Background Using intra-articular injections of autologous platelet-rich plasma (PRP) has showen promising results in treatment of knee osteoarthritis (KOA). Its regenerative properties depends on the amount of growth factors (GF) released after platelets activation. Using large-volume of blood for obtaining allogenic PRP can provide higher concentrations of platelet and GF. However once prepared, PRP is stable for only 8-hours. Freeze drying (lyophilization) can be used to stabilize the biological materials for prolonged storage without causing their damage (1).

Objectives Investigating the effectiveness of intra-articular allogenic lyophilized growth factors (L-GF) injection in patients with symptomatic KOA using clinical and knee ultrasonography assessment.

Methods 30-patients with symtomatic primary KOA, diagnosed according to revised criteria of the aCR (2), were enrolled. Local ethical approval was obtained. All patients had given a written informed consent. The study group was equally randomized into intervention and control groups. Both was subjected to baseline functional assessment using WOMAC score; evaluating pain, stiffness, and physical function (3), and ultrasonography (US) assessment of knee effusion. The patients in control group were kept on their medications without intervention. The intervention group was recieved two doses of L-GF; at baseline and after 2-months. L-GF was prepared from platelets derived from individual whole blood donations. Each unit of platelets was tested in and found to be non-reactive for HBsAg, HIV I & II antibodies, HIV p-24 antigen, HCV antibodies and antibodies to Treponema Palidum, by licensed assay methods. Seronegative plasma were further examined by Nuclear acid Testing. Further viral inactivation by UV-radiation and Riboflavin by the Mirasol system was done. The platelets in the buffy coat layer were activated using CaCl₂ to release their GF. Excess water, cellular elements and fibrinogen were removed and the remaining GF were “ultraconcentrated.” Lyophilization of the obtained GF was then processed. The L-GF was supplied as powder in tightly sealed container and was stored at 2° to 8° C. Prior to use, reconstitution of the product was done using 1-ml saline and 1-ml lignocaine then the mixture was kept at ambient temperature for 5-min. To ensure complete protein re-hydration. After 6-months the WOMAC score and knee US were repeated for all particepients. Then percent of improvement of WOMAC and US detected effusion were calculated for all patients.

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Results The patients in the intervention group was significantly older (56±9 years) and had heigher BMI (38±5.3 kg/m²) in comparison to control (44±11 years, 33±5.6 kg/m²). Both groups showed statistically insignificant difference regarding the baseline total WOMAC score and radiographic assessment. Post injection pain was reported by all patients in intervention group, it lasted only for 2.4±0.83 hours and was graded as mild. The mean of total WOMAC score and its 3-compenents in addition to knee effusion were decreased significantly in the intervention group after 2 months and 6 months of follow-up (figuer-A). After 6-months, the intervention group showed statistically significant persentage of improvement regarding WOMAC scores and effusion in comparison to the control (figuer-B).

Conclusion Allogenic L-GF was well tolerated and showed encouraging results in patients with symptomatic KOA, regarding improvement of pain, stiffness and function in addition to decreasing knee effsuion.

References [1] Pan L, et al. Aesth Plast Surg. 2016;40: 157.

[2] altman R, et al. Arthritis Rheum29:1039, 1986.

[3] Bellamy N, et al. J Rheumatol1988; 15:1833-40.

Disclosure of interests Rasmia Elgohary: None declared, amany Diab: None declared, Hala Elgndy: None declared, Hossam Fahmy: None declared, Kamel Gado Speakers bureau: have been paid as a speaker to pharmaceutical companies (Novartis, EVA pharm) and also to attend their advisory board