The purpose of this RCT is to determine the results of opening-wedge high tibial osteotomy in patients with genovarum deformity using iliac crest allograft compared to the results when using iliac crest autograft.

Inclusion Criteria:

• Varus malalignment of knee with of without osteoarthritis: the angle between the articular surface and anatomical axis of tibia< 82 degrees
• at least 7.5 mm opening wedge is needed in medial proximal tibia to correct the deformity assessed during pre-op planning

Exclusion Criteria:

• symptomatic lateral compartment osteoarthritis of knee
• rheumatoid arthritis or other inflammatory joint diseases
• less than 100 degrees of knee range of motion
• grade III laxity in knee collateral ligaments
• history of surgery or fracture in the limb
• >15 degrees flexion contracture
• age <16 or >60 years
• >20 degrees varus deformity
• failure to attend follow-up visits
• sever bone loss in medial tibial plateau or medial femoral condyle
• >1cm joint subluxation
• presence of lateral trust during walking
• presence of patella baja
• skin derangements on medial proximal tibia
• any form of nicotine addiction