Knee Osteoarthritis (KOA) is a degenerative joint disease in which the protective cartilage in the knee gradually breaks down, causing the bones to rub together. This leads to pain, stiffness, and reduced mobility, making simple daily activities difficult. Unlike rheumatoid arthritis, KOA is not an autoimmune disease. It's a mechanical process of degeneration that worsens without proper management.
KOA is influenced by several risk factors:
• Age: Risk increases significantly after 40.
• Excess Body Weight: Adds mechanical stress to the knee joints.
• Previous Injuries: Damage to ligaments or the meniscus can accelerate wear.
• Genetics: A family history of osteoarthritis increases susceptibility.
• Repetitive Stress: Physically demanding jobs or high-impact sports can strain the knees over time.
KOA patients typically demonstrate slower walking speed, reduced cadence, prolonged gait cycle time, and increased variability in step timing, reflecting cautious and unstable gait patterns. These alterations are accompanied by reduced knee flexion during stance and swing, progressive loss of overall joint range of motion, and diminished hip and ankle mobility, all of which worsen with disease severity.
To reduce stress on the knee, individuals may lean their body toward the unaffected leg or increase the curve in their lower back (increased lumbar lordosis). Additionally, the hip or ankle may exhibit abnormal movements to maintain balance. Due to pain compensation, the pressure distribution on different parts of the foot (e.g., heel or toes) changes. For example, individuals may walk more on their heels to reduce pressure on the knee.
The knee flexion-extension profile across the gait cycle is one of the measurements in the FlexiGait report. Published research describes group-level differences in this profile between people with and without knee osteoarthritis, and reports that these differences tend to be larger where disease is more advanced. FlexiTrace has not conducted a study in a knee osteoarthritis population. The measurements in the report are descriptive: they record how a person walked during a recording. They are not established as a measure of disease severity or of disease progression, and they are not a diagnostic test. Interpreting them in relation to knee osteoarthritis is a clinical judgement for a qualified healthcare professional, using the patient's full clinical picture.
Beyond looking at single joints in isolation, FlexiGait also analyzes the coordination between your hip and knee using a hip-knee cyclogram. This plot traces the knee angle against the hip angle throughout a full gait cycle, creating a visual loop that represents the dynamic relationship between these two key joints. In a healthy gait, this loop is typically large, smooth, and consistent, indicating a wide range of motion and fluid coordination. However, in individuals with KOA, the cyclogram often appears shrunken. This reduction in the loop's size directly reflects the decreased range of motion at both the knee and hip, a common adaptation to pain and stiffness.
While there is no cure for KOA, many treatments can relieve symptoms, slow progression, and improve function.
Standard treatments include:
• Medications: Over-the-counter pain relievers or NSAIDs.
• Physical Therapy: Exercises to strengthen the muscles around the knee, hip, and core.
• Lifestyle Changes: Weight management and low-impact activities like swimming.
• Injections: Corticosteroids or hyaluronic acid for temporary relief.
• Surgery: Knee replacement in severe cases.
Studies show that personalized adjustments, like changing your foot angle by 5-10° or increasing trunk sway, can provide pain relief comparable to medication. Because gait retraining is highly personal, an initial quantitative assessment—like a quantitative gait assessment—is crucial for success.
Understanding how your body moves can be a useful part of living with knee osteoarthritis. FlexiGait records how you walk and presents the measurements in a report you can share with your healthcare provider. It is one source of information among many. It does not diagnose or monitor osteoarthritis, it does not replace clinical examination or imaging, and decisions about your care remain with your provider.
For researchers: FlexiTrace collaborates with research groups studying gait in clinical populations. If you are running such a study, please get in touch.
[1] Kour, Navleen; Gupta, Sunanda; Arora, Sakshi (2020), "Gait Dataset for Knee Osteoarthritis and Parkinson's Disease Analysis With Severity Levels", Mendeley Data, V1, doi: 10.17632/44pfnysy89.1
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