PRP in OA knee - update, current confusions and future options

Platelet rich plasma and anterior cruciate ligament repair: A new frontier, or a short term adjunct

Platelet rich plasma (PRP) is an autologous blood product rich in platelets, showing promise in reducing inflammation and accelerating healing. While extensively utilized in plastic surgery, dermatology, and osteoarthritis treatment, its application in anterior cruciate ligament (ACL) injuries is limited. This article examines PRP's potential in ACL reconstruction (ACLR), exploring its history, current usage, controversies and future directions. PRP has demonstrated significant early benefits in ligamentisation and vascularisation post-ACLR, though its long-term efficacy is inconsistent. Studies suggest that PRP may serve as both an adjunct therapy in ACLR to enhance initial healing and reduce postoperative complications, and as a non-surgical alternative for small ACL tears. Despite these promising findings, outcome variability necessitates further high-quality research to optimize PRP formulations and determine its most effective applications. The exploration of PRP as a treatment modality in ACLR offers promising but varied outcomes. PRP holds considerable promise as both an adjunct and alternative to traditional ACLR. This article underscores the need for targeted research to fully realize PRP's therapeutic potential in ACL treatment, aiming to inform future studies and clinical practices. By understanding PRP's mechanisms of efficacy and identifying the most beneficial patient populations, PRP could significantly impact orthopaedics and sports medicine, improving recovery pathways and patient outcomes.

Semi-invasive therapies for pain in knee osteoarthritis: A systematic review and network meta-analysis

BACKGROUND

The increasing number of semi-invasive pain therapies in knee osteoarthritis poses challenges in decision-making. This review aimed to simultaneously compare established intra-articular therapies with newer peri-articular therapies and explore effect modifiers.

METHODS

Randomized controlled trials were searched from five electronic databases without date or language restrictions. Study selection and data extraction of reports, retrieved up to May 2024, were performed independently by paired assessors. The primary outcome was 6-month pain score. Nine treatments were included. The effect size (ES) for each treatment, relative to placebo, was estimated using standardized means difference and expressed with 95% confidence intervals (CI). The rigor of results was evaluated with subgroup/sensitivity analyses.

RESULTS

A total of 111 studies (14,695 participants) were included, with intra-articular hyaluronic acid having the greatest number of participants. Neuroablation demonstrated the greatest ES (1.08, 95% CI: 0.07, 2.10). While platelet-rich plasma (PRP) ranked second (ES: 0.75, 95% CI: 0.28, 1.22), it was the only intervention demonstrating statistically significant effect at 3, 6, and 12 months. However, this statistical significance was lost in some sensitivity analyses. Larger estimates for biologics and PRP compared with prolotherapy, steroid, and hyaluronic acid injections were consistently observed across different timepoints and in multiple sensitivity analyses. Generally, no statistically significant difference was found between the nine types of therapies.

CONCLUSION

Although there is robust evidence suggesting greater efficacy of PRP, potentially including biologics, over other interventions, future research is needed to identify the phenotype or patient subgroup that would benefit most from PRP.

Addressing Knee Osteoarthritis Pathology Through Platelet-Rich Plasma Treatment: A Comprehensive Review

Platelet-rich plasma (PRP) is gaining popularity across various medical fields, including orthopedics, for its potential in tissue regeneration and wound healing. As intra-articular treatments evolve, PRP has emerged as a promising option for managing knee osteoarthritis, meniscus, and ligament injuries. This review aims to provide an update on the current applications of PRP in treating knee osteoarthritis and its clinical implications in orthopedic and sports medicine. We reviewed 180 eligible studies, and our findings suggest that PRP injections significantly improve knee joint function compared to alternative treatments. The use of PRP across various medical fields has been growing in popularity recently. PRP is a biological product derived from the plasma portion of a patient's own blood, containing a higher concentration of platelets than normal. Its potential for tissue regeneration and wound healing has drawn significant attention from orthopedic surgeons, especially as intra-articular treatment options continue to evolve. The benefits of PRP in treating various osteoarticular conditions have sparked considerable interest within the orthopedic community, particularly for managing knee osteoarthritis, meniscus tears, and ligament injuries. This review aims to provide an updated overview of the current applications of PRP in the treatment of knee osteoarthritis and to offer clinical insights into its use in orthopedic and sports medicine practices. We reviewed 180 relevant titles and abstracts that met the inclusion criteria. Compared to other treatment options, PRP injections significantly enhance knee joint function.

Unlocking the full potential of mesenchymal stromal cell therapy for osteoarthritis through machine learning-based in silico trials

Despite the potential of mesenchymal stromal cells (MSCs) in osteoarthritis (OA) treatment, the challenge lies in addressing their therapeutic inconsistency. Clinical trials revealed significantly varied therapeutic outcomes among patients receiving the same allogenic MSCs but different treatment regimens. Therefore, optimizing personalized treatment strategies is crucial to fully unlock MSCs' potential and enhance therapeutic consistency. We employed the XGBoost algorithm to train a self-collected database comprising 37 published clinical reports to create a model capable of predicting the probability of effective pain relief and Western Ontario and McMaster Universities (WOMAC) index improvement in OA patients undergoing MSC therapy. Leveraging this model, extensive in silico simulations were conducted to identify optimal personalized treatment strategies and ideal patient profiles. Our in silico trials predicted that the individually optimized MSC treatment strategies would substantially increase patients' chances of recovery compared to the strategies used in reported clinical trials, thereby potentially benefiting 78.1%, 47.8%, 94.4% and 36.4% of the patients with ineffective short-term pain relief, short-term WOMAC index improvement, long-term pain relief and long-term WOMAC index improvement, respectively. We further recommended guidelines on MSC number, concentration, and the patients' appropriate physical (body mass index, age, etc.) and disease states (Kellgren-Lawrence grade, etc.) for OA treatment. Additionally, we revealed the superior efficacy of MSC in providing short-term pain relief compared to platelet-rich plasma therapy for most OA patients. This study represents the pioneering effort to enhance the efficacy and consistency of MSC therapy through machine learning applied to clinical data. The in silico trial approach holds immense potential for diverse clinical applications.

Exploring Platelet-Rich Plasma Therapy for Knee Osteoarthritis: An In-Depth Analysis

The use of platelet-rich plasma (PRP) in all medical fields is currently gaining popularity (1). PRP is a biological product that can be defined as a segment of the plasma fraction of autologous blood with a platelet concentration level above the baseline (2). The fact that it has uses in tissue regeneration and wound healing has caught the eye of orthopedic surgeons as well, as intra-articular treatments have continued to evolve. Its benefits in the treatment of different osteoarticular pathologies are of great interest in the evolving orthopedic community, targeting mostly knee osteoarthritis, meniscus and ligament injuries (3). The purpose of this review is to update the reader on the current uses of platelet-rich plasma (PRP) in the treatment of knee osteoarthritis pathology and to provide clinical feedback on its uses in the fields of orthopedic and sports medicine practice (4). We proceeded in studying 180 titles and abstracts eligible for inclusion. Compared to alternative treatments, PRP injections greatly improve the function of the knee joint.

A Greater Platelet Dose May Yield Better Clinical Outcomes for Platelet-Rich Plasma in the Treatment of Knee Osteoarthritis: A Systematic Review

PURPOSE

To determine whether the platelet dose administered during a platelet-rich plasma (PRP) injection for knee osteoarthritis (OA) affects clinical outcomes.

METHODS

A systematic review was performed by searching PubMed, Cochrane Library, and Embase for randomized controlled trials with at least 1 study arm using PRP for knee OA. Only studies that provided a platelet count, concentration, or dose with a minimum of 6-month outcome scores were included. Studies in which the PRP group had statistically significant positive outcomes were separated from those without statistical significance. The average platelet doses for studies with positive outcomes in the PRP group were compared with those without positive outcomes.

