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

Get in touch

Find your clinic

We offer appointments nationwide and now working with partners abroad providing cutting edge Regenerative Medicine to patients in UK, Italy, Australia, Spain and Pakistan.