The Importance of Functional Hamstring/Quadriceps Ratios in Knee Osteoarthritis.

CONTEXT

Osteoarthritis (OA) is the most common chronic joint condition. Muscle dysfunction plays a critical role in the pathogenesis of knee OA.

OBJECTIVE

It has been suggested that the agonist-antagonist strength relationship for the knee may be better described by a functional hamstring/quadriceps (H/Q) ratio (Hconcentric/Qeccentric: the representative of knee flexion and Qeccentric/Hconcentric: the representative of knee extension). Therefore, in this study, the authors aimed to investigate this ratio and its importance for knee OA.

DESIGN

Cross-sectional study.

SETTING

Research clinic. Patients or Other Participant(s): Twenty healthy women and 20 women with grade 2 or grade 3 primer knee OA between the age of 50 and 80 years were included in this study.

INTERVENTION(S): Concentric and eccentric peak torque of quadriceps and hamstring muscles were evaluated for all individuals in patient and control groups with a Cybex isokinetic device. Functional H/Q ratio is calculated manually.

MAIN OUTCOME MEASURE(S): Functional H/Q torque ratios were analyzed between the patients with OA and healthy individuals by using the isokinetic system.

RESULTS

The values of peak torque of hamstring concentric and eccentric and quadriceps concentric for the patient group were significantly lower than the control group (P < .05). No statistically important difference was found for quadriceps eccentric peak torque between 2 groups (P > .05). H/Q ratio for extension in the patient group was significantly higher than the control group (P < .05), whereas the H/Q ratio for flexion in the patient group was significantly lower than the control group (P < .05).

CONCLUSION

This study showed the weakness of both quadriceps and hamstring muscles in patients with knee OA. The combination of functional H/Q ratio with hamstring and quadriceps muscles concentric and eccentric strength values can help to analyze the knee functions and develop preventive-therapeutic approaches for knee OA.