RESULTS

After exclusion criteria were applied, 29 studies were analyzed. Of the 29, there were 31 arms that used PRP as a treatment method, of which 28 had statistically significant positive outcomes at 6 months compared with the control group. The mean platelet dose in the 28 with a positive outcome was 5,500 ± 474 × 106, whereas the 3 that had no positive difference had a mean platelet dose of 2,302 ± 437 × 106 (P < .01). There were 18 studies with 12-month outcomes, with 16 of 18 having positive outcomes. The positive studies had an average platelet dose of 5,464 ± 511, whereas the studies that had no statistical difference had an average platelet dose of 2,253 ± 753 × 106 (P < .05).

CONCLUSIONS

Improved clinical outcomes from PRP injections for knee OA may be related to a greater platelet dose.

LEVEL OF EVIDENCE

Level II, systematic review of Level I and II studies.

A novel treatment of clavicular nonunion: Combination with PRP, autologous bone grafting, and internal plate fixation

BACKGROUND

Nonunion is a major concern for orthopedic surgeons, particularly nonunion of the clavicle, which can cause severe pain, loss of full range of motion, poor sleep quality, and loss of strength in the affected individuals. Platelet-rich plasma (PRP), an important biological agent, is widely used in orthopedics.

OBJECTIVE

We used a combination of three techniques - the PRP technique, autologous bone grafting technique, and internal plate fixation technique - to ensure adequate internal fixation and enable a bone growth-supportive environment at the fracture site.

METHODS

The surgical approach was applied to a patient with clavicle nonunion.

RESULTS

Based on postoperative follow-up findings and intraoperative findings at the time of re-removal of the patient's implant, the prognosis at the fracture site was considered satisfactory.

CONCLUSION

We observed that the patient treated with this method had favorable clinical outcomes, and we recommend that this technique be used in patients with long-bone nonunion.

Comparison of Functional Outcome of Single Versus Multiple Intra-articular Platelet-Rich Plasma Injection for Early Osteoarthritis Knee

Background Osteoarthritis (OA) is a leading cause of pain and disability and has a negative impact on patients' quality of life. Platelet-rich plasma (PRP) has emerged as a promising treatment for various orthopaedic conditions, such as tendinopathies, nonunion, and arthritis of the knee. We sought to determine whether a single intra-articular platelet-rich plasma injection has better functional and pain outcomes when compared with multiple (two) articular platelet-rich plasma injections given in the early stages of OA of the knee, measured using the Western Ontario and McMaster Universities Arthritis Index (WOMAC) and the visual analogue scale for pain (VAS) at the sixth week, third month, and sixth month. Materials and methods The prospective observational study was conducted among patients diagnosed with early OA who presented to the Department of Orthopaedics, R. L. Jalappa Hospital and Research Centre, Kolar, Karnataka, India, between January 2020 and June 2021. A total of 64 patients were divided into: (i) S-PRP group (34 patients), which received a single PRP injection, and (ii) M-PRP group (30 patients), which received multiple (two) PRP injections, one on presentation and the second in the thirdmonth. VAS and WOMAC scores to assess functional outcomes were used at the first visit before the intervention and at the sixth week, third month, and sixth month. Results The average age of the patients was 55.26 years in the S-PRP group and 51.13 years in the M-PRP group. Both genders were equal among study participants in the M-PRP group, but 79.4% were females in the S-PRP group. In the S-PRP group, 74% had grade II OA and 26% had grade I OA. In the M-PRP group, 60% had grade II OA and the remaining 40% had grade I OA. The decreasing trend of pain and functional limitation, which was measured by VAS and WOMAC, respectively, was observed in both groups at pre-injection, sixth week, third month, and sixth month. These differences were statistically significant. The mean difference in VAS score between the pre-injection period and at six months was 4 in the S-PRP group, whereas it was 5.77 in the M-PRP group, and this was statistically significant (p-value = 0.001). Thus, multiple PRP injections have a greater response to pain reduction when compared to single PRP injections, according to the VAS score. According to the WOMAC score, there is no statistically significant difference in the treatment response with PRP injection between the S-PRP and M-PRP groups at any follow-up period. Conclusion According to the VAS score, single PRP injections have a lower pain score than multiple PRP injections until three months of follow-up, while at six months, single PRP injections have no better effect than multiple PRP injections. But multiple PRP injections have a higher reduction in the intensity of pain when compared to single PRP injections during the follow-up period. According to the WOMAC score, there is no statistically significant difference in the treatment response with PRP injection between S-PRP and M-PRP groups.

Effect of platelet-rich plasma versus steroid injection in plantar fasciitis: a randomized clinical trial

BACKGROUND

Plantar fasciitis (PF) is a common orthopaedic problem, with heel pain worsening the quality of life. Although steroid injection is often used if the conservative treatment fails, Platelet-Rich Plasma (PRP) injection is gaining popularity due to its safety and long-lasting effect. However, the effect of PRP versus steroid injection in PF has not been studied yet in Nepal. Therefore, this study aimed to assess the effect of PRP compared with steroid injection in the treatment of PF.

METHODS

This study was a single-center, hospital-based, open-label, parallel-group randomized clinical trial to compare the effect of PRP injection with steroid injection in plantar fasciitis between August 2020 and March 2022. A total of 90 randomly selected participants aged 18 to 60 years suffering from plantar fasciitis with failed conservative treatment were intervened. The American Orthopaedic Foot and Ankle Society (AOFAS) and the Visual Analog Scale (VAS) scoring system were used to evaluate functional mobility and pain before and after the intervention for three and six months, respectively. Statistical analyses were performed using a Student's two-sample t-test. P-value < 0.05 was considered statistically significant.

RESULTS

The PRP injection showed a better outcome than the steroid injection in six months follow-up. The mean (± SD) VAS score was significantly decreased in the PRP group (1.97 + 1.13) than in the steroid group (2.71 ± 0.94) with the group difference of -0.73 (95% CI: -1.18 to -0.28) at six months. Similarly, there was a significant increase in the AOFAS scores in the PRP group (86.04 ± 7.45) compared to the steroid group (81.23 ± 9.60) at six months of follow-up with a group difference of 4.80 (95% CI: 1.15 to 8.45). There was also a significant reduction of plantar fascia thickness in the PRP group compared to that of the steroid group (3.53 ± 0.81 versus 4.58 ± 1.02) at six months of follow-up with the group difference of -1.04 (95% CI: -1.44 to -0.65).

CONCLUSION

The PRP injection showed better outcomes than steroid injection in plantar fasciitis treatment over the course of six months. Further research with a larger population and longer follow-up than six months is needed to generalize the findings and their long-term efficacy.

TRIAL REGISTRATION

NCT04985396. First registered on 02 August 2021. ( https://clinicaltrials.gov/ct2/show/NCT04985396 ).

Relationship Between the Underlying Factors and the Treatment Results of Platelet-Rich Plasm (PRP) Injection in Degenerative Knee Disease; A Blinded Randomized Study

Background: To investigate the therapeutic effects of PRP injection + conservative treatment as the intervention group versus normal saline injection + conservative treatment as the control group. Objectives: This study we determined the effects of underlying factors, including age, gender, and Body Mass Index (BMI), on the therapeutic effects of PRP. Methods: In this single-blinded randomized clinical trial, 60 patients with grade 2 knee OA with an age of 40 - 65 years were enrolled. In the intervention group, leukocyte-poor PRP with double spinning, and in the control group, normal saline was injected with a similar protocol. All patients in both groups were also provided with a conservative protocol, including oral celecoxib 100 mg BID for four weeks, modifying physical activity, and 15 sessions of physiotherapy. Results: Demographic characteristics (age, gender, and BMI) and pre-treatment scores were similar between the two groups (all P > 0.05). The WOMAC score was improved from pre-treatment to first week post-treatment in both groups (from 54.89 ± 3.4 to 64.9 ± 3.7 in the intervention group and from 53.7 ± 3.1 to 63.8 ± 3.9 in the control group). It means that PRP + conservative treatment was effective, similar to normal saline + conservative treatment. After adjusting BMI as an underlying variable, it was indicated that in the patients with lower BMI, PRP + conservative provided a better outcome in comparison to saline + conservative treatment (P = 0.014 and P = 0.019, respectively). Also, the comparison of functional scores changes with age as an underlying variable, demonstrating that younger cases obtained a better response from PRP + conservative rather than normal saline + conservative (P = 0.012 and P = 0.007, respectively). Conclusions: PRP seems to be an appropriate choice for treatment of moderate osteoarthritis, especially in younger patients and those with lower BMI.

