Autologous Conditioned Plasma (ACP) and Osteoarthritis of the Knee: A Review of Current Clinical Evidence

The primary objective of this study is to record the clinical outcomes of autologous conditioned plasma (ACP) for the treatment of knee osteoarthritis (OA) based on published literature. Multiple databases (PubMed, Embase, Web of Science and Scopus) were searched using terms for "knee OA" and the intervention "ACP" for articles published in English to January 4, 2024. All clinical studies using ACP for knee OA were included. Studies not utilizing ACP alone, i.e. used as an adjunct with other modalities or not focusing on the management of knee OA, were excluded. Five studies, three randomized controlled trials (RCTs) and two real-world post-market studies conducted in a clinical practice met the inclusion/exclusion criteria and were included in this study. All studies demonstrated statistically significant improvements in various patient-reported outcome measures (PROMs), however the studies performed in the clinical practice reported non-accomplishment of minimally clinically important difference (MCID). The results demonstrated the potential of ACP for management of knee OA, however the MCID was not achieved in real-world clinical settings. Thus, more adequately powered RCTs with longer follow-up as well as real-world post-market studies are warranted to establish long-term efficacy and justify routine clinical use, respectively, of ACP in patients suffering with knee OA.

Lower centrifugation speed and time are positively associated with platelet concentration in a canine autologous conditioned plasma system

OBJECTIVE

To evaluate the effect of variable centrifugation protocols on the cellular composition of the final product of a canine autologous conditioned plasma double-syringe system.

ANIMALS

30 client-owned healthy adult medium- to large-breed (17- to 45-kg) dogs.

METHODS

35 mL of anticoagulated whole blood from each subject was aliquoted into 3 samples: a baseline and 2 double syringes. The syringes were processed for platelet-rich plasma (PRP). Each double syringe was randomly assigned to 1 of 5 groups, which varied in centrifugation settings between 580 and 1,304 X g and 5 and 10 minutes. CBC analysis was performed on each of the samples to determine cellular composition. A mixed-effect linear model was fit to the data.

RESULTS

60 PRP samples and 30 whole blood samples were analyzed. Manufacturer settings generated a platelet fold change > 1 but did not increase concentration to the extent expected. When comparing speed alone, increased centrifugation force was associated with lower platelet fold change. When comparing time alone, increased centrifugation time was also associated with lower platelet fold change and lower leukocyte concentration.

CLINICAL RELEVANCE

Autologous conditioned plasma double syringes require a low volume of initial whole blood, making them preferable for canine PRP in clinical settings. This study aimed to evaluate the effect of the centrifugation protocol on the final product cellular composition in dogs and add to the available data on protocols to maximize platelet yield in PRP. Due to inherent individual variability, this study emphasized the importance of evaluating biological samples prior to administration to predict and improve patient outcomes.

Core Decompression Combined with Intraosseous Autologous Conditioned Plasma Injections Decreases Pain and Improves Function in Patients with Symptomatic Knee Bone Marrow Lesions

The purpose of this prospective case series was to determine the effectiveness of using a combination of the core decompression and injection of autologous conditioned plasma (ACP) for the treatment of symptomatic knee bone marrow lesions (BML), as well as to report on the preliminary clinical results based on magnetic resonance imaging (MRI) and patient-reported outcomes (PROMs). Patients with OA-related BML who failed to improve on conservative treatment for three months underwent an identical procedure consisting of arthroscopy, core decompression, and the intraosseous injection of ACP and were followed up for 12 months. A statistically significant reduction in pain and an improvement in function, as measured by the Numeric Pain Rating Scale (NPRS) and Knee Injury and Osteoarthritis Outcome Score (KOOS), was observed at one-week follow-up (8.3 ± 0.8 to 1.5 ± 1.0; p ≤ 0.001 and 33.4 ± 10.6 to 53.9 ± 13.6; p ≤ 0.001 respectively). After six weeks, weight-bearing was allowed, but the trend did not change-the NPRS continued to be low (average 1.4 on 12-month follow-up) and the total KOOS increased 44.6 points from the baseline (average 78.0 on 12-month follow-up). The Whole-Organ Magnetic Resonance Imaging Score improved from 66.1 ± 19.4 prior to surgery to 58.0 ± 15.9 (p < 0.001) after 3 months. In our study, there was no control group, randomisation was not performed, and the sample size was relatively small. A combination of core decompression and the intraosseous injection of ACP into the affected subchondral area proved to be a safe and effective procedure that provides rapid pain relief and a significant increase in joint function up to one year postoperatively.

