Background: Opening-wedge high tibial osteotomy by hemicallotasis
for osteoarthritis in the medial compartment of the knee requires external
fixation for a long time, until callus maturation is complete. The aim of this
study was to determine if low-intensity pulsed ultrasound would accelerate
callus maturation when applied after distraction to limbs treated with
opening-wedge high tibial osteotomy by hemicallotasis.
Methods: Twenty-one patients with symmetric grades of osteoarthritis
and similar degrees of varus deformity in the two knees underwent bilateral
one-stage opening-wedge high tibial osteotomy by hemicallotasis. After
completion of distraction, the bone mineral density of the distraction callus
was measured. Then, one randomly selected limb was subjected to ultrasound
treatment for twenty minutes daily until removal of the external fixator. The
contralateral limb was left untreated to serve as the control. After four
weeks of treatment, bone mineral density was measured again.
Results: During the four-week treatment period, the mean increase in
callus bone mineral density was significantly greater in the
ultrasound-treated tibiae (0.20 ± 0.12 g/cm2) than in the
control tibiae (0.13 ± 0.10 g/cm2) (p = 0.02, unpaired t
test). In eighteen patients the increase in the bone mineral density was
greater in the ultrasound-treated limb than in the control limb, whereas in
three patients the increase was greater in the control limb.
Conclusions: We found that low-intensity pulsed ultrasound applied
during the consolidation phase of distraction osteogenesis accelerates callus
maturation after opening-wedge high tibial osteotomy by hemicallotasis in
elderly patients.
Level of Evidence: Therapeutic study, Level I-1a
(randomized controlled trial [significant difference]). See Instructions to
Authors for a complete description of levels of evidence.