Intraosseous Infiltration of Platelet-Rich Plasma for Knee Osteoarthritis: A Systematic Review of Literature and Limited Meta-analysis

Background

The role of subchondral bone as a key mediator in pathogenesis of osteoarthritis (OA) is emerging and various injectable modalities are being tried to address the subchondral pathology. Intraosseous (IO) infiltrations of PRP is biological way of addressing the pathology. This review aimed to explore the role of IO PRP in OA knees.

Methods

A systematic literature search was conducted on the electronic databases of PubMed, Embase, Scopus, Web of Science and Ovid for relevant articles on IO PRP with a predefined search strategy. Data from eligible studies were extracted and was analyzed.

Results

There were only five studies on the study topic which included 112 patients (112 knees) who received IO PRP injection. IO PRP was associated with significant improvements in VAS, KOOS and WOMAC scores. The most commonly reported complication was pain at injection site. Meta-analysis revealed that combined intraarticular (IA) and IO PRP were associated with significantly better WOMAC scores, compared to only IA PRP. However, VAS and KOOS scores were equivocal.

Conclusion

IO PRP infiltration for OA knees is safe and effective and results in improved patient-reported outcome scores based on the current limited literature. However, its added advantage over only IA PRP is not well established and clear due to limited available published data.

Current State of Platelet-Rich Plasma and Cell-Based Therapies for the Treatment of Osteoarthritis and Tendon and Ligament Injuries

➤

Orthobiologics encompass numerous substances that are naturally found in the human body including platelet-rich plasma (PRP), isolated growth factors, and cell therapy approaches to theoretically optimize and improve the healing of cartilage, fractures, and injured muscles, tendons, and ligaments.

➤

PRP is an autologous derivative of whole blood generated by centrifugation and is perhaps the most widely used orthobiologic treatment modality. Despite a vast amount of literature on its use in osteoarthritis as well as in tendon and ligament pathology, clinical efficacy results remain mixed, partly as a result of insufficient reporting of experimental details or exact compositions of PRP formulations used.

➤

Mesenchymal stromal cells (MSCs) can be isolated from a variety of tissues, with the most common being bone marrow aspirate concentrate. Similar to PRP, clinical results in orthopaedics with MSCs have been highly variable, with the quality and concentration of MSCs being highly contingent on the site of procurement and the techniques of harvesting and preparation.

➤

Advances in novel orthobiologics, therapeutic targets, and customized orthobiologic therapy will undoubtedly continue to burgeon, with some early promising results from studies targeting fibrosis and senescence.

Preparation and Characterization of Plasma-Derived Fibrin Hydrogels Modified by Alginate di-Aldehyde

Fibrin hydrogels are one of the most popular scaffolds used in tissue engineering due to their excellent biological properties. Special attention should be paid to the use of human plasma-derived fibrin hydrogels as a 3D scaffold in the production of autologous skin grafts, skeletal muscle regeneration and bone tissue repair. However, mechanical weakness and rapid degradation, which causes plasma-derived fibrin matrices to shrink significantly, prompted us to improve their stability. In our study, plasma-derived fibrin was chemically bonded to oxidized alginate (alginate di-aldehyde, ADA) at 10%, 20%, 50% and 80% oxidation, by Schiff base formation, to produce natural hydrogels for tissue engineering applications. First, gelling time studies showed that the degree of ADA oxidation inhibits fibrin polymerization, which we associate with fiber increment and decreased fiber density; moreover, the storage modulus increased when increasing the final volume of CaCl₂ (1% w/v) from 80 µL to 200 µL per milliliter of hydrogel. The contraction was similar in matrices with and without human primary fibroblasts (hFBs). In addition, proliferation studies with encapsulated hFBs showed an increment in cell viability in hydrogels with ADA at 10% oxidation at days 1 and 3 with 80 µL of CaCl₂; by increasing this compound (CaCl₂), the proliferation does not significantly increase until day 7. In the presence of 10% alginate oxidation, the proliferation results are similar to the control, in contrast to the sample with 20% oxidation whose proliferation decreases. Finally, the viability studies showed that the hFB morphology was maintained regardless of the degree of oxidation used; however, the quantity of CaCl₂ influences the spread of the hFBs.

The promising role of autologous and allogeneic mesenchymal stromal cells in managing knee osteoarthritis. What is beyond Mesenchymal stromal cells?

Mesenchymal stromal cells (MSCs) express a wide range of properties anticipated to be beneficial for treating genetic, mechanical, and age-related degeneration in diseases such as osteoarthritis (OA). Although contemporary conservative management of OA is successful in many patients with mild-moderate OA, it often fails to improve symptoms in many patients who are not a candidate for any surgical management. Further, existing conservative treatment strategies do not prevent the progression of the disease and therefore fail to provide a long-term pain-free life. On the other hand, tremendous progress has been taking place in the exciting field of regenerative medicine involving MSCs (autologous and allogeneic), with promising translation taking place from basic science to the bedside. In this review, we comprehensively discuss the potential role of MSCs in treating OA, both autologous and off-the-shelf, allogeneic stem cells. Further, newer therapies are in the offing to treat OA, such as exosomes and growth factors.

Prophylactic use of platelet-rich plasma for post-spinal low back pain following gynecological surgery: a randomized clinical trial

BACKGROUND

Post-spinal back pain is suggested to occur as a result of a localized inflammatory response that is often associated with some degree of muscle spasm. We aimed to evaluate the effect of platelet-rich plasma (PRP) in reducing the incidence of post-spinal back pain.

METHODS

One hundred patients were randomly enrolled and scheduled for elective gynecological surgery under spinal anesthesia. After the subarachnoid block, group A (placebo) received 2 mL of sodium chloride 0.9% injected into the track of spinal needle during its withdrawal (2 mm after outward withdrawal in muscles and subcutaneous tissues). While patients in group B (PRP); received 2 ml of PRP injected into the track of the spinal needle during its withdrawal. The primary outcome was the number of patients who developed post-spinal low back pain within the first week following the subarachnoid block. Secondary outcomes included the time of the first analgesic request and total meperidine consumption during the first 24 h postoperatively.

RESULTS

Fifteen patients in the PRP group developed low back pain during the first week following subarachnoid block compared to 26 patients in the placebo group (p = 0.037). There was a significant decrease in the mean meperidine consumption during first 24 h postoperatively in PRP group (174 ± 14 mg) compared to placebo group (210 ± 22 mg) (p < 0.0001). Also, the first analgesic request was significantly delayed in PRP group (243 ± 21 min.) compared to placebo group (185 ± 31 min.) (p < 0.0001).

CONCLUSION

This study demonstrated the positive effects of platelet-rich plasma on the prevention of post-spinal backache.

