PMC7183096_01
A radiograph (A) and MR images (B-D) at first presentation; B: T1-weighted axial image; C: STIR axial image; D: STIR coronal image. The tumor was located just underneath the joint cartilage (black arrows), and was surrounded by extensive oedema (*) and accompanied by hip joint effusion (white arrow).
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Radiographic studies revealed a well-defined osteolytic lesion of 2 cm in diameter in the femoral head with joint effusion and extensive oedema around the lesion (Fig. 1).
Paired registration using 10 points including the distal portion of the femur, surface marking of 36 points, and the results of registration.
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After paired registration and 36 surface markings, we were able to obtain accuracy of 0.7 mm (Fig. 2).
Intraoperative navigation monitor showing the shortest route to the tumor. The blue needle-like object represents the tracker, and the yellow line shows the distance to the tumor.
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The navigation system revealed that the tumor was accessible from anterior femoral neck with the left hip in 20 degrees of internal rotation (Fig. 3).
Hematoxylin and eosin staining of the curetted specimen.
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The pathologic diagnosis of the curetted specimen was chondroblastoma (Fig. 4).
A reconstructed CT image at two weeks post-surgery. Red arrows show the route taken to reach the tumor.
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CT images at two weeks after surgery showed that the route taken to the tumor was the shortest possible (Fig. 5).
A STIR MR image at 18 months after surgery (A) and a radiograph at 31 months after surgery (B).
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The latest radiograph showed bone regeneration in the defect after tumor removal (Fig. 6).