PMC7111179_01
Magnetic resonance imaging study showing relatively symmetrical lesions of avascular necrosis in the coronal (A), sagittal (B), and transverse (C) slices of the bilateral diaphyseal-metaphyseal junctions of the tibias. (D) Note the osteonecrotic lesion in the tubercle of the left calcaneus. LT, left; RT, right.
gr1_lrg.jpg
PMC7111179_01_gr1_lrg.jpg
fig1
The previous surgeon she had consulted had ordered a magnetic resonance imaging study and diagnosed AVN of the bilateral distal tibias (Fig. 1 ).
Computed tomography study showing lesions of avascular necrosis in the coronal (A), sagittal (B), and transverse (C) slices of the diaphyseal-metaphyseal junctions of the right tibia.
gr2_lrg.jpg
PMC7111179_01_gr2_lrg.jpg
fig2
For preoperative planning and to rule out any pathologic fractures, a computed tomography scan was ordered (Fig. 2 ).
Arthroscopic views of the right ankle showing synovitis (A and B); medial shoulder osteochondritis dissecans (C and D); and subsequent curettage and micro-fracture of the lesion (E and F). Note that the tibial cortex is intact with no signs of communication with the osteonecrotic cyst.
gr3_lrg.jpg
PMC7111179_01_gr3_lrg.jpg
fig3
On debridement of the synovitis, an osteochondral defect measuring approximately 5 mm in diameter was noted on the anteromedial shoulder (Fig. 3 ).
View of 8-cm linear incision along the anterior aspect of the distal tibia just lateral to the course of the anterior tibial tendon. Note the incision sites from the anterior medial and lateral portals from the ankle arthroscopy.
gr4_lrg.jpg
PMC7111179_01_gr4_lrg.jpg
fig4
An 8-cm liner incision was made along the anterior aspect of the distal tibia just lateral to the course of the anterior tibial tendon (Fig. 4 ).
The cortical window measuring approximately 3 x 2 cm was carefully resected using a sagittal saw.
gr5_lrg.jpg
PMC7111179_01_gr5_lrg.jpg
fig5
A cortical window measuring approximately 3 cm in length and 2 cm in width was then carefully reflected using a sagittal saw (Fig. 5 ).
An approximately 10-cm3 deficit with intact cortical bone posteriorly.
gr6_lrg.jpg
PMC7111179_01_gr6_lrg.jpg
fig6
Once all the necrotic bone had been removed, which was noted to be quite spongy in consistency, an approximately 10-cm3 deficit was left to fill (Fig. 6 ).
The defect was filled with AlloStem  and geneX  (A), and the cortical window was placed back into its original orientation (B).
gr7_lrg.jpg
PMC7111179_01_gr7_lrg.jpg
fig7
The defect was filled with AlloStem  Stem Cell Bone Growth Substitute (AlloSource, Centennial, CO), and geneX  bone putty (Biocomposites Inc., Wilmington, NC; Fig. 7 ).
The defect and cortical window were secured with a Synthes/Depuy mesh plate. Note the 1 screw going directly through the cortical window.
gr8_lrg.jpg
PMC7111179_01_gr8_lrg.jpg
fig8
The plate was secured with a combination of 2.7-mm unicortical and bicortical locking screws, with only 1 screw going directly through the cortical window (Fig. 8 ).
Radiographs (A) and computed tomography images (B) at 9 weeks postoperatively showing the hardware in good alignment, with no residual avascular necrosis. Incorporation of the bone substitutes into native bone can also be observed.
gr9_lrg.jpg
PMC7111179_01_gr9_lrg.jpg
fig9
Radiographs and computed tomography scanning showed excellent consolidation of the defect with native bone incorporation (Fig. 9 ).
Histopathologic slide showing nonviable trabecular bone with empty cellular lacunae indicative of osteonecrosis.
gr10_lrg.jpg
PMC7111179_01_gr10_lrg.jpg
fig10
The cultures and pathology specimens confirmed the diagnosis of ON with no infection present (Fig. 10 ).
Final radiographs taken 24 months postoperatively showing native bone incorporation with all hardware intact.
gr11_lrg.jpg
PMC7111179_01_gr11_lrg.jpg
fig11
Final radiographs were also taken at that time and showed excellent deficit incorporation with native bone visible (Fig. 11 ).