Effect of Fibrin Concentration on the In Vitro Production of Dermo-Epidermal Equivalents

Human plasma-derived bilayered skin substitutes were successfully used by our group to produce human-based in vitro skin models for toxicity, cosmetic, and pharmaceutical testing. However, mechanical weakness, which causes the plasma-derived fibrin matrices to contract significantly, led us to attempt to improve their stability. In this work, we studied whether an increase in fibrin concentration from 1.2 to 2.4 mg/mL (which is the useful fibrinogen concentration range that can be obtained from plasma) improves the matrix and, hence, the performance of the in vitro skin cultures. The results show that this increase in fibrin concentration indeed affected the mechanical properties by doubling the elastic moduli and the maximum load. A structural analysis indicated a decreased porosity for the 2.4 mg/mL hydrogels, which can help explain this mechanical behavior. The contraction was clearly reduced for the 2.4 mg/mL matrices, which also allowed for the growth and proliferation of primary fibroblasts and keratinocytes, although at a somewhat reduced rate compared to the 1.2 mg/mL gels. Finally, both concentrations of fibrin gave rise to organotypic skin cultures with a fully differentiated epidermis, although their lifespans were longer (25–35%) in cultures with more concentrated matrices, which improves their usefulness. These systems will allow the generation of much better in vitro skin models for the testing of drugs, cosmetics and chemicals, or even to “personalized” skin for the diagnosis or determination of the most effective treatment possible.

Potential of Exosomes for Diagnosis and Treatment of Joint Disease: Towards a Point-of-Care Therapy for Osteoarthritis of the Knee

In the knee joint, articular cartilage injury can often lead to osteoarthritis of the knee (OAK). Currently, no point-of-care treatment can completely address OAK symptoms and regenerate articular cartilage to restore original functions. While various cell-based therapies are being developed to address OAK, exosomes containing various components derived from their cells of origin have attracted attention as a cell-free alternative. The potential for exosomes as a novel point-of-care treatment for OAK has been studied extensively, especially in the context of intra-articular treatments. Specific exosomal microRNAs have been identified as possibly effective in treating cartilage defects. Additionally, exosomes have been studied as biomarkers through their differences in body fluid composition between joint disease patients and healthy subjects. Exosomes themselves can be utilized as a drug delivery system through their manipulation and encapsulation of specific contents to be delivered to specific cells. Through the combination of exosomes with tissue engineering, novel sustained release drug delivery systems are being developed. On the other hand, many of the functions and activities of exosomes are unknown and challenges remain for clinical applications. In this review, the possibilities of intra-articular treatments utilizing exosomes and the challenges in using exosomes in therapy are discussed.

Platelet-Rich Plasma Versus Hyaluronic Acid in the Treatment of Knee Osteoarthritis: A Meta-analysis of 26 Randomized Controlled Trials

PURPOSE

To compare the effectiveness and safety of platelet-rich plasma (PRP) and hyaluronic acid (HA) in patients with adult knee osteoarthritis (KOA) and to explore the most effective and safe protocol by using a meta-analysis method.

METHODS

This study was based on Cochrane methodology for conducting a meta-analysis. Only randomized controlled trials with an experimental group that used PRP and a control group that received HA were eligible for this study. The participants were adults who had KOA. The outcome measures were the Western Ontario and McMaster Universities Osteoarthritis Index (WOMAC), the visual analog scale (VAS), the EuroQol VAS, the International Knee Documentation Committee, the Tegner score, the Lequesne Scale, the Knee injury Osteoarthritis Outcome Score, satisfaction rate, and adverse events. Subgroup analyses was performed for patients with different doses, types, and times of PRP interventions and grades of OA. The Review Manager Database was used to analyze the included studies.

RESULTS

Twenty-six randomized controlled trials involving 2430 patients were included. The WOMAC total scores, WOMAC physical function scores, and VAS scores of the PRP group were better than the those of the HA group at 3, 6, and 12 months. The PRP group had better WOMAC pain, WOMAC stiffness, EuroQol VAS, and International Knee Documentation Committee scores than the HA group at 6 and 12 months. There was no significant difference in adverse events between the 2 groups (relative risk 1.21, 95% confidence interval 0.95-1.54; P = .13).

CONCLUSIONS

For the nonsurgical treatment of KOA, compared with HA, intra-articular injection of PRP could significantly reduce patients' early pain and improve function. There was no significant difference in adverse events between the 2 groups. PRP was more effective than HA in the treatment of KOA, and the safety of these 2 treatment options was comparable.

LEVEL OF EVIDENCE

Level I, meta-analysis of Level I RCTs.

Platelet-rich plasma versus hyaluronic acid in knee osteoarthritis: A meta-analysis with the consistent ratio of injection

Osteoarthritis (OA) is an extremely common form of chronic joint disease which can affect the knees and other joints of older adults, leading to debilitating disability in the knee and consequent reduction in quality of life. Intra-articular platelet-rich plasma (PRP) or hyaluronic acid (HA) injections are effective for maintaining long-term beneficial effects without increasing the risk of intra-articular infection. However, few studies have compared the relative value of HA and PRP for OA treatment. PRP is more effective than HA for OA treatment in recent studies of this topic. We systematically searched Medline, SpringerLink, Embase, Pubmed, Clinical Trials.gov, the Cochrane Library, and OVID for all articles published through May 2018. Any study was included that compared the effect of HA and PRP (consistent treatment cycle and frequency of injection) on patient's pain levels and functionality improvements. Review Manager 5.3 was used to analyze data regarding these two primary outcomes. We included 10 total studies in the present meta-analysis. International Knee Documentation Committee (IKDC; MD: 10.37, 95% confidence interval (CI): 9.13 to 11.62, p < 0.00001), Western Ontario and MacMaster Universities Osteoarthritis Index (WOMAC; MD: -20.69, 95% CI: -24.50 to -16.89, p < 0.00001, I² = 94%), and Visual Analogue Scale (VAS; MD: -1.50, 95% CI: -1.61 to -1.38, p < 0.00001, I² = 90%) differed significantly between the PRP and HA groups. Knee Osteoarthritis Outcome Scores (KOOSs) did not differ significantly (χ² = 23.53, I² = 41%, p = 0.11). Our hypothesis appears not to be confirmed because PRP and HA did not differ significantly with respect to KOOS score. However, the IKDC, WOMAC, and VAS scores differed significantly. Thus, based on the current evidence, PRP appears to be better than HA at achieving pain relief and self-reported functional improvement. Ia, meta-analyses of randomized clinical trials.

Biologics

Biologics are a growing field that has shown immense promise for the treatment of musculoskeletal conditions both in orthopedic sports medicine and interventional pain management. These procedures utilize injection of supraphysiologic levels of platelets and growth factors to invoke the body's own inflammatory cascade to augment the healing of many bony and soft tissue conditions. While many patients improve with conservative care, there is a need to address the gap between those that improve with rehabilitation alone and those who ultimately require operative management. Orthobiologic procedures have the potential to fill this void. The purpose of this review is to summarize the basic science, evidence for use, and post-injection rehabilitation concepts of platelet-rich plasma (PRP) and mesenchymal stromal cells (MSCs) as they pertain to joints, tendons, ligaments, and the spine.

Nanomechanical Properties of Articular Cartilage Due to the PRP Injection in Experimental Osteoarthritis in Rabbits

The purpose of this study was twofold. Firstly, we proposed a measurement protocol for the atomic force microscopy (AFM) method to determine the nanomechanical properties of articular cartilage in experimental osteoarthritis in rabbits. Then, we verified if mechanical properties can be evaluated with AFM shortly after platelet-rich plasma (PRP) injection. We hypothesized that the modulus determined by AFM indentation experiments could be utilized as a progressive disease marker during the treatment of osteoarthritis. The rabbits were equally divided into three groups of six: control (group 1); injections of saline (0.5 mL) and 10% surgical talc (Talcum Pharmaceutical^®, Minsk, Belarus) were delivered into the right knee under the patella (group 2 and 3); and PRP was injected into the right knee (group 3). In group 2, the arithmetic average of absolute values (Ra) change was a 25% increase; the maximum peak height (Rp) increased by over 102%, while the mean spacing between local peaks (S) increased by 28% (p < 0.05). In group 3, Ra increased by 14% and Rp increased by 32%, while S decreased by 75% (p < 0.05). The Young’s modulus of the surface layers decreased by 18% as a result of induced model of osteoarthritis (IMO) (p < 0.05), and it increased by 9% (p < 0.05) as a result of PRP therapy, which means that the mechanical properties of cartilage were partially recovered. This research demonstrates that Young’s modulus utilized on a nanometer scale has potential to be a progressive disease marker during the treatment of osteoarthritis.

