Objective. To determine if hydroxyapatite (HAP), octacalcuim phosphate (OCP
), or tricalcium phosphate (TCP) can be found in the calcium deposits in ca
Methods. Thirty-six specimens from 34 patients who had acute inflammation a
cid roentgenographically recognized calcification in soft tissue were analy
zed. Twenty-three patients with calcific tendinitis in the shoulder and 11
with calcific periarthritis at other sites were included. We prepared 2 kin
ds of samples from each specimen: a dried sample (washed and dried calcific
deposit), and a sample heated to 1000 degreesC. All were analyzed by X-ray
diffraction, Raman spectroscopy, infrared absorption spectroscopy, and X-r
ay fluorescence spectrometry for calcium and phosphorus molar ratio. Synthe
tic HAP was used as the control in each analysis.
Results. The X-ray diffraction patterns of all dried samples were similar t
o those of HAP and carbonate apatite. We found no diffraction patterns of O
CP or TCP. However. an OH- group at 3570cm(-1) was observed with Raman spec
troscopy for samples heated to 1000 degreesC and synthetic HAP, but not for
the dried samples. Infrared absorption spectroscopy also confirmed an OH-
group for samples heated to 1000 degreesC and synthetic HAP, and confirmed
that dried samples contained carbonate.
Conclusion, Calcium deposits are composed of carbonate apatite. HAP, OCP, a
nd TCP were not identified in any deposits.