Platelet-rich plasma therapy for knee joint problems: review of the literature, current practice and legal perspectives in Korea

Informed consent form for platelet rich plasma injections: evidence-based and legally guide for orthopaedic surgeons

Regarding medico-legal malpractice suits, lawyers and insurers focus on informed consent documentation. Unfortunately, there is no standard protocol for obtaining informed consent for platelet-rich plasma (PRP) injections. The objective of the present study was to create a pre-designed, evidence-based informed consent form specifically for PRP injections. The current evidence on the medico-legal implications of PRP injections was accessed, as well as informed consent in general and specifically informed consent in PRP injections. Additionally, we interviewed orthopaedic surgeons and patients who had undergone PRP injections in the past year using a semi-structured approach. A legally valid and evidence-based informed consent form for PRP injections ensures rights, encouraging open communication and transparency between the patient and surgeon. Moreover, if a lawsuit arose, informed consent would be a critical document in surgeons' defence and would withstand scrutiny from lawyers and the judiciary. An evidence-based informed consent form for PRP injections was elaborated and reviewed by a legal expert to ensure adherence to legal proprieties. The final form of the informed consent for PRP injection was administered for one year and validated at our institution.

Are leukocyte-poor or multiple injections of platelet-rich plasma more effective than hyaluronic acid for knee osteoarthritis? A systematic review and meta-analysis of randomized controlled trials

INTRODUCTION

Platelet-rich plasma (PRP) has gained popularity as a treatment option for knee osteoarthritis; however, its efficacy remains controversial. The optimal leukocyte concentration and number of injections have not been well investigated. This study was, therefore, designed to provide clinical evidence on the leukocyte concentration and number of intra-articular injections of PRP via a meta-analysis of randomized controlled trials (RCTs).

METHODS

The MEDLINE, Embase, Cochrane Library, CINAHL, and Scopus databases were searched and RCTs comparing PRP and hyaluronic acid (HA) for treating knee osteoarthritis were included. Clinical outcomes, including visual analog scale (VAS) score, Western Ontario and McMaster Universities Osteoarthritis Index (WOMAC), and adverse reactions, were evaluated.

RESULTS

A total of 138 studies were screened, of which 21 level 1 RCTs (2086 knees; 1077 PRP and 1009 HA) were included. PRPs showed significant improvement in pain according to the VAS score compared to HA at 6 and 12 months, regardless of leukocyte concentration. Both single and multiple injections of PRP improved pain better than HA at 12 months. Regarding function, both single and multiple injections of leukocyte-poor PRP and leukocyte-rich PRP led to significantly better improvement in total WOMAC score compared with HA at 6 months. There was no significant difference in procedure-related knee pain or swelling between the PRP and HA groups. Leukocyte-rich PRP had a significantly higher odds ratio for procedure-related knee pain or swelling compared to HA (odds ratio, 3.3 [95% confidence interval, 1.1-10.2], P = .037).

CONCLUSION

Based on evidence from Level 1 studies, intra-articular injection of PRP improves pain and function in patients with knee osteoarthritis for up to 12 months and is superior to HA, regardless of leukocyte concentration or number of injections. The findings of this study support the routine clinical use of intra-articular injections of PRP for the treatment of knee osteoarthritis, regardless of the type and frequency of PRP injection.

LEVEL OF EVIDENCE

Meta-analysis of level I studies.

Intra-articular injection with platelet-rich plasma compared to triamcinolone hexacetonide or saline solution in knee osteoarthritis: A double blinded randomized controlled trial with one year follow-up

OBJECTIVES

To compare the effectiveness of intra-articular injection (IAI) of Platelet-Rich Plasma (PRP) with Triamcinolone Hexacetonide (TH) and Saline Solution (SS), in patients with knee osteoarthritis (OA).

DESIGN

A randomized controlled trial, with blinded patients and assessor.

SETTING

Outpatient rheumatology service.

