Key messages
- Knee muscle strength is the main predictor of performance-based physical function.
- Pain intensity can be established as the primary determinant of selfreported physical function.
- In general, strengthening the knee muscles (both quadriceps and hamstring) should be considered as a priority in KOA.
Study information
Details of the study
“The predictors to self-reported and performance-based physical function in knee osteoarthritis patients: a cross-sectional study”1
Methods
This cross-sectional study included 135 patients with diagnosed KOA (diagnosed by the American College of Rheumatology criteria). Variables measured in the study can be divided as follows:
Dependent variables
- Self-reported physical function. It was calculated using the Knee Injury and Osteoarthritis Outcome Score (KOOS), which included the following subscales: pain, other symptoms, kneerelated quality of life, function in daily living and in sport and recreation.
- Performance-based physical function. It included the 6-meter gait speed test (6MGS) and 5 time sit-to-stand test (5STS). Both provide reliable insights for physical performance.
Independent variables
- Demographic data. During the first visit age, length of symptomatology, height, weight and body mass index (BMI) were recorded.
- Muscle strength. Knee extensor and flexor strength were measured with a hand-held dynamometer and an overall muscle strength value was obtained.
Disease severity
Radiological evaluation of all participants’ knees was performed by two physicians who used the Kellgren-Lawrence (KL) scale.
Main results
From the seven predictors established in the study (age, BMI, durations of symptoms, KL grade, knee extensor muscle strength, knee flexor muscle strength and pain-KOOS subscale), only BMI and duration of symptoms didn’t have any correlation with either self-reported or performance-based physical function. Knee extensor and flexor muscle strength as well as painKOOS subscale were positively correlated with PF-KOOS and 6MGS, whereas negatively correlated with 5STS. Age correlated negatively with 6MGS and positively with 5STS.
Mainly, pain intensity and knee flexor muscle strength were associated with self-reported physical function and had 55% of contribution to the variance in the KOOS score. Besides, both knee extensor and flexor muscle strength were associated with performance-based physical function.
Conclusion
Pain intensity is considered the main predictor of self-reported physical function, but knee flexor muscle strength and age play an important role too. Both knee extensor and flexor muscle strength are the primary risk factors of performance-based physical function. These results show the importance of managing pain correctly and strengthening knee muscles in managing either early or end-stage KOA.
Bibliography
- Wang QW, Man GCW, Choi BCY, Yeung YM, Qiu JH, Lu XM, et al. The predictors to self-reported and performance-based physical function in knee osteoarthritis patients: a cross-sectional study. Front Cell Dev Biol. 2024;12:1406830.
Link to the full study
This article is a summary based on the following study. For further information and details, please consult the full study. Please do not hesitate to contact us if you have any comments. https://pubmed.ncbi.nlm.nih.gov/38946798/
