Purpose

The purpose of this study is to evaluate long term follow-up of single injection of nSTRIDE® APS for the treatment of unilateral knee osteoarthritis (NCT02138890).

Methods and Materials

Forty-six patients underwent a 2:1 randomization process to either one single injection of APS(n=31) or salin (n=15). APS was prepared with the nSTRIDE APS Kit (Zimmer Biomet). Data up to the 3 year follow up were previously published(1). The APS cohort was asked to participate in unblinded 60-month follow-up and the saline patients were offered cross-over after 12 months and were similarly followed. Efficacy endpoints (WOMAC LK 3.1, KOOS, and VAS) were measured as a change from baseline to each time point. Data is presented as mean ± SD. Missing data was calculated as baseline carried forward(BLCF) for subjects that had exited the trial for knee OA pain.

Results

At the final follow-up for the study (60 months), 17 of the original 31 randomized to APS and 6 of the original 15 saline/crossover remained in the study. The Kaplan-Meier curve for subjects exiting for knee-related events demonstrate a 0.64 survivorship probability[95% CI 0.463,0.820](Figure 1). Using the BLCF method, the APS cohort had a mean WOMAC pain percent improvement from baseline of 64.8±29.5% at 1 year(p<0.0001), 50.4±42.1% at 3 years(p<0.0001), and 39.0±41.2% at 5 years(p<0.0001). For the subjects that accepted crossover after 1 year, the WOMAC pain improvement was 45.5±33.3% at time of crossover(p=0.0002), 44.0±37.6% at 3 years(p=0.0008), and 24.6±33.7% at 5 years(p=0.028).

Conclusion

All in all, treatment with a single, intra-articular injection of APS in subjects with knee osteoarthritis has shown long-lasting pain and function relief and indicates of the long-term durability APS for knee osteoarthritis.

[1]Kon et al. AJSM;2020;48(11):2703-2710.