Use of periosteal markers and DXA to monitor healing in callotasis
Callotasis has been studied extensively. The major applications of the technique in
trauma and congenital disorders demand objective measures to monitor its
Periosteum is thought to be important by all authors, providing a guiding envelope
during new bone formation and an important source of osteogenic cells. We
labelled the periosteum with markers in 7 patients undergoing callotasis. This
enables us to monitor its continuity and mode of elongation in an efficient way. The
periosteum elongates throughout the distraction phase. We found that the strains
during distraction indicate differential growth at different parts of it. We also found
that periosteum was not transfixed by the pins or wires of the external fixator but
the fixation points into bone were at different sites. The single most important
factor that correlated with healing of the regenerate was continuity of the
periosteum, which was efficiently monitored by the movement of the markers.
During the consolidation phase 23 simultaneous measurements of bending
stiffness of the regenerate and DXA scans were obtained on 9 patients that
underwent callotasis. Of these measurements, 15 were of tibias and 9 of femurs.
Linear correlation was calculated between the bending fracture stiffness and
several parameters derived from DXA scans that reflect mineralisation patterns of
The highest correlation (,-2=0.77, p<0.001) was found with the linear density.
Therefore, we were able to link what many people have long regarded as a
promising technique (non-invasive densitometry) and what is currently regarded as
the most reliable outcome measure (stiffness). That, we would think, is an
important step as an end-point is derived that might allow safe removal of the