Risk of Complication and Revision Total Hip Arthroplasty Among Medicare Patients with Different Bearing Surfaces

To address the long-term problems of bearing surface wear and osteolysis associated with conventional metal-polyethylene (M-PE) total hip arthroplasty (THA), metal-metal (M-M), and ceramic-ceramic (C-C) bearings have been introduced. These bearing surfaces are associated with unique risks and benefits and higher costs. However the relative risks of these three bearings in an older population is unknown. We compared the short-term risk of complication and revision THA among Medicare patients having a primary THA with metal-polyethylene (M-PE), metal-metal (M-M), and ceramic-ceramic (C-C) bearings. We used the 2005 to 2007 100% Medicare inpatient claim files to perform a matched cohort analysis in three separate cohorts of THA patients (M-PE, M-M, and C-C) who were matched by age, gender, and US census region. Multivariate Cox proportional-hazards models were constructed to compare complication and revision THA risk among cohorts, adjusting for medical comorbidities, race, socioeconomic status, and hospital factors. After adjusting for patient and hospital factors, M-M bearings were associated with a higher risk of periprosthetic joint infection (hazard ratio, 3.03; confidence interval, 1.02–9.09) when compared with C-C bearings (0.59% versus 0.32%, respectively). There were no other differences among bearing cohorts in the adjusted risk of revision THA or any other complication. The risk of short-term complication (including dislocation) and revision THA were similar among appropriately matched Medicare THA patients regardless of bearing surface. Hard-on-hard THA bearings are of questionable value in Medicare patients, given the higher cost associated with their use and uncertain long-term benefits in older patients. Level II, prognostic study. See Guidelines for Authors for a complete description of levels of evidence

Effect of local TGF-β1 and IGF-1 release on implant fixation: comparison with hydroxyapatite coating: A paired study in dogs

Background and purpose Hydroxyapatite (HA) coating stimulates the osseointegration of cementless orthopedic implants. Recently, locally released osteogenic growth factors have also been shown experimentally to stimulate osseointegration so that bone fills gaps around orthopedic implants. Here, we have compared the effect of local release of TGF-β 1 and IGF-1 with that of hydroxyapatite coating on implant fixation

A custom-made guide-wire positioning device for Hip Surface Replacement Arthroplasty: description and first results

<p>Abstract</p> <p>Background</p> <p>Hip surface replacement arthroplasty (SRA) can be an alternative for total hip arthroplasty. The short and long-term outcome of hip surface replacement arthroplasty mainly relies on the optimal size and position of the femoral component. This can be defined before surgery with pre-operative templating. Reproducing the optimal, templated femoral implant position during surgery relies on guide wire positioning devices in combination with visual inspection and experience of the surgeon. Another method of transferring the templated position into surgery is by navigation or Computer Assisted Surgery (CAS). Though CAS is documented to increase accurate placement particularly in case of normal hip anatomy, it requires bulky equipment that is not readily available in each centre.</p> <p>Methods</p> <p>A custom made neck jig device is presented as well as the results of a pilot study.</p> <p>The device is produced based on data pre-operatively acquired with CT-scan. The position of the guide wire is chosen as the anatomical axis of the femoral neck. Adjustments to the design of the jig are made based on the orthopedic surgeon's recommendations for the drill direction. The SRA jig is designed as a slightly more-than-hemispherical cage to fit the anterior part of the femoral head. The cage is connected to an anterior neck support. Four knifes are attached on the central arch of the cage. A drill guide cylinder is attached to the cage, thus allowing guide wire positioning as pre-operatively planned.</p> <p>Custom made devices were tested in 5 patients scheduled for total hip arthroplasty. The orthopedic surgeons reported the practical aspects of the use of the neck-jig device. The retrieved femoral heads were analyzed to assess the achieved drill place in mm deviation from the predefined location and orientation compared to the predefined orientation.</p> <p>Results</p> <p>The orthopedic surgeons rated the passive stability, full contact with neck portion of the jig and knife contact with femoral head, positive. There were no guide failures. The jig unique position and the number of steps required to put the guide in place were rated 1, while the complexity to put the guide into place was rated 1-2. In all five cases the guide wire was accurately positioned. Maximum angular deviation was 2.9° and maximum distance between insertion points was 2.1 mm.</p> <p>Conclusions</p> <p>Pilot testing of a custom made jig for use during SRA indicated that the device was (1) successfully applied and user friendly and (2) allowed for accurate guide wire placement according to the preoperative plan.</p

