Effects of Platelet-Rich Plasma on Tendon-Bone Healing After Anterior Cruciate Ligament Reconstruction

Most Publications Regarding Platelet-Rich Plasma Use in the Knee Are From Asia, Investigate Injection for Osteoarthritis, and Show Outcome Improvement: A Scoping Review

PURPOSE

To evaluate and synthesize the available literature related to platelet-rich plasma (PRP) treatment of knee pathologies and to provide recommendations to inform future research in the field.

METHODS

PubMed, CINAHL, and Scopus databases were queried on October 6, 2023. All identified citations were collated and uploaded into Covidence for screening and data extraction. Studies were included if they were human studies published in English with adult cohorts that received PRP as a procedural injection or surgical augmentation for knee pathologies with patient-reported outcome measures (PROMs) and level of evidence Levels I-IV.

RESULTS

Our search yielded 2,615 studies, of which 155 studies from 2006 to 2023 met the inclusion criteria. Median follow-up was 9 months (±11.2 months). Most studies (75.5%) characterized the leukocyte content of PRP, although most studies (86%) did not use a comprehensive classification scheme. In addition, most studies were from Asia (50%) and Europe (32%) and were from a single center (96%). In terms of treatment, 74% of studies examined PRP as a procedural injection, whereas 26% examined PRP as an augmentation. Most studies (68%) examined treatment of knee osteoarthritis. Many studies (83%) documented significant improvements in PROMs, including 93% of Level III/IV evidence studies and 72% of Level I/II evidence studies, although most studies (70%) failed to include minimal clinically important difference values. The visual analog scale was the most-used PROM (58% of studies), whereas the Short Form Health Survey 36-item was the least-used PROM (5% of studies).

CONCLUSIONS

Most published investigations of knee PRP are performed in Asia, investigate procedural injection for osteoarthritis, and show significant outcome improvements. In addition, this review highlights the need for better classification of PRP formulations.

LEVEL OF EVIDENCE

Level IV, scoping Review of level I-IV studies.

Effect of bone marrow aspiration concentrate and platelet-rich plasma combination in anterior cruciate ligament reconstruction: a randomized, prospective, double-blinded study

BACKGROUND

The effect of bone marrow aspirate concentrate (BMAC) and platelet-rich plasma (PRP) combination in enhancing graft maturation and tendon-bone tunnel interfacial healing after anterior cruciate ligament (ACL) reconstruction remains unclear. We hypothesised that BMAC and PRP combination could lead to better clinical results and better graft maturation/interface healing than PRP alone or conventional ACL reconstruction without any other biologic augmentation.

METHODS

In this randomised double-blind prospective study, patients undergoing ACL reconstruction surgery were randomly assigned into three groups: (1) control group (without any biologic augmentation), (2) PRP treatment group, and (3) combined BMAC and PRP (BMAC + PRP) group. Moreover, they were evaluated using the clinical functional score, laxity examination, and magnetic resonance imaging (MRI) analysis.

RESULTS

No significant difference was observed in the improvement of functional scores among groups. However, laxity improvement at 24 weeks showed a significant difference with the BMAC + PRP group having the lowest laxity. MRI analysis showed no significant change in whole graft maturation among groups. In particular, the BMAC + PRP group showed delayed signal peak and higher graft signal at 24 weeks compared with the other two groups; however, the difference was not significant. With regard to tendon-bone interfacial healing, the BMAC + PRP group showed significantly wider tendon-bone interface in the femoral bone tunnel at 24 weeks compared with the other two groups. Moreover, the BMAC + PRP group showed significantly higher peri-tunnel edema signal in the femoral bone tunnel at 12 weeks compared with the other two groups.

CONCLUSION

PRP alone and BMAC and PRP combination showed limited enhancing effect in clinical function, graft maturation and tendon-bone interfacial healing compared with control (no additional treatment). When BMAC is used in ACL reconstruction, the possibility of greater inflammation in the early stage to graft maturation and bone tunnel healing should be considered.

