equal numbers of animals from each drug group were mechanically tested at 2 weeks (n = 14/group), 4 weeks (n = 8/group), and 12 weeks (n = 8/group) after injury. Results: Ultrasound and drug intervention did not interact to influence ligament mechanical properties at any time point. After 2 weeks of intervention, ligaments treated with active low-intensity pulsed ultrasound were 34.2% stronger, 27.0% stiffer, and could absorb 54.4% more energy before failure than could ligaments treated with inactive low-intensity pulsed ultrasound, whereas ligaments from the NSAID group could absorb 33.3% less energy than could ligaments from the VEH group. There were no ultrasound or drug effects after 4 and 12 weeks of intervention. Conclusions: Low-intensity pulsed ultrasound accelerated but did not improve ligament healing, whereas the nonsteroidal anti-inflammatory drug delayed but did not impair healing. When used in combination, the beneficial low-intensity pulsed ultrasound effect was cancelled by the detrimental nonsteroidal anti-inflammatory drug effect. Clinical Relevance: Low-intensity pulsed ultrasound after ligament injury may facilitate earlier return to activity, whereas non-steroidal anti-inflammatory drugs may elevate early reinjury risk. Keywords: biomechanics ligament healing medial collateral ligament (MCL) therapeutic ultrasound