What Is the Appropriate Price for Platelet-Rich Plasma Injections for Knee Osteoarthritis? A Cost-Effectiveness Analysis Based on Evidence From Level I Randomized Controlled Trials

PURPOSE

To identify the price of treatment at which platelet-rich plasma (PRP) is cost-effective relative to hyaluronic acid (HA) and saline solution intra-articular injections.

METHODS

A systemized review process of the PubMed, Embase, and MEDLINE databases was undertaken to identify randomized controlled trials comparing PRP with HA and saline solution with up to 1 year of follow-up. Level I trials that reported Western Ontario and McMaster Universities Arthritis Index Likert scores were included. These scores were converted into utility scores. Cost data were obtained from Centers for Medicare & Medicaid Services fee schedules. Total costs included the costs of the injectable, clinic appointments, and procedures. The change in utility scores from baseline to 6 months and 1 year for the PRP, HA, and saline solution groups was divided by total cost to determine utility gained per dollar and to identify the price needed for PRP to be cost-effective relative to these other injection options.

RESULTS

Nine randomized controlled trials met the inclusion criteria. A total of 882 patients were included: 483 in the PRP group, 338 in the HA group, and 61 in the saline solution group. Baseline mean utility scores ranged from 0.55 to 0.57 for the PRP, HA, and saline solution groups. The 6-month gains in utility were 0.12, 0.02, and -0.06, respectively. The 12-month gains in utility from before injection were 0.14, 0.03, and 0.06, respectively. The lowest total costs for HA and saline solution were $681.93 and $516.29, respectively. For PRP to be cost-effective, the total treatment cost would have to be less than $3,703.03 and $1,192.08 for 6- and 12-month outcomes, respectively.

CONCLUSIONS

For patients with symptomatic knee osteoarthritis, PRP is cost-effective, from the payer perspective, at a total price (inclusive of clinic visits, the procedure, and the injectable) of less than $1,192.08 over a 12-month period, relative to HA and saline solution.

LEVEL OF EVIDENCE

Level I, systematic review.

Characteristics of autologous protein solution and leucocyte-poor platelet-rich plasma for the treatment of osteoarthritis of the knee

Recently, platelet-rich plasma (PRP) has received attention as a treatment for patients with osteoarthritis of the knee (OAK), a chronic degenerative disease, to bridge the gap between conservative and surgical treatments. Here, we investigated the differences in the humoral factors present in two types of PRP purified using the Autologous Protein Solution (APS) kit (group Z; leucocyte-rich PRP) or the Cellaid Serum Collection Set P type (group J; leucocyte-poor [LP]-PRP). Differences in humoral factors between healthy subjects (n = 10) and OAK patients (n = 12; group Z = 6, group J = 6), and the relationship between humoral factors and clinical outcome scores were investigated. Both anti-inflammatory and inflammatory cytokines were highly enriched in APS. The concentrations of tumour necrosis factor (TNF)-α, platelet-derived growth factor, fibroblast growth factor, soluble TNF-receptor 2, soluble Fas and transforming growth factor-β1 were higher in group Z, while the total amounts were higher in group J. The concentration of interleukin-1 receptor antagonist was positively correlated with the magnitude of change in the clinical outcome score and may contribute to improving knee-joint function. This is the first description of the humoral factors in APS and LP-PRP prepared from healthy subjects or OAK patients of Asian descent.

Does Platelet-rich Plasma Augmentation Following Hip Arthroscopy Improve Outcomes: A Systematic Review

Platelet-rich plasma (PRP) has gathered widespread acceptance among orthopaedic surgeons because of its multimodal effects on tissue healing. Varying results have been reported when PRP injections are combined with hip arthroscopic surgery. To evaluate the influence of PRP on clinical outcomes following hip arthroscopy. We hypothesized that patients treated with PRP would have improved postoperative outcome scores. A search of the National Institute for Health and Care Excellence (NICE) healthcare database advanced search (HDAS) via Athens (PubMed, MEDLINE, CINAHL, EMBASE, and AMED databases) was conducted from their years of inception to May 2018 with the keywords: "Hip Arthroscopy" and "Platelet-Rich Plasma". A quality assessment was performed based on the Cochrane risk of bias tool. Three studies were included for analysis; two of which had low risk of bias. The studies included 363 hips, of which 141 were randomised for PRP treatment. The mean age of all patients was 35 years and the follow-up ranged from 18.5 to 36 months. Authors used different PRP systems and preparations. Modified Harris hip score was reported in all three studies with two studies favouring the use of PRP. The use of PRP following hip arthroscopy did not lead to significantly improved postoperative pain or functional outcomes when compared to control groups in the studies included in this review.

Augmentation of Meniscal Repair With Platelet-Rich Plasma: A Systematic Review of Comparative Studies

Background:

The effect of platelet-rich plasma (PRP) augmentation for meniscal repair (MR) is unclear, as current evidence is limited to small, mostly nonrandomized studies.

Purpose:

To systematically review the literature to evaluate the efficacy and safety of MR with PRP augmentation.

Study Design:

Systematic review; Level of evidence, 3.

Methods:

A systematic review was performed by searching PubMed, the Cochrane Library, and Embase to identify studies (level of evidence 1-3) that compared the clinical efficacy of MR performed with versus without PRP. The search phrase used was platelet-rich plasma meniscus. Patients were assessed based on the Western Ontario and McMaster Universities Osteoarthritis Index (WOMAC), the visual analog scale (VAS) for pain, the Lysholm score, the Knee injury and Osteoarthritis Outcome Score (KOOS), the subjective International Knee Documentation Committee (IKDC) score, and treatment failure.

Results:

We identified 6 studies (2 studies with level 1 evidence; 4 studies with level 3 evidence) that met inclusion criteria, for a total of 309 patients undergoing MR with PRP (mean age, 31.9 years) and 445 patients without PRP augmentation (mean age, 29.6 years). The mean follow-up was 32.8 months (range, 12-72 months). Overall, 17.0% of PRP patients experienced MR failure compared with 22.1% of non-PRP patients. No differences in VAS, Lysholm, or subjective IKDC scores were found between groups except in 1 study, in which postoperative subjective IKDC scores were significantly better in the PRP group (P < .01). Another study found significantly better postoperative WOMAC scores among PRP patients, and 2 studies found significantly better KOOS subscores among PRP patients.

Conclusion:

There are a limited number of high-quality studies comparing outcomes and healing rates between patients undergoing MR with versus without PRP augmentation. Based on the available evidence, patients undergoing MR with PRP augmentation experience similar clinical outcomes at midterm follow-up when compared with conventional MR, and additional studies are needed to determine the efficacy of MR augmented with PRP.

How to Choose Platelet-Rich Plasma or Hyaluronic Acid for the Treatment of Knee Osteoarthritis in Overweight or Obese Patients: A Meta-Analysis

Objective

The purpose of this meta-analysis was to determine whether platelet-rich plasma (PRP) was better than hyaluronic acid (HA) for the treatment of knee osteoarthritis (OA) in overweight or obese patients.

Design

Two reviewers independently used the keywords combined with free words to search English-based electronic databases according to Cochrane Collaboration guidelines, such as PubMed, Embase, ScienceDirect, and Cochrane library. The pooled data were analyzed using RevMan 5.3.

Results

Ten randomized controlled trials (RCTs) with 1096 patients were included. During the first two months of follow-up, there was no significant difference between the two groups. At the 3rd, 6th, and 12th months of follow-up, the pooled analysis showed that PRP was better than HA for the treatment of knee OA in overweight or obese patients. There were significant differences between the two groups at Western Ontario and McMaster Universities Osteoarthritis Index (WOMAC) total score (3 months: MD = -1.35, [95% CI: -2.19 to -0.50], P=0.002, I 2 = 0%; 6 months: MD = -7.62, [95% CI: -13.51 to -1.72], P=0.01, I 2 = 88%; 12 months: MD = -12.11, [95% CI: -20.21 to -4.01], P=0.003, I 2 = 94%).