Strategies to promote tendon-bone healing after anterior cruciate ligament reconstruction: Present and future

At present, anterior cruciate ligament (ACL) reconstruction still has a high failure rate. Tendon graft and bone tunnel surface angiogenesis and bony ingrowth are the main physiological processes of tendon-bone healing, and also the main reasons for the postoperative efficacy of ACL reconstruction. Poor tendon-bone healing has been also identified as one of the main causes of unsatisfactory treatment outcomes. The physiological process of tendon-bone healing is complicated because the tendon-bone junction requires the organic fusion of the tendon graft with the bone tissue. The failure of the operation is often caused by tendon dislocation or scar healing. Therefore, it is important to study the possible risk factors for tendon-bone healing and strategies to promote it. This review comprehensively analyzed the risk factors contributing to tendon-bone healing failure after ACL reconstruction. Additionally, we discuss the current strategies used to promote tendon-bone healing following ACL reconstruction.

Kartogenin Combined Platelet-Rich Plasma (PRP) Promoted Tendon-Bone Healing for Anterior Cruciate Ligament (ACL) Reconstruction by Suppressing Inflammatory Response Via targeting AKT/PI3K/NF-κB

Anterior cruciate ligament (ACL) rupture is the most common sports injuries and PRP has the potential to be a kartogenin (KGN) carrier to promote collagen fibril organization and cartilage regenerative in the tendon-bone interface. This paper aimed to investigate co-injection of KGN-PRP into the bone tunnels of ACL reconstructions which could enhance tendon-bone healing graft osteointegration effectively. HPLC was used to measured release rate of KGN from KGN-PRP gel. Then, an ACL injury reconstruction model in rabbits was established and the rabbits received saline, PRP, and KGN-PRP injection onto the tendon-bone interface after reconstruction. The tissue was harvested from the tendon-bone interface at 4 weeks and 8 weeks post-surgery, and the sections were stained with Safranin O/fast green to detected tendon-bone healing. Immunochemistry staining was used to analyze VEGF, collagen I, and HIF-1α expression, and ELISA assay was used for detecting IL-6, TNF-α, and COX-2 concentrations. The expression levels of AKT/PI3K/NF-κB-related protein and mRNA were presented by Western blot and qPCR. The release rate of KGN was high within 4 h of KGN-PRP gel and followed by a slow release until 7 days. The Safranin O/fast green staining results indicated that tendon-bone interface in sham and mock group existed gap and tissue disorganization. The KGN + PRP group showed the positive color of the healing interface was more obvious and cartilage tissue began to be generated in large amounts at this interface. The maximum tensile force of KGN-PRP injection tendon-bone healing site was significantly higher than that of PRP group, and KGN-PRP effectively promoted fibro chondrogenesis and tendon-bone healing. The expression of collagen I, VEGF, and HIF-1α in regenerated tissues at the healing interface was significantly increased by KGN-PRP treatment compared with the mock and sham groups. The expressions of IL-6, TNF-α, and COX-2 after KGN-PRP treatment were significantly decreased in tendon-bone interface compared to the mock group. WB and qPCR results showed KGN-PRP treatment effectively inhibits AKT/PI3K/NF-κB activation of inflammatory pathways, thereby reducing the level of inflammation to promote wound healing. PRP is an effective carrier for KGN with the sustained release of KGN. After ACL reconstruction, injection of KGN-PRP gel significantly reduced the inflammatory response and inhibited AKT/PI3K/NF-κB activation in cartilage tissue, which promoted tendon-bone healing.

Strategies for promoting tendon-bone healing: Current status and prospects

Tendon-bone insertion (TBI) injuries are common, primarily involving the rotator cuff (RC) and anterior cruciate ligament (ACL). At present, repair surgery and reconstructive surgery are the main treatments, and the main factor determining the curative effect of surgery is postoperative tendon-bone healing, which requires the stable combination of the transplanted tendon and the bone tunnel to ensure the stability of the joint. Fibrocartilage and bone formation are the main physiological processes in the bone marrow tract. Therefore, therapeutic measures conducive to these processes are likely to be applied clinically to promote tendon-bone healing. In recent years, biomaterials and compounds, stem cells, cell factors, platelet-rich plasma, exosomes, physical therapy, and other technologies have been widely used in the study of promoting tendon-bone healing. This review provides a comprehensive summary of strategies used to promote tendon-bone healing and analyses relevant preclinical and clinical studies. The potential application value of these strategies in promoting tendon-bone healing was also discussed.