Low-intensity pulsed ultrasound accelerates bone healing via upregulation o
f cartilage formation and maturation phases of endchondral bone formation.
The current authors evaluated the effect of ultrasound therapy on the repai
r of full-thickness osteochondral defects. Bilateral, 3.2 mm. diameter by 5
.0 mm deep osteochondral defects were created in the patellar groove of 106
adult male New Zealand rabbits. The defects were treated with daily low-in
tensity pulsed ultrasound therapy on the right knee. The left knee was not
treated. In Part II, the effect of ultrasound therapy was evaluated at 4,8,
12, 24, and 52 weeks after surgery. In Part II, the effect of the length o
f treatment (5, 10, or 40 minutes of daily ultrasound therapy) compared wit
h standard 20 minute therapy was evaluated. The repair cartilage was evalua
ted and graded on a standard scale for the gross and histologic appearance.
Ultrasound treatment significantly improved the morphologic features and h
istologic characteristics of the repair cartilage compared with nontreated
controls. Earlier, better repair with less degenerative changes at later ti
mes was observed in defects treated with ultrasound. Doubling the treatment
time to 40 minutes daily significantly increased the histologic quality of
the repair cartilage. In the current animal model, daily low-intensity pul
sed ultrasound had a significant positive effect on the healing of osteocho
ndral defects.