In addition to the program given to the control group, proprioceptive neuromuscular facilitation exercise will be given to the study group as previously described (Gstoettner et al., 2011). These applications will be applied to the patients for 8 weeks, 2 days a week in the clinical environment after the initial evaluation. In addition, both groups will be told that they can contact the researcher when requested.

The control group will receive the usual post-operative care of stretching lower extremity strengthening balance exercises activities of daily living recommendations.

Proprioceptive neuromuscular facilitation exercise will be given to the study group as previously described (Gstoettner et al., 2011). These applications will be applied to the patients for 8 weeks, 2 days a week in the clinical environment after the initial evaluation. In addition, both groups will be told that they can contact the researcher when requested.

On a 10 cm straight line or numeric scale, the patient is asked to mark the pain they feel (0: no pain, 10: excruciating pain).

Functionality level in the patient group with knee OA was measured using WOMAC. WOMAC consists of 3 main headings: pain intensity, stiffness and physical function. The individuals included in the study are asked to score each item between 0 (no pain, stiffness, difficulty) and 5 (very severe pain, stiffness, difficulty). The total score ranges from 0 (no disability) to 96 (complete disability).

The inclinometer is placed distal to the tibial tuberosity. In full knee extension, the patient is asked to perform a single leg squat with eyes closed or unable to see the leg being tested. He/she is allowed to support with his/her hands to prevent loss of balance. When the knee flexion angle of 30° is reached, the patient is asked to stop and stay at this point for 5 seconds. Then return to full knee extension. This movement is repeated 3 times. This time, without any stop command, the patient is asked to reach the same 30° knee flexion angle as in the previous exercises. This application is also repeated 3 times. The "absolute angle difference", which is the difference between the targeted angle in each repetition and the angle realized by the patient, is recorded. The arithmetic mean of the 3 repetitions' absolute angle difference is recorded as the result data.

A suitable background is divided into four identical squares with a "+" shaped line using tape. The squares are numbered with numbers between 1-4 in a clockwise direction and this sequence is explained to the participant. The patient steps from the starting point to squares 1,2,3 and 4 in a way that the direction remains the same and without stepping on the lines. The test is terminated when the last foot contact is interrupted at square 4. The time elapsed during the main measurement is recorded with a stopwatch.