This study aims to examine the relationships between the ultrasonographic muscle thicknesses of the popliteus and quadriceps muscles and functional capacity, balance, and pain levels in elderly patients with knee osteoarthritis (KOA). Knee osteoarthritis is a major degenerative joint disorder causing pain, stiffness, and reduced mobility, where surrounding muscle architecture plays a pivotal role in functional performance and joint stability. The study will recruit approximately 150 participants aged 65 years and older with Grade 3-4 KOA (Kellgren-Lawrence) and intact cognitive status (SMMSE score ≥24) presenting to the Physical Medicine and Rehabilitation Outpatient Clinic of Afyonkarahisar Health Sciences University Health Application and Research Center, while excluding individuals with central nervous system, visual pathologies, or prior lower extremity surgeries. Muscle thicknesses of the popliteus and quadriceps (rectus femoris and vastus intermedius) will be measured via high-frequency B-mode ultrasonography by a specialist physician, using standardized anatomical landmarks and patient positioning. Functional capacity and mobility will be evaluated using the Timed Up and Go (TUG) and 5-Times Sit-to-Stand (5STS) tests, balance and proprioception via the Romberg Test, and knee-specific functional status and pain severity using the Knee Injury and Osteoarthritis Outcome Score (KOOS) and the Visual Analog Scale (VAS).
Study Type
OBSERVATIONAL
Enrollment
130
Afyonkarahisar Health Science University
Merkez, Afyonkarahisar, Turkey (Türkiye)
Ultrasound measurement of popliteus and quadriceps muscle thickness
Popliteus and quadriceps (rectus femoris + vastus intermedius) muscle thickness will be measured via B-mode ultrasonography using a high-frequency linear probe (10-15 MHz), with three measurements averaged per muscle. The correlation between mean popliteus and mean quadriceps thickness (mm) will be assessed using Pearson or Spearman correlation coefficients, depending on data distribution.
Time frame: Baseline (single assessment visit)
Timed Up and Go Test (TUG):
The participant sits on a standard armless chair (43-46 cm height); upon the "start" command, they stand up, walk a marked 3-meter distance, turn, walk back to the chair, and sit down. The time elapsed from the start command until the participant sits down is recorded in seconds. The individual wears comfortable footwear, walks at a normal walking speed, and any standard assistive devices (e.g., cane) used are noted
Time frame: baseline
5-Times Sit-to-Stand Test (5STS)
It is a reliable test used to assess sitting and standing ability. In older adults, it evaluates functional mobility, lower extremity muscle strength, and balance (19). The participant crosses their arms over their chest, and the time required to complete 5 consecutive sit-to-stand repetitions is measured.
Time frame: Baseline
Knee Injury and Osteoarthritis Outcome Score (KOOS)
KOOS is a comprehensive and reliable instrument for knee injuries and knee osteoarthritis. The scale consists of 5 subscales: Pain (9 items), Other Symptoms (7 items), Function in Daily Living (ADL) (17 items), Sport/Recreation Function (5 items), and Knee-Related Quality of Life (4 items). Each subscale is normalized to a score of 0-100, where 100 indicates no problems and 0 indicates extreme problems
Time frame: Baseline
Romberg Test
The patient is asked to stand upright with their feet together and arms hanging freely at their sides.The patient must wear hard, thin-soled shoes during this test. Without receiving any support, the patient is asked to stand first with eyes open and then with eyes closed. Safety precautions must be taken during this test to prevent falls; the examiner must remain close to the patient at all times and be prepared to catch them if they fall. In peripheral vestibular pathologies, the direction of sway/fall is toward the side of the lesion
Time frame: Baseline
Visual Analog Scale (VAS)
Participants will be asked to mark their average perceived pain intensity on a 10-centimeter (cm) line (defined as 0 = no pain, 10 = unbearable pain) during rest, activity, and sleep. Baseline pain scores will be obtained by measuring the distance between the marked point and the zero point using a ruler
Time frame: Baseline
Standardized Mini-Mental State Examination (SMMSE)
Developed by Folstein et al. in 1975 to assess cognitive status in adults. Its validity and reliability for the Turkish population were conducted by Güngen et al. A modified version is also available for individuals with less than five years of education. SMMSE is categorized under five main headings: orientation (10 points), registration/memory (3 points), attention and calculation (5 points), recall (3 points), and language (9 points). The scale is evaluated out of a total of 30 points. In scoring: results between 24 and 30 points indicate "normal" cognitive status, 18 to 23 points indicate "mild dementia," 12 to 17 points indicate "moderate dementia," and scores below 12 indicate "severe dementia" (Güngen et al., 2002). Individuals scoring 24 and above on the SMMSE were included in our study.
Time frame: Baseline
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