Conclusions

For overweight or obese patients with knee OA, intra-articular injection of PRP in a short time was not necessarily superior to HA, but long-term use was better than HA in pain and functional relief.

Why are we still using opioids for osteoarthritis?

Osteoarthritis is a common debilitating condition affecting a substantial portion of the population and is an accepted consequence of ageing and overuse. Whilst surgical interventions are a definitive approach, most cases are managed medically with analgesia. Pharmacological therapies have included acetaminophen, non-steroidal anti-inflammatory drugs and opiates. Although significant controversies exist in the use of opioids for chronic musculoskeletal pain, many leading guidelines continue to recommend its use despite increasing evidence to suggest an increase in addiction, morbidity and mortality. With the opiate crisis growing, we re-examine the role opiates have in this chronic condition and current data, and briefly evaluate alternative therapies.

Leukocyte-rich PRP for knee osteoarthritis: Current concepts

Knee osteoarthritis is a major painful and debilitating orthopaedic disease affecting a large number of adult individuals on a global scale. Over the years, this severe condition has been widely studied and while many alternatives have been utilized, platelet-rich plasma (PRP) remains one of the most popular solutions among researchers and clinicians alike. While there are different formulations and techniques involved in the preparation of PRP, produced either manually or via the use of commercial kits, the presence of leukocytes in a PRP mixture is a factor that raises concern due to their well-known pro-inflammatory activity. Although it is reasonable to worry about this, it should be taken into consideration that in order for the healing process to occur, the inflammatory phase is necessary. Leukocytes present in the inflammatory phase release both pro and anti-inflammatory molecules and, when combined with activated platelets, their potential increases. Additionally, due to the macrophage's plasticity to switch from the subtype 1 to subtype 2, it is suggested that the inclusion of the components from the buffy coat layer in a PRP mixture, classifying it as leukocyte-rich platelet-rich plasma or L-PRP, may provide benefits instead of detriments, from a standpoint of the regenerative potential of PRP.

Single- and double-dose of platelet-rich plasma versus hyaluronic acid for treatment of knee osteoarthritis: A randomized controlled trial

BACKGROUND

Platelet-rich plasma (PRP) and hyaluronic acid have been shown to be useful in the treatment of knee osteoarthritis. However, investigations comparing the efficacy of these two drugs together are insufficient.

AIM

To compare the outcomes of PRP vs hyaluronic acid injections in three groups of patients with bilateral knee osteoarthritis.

METHODS

This randomized controlled trial study involved 95 patients. Thirty-one subjects received a single injection of PRP (group PRP-1), 33 subjects received two injections of PRP at an interval of 3 wk (group PRP-2) and 31 subjects received three injections of hyaluronic acid at 1-wk intervals (group hyaluronic acid). The patients were investigated prospectively at the enrollment and at 4-, 8- and 12-wk follow-up with the Western Ontario and McMaster Universities Arthritis Index (WOMAC) and Visual Analogue Scale questionnaires.

RESULTS

Percentages of patients experiencing at least a 30% decrease in the total score for the WOMAC pain subscale from baseline to wk 12 of the intervention were 86%, 100% and 0% in the groups PRP-1, PRP-2 and hyaluronic acid, respectively (P < 0.001). The mean total WOMAC scores for groups PRP-1, PRP-2 and hyaluronic acid at baseline were 63.71, 61.57 and 63.11, respectively. The WOMAC scores were significantly improved at final follow-up to 42.5, 35.32 and 57.26, respectively. The highest efficacy of PRP was observed in both groups at wk 4 with about 50% decrease in the symptoms compared with about 25% decrease for hyaluronic acid. Group PRP-2 had higher efficacy than group PRP-1. No major adverse effects were found during the study.

CONCLUSION

PRP is a safe and efficient therapeutic option for treatment of knee osteoarthritis. It was demonstrated to be significantly better than hyaluronic acid. We also found that the efficacy of PRP increases after multiple injections.

Biologic Therapies for the Treatment of Knee Osteoarthritis

BACKGROUND

The use of biologic therapies for the management of knee osteoarthritis has increased, despite insufficient evidence of efficacy. Our aim was to complete a systematic review and analysis of reports utilizing the highest level-of-evidence evaluating: (1) platelet-rich plasma injections (PRPs); (2) bone marrow-derived mesenchymal stem cells (BMSCs); (3) adipose-derived mesenchymal stem cells (ADSCs); and (4) amnion-derived mesenchymal stem cells (AMSCs).

METHODS

PubMed, Embase, and Cochrane Library databases were queried for studies evaluating PRP injections, BMSCs, ADSCs, and AMSCs in patients with knee osteoarthritis. Of 1009 studies identified within the last 5 years, 123 met inclusion criteria. A comprehensive analysis of all levels-of-evidence was performed, as well as separate analysis on level-of-evidence I studies. Level-of-evidence was determined by the American Academy of Orthopedic Surgeons classification system.

RESULTS

Although the majority of PRP reports demonstrated improvements in pain and/or function, others revealed no substantial improvements. Similar findings were noted for BMSCs, ADSCs, and AMSCs. Assessments of BMSC studies yielded majority with positive clinical results, although short-lived. Studies on ADSCs revealed improved clinical outcomes, but equivocal radiographic outcomes. Studies evaluating AMSCs demonstrated improvements in pain and function, and decreased radiographic evidence of osteoarthritis.

CONCLUSION

Despite some promising early results for PRP, BMSC, ADSC, and AMSC therapies, the majority of level-of-evidence I studies have multiple problems: small sample sizes, potentially inappropriate control cohorts, short-term follow-up, and so on. Despite the limitations, there still appears to be evidence justifying their use for knee osteoarthritis management. More high-level, larger human studies utilizing standardized protocols are needed.

Cellular Components and Growth Factor Content of Platelet-Rich Plasma With a Customizable Commercial System

BACKGROUND

Platelet-rich plasma (PRP) is an autologous orthobiologic treatment option for musculoskeletal conditions with favorable results in a limited number of high-quality clinical trials. Because different blood-processing methods result in PRP with varying cellular and growth factor content, it is critical that clinicians understand the content of the specific PRP being used in clinical practice. One adjustable system, the Angel System, has few independent laboratory reports on the specific composition of its PRP. The goal of this study was to quantify the cellular and growth factor composition of PRP produced by this system at its lowest hematocrit settings.

HYPOTHESIS

The authors hypothesized that the system would significantly concentrate platelets over baseline and, at the lowest hematocrit settings, would reduce leukocytes to produce leukocyte-poor PRP.

STUDY DESIGN

Descriptive laboratory study.

METHODS

Ten healthy male volunteers donated 150 mL of whole blood for processing. Three separate processing cycles were performed for each sample at the 0%, 1%, and 2% hematocrit settings. The resultant PRP from each cycle was sent for complete blood counts and enzyme-linked immunosorbent assay to quantify the following growth factors: platelet-derived growth factor (PDGF), basic fibroblast growth factor (bFGF), insulin-like growth factor-1 (IGF-1), and vascular endothelial growth factor (VEGF).

RESULTS

The system consistently concentrated platelets 5-fold over baseline, with no significant differences among settings. Leukocytes were concentrated at all settings, between 2 and 5 times over baseline. The 0% and 1% settings had significantly lower leukocyte concentrations than the 2% setting. Lymphocytes made up >89% of the leukocyte differential, while neutrophils represented <11% of the differential at each setting. There was a significant increase in PDGF and bFGF, a significant decrease in IGF-1, and no change in VEGF, with no difference among settings.

CONCLUSION

The system consistently concentrated platelets 5 times but was unable to reduce leukocytes, therefore resulting in leukocyte-rich PRP at each setting tested. Leukocytes had a differential composition of >89% lymphocytes and <11% neutrophils. For all settings, PDGF and bFGF were concentrated; IGF-1 was reduced; and VEGF was not significantly different from baseline.

