The Effect of a Lower Body Positive Pressure Supported Treadmill Exercise Regime on Systemic Biomarkers of Inflammation and Cartilage Degradation in Individuals with Knee Osteoarthritis: A Pilot Study

Background: Knee osteoarthritis (OA) has been linked to a chronic low-grade inflammatory response and altered metabolic activity of articular cartilage. Objective: The purpose of this investigation was to evaluate the effectiveness of a 12-week (3 times/week) lower body positive pressure (LBPP) treadmill walking regime on knee pain and systemic biomarkers of inflammation and cartilage degradation. Methods: Sixteen overweight (BMI > 25 kg/m2) knee OA patients were randomized to a LBPP treadmill walking exercise group (N = 7) or non-exercise control group (N = 9). Baseline and 12-week follow-up assessments evaluated the following dependent variables: acute knee pain during full weight bearing treadmill walking; inflammatory biomarkers (C-reactive protein, interleukin-1β, interleukin-6, s100A8/A9, and tumor necrosis factor-α), and catabolic metabolism of articular cartilage (sCOMP). Results: Knee pain at baseline and follow-up remained unchanged for the non-exercise control group (P > 0.05). However, knee pain for the LBPP exercise group was significantly decreased at follow-up (P ≤ 0.05). No differences in the biomarkers of inflammation and cartilage degradation were observed for between and within group comparisons (all P > 0.05). Conclusions: Data suggested that the LBPP supported walking regime could be effectively used to promote regular weight bearing exercise without exacerbation of knee joint pain and did not increase levels of systemic inflammation or catabolic activity of articular cartilage in overweight knee OA patients. This pilot investigation offers important insight regarding the potential role that the LBPP technology could play in facilitating investigations examining the disease modifying effect of exercise on knee OA pathogenesis.