To simplify sagittal plane spinal assessment by describing a single novel angle in the lumbar spine equivalent to the difference between pelvic incidence (PI) and lumbar lordosis (LL) and evaluate its reliability. New sagittal modifiers in the classification of adult degenerative spinal deformity have been shown to be valid and reliable with the greatest variability being for pelvic incidence minus lumbar lordosis (PI-LL). This measurement can be simplified to a new angle (alpha) without the need to determine either PI or LL. This angle is between a line intersecting the bicoxofemoral centre and perpendicular to the L1 endplate (alpha line) and a line from the bicoxofemoral centre to the centre of the sacral endplate. Two readers graded 40 non-premarked cases twice each, approximately 1 week apart. Inter- and intra-rater variability and agreement were determined for PI-LL and alpha angle separately. Fleiss' kappa was used for reliability measures.Aim:
Methods:
To establish whether there is a direct relationship between pelvic morphology and lumbar segmental angulation in the sagittal plane. 40 lateral whole spine radiographs with normal sagittal profiles were reviewed. Pelvic incidence (PI), Lumbar Lordosis (LL), Thoracic Kyphosis (TK) and segmental angulation at each level from L1 to the sacrum were measured (from endplate to endplate) distinguishing the vertebral body and intervertebral disc contribution. Pearson correlation coefficients were used to analyse any relationship between pelvic parameters and segmental angulation.Aim:
Methods:
Wear debris from metal on metal (M/M) hip resurfacing and metal on polyethylene (M/P) total hip replacements have different biocompatibilities. M/P wear particles have a foreign body effect M/P wear debris contains nickel and M/M wear debris contains cobalt. Nickel and cobalt are both heavy metals, required as trace elements for some bacteria but potentially toxic to bacteria in high concentrations. Cobalt kills Helicobacter Pylori at concentrations as low as 30 ppb The purpose was to investigate the effects of nanoparticulate wear debris and their heavy metal constituents on bacterial growth. Samples of Coagulase Negative Staphylococci (CNS), Staphylococcus Aureus and MRSA were cultivated to compare their growth in M/M wear debris, M/P wear debris, nickel, cobalt and control culture mediums over 48 hours. Nickel was toxic to CNS (p=0.006) and MRSA (p=0.048). Cobalt also retarded the growth of all three bacteria. M/M wear debris increased the growth of CNS 183 times at 48 hours (p=0.044), Staphylococcus Aureus and MRSA. M/P wear increased the growth of Staphylococcus Aureus 120 times at 48 hours (p=0.021), CNS and MRSA. M/M and M/P nanoparticulate wear debris accelerate the rate of growth of common organisms that infect prosthetic hip joints, the clinical significance of which is uncertain. In isolation, the heavy metals contained within wear debris retard bacterial growth, particularly nickel. Nanoparticulate wear debris does not possess the toxic effects of its constituent metals on bacteria. This reinforces the safety of wear debris but also shows the potential for anti-bacterial effects to be harnessed.
