Georg Osterhoff

Bio: Georg Osterhoff is an academic researcher from Leipzig University. The author has contributed to research in topics: Medicine & Fracture fixation. The author has an hindex of 24, co-authored 151 publications receiving 2095 citations. Previous affiliations of Georg Osterhoff include University of Zurich & University of British Columbia.

Bone mechanical properties and changes with osteoporosis.

Abstract: This review will define the role of collagen and within-bone heterogeneity and elaborate the importance of trabecular and cortical architecture with regard to their effect on the mechanical strength of bone. For each of these factors, the changes seen with osteoporosis and ageing will be described and how they can compromise strength and eventually lead to bone fragility.

Metallic artefact reduction with monoenergetic dual-energy CT: systematic ex vivo evaluation of posterior spinal fusion implants from various vendors and different spine levels.

Abstract: To evaluate optimal monoenergetic dual-energy computed tomography (DECT) settings for artefact reduction of posterior spinal fusion implants of various vendors and spine levels. Posterior spinal fusion implants of five vendors for cervical, thoracic and lumbar spine were examined ex vivo with single-energy (SE) CT (120 kVp) and DECT (140/100 kVp). Extrapolated monoenergetic DECT images at 64, 69, 88, 105 keV and individually adjusted monoenergy for optimised image quality (OPTkeV) were generated. Two independent radiologists assessed quantitative and qualitative image parameters for each device and spine level. Inter-reader agreements of quantitative and qualitative parameters were high (ICC = 0.81–1.00, κ = 0.54–0.77). HU values of spinal fusion implants were significantly different among vendors (P < 0.001), spine levels (P < 0.01) and among SECT, monoenergetic DECT of 64, 69, 88, 105 keV and OPTkeV (P < 0.01). Image quality was significantly (P < 0.001) different between datasets and improved with higher monoenergies of DECT compared with SECT (V = 0.58, P < 0.001). Artefacts decreased significantly (V = 0.51, P < 0.001) at higher monoenergies. OPTkeV values ranged from 123–141 keV. OPTkeV according to vendor and spine level are presented herein. Monoenergetic DECT provides significantly better image quality and less metallic artefacts from implants than SECT. Use of individual keV values for vendor and spine level is recommended. • Artefacts pose problems for CT following posterior spinal fusion implants. • CT images are interpreted better with monoenergetic extrapolation using dual-energy (DE) CT. • DECT extrapolation improves image quality and reduces metallic artefacts over SECT. • There were considerable differences in monoenergy values among vendors and spine levels. • Use of individualised monoenergy values is indicated for different metallic hardware devices.

Matrix-Associated Implantation of Predifferentiated Mesenchymal Stem Cells Versus Articular Chondrocytes In Vivo Results of Cartilage Repair After 1 Year

Abstract: Background: The use of predifferentiated mesenchymal stem cells (MSC) leads to better histological results compared with undifferentiated MSC in sheep. This raises the need for a longer term follow-up study and comparison with a clinically established method.Hypothesis: We hypothesized that chondrogenic in vitro predifferentiation of autologous MSC embedded in a collagen I hydrogel leads to better structural repair of a chronic osteochondral defect in an ovine stifle joint after 1 year. We further hypothesized that resulting histological results would be comparable with those of chondrocyte-seeded matrix-associated autologous chondrocyte transplantation (MACT).Study Design: Controlled laboratory study.Methods: Predifferentiation period of ovine MSC within collagen gel in vitro was defined by assessment of several cellular and molecular biological parameters. For the animal study, 2 osteochondral lesions (7-mm diameter) were created at the medial femoral condyles of the hind legs in 9 sheep. Implantation o...

Percutaneous iliosacral screw fixation in S1 and S2 for posterior pelvic ring injuries: technique and perioperative complications.

Abstract: Objective Percutaneous iliosacral screw placement allows for minimally invasive fixation of posterior pelvic ring instabilities. The objective of this study was to describe the technique for screws in S1 and S2 using conventional C-arm and to evaluate perioperative complications.

Epidemiology of osteoporotic fractures

Abstract: Patients with vertebral, hip, distal radius, and proximal humerus fractures are most common among the osteoporosis-related fractures. The incidences of these fractures increase with age, however, the increase patterns differ between the fracture sites. The prevalence of vertebral fracture for Japanese is similar or slightly higher and the incidences of osteoporosis-related limb fractures are lower than those for Caucacians. A decrease in prevalence of vertebral fractures and an increase in the incidence of limb fractures are the secular trend in Japan. Previous fractures are significant risk factor for both vertebral and hip fractures. Greater physical activity increases the risk of distal radius fractures, and decreases the risk of proximal humerus fractures.

Comprehensive classification of fragility fractures of the pelvic ring: Recommendations for surgical treatment.

Abstract: Due to the increasing life expectancy, orthopaedic surgeons are more and more often confronted with fragility fractures of the pelvis (FFPs). These kinds of fractures are the result of a low-energy impact or they may even occur spontaneously in patients with severe osteoporosis. Due to some distinct differences, the established classifications for pelvic ring lesions in younger adults do not fully reflect the clinical and morphological criteria of FFPs. Most FFPs are minimally displaced and do not require surgical therapy. However, in some patients, an insidious progress of bone damage leads to increasing displacement, nonunion and persisting instability. Therefore, new concepts for surgical treatment have to be developed to address the functional needs of the elderly patients. Based on an analysis of 245 consecutive patients with FFPs, we propose a novel classification system for this condition. This classification is based on morphological criteria and it corresponds with the degree of instability. Also in the elderly, these criteria are the most important for the decision on the type of treatment as well as type and extent of surgery. The estimation of the degree of instability is based on radiological and clinical findings. The classification gives also hints for treatment strategies, which may vary between minimally invasive techniques and complex surgical reconstructions.

Bone mechanical properties and changes with osteoporosis.

Abstract: This review will define the role of collagen and within-bone heterogeneity and elaborate the importance of trabecular and cortical architecture with regard to their effect on the mechanical strength of bone. For each of these factors, the changes seen with osteoporosis and ageing will be described and how they can compromise strength and eventually lead to bone fragility.