Patient Specific Instrumentation (PSI) Referencing Osteotomy Technological Transfer - a Randomized Control Trial (RCT)
Condition: Osteotomy; Randomized Controlled Trial
Study type: Interventional

Summary: 
      Medial open wedge high tibial osteotomy is a surgery performed to treat knee osteoarthritis
      in young patients.Recently with our department advance of technology, the investigators
      performed computed tomography for the patient's lower limb and 3D reconstruct the image.
      Based on the 3D image, the investigators planned our planned osteotomy cut on computer
      software Materialize 3 and the investigators then 3D printed a metal jig that has a slot to
      produce the osteotomy and also protected the neurovascular bundles. Therefore these metal
      jigs are specific to each patients. The investigators have performed a few cases of HTO under
      this extra metal jig protection and guidance and noted it has improved accuracy and safety
      clinically. However, whether it has scientific significance difference in accuracy is not
      known.
    

Detailed description: 
      Medial open wedge high tibial osteotomy is a surgery performed to treat knee osteoarthritis
      in young patients. Currently the investigators perform high tibial osteotomy under the
      guidance of computer navigation to achieve the required alignment. During conventional high
      tibial osteotomy the bone cut is done by free hand cutting, there are risks of cutting into
      the posterior proximal tibia compartment and transect the neurovascular bundles which is a
      surgical disaster and may then lead to loss of limb. And the accuracy of free hand cutting is
      limited by experience of surgeons. In our conventional high tibial osteotomy transection of
      neurovascular bundles has never happened given our meticulous surgical technique but the
      investigators believe an extra protection is always beneficial to our patients. Recently with
      our department advance of technology, the investigators performed computed tomography for the
      patient's lower limb and 3D reconstruct the image. Based on the 3D image, the investigators
      planned our planned osteotomy cut on computer software Materialize 3 and the investigators
      then 3D printed a metal jig that has a slot to produce the osteotomy and also protected the
      neurovascular bundles. Therefore these metal jigs are specific to each patients. The
      investigators have performed a few cases of HTO under this extra metal jig protection and
      guidance and noted it has improved accuracy and safety clinically. However, whether it has
      scientific significance difference in accuracy is not known.
    

Intervention name(s): 3D printed patient specific metal jigs (PSI jig); HTO with navigation
Intervention type(s): Procedure; Procedure
Intervention description(s): 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.
Allocation: Randomized
Intervention model: Parallel Assignment
Intervention model description: Control group: High tibial osteotomy with navigation Intervention group: High tibial osteotomy with navigation and PSI jig
Masking: Double (Participant, Outcomes Assessor)
Primary purpose: Treatment
Keywords: Patient Specific Instrumentation; Randomized controlled trial; High Tibial Osteotomy