Ultrasound Examination of the VMO in Patellofemoral Pain Syndrome

Ultrasonography Examination of the Vastus Medialis Obliquus and Vastus Medialis Longus Muscles in Patellofemoral Pain Syndrome

The aim of this study is to examine in detail the ultrasonographic characteristics of the vastus medialis obliquus and vastus medialis longus muscles in individuals with patellofemoral pain syndrome and to compare these findings with those of healthy individuals. It is anticipated that the results obtained will contribute to a better understanding of the muscle-based mechanisms of PFAS and provide a scientific basis for the development of muscle-specific assessment and intervention strategies in physical therapy and rehabilitation practices.

Study Overview

• Status: Not yet recruiting
• Conditions: Vastus Medialis; Ultrasonographic; Patello Femoral Pain Syndrome

Detailed Description

Patellofemoral pain syndrome (PFAS) is a musculoskeletal problem characterized by pain in the front of the knee joint, commonly seen in young and physically active individuals. The etiology of PFAS is multifactorial and is associated with abnormal loading of the patella within the femoral trochlear groove, alterations in joint biomechanics, and functional deficiencies of the surrounding soft tissues. These mechanical irregularities in the patellofemoral joint can lead to pain, loss of function, and activity limitations over time. The quadriceps femoris muscle group plays a fundamental role in providing dynamic stability to the patella. The vastus medialis obliquus (VMO) and vastus medialis longus (VML) muscles within this muscle group are critical for controlling the patella medially and maintaining its proper alignment within the femoral groove. It is known that the oblique fiber structure of the VMO muscle provides medial stabilizing force to the patella, while the VML muscle contributes to force production during knee extension and overall patellar guidance with its longer fibers. In individuals with PFAS, delayed activation patterns, decreased muscle strength, and morphological changes in the vastus medialis muscle have been reported. However, it is observed in the literature that the VMO and VML muscles are treated as a single structure in most studies, and the separate morphological characteristics of these two muscles and their relationship with patellofemoral pain have not been sufficiently investigated. However, the different anatomical, biomechanical, and functional characteristics of these muscles necessitate that their roles in PFAS pathophysiology be evaluated separately. Ultrasonography is a non-invasive, reliable, and reproducible imaging method for evaluating the morphological characteristics of muscle tissue and is increasingly used in clinical research. Ultrasonographic evaluation allows for the objective examination of muscle thickness, cross-sectional area, and architectural features, thereby providing important information about structural changes in muscle function. The aim of this study is to examine in detail the ultrasonographic characteristics of the vastus medialis obliquus and vastus medialis longus muscles in individuals with patellofemoral pain syndrome and to compare these findings with healthy individuals. It is anticipated that the results will contribute to the understanding of the muscle-based mechanisms of PFAS and provide a scientific basis for the development of muscle-specific assessment and intervention strategies in physical therapy and rehabilitation practices.

• Study Type: Observational
• Enrollment (Estimated): 40

Contacts and Locations

• Study Contact: Name: Tuğba GÖNEN, Asisst. Prof. Dr.; Phone Number: 505 090 58 46; Email: tugba.badat@hku.edu.tr

Study Locations

• Turkey (Türkiye)
  • Şahinbey
    • Gaziantep, Şahinbey, Turkey (Türkiye), (505) 090-5846
      • Hasan Kalyoncu University

Participation Criteria

Eligibility Criteria

• Ages Eligible for Study: Adult; Older Adult
• Accepts Healthy Volunteers: Yes

• Sampling Method: Non-Probability Sample

Study Population

The study will include individuals aged 18-65 who have been diagnosed with patellofemoral pain syndrome, as well as healthy volunteers with similar characteristics in terms of age and gender. The study group will consist of individuals who have applied to a physical therapy and rehabilitation clinic or who have been referred to relevant units. The control group will be selected from healthy volunteers who do not have any knee pain or lower extremity musculoskeletal problems.

Description

Inclusion Criteria:

• Between the ages of 18 and 65
• Have had localized pain in the front of the knee for at least the past 3 months
• Experience pain during activities that require stair climbing, squatting, prolonged sitting, or knee flexion
• Have been diagnosed with patellofemoral pain syndrome based on clinical evaluation
• Volunteer to participate in the study and sign the informed consent form

Exclusion Criteria:

• History of previous surgery on the knee joint
• History of significant trauma to the knee region within the last 6 months
• Diagnosis of meniscus, ligament injuries, knee osteoarthritis, or inflammatory rheumatic disease
• Neurological diseases or systemic diseases affecting the musculoskeletal system
• Presence of other lower extremity pathologies causing pain at a level that could affect measurements

Study Plan

How is the study designed?

