Autologous protein solution as a therapy for middle-aged females with patellofemoral osteoarthritis: a 12-month clinical study

February 27, 2020


Purpose: Symptomatic patellofemoral osteoarthritis (OA) is twice as common in females than males above the age of 30 and appears to be resistant to most injection therapies. The purpose of this trial is to determine the response rate and pain alleviation after injection of an autologous protein solution (APS) in a middle-aged female patient cohort with symptomatic patellofemoral OA.

Methods and Materials: Forty-six women (age 40-65) diagnosed with mild to severe patellofemoral OA, who had failed at least one conservative treatment, were prospectively included and treated with an intra-articular injection of autologous protein solution (nSTRIDE APS Kit, Zimmer Biomet), a concentrated blood product containing high amounts of anti-inflammatory cytokines. KOOS pain was assessed at baseline and 1, 3, 6, and 12 months post-injection. Treatment responders were defined as ≥ 10 points improvement on KOOS pain relative to baseline. A second APS injection after minimum 3 months follow-up was administered if the clinical improvement was deemed insufficient by the patient.

Results: Overall KOOS pain score increased from 42.8±17.3 baseline to 57.3±24.7 (p<0.001) at 12 months with 48% responding patients (fig. 1). Twenty-seven patients requested a second injection between 3-12 months. While the response rate differed significantly between the single and double injected patients at 3 months (p=0.036), no statistically significant difference was observed at final follow-up (p=0.251, fig.2). Subgroup analysis for age revealed a significant difference in pain at 3 months in favor of the patient above 50 (p=0.034) while severe patellofemoral OA was associated with significantly more responders (p=0.044) and better pain outcomes (p=0.038) at 6 months.

Conclusion: This study demonstrates an acceptable response rate of 48% and significant pain improvement 12 months after APS injection in a challenging population of middle-aged female patellofemoral OA patients. A second APS injection is indicated for initially poor responding patients to establish sufficient pain relief up to 12 months.

Van Genechten W, Vuylsteke K, Rojas Martinez P, Swinnen L, Verdonk P, “Autologous protein solution as a therapy for middle-aged females with patellofemoral osteoarthritis: a 12-month clinical study.” 15th World Congress of the International Cartilage Repair Society, Vancouver, Canada, (P158), Oct. 5-8, 2019. Full manuscript in draft