Table 1.

Pearls and Pitfalls for Modified Technique of Tibial Tuberosity Transfer

Pearls

The skin incision should be positioned either slightly medial to the tibial tuberosity (when combining tibial tuberosity transfer with MPFL reconstruction) or lateral to the tibial tuberosity (when performing isolated tibial tuberosity transfer).

Internal rotation of the foot facilitates proper orientation of the osteotomy.

The distal soft-tissue attachments of the tuberosity fragment should always be preserved.

To create a smooth surface, the surgeon should avoid creating a step at the proximal end of the osteotomy.

Releasing the fat pad from the patellar tendon undersurface facilitates medialization of the tibial tuberosity fragment.

The posterior cortex should only be scored by the cannulated drill.

The surgeon should add 4 mm to the actual measured length for the cannulated screw.

Pitfalls

Placing the incision too lateral or too medial can lead to excessive soft-tissue dissection.

Performing the osteotomy with the foot externally rotated can lead to the plane of the osteotomy being downsloping.

Severance of the distal soft-tissue attachments of the tuberosity fragment can lead to proximal migration of the fragment, leading to patella alta.

Breaching the posterior cortex with the cannulated drill will lead to the guidewire backing out along with the drill.

MPFL, medial patellofemoral ligament.