Abstract
Background: Tibial valgus, a known complication of leg lengthening by external fixation, has been related to stability of the bonefixator system and, in particular to pin loosening. Hydroxyapatite coating has been reported to enhance the quality of the bone-pin interface. The aim of this study was to compare the incidence of axial deformity between tibial lengthening procedures with hydroxyapatite-coated and non-coated external-fixation pins.
Methods: A prospective trial was conducted on 34 symmetrical tibial lengthenings in 17 pathologically-short patients. For each pair of bones, one side to be lengthened with hydroxyapatite-coated pins and the other with standard uncoated pins were randomly selected. The bone angle in the frontal plane was measured before the operation and at the end of the fixation period. The difference was calculated and compared between lengthenings performed with coated and uncoated pins.
Results: Mean deviation into valgus of the tibiae was 6.5° with hydroxyapatite-coated pins and 12.5° with uncoated pins (p=0.023). Other factors previously related to valgus deformity did not significantly differ between groups.
Conclusions: Tibial lengthenings performed with hydroxyapatite-coated external-fixation pins are less prone to axial deviation in the frontal plane than those without it.
Local Host: British Society for Children’s Orthopaedic Surgery. Conference Theme: Congenital Deficiencies of the Lower Limb. These abstracts were prepared by A.Catterall.