Regenerative Medicine for Knee Osteoarthritis - The Efficacy and Safety of Intra-Articular Platelet-Rich Plasma and Mesenchymal Stem Cells Injections: A Literature Review

The prevalence of osteoarthritis (OA) has been rising exponentially in recent years. As the disease progresses, patients may eventually require surgical intervention to restore the functionality of the affected knees. The current literature review aims to explore two treatment options in regenerative medicine for OA by analyzing the efficacy and safety of platelet-rich plasma (PRP) and mesenchymal stem cells (MSCs) use, as well as determining which population will benefit from these treatments. A total of 1093 patients who were diagnosed with unilateral or bilateral knee osteoarthritis (KOA) were recruited in 23 studies. The experimental groups received either PRP or MSCs injections in comparison to the control groups receiving either hyaluronic acid (HA) or placebo (saline or dextrose) injections. Western Ontario and McMaster Universities Arthritis Index (WOMAC) was used to evaluate all participants at different time intervals of the studies. Medical imaging evaluations (X-ray or MRI) were used to look for structural improvements. In conclusion, both PRP and MSCs treatments were well tolerated, effective and safe to use. Repeated administrations and higher concentrations resulted in superior clinical improvements. A decrease in cartilage loss was observed in some MSCs trials. No severe adverse effects were documented. PRP treatment proved to be more efficacious among patients with KOA Kellgren-Lawrence (KL) grade I-II, while MSCs treatment proved to be more beneficial among the KOA KL grade II-III group.

Can hydrogel dressings reduce patients' discomfort and side effects of facial platelet-rich plasma injections?

The literature shows that facial injection of platelet-rich plasma (PRP) is a safe and effective treatment modality. Serious adverse effects have not been reported so far. Nevertheless, side effects such as redness, edema, bruising, pain, pruritus, and heat sensation have been reported. Our goal was to assess the potential effects of hydrogel dressing after injection of PRP. PRP was prepared using an ACP double-syringe system and applied on face by intradermal microdeposit injections. One half of the face was covered with a cooled (20°C) hydrogel dressing for 20 minutes before and after PRP injection. Patients rated the levels of pain separately for both sides. Physician and patient rated the overall appearance of the skin, redness, swelling, bruising, and number of bruises straight after the procedure. At 6-month follow-up, the physician rated the global aesthetic outcome. Needle prick-induced pain and edema were rated less on the hydrogel side. Our results demonstrate a significant reduction of patient's discomfort and side effects through application of hydrogel dressings. Recovery has been accelerated and the overall appearance of the skin straight after the procedure has been rated significantly better than without dressing application. At 6-month follow-up, the global aesthetic improvement was rated equally on both sides.

Platelet-Rich Plasma Shortens Return to Play in National Football League Players With Acute Hamstring Injuries

Background:

Hamstring injuries are prevalent in professional athletes and can lead to significant time loss, with recurrent injury being common. The efficacy of platelet-rich plasma (PRP) for augmentation of nonoperative treatment of partial musculotendinous hamstring injuries is not well established.

Hypothesis:

The addition of PRP injections to nonoperative treatment for acute partial musculotendinous hamstring injuries will lead to a shortened return to play in National Football League (NFL) players.

Study Design:

Cohort study; Level of evidence, 3.

Methods:

NFL players from a single team who sustained acute grade 2 hamstring injuries, as diagnosed on magnetic resonance imaging (MRI) by a musculoskeletal radiologist from 2009 to 2018, were retrospectively reviewed. Average days, practices, and games missed were recorded. Players who did and did not receive PRP (leukocyte-poor) injections were compared. Those who received PRP did so within 24 to 48 hours after injury.

