Objectives: To determine the effect of intra-articular injection of platelet-rich plasma
(PRP) in patients with primary knee osteoarthritis (OA) by clinical evaluation and ultrasonographic
(US) assessment of cartilage thickness.
Patients and Methods: A total of 100 patients with mild to severe primary knee OA using the Kellgren-
Lawrence (K-L) grading scale were included and divided into two groups. Group I included
50 patients who were given two intra-articular knee injections of PRP, 1 week apart; Group II included
50 patients who received non-steroidal anti-inflammatory drugs (NSAIDs) and chondroprotective
drugs. Functional assessment of all OA patients was done using the basal WOMAC score,
at 2 and 6 months. US assessment of femoral condylar cartilage thickness was conducted basally
and at 6 months.
Results: Improvement of WOMAC score was observed at 2 and 6 months in Group I following
PRP injection compared to Group II (p values < 0.001), The improvement of WOMAC in Group I
occurred in all severity degrees of OA (p < 0.001). Moreover, a significant increase in cartilage
thickness was found at the intercondylar area (ICA) at 6 months relative to baseline assessment by
US in Group I (p = 0.041).
Conclusion: Treatment with PRP injections can reduce pain and improve knee function in patients
with various degrees of articular degeneration. Further studies are needed to clarify the anabolic effect
of PRP on the articular cartilage.