Number of groups / cohorts

2

Cohorts and Interventions

Group / Cohort
Study Group; The study will include individuals aged 18-65 who have been diagnosed with patellofemoral pain syndrome, as well as healthy volunteers with similar characteristics in terms of age and gender.
Control group; The study will include individuals aged 18-65 who have been diagnosed with patellofemoral pain syndrome, as well as healthy volunteers with similar characteristics in terms of age and gender.

What is the study measuring?

Primary Outcome Measures

Outcome Measure	Measure Description	Time Frame
Ultrasonographic Measurement	A B-mode ultrasound device with a high-frequency (7-12 MHz) linear probe will be used to evaluate muscle architecture. Ultrasound is a reliable, reproducible, and non-invasive imaging method for assessing the morphological characteristics of muscle tissue. Ultrasonographic evaluations will be performed by an experienced researcher in musculoskeletal ultrasonography, in a quiet and standard environment. A high-frequency (7-12 MHz) linear probe will be used during measurements. Participants will be placed on the evaluation table in a supine position, with the knee joint fully extended and relaxed. Before measurements, anatomical reference points will be determined using a tape measure, and temporary markings will be made on the skin. Vastus Medialis Obliquus (VMO): VMO muscle thickness measurement will be performed in the region where the oblique orientation of the muscle fibers is prominent, using the upper-medial edge of the patella as a reference. The measurement point will be determ	through of the study, average 4 months

Collaborators and Investigators

• Sponsor: Hasan Kalyoncu University
• Investigators: Principal Investigator: Tuğba GÖNEN, Asisst. Prof. Dr., Hasan Kalyoncu University

Publications and helpful links

General Publications

• Engelina S, Antonios T, Robertson CJ, Killingback A, Adds PJ. Ultrasound investigation of vastus medialis oblique muscle architecture: an in vivo study. Clin Anat. 2014 Oct;27(7):1076-84. doi: 10.1002/ca.22413. Epub 2014 May 5.
• Castanov V, Hassan SA, Shakeri S, Vienneau M, Zabjek K, Richardson D, McKee NH, Agur AMR. Muscle architecture of vastus medialis obliquus and longus and its functional implications: A three-dimensional investigation. Clin Anat. 2019 May;32(4):515-523. doi: 10.1002/ca.23344. Epub 2019 Feb 19.
• Sawy MME, Mikkawy DMEE, El-Sayed SM, Desouky AM. Morphometric analysis of vastus medialis oblique muscle and its influence on anterior knee pain. Anat Cell Biol. 2021 Mar 31;54(1):1-9. doi: 10.5115/acb.20.258.
• Davut S, Dogramaci Y. Evaluation of the relationship between the anatomical characteristics of the vastus medialis obliquus muscle and the patella chondral lesion occurrence. Jt Dis Relat Surg. 2024 Apr 26;35(2):330-339. doi: 10.52312/jdrs.2024.771. Epub 2024 Apr 26.
• Dong C, Li M, Hao K, Zhao C, Piao K, Lin W, Fan C, Niu Y, Fei W. Dose atrophy of vastus medialis obliquus and vastus lateralis exist in patients with patellofemoral pain syndrome. J Orthop Surg Res. 2021 Feb 10;16(1):128. doi: 10.1186/s13018-021-02251-6.
• Smith TO, Nichols R, Harle D, Donell ST. Do the vastus medialis obliquus and vastus medialis longus really exist? A systematic review. Clin Anat. 2009 Mar;22(2):183-99. doi: 10.1002/ca.20737.

Study record dates

Study Major Dates

• Study Start (Estimated): February 25, 2026
• Primary Completion (Estimated): April 25, 2026
• Study Completion (Estimated): June 25, 2026

Study Registration Dates

• First Submitted: February 13, 2026
• First Submitted That Met QC Criteria: February 13, 2026
• First Posted (Actual): February 20, 2026

Study Record Updates

• Last Update Posted (Actual): February 20, 2026
• Last Update Submitted That Met QC Criteria: February 13, 2026
• Last Verified: February 1, 2026

More Information

Terms related to this study

• Keywords: Patellofemoral Pain; Vastus Medialis Obliqus; Ultrasonographic measurement
• Additional Relevant MeSH Terms: Musculoskeletal Diseases; Joint Diseases; Patellofemoral Pain Syndrome
• Other Study ID Numbers: 2025/161

Plan for Individual participant data (IPD)

• Plan to Share Individual Participant Data (IPD)?: NO

Drug and device information, study documents

• Studies a U.S. FDA-regulated drug product: No
• Studies a U.S. FDA-regulated device product: No