CLINICAL RELEVANCE

These data can serve to guide clinicians considering using this particular PRP system. It consistently yielded leukocyte-rich PRP with a lymphocyte-predominant/neutrophil-reduced profile. Further research is needed to better understand how to apply this specific PRP in clinical practice.

Triamcinolone Acetonide Extended-Release: A Review in Osteoarthritis Pain of the Knee

Triamcinolone acetonide extended-release (ER) 32 mg (Zilretta®) is approved in the USA for the management of osteoarthritis (OA) pain of the knee and is administered as a single, 5 mL intra-articular (IA) injection. Although the therapeutic effects from IA corticosteroids are typically short-lived, triamcinolone acetonide ER is formulated in poly (lactic-co-glycolic acid) (PLGA) microspheres that slowly release triamcinolone acetonide in the synovium, enabling their prolonged presence in the joint. This reduces systemic exposure and lessens corticosteroid-related systemic adverse reactions, such as blood glucose elevations. In a 24-week, randomized, phase III clinical trial, triamcinolone acetonide ER 32 mg significantly improved mean average daily pain intensity in patients with knee OA relative to placebo, and pain, stiffness and physical function (according to WOMAC criteria) relative to placebo and triamcinolone acetonide crystalline suspension (CS). Triamcinolone acetonide ER was generally well tolerated, with a tolerability profile similar to that of triamcinolone acetonide CS and placebo. Findings from a single-arm phase IIIb study indicated that a repeat administration of triamcinolone acetonide ER may be similarly efficacious to an initial injection without having deleterious effects on cartilage or other aspects of joint structure. Thus, triamcinolone acetonide ER expands the treatment options available for the management of OA pain of the knee.

Short-Term Outcomes of Percutaneous Trephination with a Platelet Rich Plasma Intrameniscal Injection for the Repair of Degenerative Meniscal Lesions. A Prospective, Randomized, Double-Blind, Parallel-Group, Placebo-Controlled Study

Meniscal tears are the most common orthopaedic injuries, with chronic lesions comprising up to 56% of cases. In these situations, no benefit with surgical treatment is observed. Thus, the purpose of this study was to investigate the effectiveness and safety of percutaneous intrameniscal platelet rich plasma (PRP) application to complement repair of a chronic meniscal lesion. This single centre, prospective, randomized, double-blind, placebo-controlled study included 72 patients. All subjects underwent meniscal trephination with or without concomitant PRP injection. Meniscal non-union observed in magnetic resonance arthrography or arthroscopy were considered as failures. Patient related outcome measures (PROMs) were assessed. The failure rate was significantly higher in the control group than in the PRP augmented group (70% vs. 48%, P = 0.04). Kaplan-Meyer analysis for arthroscopy-free survival showed significant reduction in the number of performed arthroscopies in the PRP augmented group. A notably higher percentage of patients treated with PRP achieved minimal clinically significant difference in visual analogue scale (VAS) and Knee injury and Osteoarthritis Outcome Score (KOOS) symptom scores. Our trial indicates that percutaneous meniscal trephination augmented with PRP results in a significant improvement in the rate of chronic meniscal tear healing and this procedure decreases the necessity for arthroscopy in the future (8% vs. 28%, P = 0.032).

Effects of Platelet-Rich Plasma on Pain and Muscle Strength in Patients With Knee Osteoarthritis

OBJECTIVE

No studies comparing the effects of platelet-rich plasma (PRP) injection and placebo injection in bilateral knee osteoarthritis in the same patient, or discussing muscle strength after PRP injection, have been published.

DESIGN

Twenty patients with bilateral knee osteoarthritis were eligible, and 40 knees were randomized into two groups: PRP (knees [right or left by a coin toss] receiving a single intra-articular PRP injection) and saline group (the contralateral knee of the same patient, into which single 4-mL intra-articular injection of normal saline was administered). The primary outcome measure was Western Ontario and McMaster's Universities Osteoarthritis Index and the secondary included isokinetic test results. The evaluation was at baseline and at 2 wks, 1, 3, and 6 mos after injection.

RESULTS

The PRP group showed a significant reduction in the Western Ontario and McMaster's Universities Osteoarthritis Index pain and total scores compared with normal saline group (P < 0.05). Although a significantly greater percentage of knee strength (extensor > flexor) was found in the PRP group during a longer follow-up period, PRP treatment resulted in insignificant differences in muscle strength compared with normal saline.

CONCLUSIONS

Platelet-rich plasma treatment significantly improves pain, stiffness, and disability in patients with knee osteoarthritis compared with normal saline treatment. Additional strength training is recommended to enhance muscle strength recovery.

The use of PRP injections in the management of knee osteoarthritis

Osteoarthritis (OA) is a degenerative disease involving joint damage, an inadequate healing response and progressive deterioration of the joint architecture that commonly affects the knee and/or hip joints. It is a major world public health problem and is predicted to increase rapidly with an ageing population and escalating rate of obesity. Autologous blood-derived products possess much promise in the repair and regeneration of tissue and have important roles in inflammation, angiogenesis, cell migration and metabolism in pathological conditions, including OA. Utilising platelet-rich plasma (PRP) to treat tendon, ligament and skeletal muscle has shown variable results across many studies with the current evidence base for the efficacy of PRP in treating sports injuries remaining inconclusive. More uniformly positive results have been observed by various studies for PRP in OA knee in comparison to hyaluronic acid, other intra-articular injections and placebo than in other musculoskeletal tissue. However, methodological concerns as well as satisfactory PRP product classification prevent the true characterisation of this treatment. Thus, further research is required to investigate how leukocyte inclusion, activation and platelet concentration affect therapeutic efficacy. Furthermore, the optimisation of timing, dosage, volume, frequency and rehabilitation strategies need to be ascertained. For knee OA management, these concerns must be addressed before this promising treatment can be widely implemented.

Platelet-Rich Plasma Versus Hyaluronic Acid Injections for the Treatment of Knee Osteoarthritis: Results at 5 Years of a Double-Blind, Randomized Controlled Trial

BACKGROUND

Platelet-rich plasma (PRP) injections have been proposed as a new conservative option for knee degeneration to provide symptomatic relief and delay surgical intervention. Although the current literature provides some evidence on the benefits of this technique compared with viscosupplementation, no studies have been performed to compare their long-term effects.

PURPOSE

To compare the long-term clinical outcomes provided by intra-articular injections of either PRP or hyaluronic acid (HA) to treat knee degenerative disease.

STUDY DESIGN

Randomized controlled trial; Level of evidence, 1.

METHODS

Patients with a history of chronic symptomatic knee degenerative changes and osteoarthritis (Kellgren-Lawrence grade 0-3) were enrolled: 192 patients were randomized to undergo 3 blinded weekly intra-articular injections of either PRP or HA. Patients were prospectively evaluated before the injection and then at 2, 6, 12, and 24 months and a mean of 64.3 months (SD, 7.8 months) of follow-up. Evaluation was based on International Knee Documentation Committee (IKDC) subjective (main outcome), EuroQol visual analog scale, and Tegner scores; 167 patients reached the final evaluation.

RESULTS

Both treatments were effective in improving knee functional status and symptoms over time: Mean ± SD IKDC subjective score improved significantly for both PRP and HA groups ( P < .0005) and remained stable over time up to 24 months (from 53.3 ± 14.3 to 67.3 ± 18.1 and from 50.3 ± 13.2 to 62.1 ± 20.8 for PRP and HA groups, respectively). At final evaluation, a significant IKDC reduction was observed in both treatment groups, with the PRP group still presenting significantly higher values compared with baseline: PRP 60.5 ± 19.0 ( P < .001 vs baseline), HA 55.7 ± 18.8 (not significant vs baseline). A comparative analysis showed no significant intergroup difference in any of the clinical scores at any follow-up point. The median duration of patient subjective perception of symptomatic relief was 9 months for HA and 12 months for PRP (not significant). The only significant difference was observed in the rate of reintervention at 24 months, which was significantly lower in the PRP group (22.6% vs 37.1%, P = .036).

