Knee Instability and Basic and Advanced Function Decline in Knee Osteoarthritis.

Area of Science:

• Orthopedics and Sports Medicine
• Rheumatology
• Biomedical Engineering

Background:

• Knee osteoarthritis (OA) is characterized by instability, including low knee confidence, buckling, and excessive motion.
• These instability symptoms, particularly buckling, can significantly impact activity choices and contribute to disability, especially in advanced functional tasks.
• Understanding the relationship between specific instability manifestations and functional decline is crucial for effective OA management.

Purpose of the Study:

• To investigate the association between baseline knee instability measures (overall knee confidence, buckling confidence, buckling, and frontal plane motion) and 2-year functional outcomes in individuals with knee OA.
• To determine if knee buckling and confidence levels predict future functional limitations in advanced tasks.

Main Methods:

• A prospective longitudinal study involving 212 participants with knee OA.
• Instability was assessed through self-report questionnaires (knee confidence, buckling confidence, buckling) and quantitative gait analysis (varus-valgus excursion, angular velocity).
• Logistic regression analysis was employed to examine the relationship between baseline instability measures and 2-year functional outcomes, controlling for confounders.

Main Results:

• Knee buckling was significantly associated with poor advanced function outcomes at 2 years (adjusted OR 2.08).
• Low overall knee confidence also significantly predicted poor advanced function outcomes (adjusted OR 1.65).
• Neither varus-valgus excursion nor angular velocity during gait showed a significant association with basic or advanced functional outcomes.

Conclusions:

• Knee buckling and diminished knee confidence are significant predictors of poor functional outcomes in advanced tasks for individuals with knee OA.
• Current treatments for knee OA may not adequately address these modifiable factors related to instability.
• Interventions targeting knee buckling and confidence could potentially improve functional outcomes and reduce disability in knee OA patients.