The investigators randomly divided the knee osteoarthritis patients met the inclusive criteria into two groups (study group and control group). Placement of balanced buttress absorbable spacer and total knee arthroplasty were conducted. The clinical outcome of two groups were compared in this study.

Knee osteoarthritis, caused by non-uniform settlement of medial and lateral tibial plateau, was not uncommon in clinic. Medial stenosis was the most type of the disease. The symptoms included knee pain during walking and varus deformity of lower limbs. Total knee arthroplasty and tibial osteotomy were two common conventional treatment of the knee osteoarthritis, which were not minimally invasive and bring great financial burden to patients' family. The investigators planned to recruit 150 patients of knee osteoarthritis into this study, which were randomly divided into two groups (study group and control group). For the patients of study group, a balanced buttress absorbable spacer was placed into the gap after the osteotomy of tibia and fibula to modify the lower limb line. However, total knee arthroplasty was conducted for the patients of control group. The patients were followed up and the clinical outcomes were compared in this study.

Inclusion Criteria:

• 40-80 years old
• Medial stenosis of the knee
• Varus deformity less than 20 degrees

Exclusion Criteria:

• Lateral stenosis of the knee
• Hepatic renal dysfunction
• Refuse to participate the study