Results:

A total of 108 NFL players had MRI evidence of a hamstring injury, and of those, 69 athletes sustained grade 2 injuries. Thirty players received augmented treatment with PRP injections and 39 players underwent nonoperative treatment alone. Average time missed in those treated with PRP injections was 22.5 days, 18.2 practices, and 1.3 games. In those who did not receive PRP injections, time missed was 25.7 days (P = .81), 22.8 practices (P = .68), and 2.9 games (P < .05).

Conclusion:

Augmentation with PRP injections for acute grade 2 hamstring injuries in NFL players showed no significant difference in days missed or time to return to practice but did allow for faster return to play, with a 1 game overall difference. Owing to the possible large financial impact of returning to play 1 game sooner, PRP injections for treatment of grade 2 hamstring injuries may be advantageous in professional athletes.

Successful Treatment of Alopecia Areata Barbae with Platelet-rich Plasma

Alopecia areata (AA) is a frequent autoimmune disorder in which inflammatory cells attack the hair follicles. AA affecting the beard area is well known and is referred to as alopecia areata barbae (AAB) when involvement is limited exclusively to the beard. Currently, no guidelines are established for specific therapeutic approaches for this condition. We present a case of a healthy 30-year-old male suffering from AAB. Three injections of platelet-rich plasma (PRP) with six-week intervals were applied. Stabilization of the condition was noted at the first follow-up (before the second injection), initial minimal hair regrowth was noted at the second follow-up (before the third injection) and robust regrowth at the one-year follow-up. To our knowledge, this case is the first report of a successful treatment of AAB using PRP. PRP represents a new, safe and potentially effective treatment option for AAB. More studies will be necessary to determine the efficacy of this treatment compared to conventional therapy.

Return to Play After PRP and Rehabilitation of 3 Elite Ice Hockey Players With Ulnar Collateral Ligament Injuries of the Elbow

Background:

Ulnar collateral ligament (UCL) injury is a well-described etiology of pain and decreased performance for the overhead athlete. Despite a growing volume of literature regarding the treatment of these injuries for overhead athletes, there is a paucity of such data regarding stickhandling collision sport athletes, such as ice hockey players.

Purpose/Hypothesis:

The purpose of this study was to characterize this injury among 3 elite ice hockey players and to describe the ability of these athletes to return to play, as well as to review the unique sport-specific implications of this injury, evaluation, nonsurgical management, and considerations for return to play. The authors hypothesized that elite ice hockey players will be able to return to play at the same level following nonoperative treatment of UCL injury.

Study Design:

Case series; Level of evidence, 4.

Methods:

Data from 3 elite professional ice hockey players who sustained a high-grade injury to the UCL were retrospectively reviewed. All athletes underwent 2 autologous conditioned plasma injections as part of their treatment and were evaluated with ultrasonography and magnetic resonance imaging.

Results:

Three consecutive elite ice hockey players were included in this study, and no patients were excluded. Players were cleared to full return to play at a mean 36 days postinjury. Follow-up examination at this time point demonstrated full range of motion of the elbow for all athletes, without tenderness to palpation over the UCL, including no tenderness over the humeral insertion site. Stability examination improved as well, demonstrating a soft to moderate endpoint with valgus stress, although this was not symmetric to the contralateral side. All athletes were able to continue to play at the same level of competition as before the injury occurred, without any complaints. No players had repeat injury during the same or following seasons.

Conclusion:

The authors present 3 elite-level ice hockey players who sustained a high-grade injury to the UCL. Successful return to play was possible after nonoperative treatment with injection of autologous conditioned plasma at a mean 36 days following injury. Athletes who injure either the top or bottom hand can return to play at the same elite level following this injury.

