The aim of this study is to assess the effect of balance exercise on dynamic balance and physical function in 80 patients with different grades of primary knee osteoarthritis (KOA).

The study will include 80 patients with primary knee osteoarthritis divided into 4 groups according to the Kellgren and Lawrence grading scale (KL):

Group 1: 20 patients with grade I KOA Group 2: 20 patients with grade II KOA Group 3: 20 patients with grade III KOA Group 4: 20 patients with grade IV KOA

• Patients will undergo pre-exercise and post- exercise assessment with:

  1. Western Ontario and McMaster University Osteoarthritis Index (WOMAC)
  2. Modified Stare Excursion Balance test
  3. Timed up and Go test

• Exercise program includes:

  1. Lower extremity kinesthesia and balance exercise program
  2. Strength exercise program

Inclusion Criteria:

• Patients with primary knee osteoarthritis according to the EULAR recommendations 2010.
• Patients can complete at least stage 1 of balance and exercise program (minimum of 2 weeks)

Exclusion Criteria:

• Patients that cannot complete at least stage 1 of balance and exercise program
• Patients with medical conditions affecting postural balance including visual, inner ear and neurological problems.
• Patients with lower limb joint or bony problems other than primary knee osteoarthritis .
• Patients with secondary KOA.
• Patients who received intra- articular joint injection in 1 or both knees in the past 90 days.

Post-exercise training assessment will be done by an investigator not involved in the study and unaware of the grading of KOA or of the pre-exercise assessment.