Clinical value of SPECT/CT for evaluation of patients with painful knees after total knee arthroplasty- a new dimension of diagnostics?

<p>Abstract</p> <p>Background</p> <p>The purpose of our study was to evaluate the clinical value of hybrid SPECT/CT for the assessment of patients with painful total knee arthroplasty (TKA).</p> <p>Methods</p> <p>Twenty-three painful knees in patients following primary TKA were assessed using Tc-99m-HDP-SPECT/CT. Rotational, sagittal and coronal position of the TKA was assessed on 3D-CT reconstructions. The level of the SPECT-tracer uptake (0-10) and its anatomical distribution was mapped using a validated localization scheme. Univariate analysis (Wilcoxon-Mann-Whitney, Spearmean`s-rho test, p < 0.05) was performed to identify any correlations between component position, tracer uptake and diagnosis.</p> <p>Results</p> <p>SPECT/CT imaging changed the suspected diagnosis and the proposed treatment in 19/23 (83%) knees. Progression of patellofemoral OA (n = 11), loosening of the tibial (n = 3) and loosening of the femoral component (n = 2) were identified as the leading causes of pain after TKA.</p> <p>Patients with externally rotated tibial trays showed higher tracer uptake in the medial patellar facet (p = 0.049) and in the femur (p = 0.051). Patients with knee pain due to patellofemoral OA showed significantly higher tracer uptake in the patella than others (p < 0.001).</p> <p>Conclusions</p> <p>SPECT/CT was very helpful in establishing the diagnosis and guiding subsequent management in patients with painful knees after TKA, particularly in patients with patellofemoral problems and malpositioned or loose TKA.</p

Assessment of bone ingrowth potential of biomimetic hydroxyapatite and brushite coated porous E-beam structures

The bone ingrowth potential of biomimetic hydroxyapatite and brushite coatings applied on porous E-beam structure was examined in goats and compared to a similar uncoated porous structure and a conventional titanium plasma spray coating. Specimens were implanted in the iliac crest of goats for a period of 3 (4 goats) or 15 weeks (8 goats). Mechanical implant fixation generated by bone ingrowth was analyzed by a push out test. Histomorphometry was performed to assess the bone ingrowth depth and bone implant contact. The uncoated and hydroxyapatite-coated cubic structure had significantly higher mechanical strength at the interface compared to the Ti plasma spray coating at 15 weeks of implantation. Bone ingrowth depth was significantly larger for the hydroxyapatite- and brushite-coated structures compared to the uncoated structure. In conclusion, the porous E-beam surface structure showed higher bone ingrowth potential compared to a conventional implant surface after 15 weeks of implantation. Addition of a calcium phosphate coating to the E-beam structure enhanced bone ingrowth significantly. Furthermore, the calcium phosphate coating appears to work as an accelerator for bone ingrowth

Local Application of BMP-2 Specific Plasmids in Fibrin Glue does not Promote Implant Fixation

<p>Abstract</p> <p>Background</p> <p>BMP-2 is known to accelerate fracture healing and might also enhance osseointegration and implant fixation. Application of recombinant BMP-2 has a time-limited effect. Therefore, a gene transfer approach with a steady production of BMP-2 appears to be attractive. The aim of this study was to examine the effect of locally applied BMP-2 plasmids on the bone-implant integration in a non-weight bearing rabbit tibia model using a comparatively new non-viral copolymer-protected gene vector (COPROG).</p> <p>Methods</p> <p>Sixty rabbits were divided into 4 groups. All of them received nailing of both tibiae. The verum group had the nails inserted with the COPROG vector and BMP-2 plasmids using fibrin glue as a carrier. Controls were a group with fibrin glue only and a blank group. After 28 and 56 days, these three groups were sacrificed and one tibia was randomly chosen for biomechanical testing, while the other tibia underwent histomorphometrical examination. In a fourth group, a reporter-gene was incorporated in the fibrin glue instead of the BMP-2 formula to prove that transfection was successful.</p> <p>Results</p> <p>Implant fixation strength was significantly lower after 28 and 56 days in the verum group. Histomorphometry supported the findings after 28 days, showing less bone-implant contact.</p> <p>In the fourth group, successful transfection could be confirmed by detection of the reporter-gene in 20 of 22 tibiae. But, also systemic reporter-gene expression was found in heterotopic locations, showing an undesired spreading of the locally applied gene formula.</p> <p>Conclusion</p> <p>Our results underline the transfecting capability of this vector and support the idea that BMP-2 might diminish osseointegration. Further studies are necessary to specify the exact mechanisms and the systemic effects.</p

Are Restrictions of Competition by Sports Associations Horizontal or Vertical in Nature?

