Study Design: Finite element study.
Objective: To investigate the interaction between the finite helical axis and facet joint loads under combined loading.
Summary Of Background Data: Finite helical axes (FHA) in a functional spinal unit can indicate mechanical disorders and are relevant for the development of new arthoplasty techniques. The facet joints protect the intervertebral discs from excessive movements. The relationship between the FHAs and facet joint forces is not well-understood, because previous studies have separated both, spinal motion and facet forces.
Methods: A finite element model of a lumbar spinal segment L4-L5 was used to simulate axial compression load of 500 N together with moments starting from 0 to 7.5 Nm in single anatomic main planes. Load combinations of 7.5 Nm were generated by changing the load direction in steps of 15 degrees between each pair of the 3 anatomic mainplanes.
Results: For single axes loading, the FHAs were found to be in the center of the disc under small moments, independently from load directions. The facet joints were only slightly loaded. Higher moments increased the forces in facet joints up to 105 N in axial rotation, followed by extension (50 N) and lateral bending (36 N). Combined moments did not essentially increase the facet forces compared with the same moment applied in an anatomic main direction. High facet forces might have directed the FHAs to migrate posteriorly, especially for axial rotation. This situation resulted in FHAs outside the disc toward the compressed facet joint.
Conclusion: For clinical practice, patients immediately after the operation, or patients with facet joint arthritis should reduce or avoid axial rotation alone or in combination with other load applications, especially axial rotation plus lateral bending or flexion.
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http://dx.doi.org/10.1097/BRS.0b013e31817c4319 | DOI Listing |
J Plast Reconstr Aesthet Surg
January 2025
Department of Orthopedic Surgery, Seoul National University Bundang Hospital, Seongnam, South Korea. Electronic address:
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View Article and Find Full Text PDFFoot Ankle Int
January 2025
Division of Foot and Ankle, Department of Orthopaedic Surgery, Duke University School of Medicine, Durham, NC, USA.
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View Article and Find Full Text PDFJ Clin Med
January 2025
Department of Orthopaedics, Graduate School of Medical Science, Kyoto Prefectural University of Medicine, Kawaramachi-Hirokoji, Kamigyo-ku, Kyoto 602-8566, Japan.
After open-wedge high tibial osteotomy (OWHTO), the patella is displaced distally, causing patellofemoral joint degeneration. The objective of this study was to ascertain whether the combination of OWHTO and lateral retinacular release (LRR) can prevent articular cartilage degeneration of the patellofemoral joint using magnetic resonance imaging T2 mapping. This study included 37 patients (37 knees) who underwent OWHTO alone (OWHTO group) and 37 patients (37 knees) who underwent OWHTO with LRR (OWHTO + LRR group) with a correction angle of <10° for varus knee osteoarthritis.
View Article and Find Full Text PDFOrthop Traumatol Surg Res
January 2025
Department of Orthopaedic Surgery and Traumatology, Saint-Antoine Hospital, Sorbonne Université, 184, rue du Faubourg-Saint-Antoine, 75012 Paris, France.
Introduction: The aim of our study was to describe a new anteromedial approach that allows exposure of the anteromedial facet of the coronoid process and to characterize the position of the median nerve's motor branches relative to this approach in relation to elbow positioning.
Material And Methods: We performed 16 anteromedial approaches on fresh anatomical specimens. The minimum distance between the medial edge of the trochlea and the second branch of the median nerve was measured in three elbow positions: forearm in supination with the elbow extended, forearm in pronation with the elbow extended, and forearm in supination with the elbow flexed at 90 °.
J Bone Miner Res
January 2025
McCaig Institute for Bone and Joint Health, Cumming School of Medicine, University of Calgary, Calgary AB, Canada.
Immune checkpoint inhibitors (ICI) are widely used in cancer treatment, yet their impact on bone health remains unclear. This study aimed to perform a retrospective cohort study utilizing routine computed tomography (CT) scans from patients with melanoma to perform opportunistic quantitative CT (QCT) analysis to investigate the effects of ICI treatment on skeletal health, including volumetric bone mineral density (vBMD) measurements and osteoarthritis (OA) parameters. A previously established machine-learning assisted opportunistic QCT pipeline was used to estimate lumbar spine vBMD from baseline and 12-month follow-up CT scans in patients with melanoma treated with ICI therapy and those not treated with ICI therapy.
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