Low-intensity pulsed ultrasound accelerates and a nonsteroidal anti-inflammatory drug delays knee ligament healing.
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.


OBJECTIVE
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.


METHODS
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.


CONCLUSIONS
Low-intensity pulsed ultrasound after ligament injury may facilitate earlier return to activity, whereas non-steroidal anti-inflammatory drugs may elevate early reinjury risk.
Department of Physical Therapy, Indiana University, Indianapolis, 46202, USA. stwarden@iupui.edu
Stuart J
SJ
Warden
Keith G
KG
Avin
Erin M
EM
Beck
Marie E
ME
DeWolf
Molly A
MA
Hagemeier
Kristin M
KM
Martin
D000818:Animals; D000894:Anti-Inflammatory Agents, Non-Steroidal / Q000494:pharmacology*; D001696:Biomechanical Phenomena; D000068579:Celecoxib; D005260:Female; D017888:Medial Collateral Ligament, Knee / Q000000981:diagnostic imaging / Q000293:injuries*; D011720:Pyrazoles / Q000494:pharmacology*; D051381:Rats; D017207:Rats, Sprague-Dawley; D013449:Sulfonamides / Q000494:pharmacology*; D014464:Ultrasonic Therapy / Q000379:methods*; D014463:Ultrasonography; D014945:Wound Healing / Q000187:drug effects*
D000894:Anti-Inflammatory Agents, Non-Steroidal; D011720:Pyrazoles; D013449:Sulfonamides; D000068579:Celecoxib