Isokinetic assessment of ankle dorsiflexors and plantarflexors strength in patients with knee osteoarthritis

Abstract

Purpose: To evaluate the ankle concentric dorsiflexors and plantarflexors’ strength in patients with knee osteoarthritis (OA).

Methods: Forty subjects with knee OA were included in the study. The first group consisted of 20 subjects suffering from unilateral tibiofemoral knee OA, with mean age (57.60 ± 4.50 years), mean weight (88.95 ± 11.93 kg), and mean height (169.95 ± 5.84 cm). The second group consisted of 20 subjects with no prior history of knee pain or injury, forming a control group, with mean age (58.70 ± 5.15 years), mean weight (91.10 ± 10.23 kg), and mean height (171.25 ± 6.41 cm). Dorsiflexors and plantarflexors’ concentric peak torque was measured at angular velocities 60 and 120°/second by using an isokinetic dynamometer.

Results: At angular velocity 60°/second, the peak torque of dorsiflexors and plantarflexors of the control group was significantly higher than that of the knee OA group (P = 0.001, 0.040, respectively). At angular velocity 120°/second, the peak torque of dorsiflexors and plantarflexors of the control group was significantly higher than in the knee OA group (P = 0.001, 0.010, respectively). At angular velocities 60 and 120°/second, the dorsiflexion/plantarflexion ratio of the knee OA group was significantly lower than of the control group (P = 0.003, 0.010, respectively).

Conclusions: The knee OA group displayed weakness in ankle dorsiflexor and plantarflexor muscles and a decrease in the dorsiflexion/plantarflexion strength ratio. Clinicians should consider exercises to increase ankle dorsiflexor and plantarflexor muscles’ strength when developing rehabilitation programs for patients with knee OA.

Keywords:

• Knee osteoarthritis
• Concentric contraction
• Dorsiflexors
• Plantarflexors

Acknowledgments

We would like to thank all of the patients who participated in the study.

Disclaimer statements

Contributors There are no contributors for this work.

Funding None.

Conflicts of interest There is no conflict of interest.

Ethics approval This study was approved by the Ethical Committee of Faculty of Physical Therapy, Cairo University.