The aim of this study is to introduce and investigate the efficacy
and feasibility of a new vertebral osteotomy technique, vertebral
column decancellation (VCD), for rigid thoracolumbar kyphotic deformity
(TLKD) secondary to ankylosing spondylitis (AS). We took 39 patients from between January 2009 and January 2013
(26 male, 13 female, mean age 37.4 years, 28 to 54) with AS and
a TLKD who underwent VCD (VCD group) and compared their outcome
with 45 patients (31 male, 14 female, mean age 34.8 years, 23 to
47) with AS and TLKD, who underwent pedicle subtraction osteotomy
(PSO group), according to the same selection criteria. The technique
of VCD was performed at single vertebral level in the thoracolumbar
region of AS patients according to classification of AS kyphotic
deformity. Pre- and post-operative chin-brow vertical angle (CBVA),
sagittal vertical axis (SVA) and sagittal Cobb angle in the thoracolumbar
region were reviewed in the VCD and PSO groups. Intra- , post-operative
and general complications were analysed in both group.Aims
Patients and Methods
Between March 1990 and May 1991 we performed 85 primary total hip replacements in 74 patients using the Landos Atoll hydroxyapatite (HA)-coated cup and the Corail HA-coated stem. The patients were followed up for a mean of ten years. Of the 85 cups, 26 (31%) have already been revised and a further six are radiologically unstable and awaiting revision. Two femoral stems have been revised for infection without loosening. The retrieved acetabular cups were studied by SEM and image-processing techniques to quantify the amount of residual HA on the cup. This was correlated with the clinical variables and modes of failure. The residual HA (as a percentage of the surface) on the loose cups correlated negatively with the duration of implantation (r = −0.732, p <
0.001). Six cups were stable at revision and had more residual HA coating than those which were loose (p <
0.01). The rate of failure of the Landos Atoll HA-coated, smooth hemispherical cup with screw fixation is unacceptably high. Resorption of the HA coating is markedly increased in loose cups compared with stable cups. HA coating cannot substitute for stable mechanical fixation.
