Triple injection of intra-articular PRP given one month apart significantly relieves knee OA symptoms

Najmul Huda et al found in the study that - Triple injection of intra-articular PRP given one month apart significantly relieves the symptoms of knee OA till 2 years in Kellgren-Lawrence (KL) grade I, II and III. The improvement in symptoms at 2-year follow-up did not differ across different KL grades.

PRP is the autologous plasma part of the blood that has high concentration of platelets, which contain many growth factors in their alpha granules [like platelet derived growth factor (PDGF), epidermal growth factor, vascular endothelial growth factor(VEGF), transforming growth factor, fibroblast growth factor, hepatocyte growth factor, insulin like growth factor-1,2]. These growth factors increase the anabolic activity within the joint, favour chondrocyte proliferation, increased synthesis of collagen, chondral remodeling and production of matrix molecules which leads to healing. PRP has now become an almost established treatment for OA knees.

The literature reporting a follow-up of more than one year is scarce. Hence the authors aimed to find out whether the effect of PRP, persists beyond one year. All the patients in this study were followed up for 2 years.

The authors conducted a prospective interventional study.

68 cases (105 knees) with KL grades I, II and III knee OA received 3 intra-articular injections of PRP 1 month apart. The cases were followed up for 2-years. Outcomes were measured using Western Ontario and McMaster Universities Arthritis Index (WOMAC) score and Visual analog scale (VAS) scores.

The observations of the study were:

• The mean age was 51.7 years. 18 knees had KL grade I, 55 had grade II and 32 had grade III OA.

• The mean pre treatment VAS score decreased significantly at 1 year (mean difference − 5.3, p=0.003) and 2 year follow-up (mean difference − 6, p=0.007).

• The mean pre-treatment WOMAC score decreased significantly at 1 year (mean difference − 45.9, p=0.011) and at 2 year (mean difference − 52.4, p=0.009).

• The WOMAC and VAS scores improved significantly from baseline to final follow-up across all KL grades (p=0.001 and 0.001, 0.009 and 0.007, 0.021 and 0.017 for WOMAC and VAS across KL grade I, II and III, respectively).

• There was no significant differences in WOMAC and VAS scores between three KL grades at final follow-up (p=0.17 and 0.09, respectively), although the baseline scores had significant difference (p=0.001 for both VAS and WOMAC) with worse scores in higher KL grades.

• The variables like age, sex, BMI, KL grade, baseline VAS and baseline WOMAC did not predict the final VAS and WOMAC scores.

The limitations of the study are a lack of a placebo group. A double blinded study would have been better. Though PRP showed significant functional improvement, association of this with actual changes in the articular cartilage could have been evaluated by imaging studies like MRI.

Further reading:

Role of Triple Injection Platelet Rich Plasma for Osteoarthritis Knees: A 2 Years Follow Up Study

Najmul Huda et al

Indian Journal of Orthopaedics (2022) 56:249–255

https://doi.org/10.1007/s43465-021-00459-6