Extracorporeal Shock Wave Therapy in Patellofemoral Pain Syndrome

Uğur Can Yalaki

Status: Completed

Conditions: Patellofemoral Pain Syndrome

Treatments: Device: Radial Extracorporeal Shock Wave Therapy (ESWT); Behavioral: Home-based Exercise Program

Study type: Interventional

Funder types: Other

Identifiers

NCT07273110

PFPS-ESWT-2021

Details and patient eligibility

About

Patellofemoral pain syndrome (PFPS) is a common cause of anterior knee pain and functional limitations in physically active individuals. Exercise-based rehabilitation is considered the primary treatment approach, yet a proportion of patients experience persistent symptoms. Extracorporeal shock wave therapy (ESWT) is a non-invasive modality that may reduce pain through neuromodulation and tissue-level biological responses.

This randomized controlled trial evaluated the effects of ESWT on knee pain and function in adults with PFPS. Thirty-six participants aged 18-45 years were randomly assigned to one of three groups: Exercise, Exercise plus ESWT, or ESWT alone. The exercise program consisted of home-based hip and knee strengthening performed at least three times per week for four weeks. ESWT was administered as five radial shock wave sessions at five-day intervals around the peripatellar soft tissues.

Outcomes included worst knee pain measured by the Visual Analogue Scale and functional status measured by the Kujala Patellofemoral Score at baseline, week 1, and week 8. All groups demonstrated significant improvements over time, with no significant differences between groups. The treatment was well tolerated.

This trial was retrospectively registered after patient enrollment was completed.

Enrollment: 36 patients

Sex: All

Ages: 18 to 45 years old

Volunteers: No Healthy Volunteers

Inclusion criteria

• Age 18 to 45 years.
• Clinical diagnosis of patellofemoral pain syndrome (PFPS) characterized by anterior or retropatellar knee pain lasting at least 8 weeks.
• Pain provoked during at least two of the following activities: running, jumping, squatting, stair climbing, or prolonged sitting.
• Worst knee pain score of ≥3 on the Visual Analog Scale (0-10).
• Ability to understand and follow the exercise program and assessment procedures.
• Provided written informed consent.

Exclusion criteria

• Evidence of intra-articular knee pathology other than grade 1-2 meniscal changes or grade 1 chondromalacia patella on MRI.
• Clinical signs of patellar instability.
• Localized tenderness indicating alternative diagnoses (e.g., patellar tendinopathy, iliotibial band syndrome, pes anserine bursitis).
• History of knee surgery on the affected side.
• Intra-articular injections (e.g., corticosteroids, hyaluronic acid, PRP) within the past 6 months.
• Neurological or rheumatological disorders affecting the lower extremity.
• Active infection, open wound, tumor, or severe dermatological condition at or near the ESWT application site.
• Pregnancy.

Trial design

Primary purpose: Treatment

Allocation: Randomized

Interventional model: Parallel Assignment

Masking: None (Open label)

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36 participants in 3 patient groups

Exercise

Active Comparator group

Description:

Participants performed a structured home-based exercise program targeting hip and knee musculature. The program included warm-up, stretching, and progressive strengthening exercises for the quadriceps, hip abductors, hip external rotators, and core stability muscles. Participants were instructed to complete the program at least three times per week for 4 weeks. Exercise technique and progression guidelines were explained in person, and adherence was monitored using weekly exercise diaries and telephone follow-up.

Treatment:

Behavioral: Home-based Exercise Program

ESWT

Experimental group

Description:

Participants received five sessions of radial extracorporeal shock wave therapy (ESWT) administered at 5-day intervals. Treatment was delivered using the Chattanooga Intelect® RPW device with 2000 pulses per session at 1.8-2.0 bar pressure and 8 Hz frequency. Stimulation was applied to the peripatellar soft tissues, including the medial and lateral patellofemoral retinaculum and the infrapatellar fat pad, while avoiding direct application over the patellar tendon. Pressure was progressively increased across sessions based on tolerance.

Treatment:

Device: Radial Extracorporeal Shock Wave Therapy (ESWT)

Exercise + ESWT

Experimental group

Description:

Participants performed the same home-based strengthening program as the Exercise group (hip and knee strengthening, ≥3 sessions/week for 4 weeks). In addition, they received five sessions of radial extracorporeal shock wave therapy (2000 pulses; 1.8-2.0 bar; 8 Hz) at 5-day intervals applied to the peripatellar soft tissues while avoiding the patellar tendon.

Treatment:

Behavioral: Home-based Exercise Program

Device: Radial Extracorporeal Shock Wave Therapy (ESWT)