case_images: PMC8553514_01
case_images: MRI showed a thickening of the medial plica protruding far into the medial patellofemoral joint (PFJ).
case_images: CRIOR2021-5879121.001.jpg
case_images: PMC8553514_01_CRIOR2021-5879121.001.jpg
case_images: fig1
case_images: As MRI showed a thickening of the medial plica protruding far into the medial patellofemoral joint (PFJ) (Figure 1), we performed arthroscopic resection; however, there was little improvement.
case_images: Valgus knee and patellar instability appeared on a plane X-ray with a large Q angle: 17 , tilt angle: 21 , and lateral shift: 18%.
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case_images: PMC8553514_01_CRIOR2021-5879121.002.jpg
case_images: fig2
case_images: Afterwards, valgus knee and patellar instability appeared on a plane X-ray with a large Q angle: 17 , tilt angle: 21 , and lateral shift: 18% (Figure 2).
case_images: MRI showed diffuse thickening of both ACLs, which are called celery stalk sign, with high inhomogeneous intensity in the T2-weighted and proton density weighted images.
case_images: CRIOR2021-5879121.003.jpg
case_images: PMC8553514_01_CRIOR2021-5879121.003.jpg
case_images: fig3
case_images: MRI showed diffuse thickening of both ACLs with high inhomogeneous intensity in the T2-weighted and proton density weighted images (Figure 3).
case_images: Arthroscopy showed (a, d) hypertrophied ACLs and the (b, d) presence of intraligamentous mucoid degeneration. (e) The posterolateral bundles in the ACLs were slightly loose at the lateral portion of the intercondylar notch. (c, e) Further, there was a partial depression of cartilage in the same region.
case_images: CRIOR2021-5879121.004.jpg
case_images: PMC8553514_01_CRIOR2021-5879121.004.jpg
case_images: fig4
case_images: Further, there was a partial depression of cartilage in the same region (Figure 4).
case_images: (a, c) Both hematoxylin and eosin stain, (b) Alcian blue stain, and (d) Masson trichrome stain. All of these results indicated the presence of mucoid degeneration.
case_images: CRIOR2021-5879121.005.jpg
case_images: PMC8553514_01_CRIOR2021-5879121.005.jpg
case_images: fig5
case_images: To support our interventions, pathological results also indicated the presence of mucoid degeneration in the ACLs (Figure 5).