The effects of repeated intra-articular PRP injections on clinical outcomes of early osteoarthritis of the knee

Platelet-rich plasma intra-articular knee injections from open preparation techniques do not pose a higher risk of joint infection: A systematic review of 91 randomized controlled trials and 5914 injections

Purpose

To compare the infection rate of intraarticular platelet-rich plasma (PRP) knee injections between open and closed techniques in randomized controlled trials (RCTs) published in the last decade.

Methods

Following the Preferred Reporting Items for Systematic Reviews and Meta-Analyses guidelines, PubMed, Scopus and Virtual Health Library were accessed in October 2022 using the terms 'platelet-rich plasma', 'PRP', 'knee' and 'tibiofemoral' alone and in combination with Boolean operators AND/OR. RCTs published during the last 10 years evaluating PRP intra-articular knee injections were considered eligible. Studies were excluded if the kit/preparation technique was not described. Data were presented using individual studies' absolute values, totals, and pooled percentages. Publication bias was assessed using the ROBIS tool.

Results

Ninety-one studies met the predetermined eligibility criteria. Forty-one implemented a closed technique, while 50 were open. All studies implementing a closed technique disclosed their commercial kits. Only 16 studies (17.58%) failed to report joint infections. Among the studies reporting joint infections as outcomes, 30 implemented a closed technique with 1195 patients, 1921 intra-articular knee injections and 95.44% of patient follow-up. On the other hand, 45 of them implemented an open technique with 2290 patients, 3993 intra-articular knee injections and 97.07% of patient follow-up. No patient had a joint infection among the included studies. Thirty-three studies prepared their PRP in controlled environments (36.26%). Most studies did not report where the preparation occurred (48.35%). Only twelve studies disclosed using laminar flow during preparation (13.19%). The infection rate for both techniques was 0 per 1000 knee injections.

Conclusion

Open PRP preparation techniques do not pose a higher risk of joint infection and can lower manufacturing costs when appropriate facilities are available. However, PRP preparation setting and laminar flow implementation data are deficient, and minimal requirements for good manufacturing practices demand further studies while adhering to local and regional regulations.

Level of Evidence

Level I, systematic review of RCTs.

The Efficacy of Platelet-Rich Plasma Injection Therapy in Obese versus Non-Obese Patients with Knee Osteoarthritis: A Comparative Study

Background/Objectives: Obesity is a common comorbidity in knee osteoarthritis (KOA) patients. Platelet-Rich Plasma (PRP) injection therapy may mitigate KOA. To further clarify potential patient selection for PRP injection therapy, we compared the outcomes in patients with different body mass index (BMI). Methods: A total of 91 patients with mild to moderate KOA were treated with three intra-articular PRP injections at 10 to 14-day intervals. Range of motion (ROM), Western Ontario and McMaster Universities Osteoarthritis Index (WOMAC), and Visual Analogue Scale (VAS) were documented before and after the injections at 15 days, 6 months, 12 months, and at the last follow-up. Outcomes were compared between patients with a BMI over 30 kg/m2 (obese, n = 34) and under 30 kg/m2 (non-obese, n = 57). Results: Significant difference during the follow-up was detected in WOMAC score at the last follow-up favouring BMI under 30 group [17.8 ± 18.8 versus 10.5 ± 11.7, p = 0.023]. The odds ratio (OR) in BMI over 30 kg/m2 group for total knee arthroplasty was 3.5 (95% CI 0.3-40.1, p = 0.553), and OR for any arthroplasty was 7.5 (95% CI 0.8-69.8, p = 0.085) compared to non-obese patients. Conclusions: Obese patients benefitted from PRP injections in KOA but there is a minimal difference favouring non-obese patients in symptom alleviation in follow-up stages after 12 months. The risk of arthroplasty is higher for obese KOA patients.

There Is Wide Variation in Platelet-rich Plasma Injection Pricing: A United States Nationwide Study of Top Orthopaedic Hospitals

BACKGROUND

Demand for platelet-rich plasma (PRP) injections for osteoarthritis has dramatically increased in recent years despite conflicting evidence regarding its efficacy and highly variable pricing in the top orthopaedic centers in the United States, because PRP is typically not covered by insurance. A previous study investigating the mean price of PRP injections obtained information only from centers advertising online the availability of PRP injections. Thus, there is a need for further clarification of the overall availability and variability in cost of PRP injections in the orthopaedic community as well as an analysis of relevant regional demographic and hospital characteristics that could be associated with PRP pricing.

QUESTIONS/PURPOSES

Our study purposes were to (1) report the availability and price variation of knee PRP injections at top-ranked United States orthopaedic centers, (2) characterize the availability of pricing information for a PRP injection over the telephone, (3) determine whether hospital characteristics (Orthopaedic Score [ U . S. News & World Report measure of hospital orthopaedic department performance], size, teaching status, and rural-urban status) were associated with PRP injection availability and pricing, and (4) characterize the price variation, if it exists, of PRP injections in three metropolitan areas and individual institutions.

