Duration effects of a single intra-articular injection of Autologous Protein Solution (APS) in patients with knee osteoarthritis (OA)

Author: Kon et al
Year: 2019


Purpose: Autologous anti-inflammatories (AAI) are a class of blood-derived products with high concentrations of anti-inflammatory cytokines that are currently being investigated for the treatment of mild to moderate knee osteoarthritis (OA) to determine if they can ameliorate symptoms longer or better than traditional intra-articular injections such as hyaluronic acid (HA) and steroids. The purpose of this evaluation is to determine the duration of effect from a single injection of APS before patients elect a new treatment course.

Methods and Materials: Forty-six patients underwent a 2:1 randomization process to either one single injection of APS (n=31) or saline (n=15) (NCT02138890). APS was prepared with the nSTRIDE APS Kit (Zimmer Biomet). The 12 month double-blind outcomes of the double-blind portion of the trial were previously published. The APS cohort was asked to participate in unblinded long-term follow-up. Efficacy endpoints of pain and function over time (WOMAC LK 3.1, KOOS, and VAS) were measured as a change from baseline to each time point. Quality of life (SF-36), OMERACT-OARSI responder criteria, rescue medication usage, as well as yearly x-rays and 24 month MRI imaging were completed.

Results: Survivorship of the APS cohort that agreed to long-term follow-up was 71% at 3 years. At 36 months, the mean WOMAC Pain improvement was 70%(Figure 2)(7.8 ± 4.0) in the APS cohort, which was a significant improvement compared to the baseline score(p<0.0001). APS cohort patients also showed a statistically significant improvement in their KOOS pain score (114%,33.3 ± 22.0; p<0.0001) and VAS pain score (42.7%, 2.0 ± 3.3; p=0.0012).

Conclusion: Intra-articular injections of APS for mild to moderate knee OA was safe and a portion of patients continue to have pain relief 3 years after a single injection. Clinical investigation (NCT03182374) to determine the long-term efficacy compared to a single injection hyaluronic acid is currently ongoing.


Kon E, Verdonk P, Engebretsen L Neher S, Di Martino A, Filardo G. ”Duration effects of a single intra-articular injection of Autologous Protein Solution (APS) in patients with knee osteoarthritis (OA),” 15th World Congress of the International Cartilage Repair Society, Vancouver, Canada, Program #12.4.4 (#437), Oct. 5-8, 2019. Full manuscript in

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