This prospective multicentre study was undertaken
to determine segmental movement, disc height and sagittal alignment
after total disc replacement (TDR) in the lumbosacral spine and
to assess the correlation of biomechanical properties to clinical
outcomes. A total of 173 patients with degenerative disc disease and low
back pain for more than one year were randomised to receive either
TDR or multidisciplinary rehabilitation (MDR). Segmental movement
in the sagittal plane and disc height were measured using distortion
compensated roentgen analysis (DCRA) comparing radiographs in active flexion
and extension. Correlation analysis between the range of movement
or disc height and patient-reported outcomes was performed in both
groups. After two years, no significant change in movement in the
sagittal plane was found in segments with TDR or between the two
treatment groups. It remained the same or increased slightly in
untreated segments in the TDR group and in this group there was
a significant increase in disc height in the operated segments.
There was no correlation between segmental movement or disc height
and patient-reported outcomes in either group. In this study, insertion of an intervertebral disc prosthesis
TDR did not increase movement in the sagittal plane and segmental
movement did not correlate with patient-reported outcomes. This
suggests that in the lumbar spine the movement preserving properties
of TDR are not major determinants of clinical outcomes. Cite this article:
When cerebral palsy involves the entire body pelvic asymmetry indicates that both hips are ‘at risk’. We carried out a six-year retrospective clinical, radiological and functional study of 30 children (60 hips) with severe cerebral palsy involving the entire body to evaluate whether bilateral simultaneous combined soft-tissue and bony surgery of the hip could affect the range of movement, achieve hip symmetry as judged by the windsweep index, improve the radiological indices of hip containment, relieve pain, and improve handling and function. The early results at a median follow-up of three years showed improvements in abduction and adduction of the hips in flexion, fixed flexion contracture, radiological containment of the hip using both Reimer’s migration percentage and the centre-edge angle of Wiberg, and in relief of pain. Ease of patient handling improved and the satisfaction of the carer with the results was high. There was no difference in outcome between the dystonic and hypertonic groups.
We assessed the results of 17 limb-salvage procedures using osteoarticular allografts after wide resection of high-grade malignant bone tumours. All patients received chemotherapy. At the five-year follow-up, three patients had died from metastases. The allografts survived for five years in only seven patients all of whom had good function, ranging from 73% to 90% of normal. The allografts were removed because of fracture in seven patients and infection in one, and in all of these a second limb-salvage procedure was undertaken. With such a low rate of survival of osteoarticular allografts, we believe that their use in the management of high-grade malignant bone tumours should, at best, be considered a temporary solution.
Randomised controlled trials represent the gold standard in the evaluation of outcome of treatment. They are needed because differences between treatment effects have been minimised and observational studies may give a biased estimation of the outcome. However, conducting this kind of trial is challenging. Several methodological issues, including patient or surgeon preference, blinding, surgical standardisation, as well as external validity, have to be addressed in order to lower the risk of bias. Specific tools have been developed in order to take into account the specificity of evaluation of the literature on non-pharmacological intervention. A better knowledge of methodological issues will allow the orthopaedic surgeon to conduct more appropriate studies and to better appraise the limits of his intervention.
We developed a method of applying vibration to the impaction bone grafting process and assessed its effect on the mechanical properties of the impacted graft. Washed morsellised bovine femoral heads were impacted into shear test rings. A range of frequencies of vibration was tested, as measured using an accelerometer housed in a vibration chamber. Each shear test was repeated at four different normal loads to generate stress-strain curves. The Mohr-Coulomb failure envelope from which shear strength and interlocking values are derived was plotted for each test. The experiments were repeated with the addition of blood in order to replicate a saturated environment. Graft impacted with the addition of vibration at all frequencies showed improved shear strength when compared with impaction without vibration, with 60 Hz giving the largest effect. Under saturated conditions the addition of vibration was detrimental to the shear strength of the aggregate. The civil-engineering principles of particulate settlement and interlocking also apply to impaction bone grafting. Although previous studies have shown that vibration may be beneficial in impaction bone grafting on the femoral side, our study suggests that the same is not true in acetabular revision.
We report 60 benign bone tumours treated by resection and curettage followed by the implantation of calcium hydroxyapatite ceramic (CHA). After follow-up of six to 60 months (average 36), no patient had local recurrence of the tumour or any adverse effects from the implants. In almost all cases radiography showed that the CHA was well-incorporated into the host bone, with new bone formation in and around the CHA. Corrective remodelling of deformed bone and normal fracture healing suggested that there was normal bone turnover in the presence of the CHA. Histology of biopsies from seven patients showed bone ingrowth into the pore structure of CHA in the central zone of some defects by one year after implantation. CHA appears to be a useful substitute for bone graft in the treatment of some benign tumours.
We report a retrospective review of 127 low friction arthroplasties carried out for the failure of a previous hip operation. After an average follow-up of 10.4 years, 20% of cases required further revision, over half of them for deep infection. We estimated from the radiographic appearances that eventual failure by loosening was probable in 58% on the femoral side and 56% on the acetabular side of the arthroplasties.
