Knee osteoarthritis (KOA) is a chronic progressive disease that imparts substantial socioeconomic burden to society and healthcare systems. The prevalence of KOA has dramatically risen in recent decades due to consistent increases in life expectancy, and demand for joint replacement continues to rise. Total knee replacement is indicated for end-stage KOA, as it is very effective in terms of pain relief, improvement of function, and quality of life. However, the investigators will be facing an unsustainable joint replacement burden, with significant healthcare budget and health workforce implications. To alleviate this problem, different strategies including reinforce the importance of education and exercise are included; as previous studies showed that less than 40% of patients with KOA received non-pharmacological treatment, indicating that the uptake of evidence-based guidelines in clinical practice and rehabilitation is still suboptimal. Several literatures revealed that quadriceps and hamstrings strength exercise could effectively reduce pain. It has widely accepted that patients with end stage KOA will eventually pursue total knee replacement as the only viable option, and exercise has low efficacy in reduction of pain and disability in this group of patients. So, the investigators would like to know whether exercise therapy can help severe KOA patients

Inclusion Criteria:

• Patients with end-stage knee osteoarthritis on queue for scheduling primary total knee replacement
• Completed 8-week course of physiotherapy program

Exclusion Criteria:

• TKR during the last 12 months
• Severe heart failure or neurological diseases affecting physical functions