Whole-Body Vibration in Patients With Patellofemoral Pain Syndrome

Subjective symptoms and functional limitations of patients with Patellofemoral Pain Syndrome (PFPS) were evaluated using the Kujala Patellofemoral Scoring System. This scoring system was developed by Kujala et al. in 1993, and it allows for functional assessment of knee pathologies related to the patellofemoral structure. The Kujala Patellofemoral Pain Score consists of 13 subcategories evaluating limping, weight bearing, walking, stair activities, squatting, jumping, prolonged sitting with knees flexed at 90°, running, pain, swelling, abnormal painful patellar movement, thigh atrophy, and loss of flexion. The total score ranges from 0 to 100 points, with 100 indicating the best functional status.

The quality of life of all patients will be assessed using the Short Form-36 Health Survey (SF-36). This instrument consists of 36 items and measures eight health domains:

Physical functioning (10 items), Social functioning (2 items), Role limitations due to physical problems (4 items), Role limitations due to emotional problems (3 items), Mental health (5 items), Energy/vitality (4 items), Bodily pain (2 items), and General health perception (5 items)

Muscle mass measurements of the vastus medialis and gluteus medius muscles will be performed using ultrasound (Clarius™ by Clarius Mobile Health) both before and after treatment.

For the vastus medialis, the patient will be positioned supine with the knee in approximately 30 degrees of flexion. The ultrasound probe will be placed on the medial quadriceps region, between the medial border of the patella and the medial femoral condyle. The probe will be angled at approximately 45° to the long axis of the femur, oriented parallel to the muscle fibers.

For the gluteus medius, the patient will be positioned in side-lying, with the painful side facing upward. The probe will be placed at the lower half of the distance between a line connecting the anterior superior iliac spine (ASIS) and the posterior superior iliac spine (PSIS) and the greater trochanter.

Measurements will be performed by the same evaluator at baseline and at the 8th week following treatment.

Isokinetic assessment of the symptomatic (painful) knee will be performed using the IsoMed 2000 Isokinetic System. Participants will be seated in an upright position with stabilization of the trunk and lower limbs. Peak Torque (PT, measured in Newton-meters, Nm) represents the maximum torque generated during knee flexion and extension at an angular velocity of 60°/s. Participants will perform four maximal repetitions following three familiarization trials. The change in PT from baseline to week 8 will be used to assess improvement in knee muscle endurance at higher movement speeds.

Isokinetic assessment of the symptomatic (painful) knee will be performed using the IsoMed 2000 Isokinetic System. Participants will be seated in an upright position with stabilization of the trunk and lower limbs.

Peak Torque (PT, measured in Newton-meters, Nm) represents the maximum torque generated during knee flexion and extension at an angular velocity of 240°/s. Participants will perform ten maximal repetitions following three familiarization trials.

The change in PT from baseline to week 8 will be used to assess improvement in knee muscle endurance at higher movement speeds.

The H/Q ratio will be calculated using the peak torque values obtained from the isokinetic tests at 60°/s.

Specifically, it is determined by dividing the hamstring peak torque by the quadriceps peak torque measured during the same test session.

The H/Q ratio at this slower speed reflects the strength balance between the knee flexors and extensors under controlled movement conditions.

A balanced ratio is crucial for joint stability and injury prevention, particularly in patients with knee pain or dysfunction.

Testing will be conducted using the IsoMed 2000, with the patient's position and stabilization identical to other isokinetic assessments.

The H/Q ratio will also be calculated at 240°/s, based on the peak torque values obtained from the high-velocity isokinetic test.

It is computed by dividing the hamstring peak torque by the quadriceps peak torque at this higher angular velocity.

The H/Q ratio at 240°/s assesses the dynamic balance and neuromuscular coordination between flexor and extensor muscle groups during rapid movements.

Maintaining an appropriate H/Q ratio at faster speeds is considered an important indicator of functional knee stability and injury resilience.

All procedures (positioning, stabilization, familiarization, and repetitions) will be performed identically to the other isokinetic test conditions, using the IsoMed 2000 system.

Isokinetic assessments of the symptomatic (painful) knee will be performed using the IsoMed 2000 Isokinetic System. Participants will be seated in an upright position, with the chest, waist, and lower limbs secured to ensure proper body stabilization and minimize compensatory movements.

To obtain reliable data on muscle performance, testing at an angular velocity of 60°/s will include four consecutive maximal concentric repetitions of knee flexion and extension. Prior to the test, participants will perform three familiarization repetitions at the same velocity to become accustomed to the movement and the device.

Total Work (TW), measured in Joules (J), represents the total amount of work performed by the knee flexor and extensor muscles across all repetitions at 60°/s.

This parameter reflects overall muscular endurance and energy output of the quadriceps and hamstrings during slower, controlled movements.

Isokinetic assessments of the symptomatic (painful) knee will be conducted using the IsoMed 2000 Isokinetic System. Participants will be positioned in an upright seated position, and the chest, waist, and lower limbs will be secured with straps to ensure body stabilization during testing.

For this evaluation, an angular velocity of 240°/s will be used, and patients will perform ten consecutive maximal concentric repetitions of knee flexion and extension. Before the test, three familiarization repetitions at the same angular velocity will be completed to ensure accurate and consistent performance.

Total Work (TW), expressed in Joules (J), will represent the total energy output of the knee flexor and extensor muscles during all repetitions at 240°/s.

This measurement provides information on muscular endurance, power, and performance efficiency of the knee muscles under high-velocity dynamic conditions.