The Effects of Platelet-Rich Plasma (PRP) in the Management of Knee Osteoarthritis A Review of Current Literature with Long Term Follow-Up

Abstract

Background: Symptomatic osteoarthritis (OA) of the knee is a common and debilitating degenerative condition causing significant pain and functional limitations. Previous conservative modalities have been unable to provide longer-term symptomatic relief. Autologous blood products, such as platelet-rich plasma (PRP), may provide extended benefits to patients with knee OA due to the proposed disease-modifying and anti-inflammatory effects. This literature review aims to investigate and consolidate current literature on the potential long-term therapeutic effects of PRP (greater than twelve months) in osteoarthritis of the knee. A secondary goal is to identify which demographic of patients sustain longer-lasting results and thus may optimally benefit from conservative management with intra-articular PRP. Methods: A review of the literature was undertaken utilizing the PubMed database to identify articles examining the duration of beneficial effects following intra-articular PRP injection on knee osteoarthritis. Primary studies were reviewed within the past ten years (2011-2021) with follow-up periods greater than twelve months. A total of five articles were included in the final literature review. Results: There was significant variability in the overall study design of the five articles of interest included in this review. All studies utilized clinical scoring systems, which demonstrated an improvement in scores post intra-articular PRP injection. However, a decline in scores was observed at follow-up periods beyond twelve months. The longest duration of action was found in male patients with less advanced degrees of osteoarthritis. Conclusion: PRP is a promising and safe option for the management of knee osteoarthritis. However, the long-term therapeutic effects were observed to be ill-sustained beyond twelve months post-injection in the studies of interest. Younger male patients with mild grades of radiographic osteoarthritis demonstrated superior outcomes post intra-articular PRP injection. Repeated cyclical injections, intra-articular/intra-osseous injection protocols, and combined PRP and hyaluronic acid regimens may provide further symptomatic improvement. Due to the high degree of variability between PRP products and injection regimens utilized, a universally accepted classification system must be adopted. Additionally, high-quality studies are necessary to further delineate the proposed biological interactions of PRP in knee osteoarthritis and define future treatment protocols.