In terms of pain relief and KOOS ratings, subchondral PRP injections did not provide additional benefits over intra-articular PRP injections in patients with osteoarthritis.

A parallel, 2-group, prospective, randomized clinical study examined the effectiveness of intra-articular, intra-osseous platelet-rich plasma (PRP) injections in osteoarthritis knee and compared them to intra-articular PRP injections.

Overall, 64 individuals with knee osteoarthritis and a Kellgren-Lawrence score of 3 were randomly divided into 2 groups. Individuals in Group I was administered a single intra-articular PRP injection of 8 ml. The subjects in Group II received a single intra-articular injection of 8 ml of PRP (for a total of 18 ml of PRP, for a single joint) and 18 ml of PRP (two intra-osseous injections of 5 ml each in the femoral-condyle and tibia plateau) in the target knee joint under fluoroscopic guidance.

At 3 and 6 months, all individuals (n = 64) were followed up. The knee injury and osteoarthritis outcome score (KOOS) questionnaire and visual analogue (VAS) pain intensity scores were used to assess clinical outcomes.

In terms of both the group's clinical parameters and baseline demographic, no difference was found. At baseline, three and six months later, both groups showed clinically meaningful betterment in VAS pain scores and KOOS scores (quality of life, sport/recreation, Activities of daily living [ADL], symptoms, and pain).

At 6 months, there was no discernible difference between the groups in terms of KOOS and VAS scores. Following treatments, people in Group II reported more pain related to the injection. With the exception of injection-related pain, no other adverse events were noted in any person.

Although PRP injections significantly improved both groups' conditions, subchondral PRP injections did not offer add-on advantages over intra-articular PRP injections in terms of pain reduction and KOOS scores at six months.