Serum levels of bone markers were measured prospectively for 1 year in 30 a
dult patients with an intramedullary fixed tibial fracture, In a double bli
nded design, half of the patients received low intensity ultrasound. All fr
actures healed, although in seven of 30 the healing was delayed more than 6
months, There was no significant difference in radiologic healing time bet
ween the ultrasound group (median, 113 days) and the placebo group (median,
112 days). The marker for bone resorption, crosslinked telopeptide, peaked
at 1 to 4 weeks, whereas markers for bone formation peaked at 10 to 16 wee
ks for bone specific alkaline phosphatase and osteocalcin, Crosslinked telo
peptide was lower at 1 week in patients treated with ultrasound than in tho
se receiving placebo. Patients with delayed healing did not differ in cross
linked telopeptide compared with patients with normal healing. There were n
o differences in bone formation markers between patients who received ultra
sound or placebo. Patients with delayed healing had lower levels of bone sp
ecific alkaline phosphatase between 4 and 7 weeks than did patients with no
rmal healing, although no such differences were seen for osteocalcin, The r
esults indicate that low intensity ultrasound might slow bone resorption, a
lthough there is no visible effect on bone formation. Patients with delayed
healing had adequate bone resorption but slower early bone formation than
did patients with normal healing.