SUBJECTS

Patients with knee osteoarthritis grades II and III.

INTERVENTIONS

Patients received IAI with PRP, 40 mg TH, or SS.

METHODS

Patients were assessed at baseline and after 4, 8, 12 e 52 weeks with: visual analogue scale (VAS) for pain at rest and movement, WOMAC questionnaire, Timed to Up and Go test, 6-min walk test, percentage of improvement, goniometry, quality of life SF-36 questionnaire, Likert scale and Kelgreen & Lawrence (KL) radiographic scale (only at baseline and 52 weeks).

RESULTS

100 patients were studied, with a mean age of 67.13(6.56) years. The TH group was superior for: percentage of improvement (versus SS group from 4 to 52 weeks); WOMAC total and pain (versus PRP group at 4 weeks); and WOMAC stiffness (versus SS group at 12 weeks). The SS group was inferior for WOMAC function (from 8 to 52 weeks). The PRP group showed lowest radiographic progression [TH 17 (51.51%) to 24 (72.72%); SS 17 (51.51%) to 30 (90.90%); PRP 20 (58.82%) to 21 (61.76%)].

CONCLUSION

The Triamcinolone Hexacetonide group was superior for percentage of improvement and WOMAC, pain and stiffness. For the WOMAC function, the Platelet-Rich Plasma group and Triamcinolone Hexacetonide group were superior to the Saline group. The Platelet-Rich Plasma group showed the lowest radiographic progression at 52 weeks of follow-up.

Adverse Reactions and Clinical Outcomes for Leukocyte-Poor Versus Leukocyte-Rich Platelet-Rich Plasma in Knee Osteoarthritis: A Systematic Review and Meta-analysis

Background:

Platelet-rich plasma (PRP) has gained attention as a therapeutic option for knee osteoarthritis; however, its efficacy varies widely. Leukocytes in PRP raise the concern of aggravating proinflammatory activity. To date, PRP has rarely been investigated with regard to leukocyte concentration.

Purpose:

To provide clinical evidence of the intra-articular injection of PRPs containing different leukocyte concentrations.

Study Design:

Systematic review; Level of evidence, 4.

Methods:

We systematically searched the MEDLINE, Embase, Cochrane Library, CINAHL, and Scopus databases. PRP was classified into leukocyte-poor (LP-PRP) and leukocyte-rich (LR-PRP). Clinical outcomes including Western Ontario and McMaster Universities Osteoarthritis Index (WOMAC), visual analog scale (VAS) for pain score, International Knee Documentation Committee (IKDC) subjective score, and adverse reactions were evaluated. The Methodological Index for Non-Randomized Studies criteria were used for quality assessment.

Results:

Included were 32 studies with an evidence level between 1 and 4. Both LP-PRP and LR-PRP showed improvements above the minimal clinically important difference (MCID) in VAS pain score. No significant intergroup difference was seen at 3, 6, or 12 months of follow-up. Regarding function, both LP-PRP and LR-PRP showed improvements above the MCID in the WOMAC and IKDC scores, with no significant difference between the groups. Adverse reactions for pain were significantly higher in LR-PRP than in LP-PRP (odds ratio, 1.64; 95% confidence interval, 1.29-2.10; P = .01). After intra-articular PRP injection, LR-PRP showed a significantly higher rate of swelling than LP-PRP (odds ratio, 1.56; 95% confidence interval, 1.22-1.99; P = .02). The mean Methodological Index for Non-Randomized Studies score of the included studies was 18.6 (range, 10-24).

Conclusion:

Intra-articular PRP injection resulted in improvements above the MCID in terms of pain and function in patients with knee osteoarthritis up to 12 months. The risk of local adverse reactions appeared to be increased after LR-PRP compared with LP-PRP injection. The findings of this review can support the potential use of intra-articular PRP injection for the treatment of knee osteoarthritis. In clinical application, clinicians need to consider selecting a specific type of PRP for knee osteoarthritis.