CONCLUSION

Both treatments were effective in improving knee functional status and symptoms over time. PRP did not provide an overall superior clinical improvement compared with HA in terms of either symptomatic-functional improvement at different follow-up points or effect duration.

REGISTRATION

NCT01670578 (ClinicalTrials.gov identifier).

Targeting anti-chondrogenic factors for the stimulation of chondrogenesis: A new paradigm in cartilage repair

Trauma and age-related cartilage disorders represent a major global cause of morbidity, resulting in chronic pain and disability in patients. A lack of effective therapies, together with a rapidly aging population, creates an impressive clinical and economic burden on healthcare systems. In this scenario, experimental therapies based on transplantation or in situ stimulation of skeletal Mesenchymal Stem/progenitor Cells (MSCs) have raised great interest for cartilage repair. Nevertheless, the challenge of guiding MSC differentiation and preventing cartilage hypertrophy and calcification still needs to be overcome. While research has mostly focused on the stimulation of cartilage anabolism using growth factors, several issues remain unresolved prompting the field to search for novel solutions. Recently, inhibition of anti-chondrogenic regulators has emerged as an intriguing opportunity. Anti-chondrogenic regulators include extracellular proteins as well as intracellular transcription factors and microRNAs that act as potent inhibitors of pro-chondrogenic signals. Suppression of these inhibitors can enhance MSC chondrogenesis and production of cartilage matrix. We here review the current knowledge concerning different types of anti-chondrogenic regulators. We aim to highlight novel therapeutic targets for cartilage repair and discuss suitable tools for suppressing their anti-chondrogenic functions. Further effort is needed to unveil the therapeutic perspectives of this approach and pave the way for effective treatment of cartilage injuries in patients. © 2018 Orthopaedic Research Society. Published by Wiley Periodicals, Inc. J Orthop Res.

Platelet-Rich Plasma and the Knee-Applications in Orthopedic Surgery

PURPOSE OF REVIEW

To consolidate and synthesize the most recent evidence on the effects of platelet-rich plasma (PRP) in the knee with respect to osteoarthritis, meniscal injuries, ACL reconstruction, total knee arthroplasty (TKA), and high tibial osteotomy.

RECENT FINDINGS

PRP has been shown to be more beneficial in the context of knee osteoarthritis compared to both placebo and hyaluronic acid. Direct comparison with corticosteroid injections has been sparsely studied. It has also been shown to improve the clinical postoperative course in meniscal injuries and to a lesser extent TKA. Radiographic improvements without clinically significant benefits have been observed with ACL reconstructions treated with PRP. PRP injections may be more beneficial than other current non-surgical management options for specific knee pathologies. Further research should broaden the knowledge of PRP effects on the knee, and identify the type of PRP, growth factor distribution, and route of administration associated with the most benefit.

Biological Treatment for Osteoarthritis of the Knee: Moving from Bench to Bedside-Current Practical Concepts

Biological-based therapies for cartilage pathology have gained considerable recognition in the last few decades due to their potential benefits including their minimal invasiveness, capacity for unprecedented healing, and potential for rapid recovery. Consequently, these therapies are likely to have the most noteworthy impact on patients with degenerative joint changes who want to remain active. Currently, the most researched treatments include platelet-rich plasma (PRP), bone marrow aspirate concentrate (BMAC), and cell-based therapies. Although further basic science research and well-designed randomized clinical trials are needed to elucidate the long-term role of these therapies in the treatment of osteoarthritis, there is compelling evidence for their use for certain indications. This article aims to review the existing literature for biological-based treatment options for osteoarthritis, critically assessing the current evidence-based recommendations and identify potential avenues for development.

The Effects of Hyperacute Serum on the Elements of the Human Subchondral Bone Marrow Niche

Mesenchymal stem cells (MSCs) are widely used in laboratory experiments as well as in human cell therapy. Their culture requires animal sera like fetal calf serum (FCS) as essential supplementation; however, animal sera pose a risk for clinical applications. Human blood derivatives, for example, platelet-rich plasma (PRP) releasates, are potential replacements of FCS; however, it is unclear which serum variant has the best effect on the given cell or tissue type. Additionally, blood derivatives are commonly used in musculoskeletal diseases like osteoarthritis (OA) or osteonecrosis as “proliferative agents” for the topical MSC pool. Hyperacute serum (HAS), a new serum derivative, has been designed to approximate the natural coagulation cascade with a single-step, additive-free preparation method. We investigated the effects of HAS on monolayer MSC cultures and in their natural niche, in 3D subchondral bone and marrow explants. Viability measurements, RT-qPCR evaluation for gene expression and flow cytometry for cell surface marker analysis were performed to compare the effects of FCS-, PRP-, or HAS-supplemented culture media. Monolayer MSCs showed significantly higher metabolic activity following 5 days' incubation in HAS, and osteoblast-specific mRNA expression was markedly increased, while cells also retained their MSC-specific cell surface markers. A similar effect was observed on bone and marrow explants, which was further confirmed with confocal microscopy analysis. Moreover, markedly higher bone marrow preservation was observed with histology in case of HAS supplementation compared to FCS. These findings indicate possible application of HAS in regenerative solutions of skeletal diseases like OA or osteonecrosis.

PRP Therapy

Osteochondral lesions remain as a clinical challenge despite the advances in orthopedic regenerative strategies. Biologics, in particular, platelet-rich plasma, has been applied for the reparative and regenerative effect in many tissues, and osteochondral tissue is not an exception. Platelet-rich plasma is an autologous concentrate prepared from the collected blood; thus, this safe application is free of immune response or risk of transmission of disease. It has a high potential to promote regeneration, thanks to its content, and can be applied alone or can reinforce a tissue engineering strategy. The relevant works making use of platelet-rich plasma in osteochondral lesions are overviewed herein. The practical success of platelet-rich plasma is uncertain since there are many factors involved including but not limited to its preparation and administration method. Nevertheless, today, the issues and challenges of platelet-rich plasma have been well acknowledged by researchers and clinicians. Thus, it is believed that a consensus will be built it, and then with high-quality randomized controlled trials and standardized protocols, the efficacy of platelet-rich plasma therapy can be better evaluated.

HIGHLIGHTS

The need of treating the osteochondral lesions has not been yet met in the clinics. Thanks to being an autologous source of growth factors, interleukins, and other cytokines and relative ease of clinical application, i.e., during a single-step surgical procedure, the use of platelet-rich plasma is of great interest. The high theoretical potential of the role of platelet-rich plasma in the regeneration process of osteochondral lesions is known, and the efficiency needs to be confirmed by high-quality randomized controlled trials for a robust position in the treatments of osteochondral lesions in the clinics.

Clinical Management in Early OA

Knee osteoarthritis affects an important percentage of the population throughout their life. Several factors seem to be related to the development of knee osteoarthritis including genetic predisposition, gender, age, meniscal deficiency, lower limb malalignments, joint instability, cartilage defects, and increasing sports participation. The latter has contributed to a higher prevalence of early onset of knee osteoarthritis at younger ages with this active population demanding more consistent and durable outcomes. The diagnosis is complex and the common signs and symptoms are often cloaked at these early stages. Classification systems have been developed and are based on the presence of knee pain and radiographic findings coupled with magnetic resonance or arthroscopic evidence of early joint degeneration. Nonsurgical treatment is often the first-line option and is mainly based on daily life adaptations, weight loss, and exercise, with pharmacological agents having only a symptomatic role. Surgical treatment shows positive results in relieving the joint symptomatology, increasing the knee function and delaying the development to further degenerative stages. Biologic therapies are an emerging field showing early promising results; however, further high-level research is required.