Table 1.

Pearls and Pitfalls

Pearls

• Position the leg holders so that the knee is maintained at 60° of flexion and to obtain a perfect lateral fluoroscopic view

•Place the plate to the bone to assess where the starting point of the osteotomy should be for adequate fixation distal to the osteotomy

•When placing the second K-wire obtain a perfect lateral fluoroscopic view of the distal femur and use a radio-opaque tool to assess that you are creating a perpendicular saw cut. We prefer an army/navy retractor

•It is important to preserve 0.5 to 1 cm of medial femoral cortex as a “hinge” to preserve stability of the osteotomy.

•Make saw cut along the upper surface of the K-wires to avoid drifting distally and risking fracture into the articular surface

•Use a smaller quarter-inch saw blade and a thin, flexible osteotome to make the perpendicular biplanar cut along the anterior cortex

Pitfalls

•Ensure placement of the posterior retractor along the plane of the saw blade to protect the posterior neurovascular structures

•Perform saw cut with knee in flexed position to allow posterior neurovascular structures to fall away from the surgical field

•Open osteotomy slowly with passive force to avoid iatrogenic fracture of medial hinge

•Assess alignment intraoperatively using an alignment rod after placement of the allograft bone wedge to ensure accurate correction

•Use care when extending and flexing the knee for images to avoid iatrogenic fracture of the anterior flange