Dynamic Q-angle is increased in patients with chronic patellofemoral instability and correlates positively with femoral torsion

• Published in: Knee surgery, sports traumatology, arthroscopy : official journal of the ESSKA sports traumatology, arthroscopy : official journal of the ESSKA, 2021-04, Vol.29 (4), p.1224-1231
• Main Authors: Imhoff, Florian B., Cotic, Matthias, Dyrna, Felix G. E., Cote, Mark, Diermeier, Theresa, Achtnich, Andrea, Imhoff, Andreas B., Beitzel, Knut
• Format: Article
• Language: English
• Subjects: Adult; Biomedical materials; Body mass; Body mass index; Body size; Control stability; Correlation analysis; Dynamic stability; Evaluation; Female; Femur; Femur - diagnostic imaging; Femur - physiopathology; Gait; Gait Analysis; Grooves; Humans; Instability; Joint Instability - diagnostic imaging; Joint Instability - physiopathology; Knee; Leg; Male; Medicine; Medicine & Public Health; Orthopedics; Parameters; Patellofemoral Joint - diagnostic imaging; Patellofemoral Joint - physiopathology; Patients; Prospective Studies; Radiography; Recurrence; Regression analysis; Regression models; Reproducibility of Results; Rotation; Stability analysis; Statistical analysis; Tibia - diagnostic imaging; Tibia - physiopathology; Videography; Walking; Young Adult
• ISSN: 0942-2056; 1433-7347
• DOI: 10.1007/s00167-020-06163-6

Purpose The purpose of the study was to evaluate the frontal gait patterns in patients with chronic patellofemoral instability compared to healthy controls. The hypothesis was that internal-rotation–adduction moment of the knee as altered dynamic Q-angle is evident in patients and correlates positively with increased femoral torsion. Methods Thirty-five patients with symptomatic recurrent patellofemoral instability requiring surgical treatment were matched for average age, sex, and body mass index with 15 healthy controls (30 knees). Several clinical and radiographic measurements were taken from each participant: internal and external rotation (hipIR, hipER), Q-angle, tubercle sulcus angle (TS-angle), femoral antetorsion (femAT), tibial tubercle–trochlear groove (TT-TG) distance, and frontal leg axis. Additionally, three frontal gait patterns were defined and recorded: (1) internal-rotation–adduction moment of the knee during normal walking, (2) dynamic valgus of the knee, and (3) Trendelenburg’s sign in a single-leg squat. Randomized videography was evaluated by three independent blinded observers. Statistical analysis was performed using regression models and comparisons of gait patterns and clinical and radiological measurements. Furthermore, observer reliability was correlated to gradings of radiological parameters. Results Patients showed altered dynamic Q-angle gait pattern during normal walking ( p