Quadriceps Muscle Quality and Clinical Outcomes in Knee Osteoarthritis

April 14, 2026 updated by: Bugra Ince, Izmir City Hospital

The Relationship of Quadriceps Muscle Echogenicity and Thickness Change During Isometric Contraction With Pain, Function, Quality of Life, and Patient Global Assessment in Knee Osteoarthritis

The purpose of this cross-sectional, observational study is to evaluate the relationship between quadriceps muscle quality-specifically muscle echogenicity and thickness change during isometric contraction-and clinical outcomes such as pain, physical function, quality of life, and Patient Global Assessment (PtGA) in female patients with knee osteoarthritis. Participants will undergo a non-invasive ultrasound evaluation of their thigh muscles and complete standard clinical questionnaires to help determine how muscle structural and functional properties impact the daily lives of patients with knee osteoarthritis.

Study Overview

Status

Enrolling by invitation

Conditions

Detailed Description

Knee osteoarthritis (OA) is a highly prevalent degenerative joint disease characterized by pain, loss of function, and reduced quality of life. A critical factor related to the clinical course of the disease is quadriceps muscle weakness and deterioration in muscle quality, including intra-muscular fatty infiltration and fibrotic changes.

This single-center, cross-sectional observational study aims to comprehensively assess quadriceps muscle quality using ultrasonography (USG) and investigate its relationship with core clinical outcomes in patients with knee OA. Specifically, the study will measure muscle echogenicity (a surrogate marker of fat infiltration and fibrosis) and the rate of muscle thickness change during maximum voluntary isometric contraction (MVIC), which reflects the dynamic functional response of the muscle.

Female patients aged 40 to 70 years with radiographically confirmed Kellgren-Lawrence grade 2-3 knee OA will be recruited from the physical medicine and rehabilitation clinic. Following informed consent, participants will undergo clinical assessments using standardized patient-reported outcome measures. These include the Visual Analog Scale (VAS) for pain intensity, the Patient Global Assessment (PtGA), and the Knee Injury and Osteoarthritis Outcome Score (KOOS) subscales for physical function (KOOS-PS) and quality of life (KOOS-QoL).

Ultrasonographic evaluations will be performed by a single evaluator using a linear high-resolution probe (5-10 MHz). Rectus femoris (RF) and vastus intermedius (VI) muscle thicknesses will be recorded at rest and during a 5-second MVIC to calculate the thickness change ratio. Furthermore, muscle echogenicity (grayscale median) will be quantified via image analysis software and mathematically corrected for subcutaneous fat thickness to ensure accuracy.

By evaluating both the structural and functional ultrasonographic features of the quadriceps muscle simultaneously, this study seeks to provide a holistic understanding of how muscle quality impacts the core outcome domains recommended by OMERACT-OARSI for knee osteoarthritis, ultimately contributing to better prognostication and more individualized rehabilitation strategies.

Study Type

Observational

Enrollment (Estimated)

58

Contacts and Locations

This section provides the contact details for those conducting the study, and information on where this study is being conducted.

Study Locations

  • Turkey (Türkiye)
    • Bayraklı/izmir
      • Izmir, Bayraklı/izmir, Turkey (Türkiye)
        • Izmir Cıty Hospital

Participation Criteria

Researchers look for people who fit a certain description, called eligibility criteria. Some examples of these criteria are a person's general health condition or prior treatments.

Eligibility Criteria

Ages Eligible for Study

  • Adult
  • Older Adult

Accepts Healthy Volunteers

Yes

Sampling Method

Non-Probability Sample

Study Population

Female patients aged 40-70 years diagnosed with knee osteoarthritis (OA) who apply to the Physical Medicine and Rehabilitation Clinic of Izmir City Hospital will be screened according to the study criteria. Individuals diagnosed clinically and radiographically with Kellgren-Lawrence Grade 2-3 knee osteoarthritis, who are capable of performing isometric quadriceps contractions, and who volunteer to participate in the study will be included after signing the informed consent form.

Description

Inclusion Criteria:

  • Female sex
  • Aged between 40 and 70 years
  • Diagnosed with clinical and radiographic primary knee osteoarthritis (Kellgren-Lawrence Grade 2 or 3)
  • Ability to perform isometric contraction at 90° of knee flexion
  • Voluntary participation and provision of written informed consent

Exclusion Criteria:

  • History of knee surgery within the last 6 months
  • Intra-articular injection (e.g., corticosteroids, hyaluronic acid) within the last 3 months
  • Presence of inflammatory rheumatic diseases (e.g., Rheumatoid Arthritis, Spondyloarthropathy)
  • Known neuromuscular disorders affecting the lower extremities
  • Severe cardiopulmonary comorbidities that prevent participation in clinical assessments
  • Severe patellofemoral instability

Study Plan

This section provides details of the study plan, including how the study is designed and what the study is measuring.

How is the study designed?

Design Details

Cohorts and Interventions

Group / Cohort
Female Patients with Knee Osteoarthritis

This group consists of female patients aged 40-70 years diagnosed with primary knee osteoarthritis (Kellgren-Lawrence Grade 2 and 3) according to the American College of Rheumatology (ACR) criteria. All participants in this cohort will undergo:

  1. Ultrasonographic Assessment: Measurement of Rectus Femoris and Vastus Intermedius muscle thickness at rest and during maximum voluntary isometric contraction, along with muscle echogenicity analysis.
  2. Clinical Evaluation: Assessment of pain intensity via Visual Analog Scale (VAS), and evaluation of functional status and quality of life using the Knee Injury and Osteoarthritis Outcome Score (KOOS) and Patient Global Assessment (PtGA).
Healthy Control Group

This group consists of healthy female volunteers aged 40-70 years with no clinical or radiographic evidence of knee osteoarthritis and no history of chronic knee pain. Participants in this control group will undergo the same standardized evaluation protocol as the patient group to provide baseline values for:

  1. Ultrasonographic Assessment: Measurement of Rectus Femoris and Vastus Intermedius muscle thickness at rest and during maximum voluntary isometric contraction, along with muscle echogenicity analysis.
  2. Clinical Evaluation: Assessment of pain intensity via Visual Analog Scale (VAS), and evaluation of functional status and quality of life using the Knee Injury and Osteoarthritis Outcome Score (KOOS) and Patient Global Assessment (PtGA).

What is the study measuring?

Primary Outcome Measures

Outcome Measure
Measure Description
Time Frame
Knee Injury and Osteoarthritis Outcome Score - Physical Function Short Form (KOOS-PS)
Time Frame: Baseline
The primary outcome is physical function, reflecting the capacity to perform activities of daily living. KOOS-PS is a 7-item patient-reported measure assessing functional difficulties (e.g., getting in/out of bed, putting on socks, squatting). Scores for each item range from 0 to 4, and the total score is transformed to a 0-100 scale. A higher score indicates better physical function.
Baseline

Secondary Outcome Measures

Outcome Measure
Measure Description
Time Frame
Pain Intensity via Visual Analog Scale (VAS)
Time Frame: Baseline
Participants' pain levels will be assessed using the Visual Analogue Scale (VAS). The VAS is a validated tool designed to convert subjective sensations, such as pain, into quantitative data. During the assessment, a 10-cm horizontal line will be utilized, with the endpoints defined as '0: No pain' and '10: Most severe pain imaginable.' Patients will be instructed to mark the point on this line that best represents their current pain intensity.
Baseline
Knee Injury and Osteoarthritis Outcome Score - Quality of Life (KOOS-QoL)
Time Frame: Baseline
This 4-item subscale evaluates the impact of knee problems on the patient's quality of life, including awareness of knee problems, lifestyle modifications to protect the knee, lack of confidence in the knee, and general knee-related difficulties. Each item is scored on a Likert scale from 0 to 4. The raw scores are transformed to a 0-100 scale, where 100 represents no symptoms/best possible quality of life and 0 represents extreme symptoms/worst possible quality of life.
Baseline
Patient Global Assessment (PtGA)
Time Frame: Baseline
The Patient Global Assessment (PtGA) is a patient-reported outcome measure reflecting the individual's subjective perception of their overall knee joint status. It integrates the general impact of knee osteoarthritis on the patient's life, including symptom severity and functional burden, into a single indicator. In this study, PtGA will be measured using a 0-10 cm Visual Analog Scale (VAS) based on the standard question: "How would you rate your knee condition in general over the past 7 days?". The scale ranges from 0 (very well) to 10 (very poor). The VAS provides a one-dimensional, practical, and validated method to quantify the patient's global health status related to the knee joint.
Baseline

Collaborators and Investigators

This is where you will find people and organizations involved with this study.

Sponsor

Izmir City Hospital

Investigators

  • Principal Investigator: Buğra İnce, İzmir City Hospital

Publications and helpful links

The person responsible for entering information about the study voluntarily provides these publications. These may be about anything related to the study.

General Publications

Study record dates

These dates track the progress of study record and summary results submissions to ClinicalTrials.gov. Study records and reported results are reviewed by the National Library of Medicine (NLM) to make sure they meet specific quality control standards before being posted on the public website.

Study Major Dates

Study Start (Actual)

April 14, 2026

Primary Completion (Estimated)

December 1, 2026

Study Completion (Estimated)

December 1, 2026

Study Registration Dates

First Submitted

April 14, 2026

First Submitted That Met QC Criteria

April 14, 2026

First Posted (Actual)

April 21, 2026

Study Record Updates

Last Update Posted (Actual)

April 21, 2026

Last Update Submitted That Met QC Criteria

April 14, 2026

Last Verified

April 1, 2026

More Information

Terms related to this study

Keywords

Additional Relevant MeSH Terms

Other Study ID Numbers

  • HIC26

Plan for Individual participant data (IPD)

Plan to Share Individual Participant Data (IPD)?

UNDECIDED

IPD Plan Description

No final decision has yet been made regarding the future availability of the data.

Drug and device information, study documents

Studies a U.S. FDA-regulated drug product

No

Studies a U.S. FDA-regulated device product

No

This information was retrieved directly from the website clinicaltrials.gov without any changes. If you have any requests to change, remove or update your study details, please contact register@clinicaltrials.gov. As soon as a change is implemented on clinicaltrials.gov, this will be updated automatically on our website as well.

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