In this paper, we discuss from an economic perspective two alternative views of restrictions of competition by sports associations. The horizontal approach views such restrictions as an agreement among the participants of a sports league with the sports association merely representing an organization executing the horizontal cooperation. In contrast, the vertical approach views the sports association as being a dominant upstream firm enjoying a monopoly position on the market stage for competition organizing services, an important input for the actual product - the sports game. Taking the recent financial fair play (FFP) initiative by UEFA (the Union of European Football Associations) as an example, we demonstrate that the different views lead to different assessments of restrictive effects and, thus, matter for competition policy decisions. The economic story of the potential restrictive effect of FFP on players' and player agents' income may fit more plausibly to the horizontal approach, whereas the potentially anticompetitive foreclosure and deterrence effects of FFP may be economically more soundly reasoned by taking the vertical view

Adherence of hip and knee arthroplasty studies to RSA standardization guidelines

Peer reviewe

Do tracks yield reliable information on gaits? &ndash; Part 1: The case of horses

During their lifetime animals leave many tracks and traces behind, which can provide insights into the animals' behaviour. Single footprints of extant vertebrates are frequently found in sediments all over the world, often arranged into trackways. The study of footprints and trackways lead to interpretations about the mode of locomotion of the trackmaker. Here we show an approach to identify gaits from tracks. A series of experiments with horses was performed to determine whether gaits could be identified on the basis of fossil trackways, e.g. those left behind by sauropod dinosaurs of the Mesozoic era or Tertiary mammals, to unveil their locomotor abilities. The generally valid rules for quadrupedal locomotion were taken into consideration. Symmetrical gaits result in very similar trackways; a further differentiation can be made by application of statistics on step lengths, excursion angles and overstepping. A clear difference exists between the trot and the pace. These rapid, symmetric gaits imply high ground reaction forces (GRF) because of their long phases of aerial suspension at higher speeds. The resulting GRF seem to be too high to be sustained by the limb bones of huge graviportal animals like sauropods. Unfortunately, most of these factors are rarely available in the case of fossil tracks. Likewise, the asymmetrical, springing gaits can be excluded for sauropods because of the enormous GRF. Provided that limb length as well as trunk length can be approximated, and left and right, as well as forefoot and hindfoot imprints can be discriminated, the symmetrical gaits (walk, amble, pace, trot) used when making a trackway can be discerned

Do tracks yield reliable information on gaits? – Part 1: The case of horses

During their lifetime animals leave many tracks and traces behind, which canprovide insights into the animals' behaviour. Single footprints of extantvertebrates are frequently found in sediments all over the world, oftenarranged into trackways. The study of footprints and trackways lead tointerpretations about the mode of locomotion of the trackmaker. Here we showan approach to identify gaits from tracks.A series of experiments with horses was performed to determine whether gaitscould be identified on the basis of fossil trackways, e.g. those left behindby sauropod dinosaurs of the Mesozoic era or Tertiary mammals, to unveiltheir locomotor abilities. The generally valid rules for quadrupedallocomotion were taken into consideration. Symmetrical gaits result in verysimilar trackways; a further differentiation can be made by application ofstatistics on step lengths, excursion angles and overstepping.A clear difference exists between the trot and the pace. These rapid,symmetric gaits imply high ground reaction forces (GRF) because of their longphases of aerial suspension at higher speeds. The resulting GRF seem to be too high to be sustained by the limb bones of hugegraviportal animals like sauropods. Unfortunately, most of these factors arerarely available in the case of fossil tracks. Likewise, the asymmetrical,springing gaits can be excluded for sauropods because of the enormous GRF. Provided that limb length as well as trunk length can beapproximated, and left and right, as well as forefoot and hindfoot imprints canbe discriminated, the symmetrical gaits (walk, amble, pace, trot) used whenmaking a trackway can be discerned