Static balance assessment in patients with severe osteoarthritis of the knee.

Background: Pain related to severe knee osteoarthritis may lead to static balance disorders. Patients with severe knee arthrosis with arthroplasty indication should be aware of the postoperative rehabilitation menu because their balance ability has decreased.

Methods: The study involved 33 patients with unilateral severe osteoarthritis (the study group) and 33 healthy subjects (the control group). We conducted the measurements of static balance with the CQStab2P platform. Functional disability was assessed using the Knee Society Score (KSS).

Results: In the study group, balance distribution asymmetry between lower limbs was higher. Patients unloaded the painful joints due to pain and knee instability. We observed statistically significant differences both with eyes open and with eyes closed only for balance symmetry. The study group had mean results of 53.9 (±19.1 SD) points in the KSS scales and 52.1 (±24.1) in the KSS function. There were statistically significant positive correlations regarding KSS and body height (0.270; P < 0.05), and negative correlations for body mass index (0.329; P < 0.01). In measurements with open eyes, patients' KSS correlated with mean amplitude of sways (-0,227; P < 0.01) and max anteroposterior (-0.279; P < 0.01). In measurements with eyes closed, KSS function correlated with number of sways in the sagittal plane (0.331; P < 0.01).

Conclusions: Patients with severe osteoarthritis suffered from balance disorders regarding limbs' asymmetrical loading both under visual control and without visual control.