Unicompartmental knee arthroplasty (UKA) and High Tibial Osteotomy are both valid treatment options for isolated medial knee osteoarthritis. Literature to date is lacking high grade evidence of the outcomes between these procedures. This is a study protocol for randomized controlled trial comparing UKA vs HTO in late stage medial knee osteoarthritis.

Inclusion Criteria:

• Isolated KL 3-4 medial knee arthrosis
• Varus > 3 degrees
• Age 45-65 years

Exclusion Criteria:

• Post-traumatic arthrosis
• Arthrosis in the lateral compartment more than KL grade I in MRI
• Post- traumatic arthrosis
• Instability
• Malignancy Obesity