Effect of Q-angle on patellar positioning and thickness of knee articular cartilages

2010 ◽  
Vol 33 (2) ◽  
pp. 97-104 ◽  
Author(s):  
Aikaterini E. Tsakoniti ◽  
Dimitris G. Mandalidis ◽  
Spyros I. Athanasopoulos ◽  
Christoforos A. Stoupis
Keyword(s):  
Q Angle ◽  
Articular Cartilages

scholarly journals Kinect Azure–Based Accurate Measurement of Dynamic Valgus Position of the Knee—A Corrigible Predisposing Factor of Osteoarthritis

2021 ◽  
Vol 11 (12) ◽  
pp. 5536
Author(s):  
Ádám Uhlár ◽  
Mira Ambrus ◽  
Márton Kékesi ◽  
Eszter Fodor ◽  
László Grand ◽  
...  
Keyword(s):  
Motion Capture ◽  
Optical System ◽  
Lower Limb ◽  
Cruciate Ligament ◽  
Movement Pattern ◽  
Recognition Algorithm ◽  
Predisposing Factor ◽  
Lower Limb Injury ◽  
Q Angle ◽  
Dynamic Valgus

(1) Dynamic knee valgus is a predisposing factor for anterior cruciate ligament rupture and osteoarthritis. The single-leg squat (SLS) test is a widely used movement pattern test in clinical practice that helps to assess the risk of lower-limb injury. We aimed to quantify the SLS test using a marker-less optical system. (2) Kinect validity and accuracy during SLS were established by marker-based OptiTrack and MVN Xsens motion capture systems. Then, 22 individuals with moderate knee symptoms during sports activities (Tegner > 4, Lysholm > 60) performed SLS, and this was recorded and analyzed with a Kinect Azure camera and the Dynaknee software. (3) An optical sensor coupled to an artificial-intelligence-based joint recognition algorithm gave a comparable result to traditional marker-based motion capture devices. The dynamic valgus sign quantified by the Q-angle at the lowest point of the squat is highly dependent on squat depth, which severely limits its comparability among subjects. In contrast, the medio-lateral shift of the knee midpoint at a fixed squat depth, expressed in the percentage of lower limb length, is more suitable to quantify dynamic valgus and compare values among individual patients. (4) The current study identified a new and reliable way of evaluating dynamic valgus of the knee joint by measuring the medial shift of the knee-over-foot at a standardized squat depth. Using a marker-less optical system widens the possibilities of evaluating lower limb functional instabilities for medical professionals.

scholarly journals Isolation of dermatan sulfate proteoglycans from mature bovine articular cartilages.

1985 ◽  
Vol 260 (10) ◽  
pp. 6304-6313
Author(s):  
L C Rosenberg ◽  
H U Choi ◽  
L H Tang ◽  
T L Johnson ◽  
S Pal ◽  
...  
Keyword(s):  
Dermatan Sulfate ◽  
Articular Cartilages

scholarly journals Clinical rearfoot and knee static alignment measurements are not associated with patellofemoral pain syndrome

2012 ◽  
Vol 19 (1) ◽  
pp. 45-51 ◽  
Author(s):  
Sandra Aliberti ◽  
Mariana Souza Xavier Costa ◽  
Sílvia Maria Amado João ◽  
Anice de Campos Pássaro ◽  
Antonio Carlos Arnone ◽  
...  
Keyword(s):  
Odds Ratio ◽  
Pain Syndrome ◽  
Patellofemoral Pain Syndrome ◽  
Patellofemoral Pain ◽  
Cross Sectional ◽  
Q Angle ◽  
Limited Applicability ◽  
Mean Differences ◽  
Continuous Measures ◽  
Control Study