Platelet-rich Plasma for Skin Rejuvenation and Treatment of Actinic Elastosis in the Lower Eyelid Area

Background

Treatment of the lower eyelid region to rejuvenate the skin or treat actinic elastosis often proves difficult. Established treatment options, such as hyaluronic acid injections, botulinum toxin injections, microneedling, skin resurfacing (microdermabrasion, chemical peel (exfoliation), laser treatment), as well as blepharoplasties and autologous fat transfers, can be associated with significant risks and increased patient burden. Furthermore, they may not be effective for treating the signs of skin aging or actinic elastosis, including dark rings under the eyes, a lack of volume and cutis laxa. A minimally invasive treatment approach which visibly improves the above-mentioned conditions and which involves minimal risk and patient burden would be a desirable alternative.

Materials & methods

Twenty patients were treated a total of three times at monthly intervals with PRP (platelet-rich plasma). The patients were examined on the days of treatment and one month after the third injection. The PRP was obtained directly prior to treatment using the Arthrex ACP double syringe at the point of care. The injections (2 ml PRP per side) were administered laterally using 27 G 38 mm cannulas. Accurate photographic documentation and skin elasticity measurements using a cutometer were performed to objectify the subjective assessments from the patient and practitioner questionnaires.

Results

A progressive improvement in the esthetic outcome and a high level of patient satisfaction were determined. The cutometer measurements showed a statistically significant higher level of skin firmness (due to increased collagen production) and a statistically significant increase in skin elasticity (thanks to increased elastin production). Other than the anticipated visible swelling directly after the PRP injection, no other undesirable side effects or complications occurred. The typical burning sensation during the injection had not been reported.

Conclusion

The results indicate that a series of PRP injections in the lower eyelid region is a safe, efficient, virtually pain-free, simple and rapid treatment option for an area with otherwise limited treatment alternatives.

Cell-Based Therapies for Joint Disease in Veterinary Medicine: What We Have Learned and What We Need to Know

Biological cell-based therapies for the treatment of joint disease in veterinary patients include autologous-conditioned serum, platelet-rich plasma, and expanded or non-expanded mesenchymal stem cell products. This narrative review outlines the processing and known mechanism of action of these therapies and reviews current preclinical and clinical efficacy in joint disease in the context of the processing type and study design. The significance of variation for biological activity and consequently regulatory approval is also discussed. There is significant variation in study outcomes for canine and equine cell-based products derived from whole blood or stem cell sources such as adipose and bone marrow. Variation can be attributed to altering bio-composition due to factors including preparation technique and source. In addition, study design factors like selection of cases with early vs. late stage osteoarthritis (OA), or with intra-articular soft tissue injury, influence outcome variation. In this under-regulated field, variation raises concerns for product safety, consistency, and efficacy. Cell-based therapies used for OA meet the Food and Drug Administration’s (FDA’s) definition of a drug; however, researchers must consider their approach to veterinary cell-based research to meet future regulatory demands. This review explains the USA’s FDA guidelines as an example pathway for cell-based therapies to demonstrate safety, effectiveness, and manufacturing consistency. An understanding of the variation in production consistency, effectiveness, and regulatory concerns is essential for practitioners and researchers to determine what products are indicated for the treatment of joint disease and tactics to improve the quality of future research.

Outcome of Treatment of Osteoarthritis with Arthroscopic Debridement and Autologous Conditioned Plasma

Introduction

Worldwide estimates are that 9.6% of men and 18.0% of women aged over 60 years have symptomatic osteoarthritis. The current treatment options vary from conservative to joint replacement. Recently, debridement of the joint has become an option for symptomatic relief. We evaluated the outcome of arthroscopic debridement with autologous conditioned plasma. The latter helps to promote cellular repair. We have evaluated our results over a two year period.

Materials and Methods

We retrospectively analyzed a cohort of 52 patients who underwent arthroscopic knee debridement with autologous conditioned plasma in 2011. The patients were followed up in clinic till discharge. The case notes were reviewed and baseline demographic data obtained. This included age, medical history, occupation, range of movement, BMI measurements, duration of operation and radiographic scores. We analyzed the outcomes against those factors.

Results

Of the 52 patients in our study, 16 were female and 36 were male. The mean follow-up period in the clinic was 6.5 months. The Kellgren-Lawrence score was 21.2% Grade 1, 13.5% Grade 2, 51.9% Grade 3 and 13.5% Grade 4. Improvement in range of movement was seen in 32.7% of patients.

