PMC5310171_01
Preoperative anteroposterior (A) radiograph of the left knee of the 17-year-old female patient showing periosteal reaction on the medial aspect of the distal femur. The coronal (B) and axial (C) preoperative MRI showed tumor localization in the distal diaphysis of the femur.
gr1.jpg
PMC5310171_01_gr1.jpg
fig0005
Radiographs of the knee demonstrated periosteal reaction, an osteolytic lesion in the medial part of the distal femur, and that the growth plate was closed (Fig. 1a). Preoperative MRI showed the tumor involving most of the distal femur, but the previously seen contamination of the medial part of the articular capsule and the patella were no longer appreciable (Fig. 1b, c).
Computer simulation view of endoprosthesis implantation in the tibia (A-F). (A-C) axial section from proximal to distal, (D-F) sagittal views from center to medial. These sequential views showed the canal of the tibia was too narrow to allow for insertion of the endoprosthesis.
gr2.jpg
PMC5310171_01_gr2.jpg
fig0010
Preoperative planning with the Mimics (Biomet Japan, LLC., Tokyo, Japan) computer simulation system revealed that the medullary cavity of the proximal part of the tibia was too narrow for insertion of the smallest diameter prosthesis available in Japan, although the femur component of the prosthesis was of appropriate size (Fig. 2a-f).
3-D plaster model (A-C). Bilateral lines were planned as split line.
gr3.jpg
PMC5310171_01_gr3.jpg
fig0015
We made a 3D plaster model to confirm the split lines needed during the operation (Fig. 3).
Two months after distal femur replacement. Anteroposterior (A) and lateral (B) radiographs. Lateral radiograph demonstrates split lines below band.
gr4.jpg
PMC5310171_01_gr4.jpg
fig0020
Postoperative radiographs showed bilateral split lines (Fig. 4a, b).
15 months after distal femur replacement. Anteroposterior (A) and lateral (B) radiographs. Lateral radiograph demonstrates healing split lines.
gr5.jpg
PMC5310171_01_gr5.jpg
fig0025
ROM was extension to -5  and flexion to 120 . Radiographs demonstrated shortening of the bilateral longitudinal splits (Fig. 5a, b).
CT views of bilateral split lines 2 months after operation (A-D) and 15 months after operations (E-H). Each section shows bony union of the bilateral split clefts.
gr6.jpg
PMC5310171_01_gr6.jpg
fig0030
The bilateral clefts were healing spontaneously evident by comparing the CT from 2 months after operation and the CT from 15 months after the operation (Fig. 6a-h).