The effects of low-intensity ultrasound on medial collateral ligament healing in the rabbit model.
BACKGROUND
Ruptured medial collateral ligaments are capable of healing over time, but biomechanical and biochemical properties remain inferior to normal tissue. Low-intensity ultrasound may improve healing.


OBJECTIVE
Medial collateral ligaments treated with ultrasound will demonstrate superior healing.


METHODS
Controlled laboratory study.


METHODS
Twenty-one late-adolescent male rabbits underwent bilateral ligament transection. One ligament from each rabbit received ultrasound treatment every other day for 6 total treatments. Contralateral ligaments received sham treatments. After 3 or 6 weeks, ligaments were evaluated biomechanically and assayed for collagen concentration and the relative proportions of types I and III collagen.


RESULTS
Areas of sonicated specimens were significantly larger (10.6% +/- 4.90%) at 6 weeks. Ultimate load (39.5% +/- 17.0%), ultimate displacement (24.5% +/- 8.0%), and energy absorption (69.1% +/- 22.0%) were significantly higher for sonicated specimens at 6 weeks. No significant biomechanical differences were observed at 3 weeks. The relative proportion of type I collagen was significantly higher in sonicated ligaments at 3 weeks (8.61% +/- 4.0%) and 6 weeks (6.91% +/- 3.0%). No significant differences in collagen concentration were observed at either 3 or 6 weeks.


CONCLUSIONS
Subtle improvement with ultrasound treatment may be apparent by 3 weeks after injury, suggested by increased proportion of type I collagen. Ultrasound appears to improve some structural properties and to modestly increase scar cross-sectional area and type I collagen present at 6 weeks after injury in this model.


CONCLUSIONS
Ultrasound treatments after ligament injury may facilitate earlier return to activities and decrease risk of reinjury.
Sparrow
Karen J
KJ
Virginia Commonwealth University, Department of Physical Therapy, School of Allied Health, 1200 East Broad Street, PO Box 980224, Richmond, VA 23298-0224, USA.
Finucane
Sheryl D
SD
Owen
John R
JR
Wayne
Jennifer S
JS
D000818:Animals; D001696:Biomechanical Phenomena; D017888:Medial Collateral Ligament, Knee / Q000000981:diagnostic imaging*; D011817:Rabbits; D014464:Ultrasonic Therapy; D014463:Ultrasonography; D014945:Wound Healing