The condition of the contralateral knee may induce different degrees of knee extensor strength asymmetry and affect functionality in individuals with unilateral or bilateral osteoarthritis

• Published in: The knee 2020-12, Vol.27 (6), p.1795-1800
• Main Authors: Domínguez-Navarro, Fernando, Roig-Casasús, Sergio, Díaz-Díaz, Beatriz, Silvestre, Antonio, Martínez-Garrido, Ignacio, Pérez-Maletzki, José, Pinazo, Luís, Hernández-Guillen, David, Blasco, José-María
• Format: Article
• Language: English
• Subjects: Age; Age Factors; Aged; Aged, 80 and over; Arthritis; Asymmetry; Data collection; Ethics; Exercise Test; Female; Humans; Joint surgery; Knee; Knee Joint - physiopathology; Knee osteoarthritis; Male; Muscle strength; Muscle Strength - physiology; Muscle strength dynamometer; Osteoarthritis; Osteoarthritis, Knee - physiopathology; Pain; Quadriceps muscle; Sex Factors; Symmetry; Values; Variance analysis
• ISSN: 0968-0160; 1873-5800
• DOI: 10.1016/j.knee.2020.09.021

•Knee strength asymmetry differs in case of unilateral or bilateral osteoarthritis.•Overall, unilateral condition induces 20% of knee extensors strength asymmetry.•Bilateral condition induces symmetrical knee extensors strength distribution.•Higher inter-limb asymmetry associates with increased self-reported funciton.•Sex and age should be considered as influencing factors in knee strength asymmetry. Loss of knee extensor strength in individuals with knee osteoarthritis (KOA) may induce inter-limb strength asymmetries and alter functionality. The aims were to analyse whether the condition of the uninvolved knee (advanced to severe KOA or no affection) may induce different degrees of knee extensor strength asymmetry in individuals with KOA and to study whether functionality may differ in cases of unilateral or bilateral KOA. Sixty-eight subjects with advance-to-severe KOA were categorized into two groups (unilateral or bilateral KOA). The knee extensor strength ratio (KESR), and self-reported and performance-based functionality were analysed and compared. Sex and age were independent factors. One- and two-way analysis of variance assessed for significant between-group differences (95% confidence interval (CI)). Participants with unilateral KOA presented with 20% knee extensor strength asymmetry. The mean difference with the bilateral KOA group in terms of Knee Extensors Strength Ratio was 0.2 (95% CI 0–0.3; P = 0.021), of the Oxford Knee Scale score was 4.2 (95% CI 3.4–5.1; P = 0.037), and of the Timed Up and Go was 1.3 s (95% CI 0.5–2.2; P > 0.05). There were significant sex and age interactions (P