case_images: PMC9301303_01
case_images: Preoperative x-ray of the left knee. (A) AP view; (B) lateral view; (C) full-weight bearing view; (D) merchant view. *Pellegrini-Stieda lesion.
case_images: fsurg-09-922896-g001.jpg
case_images: PMC9301303_01_fsurg-09-922896-g001.jpg
case_images: F1
case_images: An x-ray of the left knee indicated a degenerative lesion in the medial knee compartment, presented as narrowed joint space and subchondral sclerosis (Figure 1A). A strip-shaped high-density shadow in the medial is noticeable (Figures 1A, C). According to the anteroposterior and lateral view of the x-ray, the cartilage wear area was mainly located in the anteromedial of the left knee (Figures 1A, B). The full-weight-bearing x-ray showed varus deformity of the left knee, and the intra-articular deformity occupied the main (Figure 1D).
case_images: Preoperative MRI of the left knee. (A) Coronal T2 weighted image (T2WI); (B) transverse axis proton density weighted image (PDWI); (C) sagittal T2WI. *Pellegrini-Stieda lesion.
case_images: fsurg-09-922896-g002.jpg
case_images: PMC9301303_01_fsurg-09-922896-g002.jpg
case_images: F2
case_images: Further MRI examination of the left knee showed ossification involving medial collateral ligament (MCL) and medial joint capsule (Figure 2).
case_images: Pathology of the synovium.
case_images: fsurg-09-922896-g003.jpg
case_images: PMC9301303_01_fsurg-09-922896-g003.jpg
case_images: F3
case_images: The pathology of the synovium found villous hyperplasia and indicated acute and chronic inflammation (Figure 3).
case_images: Postoperative x-ray during discharge and follow-up. (A-C) X-ray at discharge, *Pellegrini-Stieda lesion; (D) postoperative 3 months; (E) postoperative 9 months; (F) postoperative 3.5 years.
case_images: fsurg-09-922896-g004.jpg
case_images: PMC9301303_01_fsurg-09-922896-g004.jpg
case_images: F4
case_images: The postoperative x-ray indicated that the varus deformity was corrected, and the position of the prosthesis was satisfactory (Figures 4A-C). However, the postoperative 3-month x-ray showed that the ossification lesion shrank obviously and became discontinuous (Figure 4D). Nine months after surgery, the x-ray found that the ossification lesion entirely disappeared (Figure 4E). The latest outpatient follow-up was on postoperative 3.5 years, and no relapse of the ossification lesion was found on the x-ray (Figure 4F).