Experimentelle Bewertung der Spannungen und der zugehörigen Implantate bei anterioren Beckenfrakturen vom Typ I

Scientific Conference (2022, October 28)

Biomechanische Untersuchung zu verschiedenen Verfahren der Stabilisierung von Insuffizienzfrakturen des vorderen Beckenringes

Poster (2022, October 26)

INVESTIGATING THE INFLUENCE OF PERSONALIZED MUSCULOSKELETAL MODELS ON THE CALCULATED STRESSES IN THE PELVIC RING

Poster (2021, September)

This study investigates the influence of personalizing musculoskeletal models (MS) on muscles, contact joints forces and on stresses in the pelvic ring bones during normal gait loading cycle. All ... [more ▼]

This study investigates the influence of personalizing musculoskeletal models (MS) on muscles, contact joints forces and on stresses in the pelvic ring bones during normal gait loading cycle. All calculated forces are utilized to predict stress states in pelvis bones using Finite Element (FE) software. Customized MS models provides more precise muscle and contact forces. Additionally, it enables more automatic coupling between MS and FE environments by data transfer. [less ▲]

Numerical Assessment of two Implants for Pubic Ramus Fracture of human Pelvis applying Normal Gait loading

Poster (2020, October)

Fractures of the anterior pelvic ring reduce patients` mobility and independence and increase mortality. Pelvic instability impairs the load transfer to the lower extremity. Restoring stability has ... [more ▼]

Fractures of the anterior pelvic ring reduce patients` mobility and independence and increase mortality. Pelvic instability impairs the load transfer to the lower extremity. Restoring stability has therefore been a crucial point of research. Most of the reported studies refer to loading on one leg stand without consideration of physiological muscle and contact-joint forces of the common vital daily movements. Our present study considers physiological gait loading of all acting muscles and Hip Joint Contact (HJC) forces of the pelvis. Those muscles and HJC forces were calculated by inverse dynamics for normal gait motion data and applied in Finite Element Analyses (FEA). The biomechanical stability provided to the anterior pelvic ring by two reconstructive techniques was investigated numerically: the iliopubic Subcutaneous Plate (SP) and the Supra-Acetabular External Fixator (SAFE). Numerical biomechanical assessment of two reconstructive devices for pubic ramus fracture. All muscles and HJC forces of normal gait were calculated by means of inverse dynamics software for a healthy patient considering a musculoskeletal model previously validated experimentally. The Finite Element (FE) model was developed for a pelvis with and without superior and/or inferior rami fractures. Furthermore, two FE models for SP and SAFE mounted on the rami fractured pelvis were designed considering fixation bearing at the lumbosacral joint. The calculated forces were implemented on the FE models following the anatomical orientation and attachments/insertions of each muscle. During the two moments of the gait with higher stresses: Left Heel Strike (LHS) and Right Toe-Off (RTO), strains and displacements were recorded and investigated at the fracture location in addition to the implant fixation points. Considering only right superior ramus fracture during LHS and RTO, recorded strains and displacements for both implants showed similar results. However, during RTO, the SAFE showed a slight reduction of strains at the posterior location by 6% compared to SP. When including both superior and inferior right ramus fractures, both devices did not show considerable difference in recorded strains. However, there were significant differences in the displacements between fracture extremities. The SP technique reduced these motions for both LHS and RTO by 40% compared to the gold standard SAFE technique. In cases of superior ramus fracture only, displacements for both reconstructive devices were similar due to the remaining stability provided by the intact inferior ramus. Both devices reduced stresses of the sacrum wing in LHS and RTO with slightly better results for SAFE. In case of superior and inferior pubic ramus fractures, the SP technique reduced the frontal opening of the fractured right pubic bone. The SAFE did not provide any improvements compared to the SP technique. [less ▲]

Finite element analysis of the pelvis including gait muscle forces: an investigation into the effect of rami fractures on load transmission

in Journal of Experimental Orthopaedics (2018), 5(33), 1-9

Was wissen wir über die Osteitis pubis bei Sporttreibenden?

in Sportverletzung Sportschaden: Organ der Gesellschaft für Orthopadisch-Traumatologische Sportmedizin (2018)

