Children treated for osteosarcoma around the knee often have
a substantial leg-length discrepancy at skeletal maturity. The aim
of this study was to investigate the results of staged skeletal
reconstruction after a leg lengthening procedure using an external
fixator in these patients. We reviewed 11 patients who underwent staged reconstruction with
either an arthroplasty (n = 6) or an arthrodesis (n = 5). A control
group of 11 patients who had undergone wide excision and concurrent
reconstruction with an arthroplasty were matched for gender, location,
and size of tumour. We investigated the change in leg-length discrepancy,
function as assessed by the Musculoskeletal Tumor Society Scale
(MSTS) score and complications.Aims
Patients and Methods
Cancellous allograft bone chips are commonly
used in the reconstruction of defects in bone after removal of benign tumours.
We investigated the MRI features of grafted bone chips and their
change over time, and compared them with those with recurrent tumour.
We retrospectively reviewed 66 post-operative MRIs from 34 patients
who had undergone curettage and grafting with cancellous bone chips
to fill the defect after excision of a tumour. All grafts showed
consistent features at least six months after grafting: homogeneous
intermediate or low signal intensities with or without scattered
hyperintense foci (speckled hyperintensities) on T1 images; high
signal intensities with scattered hypointense foci (speckled hypointensities)
on T2 images, and peripheral rim enhancement with or without central
heterogeneous enhancements on enhanced images. Incorporation of
the graft occurred from the periphery to the centre, and was completed
within three years. Recurrent lesions consistently showed the same signal
intensities as those of pre-operative MRIs of the primary lesions.
There were four misdiagnoses, three of which were chondroid tumours. We identified typical MRI features and clarified the incorporation
process of grafted cancellous allograft bone chips. The most important
characteristics of recurrent tumours were that they showed the same
signal intensities as the primary tumours. It might sometimes be
difficult to differentiate grafted cancellous allograft bone chips
from a recurrent chondroid tumour. Cite this article:
