Knee Arthritis, Osteoarthritis, Osteo Arthritis of the Knee
Conditions
Keywords
Knee Osteoarthritis, Ultrasonography, Quadriceps Muscle Thickness, Quadriceps Echogenicity, Knee Injury and Osteoarthritis Outcome Score, KOOS
Brief summary
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.
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.
Interventions
None listed
Sponsors
Izmir City Hospital
Study design
Observational model
CASE_CONTROL
Time perspective
CROSS_SECTIONAL
Eligibility
Sex/Gender
FEMALE
Age
40 Years to 70 Years
Healthy volunteers
Yes
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
Design outcomes
Primary
| Measure | Time frame | Description |
|---|---|---|
| Knee Injury and Osteoarthritis Outcome Score - Physical Function Short Form (KOOS-PS) | 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. |
Secondary
| Measure | Time frame | Description |
|---|---|---|
| Pain Intensity via Visual Analog Scale (VAS) | 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. |
| Knee Injury and Osteoarthritis Outcome Score - Quality of Life (KOOS-QoL) | 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. |
| Patient Global Assessment (PtGA) | 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. |
Countries
Turkey (Türkiye)
Contacts
CONTACTHalil İbrahim Candal
PRINCIPAL_INVESTIGATORBuğra İnce
Izmir City Hospital
Outcome results
None listed