Hintergrund Die Osteitis pubis ist eine häufige Ursache chronischer Leistenbeschwerden. Aufgrund hoher klinischer Unsicherheit sowie dem unterschiedlichen Verlauf der Erkrankung wird die Diagnose nicht ... [more ▼]

Hintergrund Die Osteitis pubis ist eine häufige Ursache chronischer Leistenbeschwerden. Aufgrund hoher klinischer Unsicherheit sowie dem unterschiedlichen Verlauf der Erkrankung wird die Diagnose nicht selten erst spät gestellt. Das Krankheitsbild betrifft insbesondere Sportlerinnen und Sportler, wobei auch Patienten aus den Bereichen Orthopädie, Traumatologie, Neurologie, Urologie, Gynäkologie sowie der Rheumatologie betroffen sein können. Therapeutisch kommen sowohl konservative als auch operative Verfahren zum Einsatz. Material und Methoden Systematische Literaturrecherche, deskriptive Darstellung der Studienlage und Interpretation der Ergebnisse im Sinne der evidenzbasierten Medizin. Ergebnisse Das wissenschaftliche Niveau der Studien über die Osteitis pubis ist, wie die Anzahl der in Studien inkludierten Sporttreibenden, insgesamt niedrig. Aufgrund der Heterogenität der Publikationen ist ihr statistischer Vergleich methodisch schwierig. Klinisch führendes Symptom der Osteitis pubis ist die schmerzhafte Symphysis pubica, wobei ein klassisches pathognomonisches Zeichen fehlt. Die Diagnose basiert nach Ausschluss zahlreicher Differentialdiagnosen (z. B. „Sportlerleiste“, FA-Impingement, Adduktorenläsion) auf der Zusammenschau von Anamnese, klinischer Untersuchung sowie bildgebender Verfahren. Die Osteitis pubis ist eine durch Sportkarenz oftmals selbstlimitierende Erkrankung, die initial konservativ behandelt wird. Bei frustranem Verlauf sind operative Verfahren, in Abhängigkeit der Begleitpathologien, in Betracht zu ziehen. Schlussfolgerung Es existieren bis dato keine Leitlinien hinsichtlich Diagnostik und Therapie der Osteitis pubis, allerdings ein Konsens darüber, dass der operativen Behandlung eine konservative vorangehen muss. Das Evidenzniveau der Studien ist niedrig. Eine metaanalytische Auswertung ist mit den derzeitig vorhandenen Publikationen nicht möglich. Die Anzahl der untersuchten Sporttreibenden ist in Relation zu den sozioökonomischen Folgen der Erkrankung, insbesondere im Profisport, niedrig. [less ▲]

Design, Repeatability, and Comparison to Literature Data of a New Noninvasive Device Called "Rotameter" to Measure Rotational Knee Laxity

in International Scholarly Research Notices Orthopedics (2015), Volume 2015, Article ID 439095

The present paper deals with the design, the repeatability, and the comparison to literature data of a new measuring device called “Rotameter” to characterize the rotational knee laxity or the tibia ... [more ▼]

The present paper deals with the design, the repeatability, and the comparison to literature data of a new measuring device called “Rotameter” to characterize the rotational knee laxity or the tibia-femoral rotation (TFR). The initial prototype P1 of the Rotameter is shortly introduced and then modified according to trials carried out on a prosthetic leg and on five healthy volunteers, leading therefore to an improved prototype P2. A comparison of results obtained from P1 and P2 with the same male subject shows the enhancements of P2. Intertester and intratester repeatability of this new device were shown and it was observed that rotational laxities of left and right knees are the same for a healthy subject. Moreover, a literature review showed that measurements with P2 presented lower TFR values than other noninvasive devices.The measured TFR versus torque characteristic was quite similar to other invasive devices, which are more difficult to use and harmful to the patient. Hence, our prototype P2 proved to be an easy-to-use and suitable device for quantifying rotational knee laxity. A forthcoming study will validate the Rotameter thanks to an approach based on computed tomography in order to evaluate its precision. [less ▲]