Original Research The Impaired Balance Systems Identified by the BESTest in Older Patients With Knee Osteoarthritis

Background: Balance decreases and activities of daily living (ADL) deteriorate in older people with knee osteoarthritis (KOA); however, little is known about the systems underlying poor balance control and how those impaired systems are related to decreased ADL. Objectives: To explore which balance systems are particularly impaired and to examine the relationship between physical ADL and balance in older people with KOA. Design: Case-control study. Setting: Outpatient clinic. Participants: Thirty people with KOA (mean age: 75.4 years) and 30 age-matched healthy adults (mean age: 75.4 years). Methods: The Balance Evaluation Systems Test (BESTest), consisting of 6 sections to evaluate theoretically driven balance control systems, was used for balance assessment. BESTest section scores were compared by use of the Wilcoxon rank-sum test. Pain and physical ADL in the KOA group were evaluated with the Japanese edition of the Western Ontario and McMaster Universities Osteoarthritis Index. Spearman correlation coefficients and partial rank correlation coefficients were used to investigate the relationship between physical ADL and the BESTest scores, pain, radiography findings, and body mass index. Main Outcome Measurements: The BESTest total and section scores. Results: Compared with controls, 5 of 6 BESTest section scores were significantly lower in the KOA group. Physical ADL was significantly correlated with the total BESTest score (r ¼� 0.484, P ¼ .007), pain (r ¼ 0.635, P < .001), Kellgren and Lawrence grade (r ¼ 0.601, P <.001), and body mass index (r ¼ 0.403, P ¼.027). Partial rank correlation coefficients between physical ADL and the total BESTest score (r ¼� 0.443, P ¼ .021) or section VI-Stability in Gait (r ¼� 0.466, P ¼ .014) were significant after we controlled for other variables. Conclusions: Most balance systems were impaired in older people with KOA, and this impairment was associated independently with decreased physical ADL.