METHODS

In this prospective study, a scripted telephone call to publicly listed clinic telephone numbers was used to determine the availability and price estimate (amount to be paid by the patient) of a PRP injection for knee osteoarthritis from the top 25 hospitals from each United States Census region selected from the U.S. News & World Report ranking of best hospitals for orthopaedics. Univariable analyses examined factors associated with PRP injection availability and willingness to disclose pricing, differences across regions, and the association between hospital characteristics (Orthopaedic Score, size, teaching status, and rural-urban status) and pricing. The Orthopaedic Score is a score assigned to each hospital by U . S. News & World Report as a measure of hospital performance based partly on patient outcomes, with higher scores indicating better outcomes.

RESULTS

Overall, 87% (87 of 100) of respondents stated they offered PRP injections. Pricing ranged from USD 350 to USD 2815 (median USD 800) per injection, with the highest prices in the Northeast. The largest price range was in the Midwest, where more than two-thirds of PRP injections given at hospitals that disclosed pricing cost USD 500 to USD 1000. Of the hospitals that offered PRP injections, 68% (59 of 87) were willing to disclose price information over the telephone. PRP injection pricing was inversely correlated with hospital Orthopaedic Score (-3% price change [95% CI -5% to -1%]; p = 0.01) and not associated with any of the other hospital characteristics that were studied, such as patient population median income and total hospital expenses. An intracity analysis revealed wide variations in PRP pricing in all metropolitan areas that were analyzed, ranging from a minimum of USD 300 within 10 miles of metropolitan area B to a maximum of USD 1269 within 20 miles of metropolitan area C.

CONCLUSION

We found that although PRP injections are widely available, pricing continues to be a substantial financial burden on patients, with large price variability among institutions. We also found that if patients are willing to shop around in a metropolitan area, there is potential to save a meaningful amount of money.

CLINICAL RELEVANCE

As public interest in biologics in orthopaedic surgery increases, knowledge of its pricing should be clarified to consumers. The debated efficacy of PRP injections, combined with our findings that it is an expensive out-of-pocket procedure, suggests that PRP has limited cost-effectiveness, with variable, discrete pricing. As such, the price of PRP injections should be clearly disclosed to patients so they can make informed healthcare decisions.

Experts Achieve Consensus on a Majority of Statements Regarding Platelet-Rich Plasma Treatments for Treatment of Musculoskeletal Pathology

PURPOSE

To establish consensus statements on platelet-rich plasma (PRP) for the treatment of musculoskeletal pathologies.

METHODS

A consensus process on the treatment of PRP using a modified Delphi technique was conducted. Thirty-five orthopaedic surgeons and sports medicine physicians participated in these consensus statements on PRP. The participants were composed of representatives of the Biologic Association, representing 9 international orthopaedic and musculoskeletal professional societies invited due to their active interest in the study of orthobiologics. Consensus was defined as achieving 80% to 89% agreement, strong consensus was defined as 90% to 99% agreement, and unanimous consensus was indicated by 100% agreement with a proposed statement.

RESULTS

There was consensus on 62% of statements about PRP.

CONCLUSIONS

(1) PRP should be classified based on platelet count, leukocyte count, red blood count, activation method, and pure-plasma versus fibrin matrix; (2) PRP characteristics for reporting in research studies are platelet count, leukocyte count, neutrophil count, red blood cell count, total volume, the volume of injection, delivery method, and the number of injections; (3) the prognostic factors for those undergoing PRP injections are age, body mass index, severity/grade of pathology, chronicity of pathology, prior injections and response, primary diagnosis (primary vs postsurgery vs post-trauma vs psoriatic), comorbidities, and smoking; (4) regarding age and body mass index, there is no minimum or maximum, but clinical judgment should be used at extremes of either; (5) the ideal dose of PRP is undetermined; and (6) the minimal volume required is unclear and may depend on the pathology.

LEVEL OF EVIDENCE

Level V, expert opinion.

Current Progress of Platelet-Rich Derivatives in Cartilage and Joint Repairs

In recent years, several types of platelet concentrates have been investigated and applied in many fields, particularly in the musculoskeletal system. Platelet-rich fibrin (PRF) is an autologous biomaterial, a second-generation platelet concentrate containing platelets and growth factors in the form of fibrin membranes prepared from the blood of patients without additives. During tissue regeneration, platelet concentrates contain a higher percentage of leukocytes and a flexible fibrin net as a scaffold to improve cell migration in angiogenic, osteogenic, and antibacterial capacities during tissue regeneration. PRF enables the release of molecules over a longer period, which promotes tissue healing and regeneration. The potential of PRF to simulate the physiology and immunology of wound healing is also due to the high concentrations of released growth factors and anti-inflammatory cytokines that stimulate vessel formation, cell proliferation, and differentiation. These products have been used safely in clinical applications because of their autologous origin and minimally invasive nature. We focused on a narrative review of PRF therapy and its effects on musculoskeletal, oral, and maxillofacial surgeries and dermatology. We explored the components leading to the biological activity and the published preclinical and clinical research that supports its application in musculoskeletal therapy. The research generally supports the use of PRF as an adjuvant for various chronic muscle, cartilage, and tendon injuries. Further clinical trials are needed to prove the benefits of utilizing the potential of PRF.

