No effect of creatine monohydrate supplementation on inflammatory and cartilage degradation biomarkers in individuals with knee osteoarthritis

The study purpose was to evaluate the effectiveness of creatine monohydrate supplementation (20 grams/day for 1 week and then 5 grams/day for 11 weeks) on inflammation (C-reactive protein, interleukin-1β, interleukin-6, s100 A8/A9, and tumor necrosis factor-α) and cartilage degradation (serum cartilage oligomeric matrix protein) in patients with knee osteoarthritis. We hypothesized that supplementing with creatine monohydrate for 12 weeks would lower biomarkers of inflammation and cartilage degradation in patients with knee osteoarthritis when compared to placebo. A total of 18 patients with mild to moderate knee osteoarthritis were recruited and randomized in a double blind fashion to either a creatine supplementation group (N = 9) or a placebo (N = 9). At baseline and after 12 weeks of supplementation patients had inflammatory and cartilage degradation biomarkers measured in the systemic blood. Further, patients completed the Knee injury and Osteoarthritis Outcome (KOOS) questionnaire as well as had their isometric thigh strength evaluated using an isokinetic dynamometer at both time points. Results indicated that there was no difference between the creatine and placebo groups at 12 week follow up in the inflammatory biomarkers measured nor was there any difference between the groups for cartilage degradation (all P>.05). No statistical differences were noted for the KOOS questionnaire subscales or total score (all P>.05). Muscle strength testing indicated a main effect of time for both groups where isometric thigh strength at 0° of knee flexion was lowered significantly (P=.047). No other significant differences were found in the strength data. We conclude that 12 weeks of supplementation with creatine monohydrate does not affect inflammatory biomarkers, cartilage degradation, KOOS scores, or muscle strength in patients with mild to moderate knee osteoarthritis.