Conclusions

This study shows that arthroscopic debridement with autologous conditioned plasma (ACP) has a role to play in the treatment of osteoarthritis. In view of these findings, we recommend that surgeons should consider arthroscopic debridement with autologous conditioned plasma as part of their treatment armamentarium.

Intra-articular Autologous Conditioned Plasma Injections Provide Safe and Efficacious Treatment for Knee Osteoarthritis: An FDA-Sanctioned, Randomized, Double-blind, Placebo-controlled Clinical Trial

BACKGROUND

Platelet-rich plasma (PRP) injections have become an intriguing treatment option for osteoarthritis (OA), particularly OA of the knee. Despite the plethora of PRP-related citations, there is a paucity of high-level evidence that is comparable, cohort specific, dose controlled, injection protocol controlled, and double-blinded.

PURPOSE

To determine the safety and efficacy of leukocyte-poor PRP autologous conditioned plasma (ACP) for knee OA treatment through a feasibility trial regulated by the US Food and Drug Administration (FDA).

STUDY DESIGN

Randomized controlled trial; Level of evidence, 1.

METHODS

In accordance with FDA protocol, patient selection was based on strict inclusion/exclusion criteria; 114 patients were screened, and 30 were ultimately included in the study. These patients were randomized to receive either ACP (n = 15) or saline placebo (n = 15) for a series of 3 weekly injections. Western Ontario and McMaster Universities Osteoarthritis Index (WOMAC) scores served as the primary efficacy outcome measure. Patients were followed for 1 year.

RESULTS

No adverse events were reported for ACP administration. Furthermore, the results demonstrated no statistically significant difference in baseline WOMAC scores between the 2 groups. However, in the ACP group, WOMAC scores at 1 week were significantly decreased compared with baseline scores, and the scores for this group remained significantly lower throughout the study duration. At the study conclusion (12 months), subjects in the ACP group had improved their overall WOMAC scores by 78% from their baseline score, compared with 7% for the placebo group.

CONCLUSION

ACP is safe and provides quantifiable benefits for pain relief and functional improvement with regard to knee OA. No adverse events were reported for ACP administration. After 1 year, WOMAC scores for the ACP subjects had improved by 78% from their baseline score, whereas scores for the placebo control group had improved by only 7%. Other joints affected with OA may also benefit from this treatment.

Canine Platelet-Rich Plasma Systems: A Prospective Analysis

Objective

To quantitate key parameters of the platelet-rich plasma (PRP) product from five commercial canine PRP systems in healthy, adult canines.

Materials and Methods

A prospective study was performed from January 2013 to April 2014. Five commercial systems were analyzed using 10 healthy dogs per system.^1–5 Blood was obtained according to the manufacturer’s protocol for each system. The mean baseline whole blood platelet, RBC, WBC, neutrophil, monocyte, and lymphocyte concentrations were determined for each PRP system. All blood samples were processed according to the manufacturer’s protocols. The mean PRP product platelet, RBC, WBC, neutrophil, monocyte, and lymphocyte concentrations were determined for each PRP system. These values were then compared to the mean baseline values. Comparisons of mean whole blood and mean PRP product parameters were calculated using a paired t-test with significance established at p = 0.05.⁶

Results

Platelet concentration was significantly increased for System 1 (p = 0.0088) and System 3 (p < 0.0001), and was significantly decreased for System 2 (p < 0.0001). All five systems significantly decreased the red blood cell concentration (p < 0.0001 for each system comparison). Neutrophil concentration was significantly decreased for System 2, System 3, and System 4 (p < 0.0001 for each system comparison). Neutrophil concentration was significantly increased for System 5 (p = 0.0089).

Clinical Relevance

The systems with the highest platelet yield were System 1 and System 3. System 3 increased platelet concentration while significantly reducing the RBC and neutrophil concentrations. Further study is indicated to assess the efficacy of PRP therapy in canines, the efficacy of canine PRP systems, and the clinical applications for PRP therapy in dogs.