The aim of the present study was to investigate the association between the patellofemoral pain syndrome and the clinical static measurements: the rearfoot and the Q angles. The design was a cross-sectional, observational, case-control study. We evaluated 77 adults (both genders), 30 participants with patellofemoral pain syndrome, and 47 controls. We measured the rearfoot and Q angles by photogrammetry. Independent t-tests were used to compare outcome continuous measures between groups. Outcome continuous data were also transformed into categorical clinical classifications, in order to verify their statistical association with the dysfunction, and χ2 tests for multiple responses were used. There were no differences between groups for rearfoot angle [mean differences: 0.2º (95%CI -1.4-1.8)] and Q angle [mean differences: -0.3º (95%CI -3.0-2.4). No associations were found between increased rearfoot valgus [Odds Ratio: 1.29 (95%CI 0.51-3.25)], as well as increased Q angle [Odds Ratio: 0.77 (95%CI 0.31-1.93)] and the patellofemoral pain syndrome occurrence. Although widely used in clinical practice and theoretically thought, it cannot be affirmed that increased rearfoot valgus and increased Q angle, when statically measured in relaxed stance, are associated with patellofemoral pain syndrome (PFPS). These measures may have limited applicability in screening of the PFPS development.

scholarly journals Finite Element Modelling Simulated Meniscus Translocation and Deformation during Locomotion of the Equine Stifle

Animals ◽  
2019 ◽  
Vol 9 (8) ◽  
pp. 502
Author(s):  
Pasquale Zellmann ◽  
Iris Ribitsch ◽  
Stephan Handschuh ◽  
Christian Peham
Keyword(s):  
Finite Element ◽  
Lateral Meniscus ◽  
Element Model ◽  
Magnetic Resonance Images ◽  
Fem Model ◽  
Stifle Joint ◽  
Loading Patterns ◽  
Articular Cartilages ◽  
Tissue Material ◽  
Treatment Surgery

We developed a finite element model (FEM) of the equine stifle joint to identify pressure peaks and simulate translocation and deformation of the menisci. A series of sectional magnetic resonance images (1.5 T) of the stifle joint of a 23 year old Shetland pony gelding served as basis for image segmentation. Based on the 3D polygon models of femur, tibia, articular cartilages, menisci, collateral ligaments and the meniscotibial ligaments, an FEM model was generated. Tissue material properties were assigned based on data from human (Open knee(s) project) and bovine femoro-tibial joint available in the literature. The FEM model was tested across a range of motion of approximately 30°. Pressure load was overall higher in the lateral meniscus than in the medial. Accordingly, the simulation showed higher translocation and deformation in the lateral compared to the medial meniscus. The results encourage further refinement of this model for studying loading patterns on menisci and articular cartilages as well as the resulting mechanical stress in the subchondral bone (femur and tibia). A functional FEM model can not only help identify segments in the stifle which are predisposed to injury, but also to better understand the progression of certain stifle disorders, simulate treatment/surgery effects and to optimize implant/transplant properties.

scholarly journals Ultrastructural Changes in Articular Cartilages of Immature Beagle Dogs Dosed with Difloxacin, a Fluoroquinolone

1992 ◽  
Vol 29 (3) ◽  
pp. 230-238 ◽  
Author(s):  
J. E. Burkhardt ◽  
M. A. Hill ◽  
J. J. Turek ◽  
W. W. Carlton
Keyword(s):  
Extracellular Matrix ◽  
Body Weight ◽  
Electron Micrographs ◽  
Collagen Fibrils ◽  
Ultrastructural Changes ◽  
Pericellular Matrix ◽  
Skeletally Immature ◽  
Beagle Dogs ◽  
Cross Sectional ◽  
Articular Cartilages

The ultrastructural features of quinolone-induced arthropathy were studied in' the humeral and femoral heads of nine skeletally immature Beagle dogs (3 months old) that were dosed orally with difloxacin at 300 mg/kg body weight and euthanatized 24, 36, or 48 hours later in groups of three. Three age-matched dogs were given a placebo and euthanatized after 48 hours. Mitochondria in chondrocytes had significantly greater cross-sectional areas ( P < 0.05) in electron micrographs from dogs euthanatized after 48 hours of treatment than did those in other groups. There was also a significantly greater percentage of chondrocytes with swollen mitochondria in treated dogs than in the controls ( P < 0.05). These changes preceded the necrosis observed in some chondrocytes in the dogs of the 48-hour group. Disruption of extracellular matrix was first observed in the pericellular matrix of necrotic chondrocytes, indicating that this change was secondary to the changes in chondrocytes. Fissures within cartilages apparently resulted from the loss of the normal association of proteoglycans with collagen fibrils.

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