The KOOS consists of five subscales - Symptoms (S), Pain (P), Functional activities of daily living (ADL), Sport and Recreation Function (Sport/Rec) and Knee-Related Quality of life (QOL) - and total KOOS Outcome (O) scores. Standardized answer options are provided (5 Likert boxes), and each question is assigned a score from 0 to 4. A normalized score (100 indicating no symptoms and 0 indicating extreme symptoms) is calculated for each subscale.

OKS consists of 12 questions. Standardized answer options are provided (5 Likert boxes), and each question is assigned a score from 0 to 4. A score of 40-48 indicates no symptoms or satisfactory joint function, 30-39 moderate knee arthritis, 20-29 moderate to severe knee arthritis, and 0-19 severe knee arthritis.

Quadriceps and hamstring muscle strength at 60˚/s and 180˚/s were measured with an isokinetic dynamometer. For 180˚/s, five trial and fifteen testing repetitions were used, and for 60˚/s, three trial and three testing repetitions were used. The resting time between trial and testing was two minutes, between different speeds one minute, and between legs two minutes. The maximum peak torques were used in the statistical analysis.

The single-leg hop test (SLHT) for distance was used for lower limb functional testing. The test started with the participant standing on one leg, toes behind a marked line, and hands on hips throughout to avoid aiding the jump by swinging the arms. The participant was instructed to jump as far as possible and land on the same leg without losing balance. If the patient made contact with the ground with the contralateral limb, lost balance, or made additional hops after landing, the distance was not measured and the jump void. The distance was measured from the starting line to the heel of the leg being tested. For both legs, three trials and three jumps for maximal effort were allowed. The longest distance for both the left leg and the right leg were used in the statistical analysis.

The Y-balance test (YBT) (Move2Perform, United States) for anterior reach was used to measure dynamic balance. Participants performed three trials to familiarize themselves with the test, and then undertook three tests. The test started with the participant standing barefoot on the testing kit. The patients had to push a wooden box with the contralateral leg as far as possible with continuous movement and return to their starting position without losing balance. The longest distance achieved was used in the statistical analysis.

Body mass (kg) and height (cm) were measured, and the body mass index (BMI) was calculated as kg/m2.

The Tampa Scale of Kinesiophobia (TSK-17) was developed as a self-reported checklist to measure fear of pain during movement and fear of reinjury. The TSK-17 consists of 17 questions. Standardized answer options are given as a 4-point Likert scale, and each question is assigned a score from 1 to 4. A normalized score between 17 and 68 points is calculated. A score of 37 or over indicates kinesiophobia.

Quadriceps and hamstring muscle strength at 60˚/s and 180˚/s were measured with an isokinetic dynamometer. For 180˚/s, five trial and fifteen testing repetitions were used, and for 60˚/s, three trial and three testing repetitions were used. The resting time between trial and testing was two minutes, between different speeds one minute, and between legs two minutes. The maximum peak torques were used in the statistical analysis.

The single-leg hop test (SLHT) for distance was used for lower limb functional testing. The test started with the participant standing on one leg, toes behind a marked line, and hands on hips throughout to avoid aiding the jump by swinging the arms. The participant was instructed to jump as far as possible and land on the same leg without losing balance. If the patient made contact with the ground with the contralateral limb, lost balance, or made additional hops after landing, the distance was not measured and the jump void. The distance was measured from the starting line to the heel of the leg being tested. For both legs, three trials and three jumps for maximal effort were allowed. The longest distance for both the left leg and the right leg were used in the statistical analysis.

The Y-balance test (YBT) (Move2Perform, United States) for anterior reach was used to measure dynamic balance. Participants performed three trials to familiarize themselves with the test, and then undertook three tests. The test started with the participant standing barefoot on the testing kit. The patients had to push a wooden box with the contralateral leg as far as possible with continuous movement and return to their starting position without losing balance. The longest distance achieved was used in the statistical analysis.