Q-angle and J-sign: Indicative of Maltracking Subgroups in Patellofemoral Pain

Abstract

Mechanical factors related to patellofemoral pain syndrome and maltracking are poorly understood. Clinically, the Q-angle, J-sign, and lateral hypermobility commonly are used to evaluate patellar maltracking. However, these measures have yet to be correlated to specific three-dimensional patellofemoral displacements and rotations. Thus, we tested the hypotheses that increased Q-angle, lateral hypermobility, and J-sign correlate with three-dimensional patellofemoral displacements and rotations. We also determined whether multiple maltracking patterns can be discriminated, based on patellofemoral displacements and rotations. Three-dimensional patellofemoral motion data were acquired during active extensionflexion using dynamic MRI in 30 knees diagnosed with patellofemoral pain and at least one clinical sign of patellar maltracking (Q-angle, lateral hypermobility, or J-sign) and in 37 asymptomatic knees. Although the Q-angle is assumed to indicate lateral patellar subluxation, our data supported a correlation between the Q-angle and medial, not lateral, patellar displacement. We identified two distinct maltracking groups based on patellofemoral lateral-medial displacement, but the same groups could not be discriminated based on standard clinical measures (eg, Q-angle, lateral hypermobility, and J-sign). A more precise definition of abnormal three-dimensional patellofemoral motion, including identifying subgroups in the patellofemoral pain population, may allow more targeted and effective treatments.

Relationship of the Frontal Knee Alignment Measured by the HKA-Angle with the Relative Activation of the Quadriceps Muscles

“…These findings from our results may partially suggest a plausible explanation on the causes creating controversies among the studies over the Q-angle and PFPS (Freedman et al, 2014;Park & Stefanyshyn, 2011;Sheehan et al, 2010).…”

Demystifying Tibial-Tuberosity Trochlear Groove Distance, the J-Sign and Trochlear Dysplasia: An Imaging Encomium

“…To the best of our efforts, we have not been able to detect a comparable study to analogize. If the TTTG distance were indeed a radiological analogue of the Q-angle, which in itself is dubious, we could draw a parallel with the study by Sheehan et al [18] who found no correlation of the Qangle and the clinical J-sign. McDermott et al [19] deemed the J-sign useful as preoperative estimation of the distance needed for tibial tuberosity transfer, quantifying the clinical J-sign with the help of preoperative axial MRI-images in full knee extension and 30 degrees of flexion.…”

Comparison of Exercise Open Kinetic Chain and Closed Kinetic Chain in The Rehabilitation of Patellofemoral Dysfunction: an Updated Revision

“…However, pain retro patella and the lateral face can also be diagnosed (4). These symptoms are caused by structural orbiomechani cal changes of the joint, which becomes exacerbated by activities such as going up and down stairs, sit for a prolonged period, squatting or kneeling (2,5,21), resulting in increased compressive forces in the joint patellofemoral (4,6). Other signs are also present as the patellar crepitus, swelling, and joint blockage (6).…”

“…The mechanism may be multifaceted (22,23). However, it may be related to abnormal biomecha nics, highlighting, among these, the static and dynamic unbalance (1,21).…”