Q Angle in Static and Dynamic Postures
Condition: Quadriceps Muscle; Orthopedic Disorder
MeSH terms: Musculoskeletal Diseases
Study type: Observational

Summary: 
      The Q angle, also known as the quadriceps angle, is defined as the angle formed between the
      quadriceps muscles and the patella tendon. It was first described by Brattstrom in 1964 (1).
      The Q angle is the angle between the line extending from the anterior superior of the spina
      iliaca to the midpoint of the patella and the line extending from the midpoint of the patella
      to the tuberositas tibia (2). Normally, this angle is between 8-14 degrees in men and 11-20
      degrees in women. Any alignment change that increases the Q angle is thought to increase the
      lateral force on the patella.

      The Q angle is generally evaluated in static postures in the literature. The Q angle value
      varies according to the patient's gender, the contractility of the quadriceps, and the
      patient's posture (standing or supine) (3).

      Q angle was evaluated in a static posture with a standard goniometer or computerized
      biophotogrammetry (4) Q angle changes with the forces applied by dynamic structures. It is
      insufficient to evaluate only in a static posture. Therefore, the aim of this study is to
      examine the effect of dynamic structures on the Q angle using 2D gait analysis (video) and to
      detect the early signs of deviation of changes in the q angle.
    

Detailed description: 
      The Q angle is a very important tool in evaluating the function of the knee joint and
      describing the biomechanical alignment and function of the lower extremity (5). Abnormal
      values may cause joint problems later on, and in some cases, may affect the quadriceps reflex
      time, causing subluxation of the patella or an increased risk of developing anterior cruciate
      ligament ACL injury (5). For this reason, the Q angle is routinely and regularly used as an
      evaluation parameter when diagnosing many knee-related problems, including anterior knee
      pain, osteoarthritis, and degenerative knee disorders. When evaluated correctly, it provides
      very useful information about the alignment of the pelvis, legs and feet (6-8).

      Therefore, determining the Q angle is very important, especially for athletic and physically
      active patients (9). In most studies, the Q angle was measured using a goniometer or with a
      modified goniometer (10-12). Biedert et al. by radiography (3). Braz et al. determined the Q
      angle with digital photogrammetry (13). In the literature, the q angle was generally
      evaluated in the supine or standing position (14). Higher Q angle values have been reported
      when transitioning from the supine position to the standing position (15). The increased Q
      angle while standing has been attributed to changes in lower extremity alignment due to
      weight bearing. In studies in the literature, the q angle was generally evaluated in static
      postures. In an ideal postural alignment, there should be a dynamic balance between muscles,
      joints and skeletal structures (16-17). Not only static structures but also dynamic
      structures are responsible for problems related to the alignment of the patella. For this
      reason, it is important to know the changes in the q angle not only in static postures but
      also in dynamic postures. Evaluation in correct postures is essential for diagnosis, planning
      and follow-up of the development and results of physical therapy (16).

      The primary aim of this study was to report the prevalence and normative reference values of
      the q angle in the midstance phase of gait using 2D analysis (video).

      The secondary aim of this study is to examine the variation of q angles during the midstance
      phase gait with Q angle values in static postures.

      The tertiary aim of this study is to examine the relationship of q angles with different
      parameters such as age, gender, BMI, lower extremity strength, and hypermobility.

      Demographic information (age, weight, height, etc.) will be obtained from healthy volunteers
      included in the study. As primary outcome measures, q-angles will be measured in static
      posture (supine and standing) and dynamic posture (with video analysis). Markers will be
      placed on the relevant places (SIAS, Patella middle and tuberositas tibia). Afterward, the
      video recordings will be played in slow motion and the evaluators will pause the video during
      the mid-stance phases of the gait, and the q-angles will be determined with the
      two-dimensional video analysis software (Kinoveav.0.8.15).

      As secondary outcome measures, pelvis width and thigh length with a tape measure and femoral
      anteversion goniometer with quadriceps muscle strength, hamstring muscle strength, Hip
      abduction, adduction, internal and external rotation and extension muscle strength with
      hand-held dynamometer, joint mobility with Beighton score, foot posture index and
      functionality will be evaluated by walking 8 meters.
    

Intervention name(s): Evaluation of q angles different positions; Physical examination; Functional mobility assessment
Intervention type(s): Other; Other; Other
Intervention description(s): Q angle evaluation in two different static postures (upright and supine position) and dynamic posture during the midstance phase of the gait; With goniometric evaluations, the femoral anteversion angle will be measured. Pelvis width and thigh length will be measured with a tape measure. Quadriceps muscle strength, hamstring muscle strength, Hip abduction, adduction, internal and external rotation and extension muscle strength will be measured with hand-held dynamometer.
Joint mobility will be assessed with the Beighton score and foot posture will be evaluated with the foot posture index-6 (FPI-6).; 10-meter walking test will be conducted to understand functional mobility.
Observational model: Cohort
Time perspective: Prospective
Sampling method: Probability Sample
Study population: 
        Volunteers aged 18-25 years, healthy individuals without any spinal or neurologic injury
        and any injury leading to ligament, muscle or bone defect in their lower extremities.
      
Keywords: q angle; dynamic q angle; lower extremity function