Efficacy of undenatured collagen in knee osteoarthritis: review of the literature with limited meta-analysis

Background: Early knee osteoarthritis (OA) treatment is multimodal, with physical therapy and pharmacotherapy commonly used. Although popular, oral supplements like glucosamine and diacerein have not been reported to have high efficacy. Undenatured collagen type II (UC-II) has been introduced for therapy in early OA; it helps in cartilage repair and preservation. The present review was done to ascertain its efficacy in pain relief and knee function. Materials and methods: A systematic literature search was performed on MEDLINE (PubMed), Embase, Scopus, and Cochrane Library for published literature; studies comparing the outcome of UC-II supplementation with placebo/control in adult humans with early knee OA were included. The outcomes evaluated were VAS Score, quality of life - Western Ontario and McMaster Universities (WOMAC-score), Knee function, Knee range of motion, and any complications during the course of treatment. Results: A total of 293 results were obtained after a primary search; 8 randomized control trials (RCT) were finally included. A total of 243 patients received UC-II supplementation (91 men and 152 women). The overall mean age range for the intervention group was 53.5 +/- 0.99 to 68.7 +/- 5.3 years across all included studies, and the mean follow-up duration was 3 to 6 months. Outcome measures like WOMAC and VAS scores showed better outcomes with UC-II in comparison to placebo. Walking measurements improved significantly from the baseline, reflected in improved timed up-and-go and 6-minute walk tests (6MWT). The overall complications were similar to other supplements. Conclusion: With limited literature, UC-II has shown promise as a potent supplement in early knee OA with good pain relief and improved function. However, further large-scale studies are needed to substantiate these findings.