Bilateral Variability of the Quadriceps Angle (Q angle) in an Adult Kashmiri population

(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.

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Greater Q angle may not be a risk factor of Patellofemoral Pain Syndrome

Clinical Biomechanics ◽

10.1016/j.clinbiomech.2010.11.015 ◽

2011 ◽

Vol 26 (4) ◽

pp. 392-396 ◽

Cited By ~ 23

Author(s):

Sang-Kyoon Park ◽

Darren J. Stefanyshyn

Keyword(s):

Risk Factor ◽

Pain Syndrome ◽

Patellofemoral Pain Syndrome ◽

Patellofemoral Pain ◽

Q Angle

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

Surgical and Radiologic Anatomy ◽

10.1007/s00276-010-0715-4 ◽

2010 ◽

Vol 33 (2) ◽

pp. 97-104 ◽

Cited By ~ 8

Author(s):

Aikaterini E. Tsakoniti ◽

Dimitris G. Mandalidis ◽

Spyros I. Athanasopoulos ◽

Christoforos A. Stoupis

Keyword(s):

Q Angle ◽

Articular Cartilages

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Response to letter to the editor “A reliable Q angle measurement using a standardized protocol”

The Knee ◽

10.1016/j.knee.2020.07.091 ◽

2020 ◽

Vol 27 (6) ◽

pp. 2023-2024

Author(s):

Alan C. Merchant

Keyword(s):

Angle Measurement ◽

Standardized Protocol ◽

Letter To The Editor ◽

Q Angle

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

Fisioterapia e Pesquisa ◽

10.1590/s1809-29502012000100009 ◽

2012 ◽

Vol 19 (1) ◽

pp. 45-51 ◽

Cited By ~ 2

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.

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