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

Patient Specific Instrumentation (PSI) Referencing Osteotomy Technological Transfer and Education - a PSI High Tibial Osteotomy, Double-blinded, Randomized Controlled Trial - the PROTECTED HTO (High Tibial Osteotomy) Trial

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.

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.

Inclusion Criteria:

• symptomatic patient with medial compartment knee OA
• medial compartment OA was grade 3 or milder according to Kellgren-Lawrence classification

Exclusion Criteria:

• lateral compartment OA
• symptomatic patellofemoral compartment OA,
• inflammatory arthritis,
• significant loss of knee joint range in flexion (less than 100°) or in extension (less than - 10°),
• ligamentous instability,
• obesity with a body mass index greater than 30,
• significant psychological disorder
• inability to communicate in Chinese or English language