Clinical Efficacy of Platelet-Rich Plasma Injection and Its Association With Growth Factors in the Treatment of Mild to Moderate Knee Osteoarthritis: A Randomized Double-Blind Controlled Clinical Trial As Compared With Hyaluronic Acid

BACKGROUND

Although platelet-rich plasma (PRP) has potential as a regenerative treatment for knee osteoarthritis, its efficacy varies. Compositional differences among types of PRP could affect clinical outcomes, but the biological characterization of PRP is lacking.

PURPOSE

To assess the efficacy of intra-articular PRP injection in knee osteoarthritis as compared with hyaluronic acid (HA) injection and to determine whether the clinical efficacy of PRP is associated with its biological characteristics.

STUDY DESIGN

Randomized controlled trial; Level of evidence, 1.

METHODS

A total of 110 patients with symptomatic knee osteoarthritis received a single injection of leukocyte-rich PRP (1 commercial kit) or HA. Clinical data were assessed at baseline and at 6 weeks and 3 and 6 months after injection. The primary endpoint was an improvement in the International Knee Documentation Committee (IKDC) subjective score at 6 months, and the secondary endpoints were improvements in scores based on the Patient Global Assessment, the visual analog scale (VAS) for pain, the Western Ontario and McMaster Universities Osteoarthritis Index, and the Samsung Medical Center patellofemoral score. Cell counts and concentrations of growth factors and cytokines in the injected PRP were assessed to determine their association with clinical outcomes.

RESULTS

PRP showed significantly improvement in IKDC subjective scores at 6 months (11.5 in the PRP group vs 6.3 in the HA group; P = .029). There were no significant differences between groups in other clinical outcomes. The Patient Global Assessment score at 6 months was better in the PRP group (P = .035). The proportion of patients who scored above the minimal clinically important difference (MCID) for VAS at 6 months was significantly higher in the PRP group (P = .044). Within the PRP group, the concentrations of platelet-derived growth factors were high in patients with a score above the MCID for VAS at 6 months. The incidence of adverse events did not differ between the groups (P > .05).

CONCLUSION

PRP had better clinical efficacy than HA. High concentrations of growth factors were observed in patients who scored above the MCID for clinical outcomes in the PRP group. These findings indicate that concentration of growth factors needs to be taken into consideration for future investigations of PRP in knee osteoarthritis.

REGISTRATION

NCT02211521 (ClinicalTrials.gov identifier).

Effect of Platelet-Rich Plasma Injection on Mild or Moderate Carpal Tunnel Syndrome: An Updated Systematic Review and Meta-Analysis of Randomized Controlled Trials

Objective

To evaluate efficacy of platelet-rich plasma (PRP) injection in carpal tunnel syndrome (CTS), we conducted this meta-analysis, as well as proposed a protocol for its application in curative processes.

Methods

All randomized controlled trials (RCTs) of PRP for the management of mild or moderate CTS were included in this study. Database search was conducted from study inception to July 2020, including PubMed, Embase, Web of Science, and Cochrane Library. We used visual analogue scores (VAS) and the Boston Carpal Tunnel Questionnaire (BCTQ) as evaluation tools for primary outcomes. Second outcomes comprised cross-sectional area (ΔCSA) and electrophysiological indexes including distal motor latency (DML), sensory peak latency (SPL), motor nerve conduction velocity (MNCV), sensory nerve conduction velocity (SNCV), compound muscle action potential (CMAP), and sensory nerve action potential (SNAP). The pooled data were analyzed using RevMan 5.3. Subgroup and sensitivity analyses were conducted with the evidence of heterogeneity. Egger' test was used to investigate publication bias.

