Quantifying strength, flexibility, and girth of calf muscle in patients with knee osteoarthritis

Abstract

Background: Knee osteoarthritis (OA) is one of the most common musculoskeletal illnesses. Pain and functional limitation are the most frequent clinical features associated with it. Deficits in thigh muscles such as quadriceps and hamstring have been demonstrated in patients with knee OA. However, trials on the characteristics of the calf muscle in these patients are lacking. Study design: A case-control study. Purpose: The primary aim of this study was to quantify the calf muscle girth, strength, and flexibility in patients with knee OA and compare them with normal people. The secondary aim was to investigate the correlation between these variables. Methods: Fifteen patients with knee OA and 15 healthy controls were recruited. The three outcome measures and instruments were: calf muscle girth (flexible non-elastic tape), calf muscle strength (handheld dynamometer), and calf muscle flexibility via ankle dorsiflexion range of motion (ROM) (standard goniometer). The measurements were undertaken in one session which lasted for approximately an hour. Statistical analysis: Independent t-test was used to investigate the differences between the two groups in the baseline characteristics and the outcome measures. Cohen’s d was calculated to measure the effect size. Pearson’s correlation coefficient was performed for correlation analysis. Results: Significant decrease of the calf muscle strength was found in knee OA patients compared to the control group (p= 0.012) with a small effect size. No significant differences were found between the two groups in flexibility of the calf muscle (p= 0.177) or in the girth of the calf muscle (p= 0.852). There were no significant correlations between any of these variables (p ≥ 0.260). Conclusion: There was a significant decrease in the calf muscle strength in knee OA group compared to the control group. We recommend considering the calf muscle strength examination and treatment in the management of patients with knee OA