Magnetic resonance imaging for assessment of the quadriceps tendon cross-sectional area as an adjunctive diagnostic parameter in patients with patellofemoral pain syndrome

Objectives: In this study, we aimed to provide a more valuable diagnostic parameter and more equivocal assessment of the diagnostic potential of patellofemoral pain syndrome (PFPS) by comparing the quadriceps tendon cross-sectional area (QTCSA) with the quadriceps tendon thickness (QTT), a traditional measure of quadriceps tendon hypertrophy. Patients and methods: Between March 2014 and August 2020, a total of 30 patients with PFPS (16 males, 14 females; mean age, 30.4 +/- 11.2 years; range, 16 to 49 years) and 30 healthy individuals (19 males, 11 females; mean age: 30.8 +/- 13.8 years; range, 17 to 62 years) who underwent knee magnetic resonance imaging (MRI) were retrospectively analyzed. T1-weighted turbo spin-echo transverse MRI scans were obtained. The QTCSA was measured on the axial angled phases of the images by drawing outlines, and the QTT was measured at the most hypertrophied quadriceps tendon. Results: The mean QTT and QTCSA in the patients with PFPS (6.33 +/- 0.80 mm and 155.77 +/- 36.60 mm2, respectively) were significantly higher than those in the control group (5.77 +/- 0.36 mm and 111.90 +/- 24.10 mm2, respectively; p<0.001, for both). The receiver operating characteristic curve was used to confirm the sensitivities and specificities for both the QTT and QTCSA as predictors of PFPS. The optimal diagnostic cut-off value for QTT was 5.98 mm, with a sensitivity of 66.7%, a specificity of 70.0%, and an area under the curve (AUC) of 0.75 (range, 0.62 to 0.88). The optimal diagnostic cut-off value for QTCSA was 121.04 mm(2), with a sensitivity of 73.3%, a specificity of 70.0%, and an AUC of 0.83 (range, 0.74 to 0.93). Conclusion: Based on our study results, the QTCSA seems to be a more reliable diagnostic indicator for PFPS than QTT. Keywords: Diagnosis, hypertrophy, magnetic resonance imaging, patellofemoral pain syndrome, quadriceps muscle.