Results

9 RCTs were finally screened out with 434 patients included. Control groups comprised corticosteroid injection in 5 trials, saline injection in 1 trial, and splint in 3 trials. At the 1st month after follow-up, only ΔCSA between the PRP group and the control group showed significant difference (P < 0.05). In the 3rd month, there were statistically significant differences in VAS, BCTQ, SPL, SNCV, and ΔCSA between two groups (P < 0.05), while no statistically significant differences were found in the remaining outcomes. In the 6th month, there were statistically significant differences at BCTQ (P < 0.05) in primary outcomes and ΔCSA (P < 0.05) in secondary outcomes between two groups. As to adverse events in PRP injection, only one study reported increased pain sensation within 48 h after injections.

Conclusion

This systematic review and meta-analysis demonstrates that the PRP could be effective for mild to moderate CTS and superior to traditional conservative treatments in improving pain and function and reducing the swelling of the median nerve for a mid-long-term effect. To some extent, the electrophysiological indexes also improved after PRP injection compared with others conservative treatments.

Variability of the Composition of Growth Factors and Cytokines in Platelet-Rich Plasma From the Knee With Osteoarthritis

PURPOSE

To investigate the composition and concentration of growth factors and cytokines in platelet-rich plasma (PRP) with knee osteoarthritis and to explore the association of the concentration of growth factors and cytokines with the platelet count of PRPs.

METHODS

Patients who visited outpatient clinic with symptomatic knee osteoarthritis (Kellgren-Lawrence grades 1 to 3) and had no blood dyscrasia were enrolled from October 2014 to March 2015. PRPs were obtained using a commercial system. Concentrations of growth factors and cytokines were measured with an enzyme-linked immunosorbent assay. Anabolic factors (platelet-derived growth factor [PDGF]-AA, -BB, and -AB, transforming growth factor-β, vascular endothelial growth factor [VEGF], epidermal growth factor [EGF], basic fibroblast growth factor [bFGF], and insulin-like growth factor 1), catabolic factors (interleukin [IL]-1β and matrix metalloproteinase 13), and catabolic blockers (IL-1 receptor antagonist) were included. The degree of variation was determined by coefficient of variation (CoV).

RESULTS

105 patients were included. Growth factors and cytokines showed wide variation. bFGF showed the highest variation (CoV 78.45), and transforming growth factor-β1 showed the lowest variation (CoV 5.30). Platelet count in PRP showed a positive correlation with PDGF-BB and -AB, and VEGF (r = 0.270, P = .005; r = 0.231, P = .018; and r = 0.200, P = .041, respectively) and was negatively correlated with IL-1β (r = -0.220, P = .025).

CONCLUSION

Growth factors and cytokines in PRPs obtained from patients with knee osteoarthritis show a wide variation; the highest variation was shown in bFGF. Platelet counts associated positively with PDGF-AB and -BB and VEGF and negatively with IL-1β.

CLINICAL RELEVANCE

This information leads to the concept that variation and association of specific factors needs to be taken into consideration for future investigations of PRPs in clinical application in patients with knee osteoarthritis.

An overview of platelet products (PRP, PRGF, PRF, etc.) in the Iranian studies

Aim

The aim of the study was to carry out a review of published studies on various platelet products in Iranian studies.

Materials & methods

Electronic databases were searched for relevant articles. Two review authors independently extracted data via a tested extraction sheet, and disagreements were resolved by a meeting with a third review author.

Results

Bone disorders (25%), wound and fistula (16%), dental and gingival disorders (14%) and osteoarthritis (11%) have more relative frequency based on different fields.

Conclusion

The necessity of pursuing standard protocols in the preparation of platelet products, stating the precise content of platelets and growth factors, and long-term follow-up of study subjects were the most important points in Iranian studies.

