Patient Specific Instrumentation (PSI) Referencing Osteotomy Technological Transfer - a Randomized Control Trial (RCT)

PSI jig is created based on the pre-operative CT image. Standard medial open wedge osteotomy described previously is performed. Incision is made in the midway between posteromedial border of the tibia and medial aspect of the tibial tuberosity. Sartorius fascia is cut and retracted medially to expose the medial collateral ligament (MCL). Then the PSI jig is positioned onto the tibia. Due to the jig patient specific design (individually based on each patient's CT image), it can fit closely to the proximal tibia. The slot opening on the PSI jig corresponds to 4 cm below the medial joint line and the slot design allow the sawblade cut direction toward the safe zone of the lateral cortex under fluoroscopy. The PSI Jig is removed after the bone cut completed and would not retain in patient's body.

In brief, an incision is made in the midway between posteromedial border of the tibia and medial aspect of the tibial tuberosity. Sartorius fascia is cut and retracted medially to expose the medial collateral ligament (MCL). Two to three K-wires are placed 4 cm below the medial joint line toward the safe zone (an area between the tip of the fibular head and the remnant of fibular head epiphysis line) of the lateral cortex under fluoroscopy and osteotomy is done below and parallel to the k-wires using an oscillating saw leaving the lateral 10 mm intact.