Maintenance of bone mineral density after implantation of a femoral neck hip prosthesis

<p>Abstract</p> <p>Background</p> <p>Stress shielding of the proximal femur has been observed in a number of conventional cementless implants used in total hip arthroplasty. Short femoral-neck implants are claiming less interference with the biomechanics of the proximal femur. The goal of this study was to investigate the changes of bone-mineral density in the proximal femur and the clinical outcome after implantation of a short femoral-neck prosthesis.</p> <p>Methods</p> <p>We prospectively assessed the clinical outcome and the changes of bone mineral density of the proximal femur up to one year after implantation of a short femoral neck prosthesis in 20 patients with a mean age of 47 years (range 17 to 65). Clinical outcome was assessed using the Harris Hip Score. The WOMAC was used as a patient-relevant outcome-measure. The bone mineral density was determined using dual energy x-ray absorptiometry, performed 10 days, three months and 12 months after surgery.</p> <p>Results</p> <p>The Harris Hip Score improved from an average preoperative score of 46 to a postoperative score at 12 months of 89 points, the global WOMAC index from 5,3 preoperatively to 0,8 at 12 months postoperatively. In contrast to conventional implants, the DEXA-scans overall revealed a slight increase of bone mineral density in the proximal femur in the 12 months following the implantation.</p> <p>Conclusion</p> <p>The short femoral neck stem lead to a distinct bone reaction. This was significantly different when compared to the changes in bone mineral density reported after implantation of conventional implants.</p

Does fixed-angle plate osteosynthesis solve the problems of a fractured proximal humerus?: A prospective series of 87 patients

Background and purpose There is considerable controversy about the treatment of complex, displaced proximal humeral fractures. Various types of head-preserving osteosynthesis have been suggested. This prospective case series was designed to evaluate the perioperative and early postoperative complications associated with fixed-angle implants and to record outcome after bone healing

Wirtschaftsbauten in der antiken Stadt

Über die Wirtschaft der Antike sind wir gut informiert. Für den Waren- und Geldverkehr standen in den Städten eigene Gebäude zur Verfügung, die im römischen Reich von Speicherbauten in bedeutenden Wirtschaftszentren und Hafenorten bis zu Bank- und Börsengebäuden an den zentralen Plätzen der Städte reichten. Diese Bauten wurden von Archäologen und Bauhistorikern vielfach untersucht, wobei Bauweise und Gestaltung im Vordergrund standen. Wirtschaftshistoriker befassten sich intensiv mit Handels- und Geldgeschäften, ohne Zusammenhänge mit Baulichkeiten in den Blick zu nehmen. Interdisziplinäre Zusammenarbeit eröffnet neue Perspektiven. Mit dem Wissen über wirtschaftliche Vorgänge lassen sich Bauten besser verstehen, und Bauwerke können ökonomische Vorgänge sichtbar machen. Das wurde beim erstmaligen Gedankenaustausch zwischen den verschiedenen Forschungsdisziplinen rasch deutlich. Der vorliegende Tagungsband enthält Beiträge über Handelsformen und Handelsbeziehungen, er stellt Speichergebäude und Kaufmannshäuser vor und beleuchtet mit dem Magdalensberg bei Kärnten ein bedeutendes Zentrum der Erzgewinnung und der Metallverarbeitung. Einen besonderen Platz nimmt die römische Basilika als großartiges Bank- und Börsengebäude ein, dessen Entwicklung um 200 v. Chr. quasi schlagartig am Forum Romanum begann und die neue Vormacht Rom als Zentrum der antiken Wirtschaft und zentrale Instanz des Wirtschafts- und Steuerrechts mit neuen Maßstäben auch städtebaulich prägte. Die beiden letzten Beiträge befassen sich mit der weiteren Entwicklung des Begriffes Basilika und seinen Nachwirkungen im Kirchenbau und in der Architekturtheorie bis heute

Navigated cup implantation in hip arthroplasty: A meta-analysis

Background and purpose Many studies have suggested that navigation-based implantation can improve cup positioning in total hip arthroplasty (THA). We conducted a systematic review and meta-analysis to compile the best available evidence, and to overcome potential shortcomings because of small sample sizes in individual studies