PRP and articular cartilage: a clinical update

The convincing background of the recent studies, investigating the different potentials of platelet-rich plasma, offers the clinician an appealing alternative for the treatment of cartilage lesions and osteoarthritis. Recent evidences in literature have shown that PRP may be helpful both as an adjuvant for surgical treatment of cartilage defects and as a therapeutic tool by intra-articular injection in patients affected by osteoarthritis. In this review, the authors introduce the trophic and anti-inflammatory properties of PRP and the different products of the available platelet concentrates. Then, in a complex scenario made of a great number of clinical variables, they resume the current literature on the PRP applications in cartilage surgery as well as the use of intra-articular PRP injections for the conservative treatment of cartilage degenerative lesions and osteoarthritis in humans, available as both case series and comparative studies. The result of this review confirms the fascinating biological role of PRP, although many aspects yet remain to be clarified and the use of PRP in a clinical setting has to be considered still exploratory.

Comparison between two different platelet-rich plasma preparations and control applied during anterior cruciate ligament reconstruction. Is there any evidence to support their use?

INTRODUCTION

To compare the clinical, analytical and graft maturation effects of two different platelet-rich plasma (PRP) preparations applied during anterior cruciate ligament (ACL) reconstruction.

MATERIALS AND METHODS

A total of 150 patients with ACL disruption were included in the study. Arthroscopic ACL reconstruction with patellar tendon allograft was conducted on all knees using the same protocol. One hundred patients were prospectively randomised to either a group to receive double-spinning platelet-enriched gel (PRP) with leukocytes (n=50) or to a non-gel group (n=50). Finally, we included 50 patients treated with a platelet-rich preparation from a single-spinning procedure (PRGF Endoret(®) Technology) without leukocytes. Inflammatory parameters, including C-reactive protein (CRP) and knee perimeters (PER), were measured 24 hours and 10 days after surgery. Postoperative pain score (visual analogue score [VAS]) was recorded the day after surgery. Follow-up visits occurred postoperatively at 3, 6, and 12 months. The International Knee Documentation Committee scale (IKDC) was included to compare functional state, and MRI was conducted 6 months after surgery.

RESULTS

The PRGF group showed a statistically significant improvement in swelling and inflammatory parameters compared with the other two groups at 24 hours after surgery (p<0.05). The results did not show any significant differences between groups for MRI and clinical scores.

CONCLUSIONS

PRGF used in ACL allograft reconstruction was associated with reduced swelling; however, the intensity and uniformity of the graft on MRI were similar in the three groups, and there was no clinical or pain improvement compared with the control group.

LEVEL OF EVIDENCE

II.

Does intra articular platelet rich plasma injection improve function, pain and quality of life in patients with osteoarthritis of the knee? A randomized clinical trial

We designed a randomized clinical trial with control group, to investigate the effects of platelet rich plasma (PRP) on pain, stiffness, function and quality of life in patients with knee osteoarthritis. Patients were randomly divided in two groups. For both groups of participants, therapeutic exercise was prescribed. In the PRP group, two courses of leukocyte rich PRP (5.6 fold higher platelet concentration) with a 4-week interval was injected. For each participant, Western Ontario and McMaster University’s Arthritis Index (WOMAC) and the SF-36 questionnaire (Farsi version) were filled at the baseline and 6 months after treatments. Thirty-one patients in the PRP group and 31 patients in the control group were studied. Mean changes of total WOMAC, physical component summery and mental component summery of Short Form-36 in PRP group showed better improvement than control group (P<0.05). This study showed that intra articular PRP knee injection combined with therapeutic exercise can be more effective in pain reduction and improvement of stiffness and quality of life, compared with therapeutic exercise alone.

Hip osteoarthritis in dogs: a randomized study using mesenchymal stem cells from adipose tissue and plasma rich in growth factors

Purpose: The aim of this study was to compare the efficacy and safety of a single intra-articular injection of adipose mesenchymal stem cells (aMSCs) versus plasma rich in growth factors (PRGF) as a treatment for reducing symptoms in dogs with hip osteoarthritis (OA). Methods: This was a randomized, multicenter, blinded, parallel group. Thirty-nine dogs with symptomatic hip OA were assigned to one of the two groups, to receive aMSCs or PRGF. The primary outcome measures were pain and function subscales, including radiologic assessment, functional limitation and joint mobility. The secondary outcome measures were owners’ satisfaction questionnaire, rescue analgesic requirement and overall safety. Data was collected at baseline, then, 1, 3 and 6 months post-treatment. Results: OA degree did not vary within groups. Functional limitation, range of motion (ROM), owner’s and veterinary investigator visual analogue scale (VAS), and patient’s quality of life improved from the first month up to six months. The aMSCs group obtained better results at 6 months. There were no adverse effects during the study. Our findings show that aMSCs and PRGF are safe and effective in the functional analysis at 1, 3 and 6 months; provide a significant improvement, reducing dog’s pain, and improving physical function. With respect to basal levels for every parameter in patients with hip OA, aMSCs showed better results at 6 months.

Orthobiologics and platelet rich plasma

Orthobiologics have evolved to the extent that they significantly influence modern orthopedic surgical practice. A better understanding of the role of various growth factors and cells in the process of tendon healing, ligament repair, cartilage regeneration and bone formation has stimulated focused research in many chronic musculoskeletal ailments. Investigators have published results of laboratory as well as clinical studies, using orthobiologics like platelet rich plasma, stem cells, autologous conditioned serum etc., with variable results. However, a clear consensus over the best orthobiologic substance and the method of preparation and usage of these substances is lacking. Much of the confusion is due to the fact that studies ranging from RCTs to case reports present variable results, and the interpretations are wide-ranging. We have reviewed the available orthobiologics related data with a focus on platelet rich plasma in orthopedic conditions.

The effect of platelet-rich plasma on pain, function, and quality of life of patients with knee osteoarthritis

Background. New studies in the management of knee osteoarthritis have focused on modern therapeutic methods stimulating cartilage healing process. In the present study, we evaluated the effects of 2 courses of leucocyte-rich PRP (LR-PRP) injections on patients' QOL and functions and also the relationship between the PRP concentration and mentioned variables. Material and Methods. Sixty-five patients were evaluated. For each participant, WOMAC and the native (Farsi) edition of the SF-36 questionnaire were filled. Two courses of LR-PRP injections with 4-week interval were used. After 6 months, SF-36 and WOMAC questionnaires were filled again for each patient. Results. 60 patients were included in the final analysis. The mean platelet concentrations and white blood cell in PRP was 5-fold increase and 220 per microliter, respectively. The mean total WOMAC revealed significant change (P = 0.001). In SF-36, the mean changes of 2 major physical and mental domains were meaningful (P = 0.001). Discussion. In our study, 2 injections of PRP, with 4-week interval, improved the pain, stiffness, and functional capacity. Improvements in QOL (both PCS and MCS) were meaningful after injections. These changes were more significant in physical domains. PRP injection may be an alternative therapy in selective patients resistant to current nonsurgical treatments of knee osteoarthritis.

Intraarticular Injections of Platelet-rich Plasma (PRP) in the Management of Knee Osteoarthritis

The clinical use of PRP therapy in the practical setting of orthopaedic fields is increasing partly because of the accessibility of devices that are used in outpatient preparation and delivery. Another reason is the strong advertisement of PRP procedures as the ultimate treatment and novel technology for knee problems by a few orthopaedic surgeons based on claims of abundant scientific evidence. Hence, PubMed articles related to the clinical use of PRP in knee osteoarthritis were searched using the key words: PRP, knee and osteoarthritis in order to study these claims. A total of 20 reports were found directly related to the topic. The aforementioned clinical studies suggest that intraarticular injections of PRP could have preventive effects against osteoarthritis progression. However, presently there is no clear evidence from well-designed clinical trials that intraarticular injections of PRP are efficacious in osteoarthritis. Therefore, at this time the efficacy of PRP requires more investigation, wherein better scientific studies should be performed that include high powered randomized controlled trials.