Autologous microfragmented adipose tissue and leukocyte-poor platelet-rich plasma combined with hyaluronic acid show comparable clinical outcomes for symptomatic early knee osteoarthritis over a two-year follow-up period: a prospective randomized clinical trial

PURPOSE

The purpose of this prospective randomized clinical trial is to compare the clinical outcomes of three injections of leucocyte-poor platelet-rich plasma (LP-PRP) and hyaluronic acid (HA) to a single dose of autologous microfragmented adipose tissue (AMAT) in patients with mild osteoarthritis at a two-year follow-up.

METHODS

Eighty symptomatic knees in fifty patients (mean age: 62.38 ± 11.88 years) with Kellgren-Lawrence grade 0 to 2 osteoarthritis were non blinded, randomly allocated into two equal groups. Group 1 consisted of 40 knees that received autologous LP-PRP + HA; Group 2 consisted of 40 knees treated with a single dose of AMAT injection. The outcomes were measured by Tegner, Marx, Visual Analogue Scale (VAS) for pain, International Knee Documentation Committee, and Knee Injury and Osteoarthritis Outcome Score (KOOS) at 6 (T1), 12 (T2), and 24 (T3) months. Adverse events were recorded at each follow-up timepoint. To assess score differences among subjects of the same gender and age, a subgroup analysis was performed.

RESULTS

Both groups had significant clinical and functional improvement at 6, 12, and 24 months (p < 0.05). Comparing the two groups, the AMAT groups showed significantly higher pre-operative Marx score (3.35 ± 4.91 vs. 1.78 ± 3.91) and VAS score (5.03 ± 2.02 vs. 3.85 ± 1.68) (p < 0.05), higher VAS (3.89 ± 2.51 vs. 2.64 ± 2.00) at T2 and KOOS-ADL (79.60 ± 20.20 vs. 65.68 ± 23.62), and lower KOOS-Sports (50.30 ± 30.15 vs. 68.35 ± 30.39) at T3 (p < 0.05). No patient from either group had experienced major adverse effects. In the LP-PRP group 12 (30%) patients presented swelling, redness, and mild pain for one day after injection and two patients had synovitis for two days and required paracetamol and local ice. In AMAT group 5 (12.5%) patients had ecchymosis and bruising at the fat aspiration site for three days.

CONCLUSION

AMAT did not show significant superior clinical improvement compared with three LP-PRP combined with HA injections in terms of functional improvement at different follow-up points. Both procedures were safe with no major complications reporting good results at mid-term follow-up, improving knee function, pain, and quality of live regardless of age and gender.

LEVEL OF EVIDENCE

Level I-Prospective Randomized Clinical Trial.

Hypoxia Preconditioned Serum (HPS) Promotes Proliferation and Chondrogenic Phenotype of Chondrocytes In Vitro

Autologous chondrocyte implantation (ACI) for the treatment of articular cartilage defects remains challenging in terms of maintaining chondrogenic phenotype during in vitro chondrocyte expansion. Growth factor supplementation has been found supportive in improving ACI outcomes by promoting chondrocyte redifferentiation. Here, we analysed the chondrogenic growth factor concentrations in the human blood-derived secretome of Hypoxia Preconditioned Serum (HPS) and assessed the effect of HPS-10% and HPS-40% on human articular chondrocytes from osteoarthritic cartilage at different time points compared to normal fresh serum (NS-10% and NS-40%) and FCS-10% culture conditions. In HPS, the concentrations of TGF-beta1, IGF-1, bFGF, PDGF-BB and G-CSF were found to be higher than in NS. Chondrocyte proliferation was promoted with higher doses of HPS (HPS-40% vs. HPS-10%) and longer stimulation (4 vs. 2 days) compared to FCS-10%. On day 4, immunostaining of the HPS-10%-treated chondrocytes showed increased levels of collagen type II compared to the other conditions. The promotion of the chondrogenic phenotype was validated with quantitative real-time PCR for the expression of collagen type II (COL2A1), collagen type I (COL1A1), SOX9 and matrix metalloproteinase 13 (MMP13). We demonstrated the highest differentiation index (COL2A1/COL1A1) in HPS-10%-treated chondrocytes on day 4. In parallel, the expression of differentiation marker SOX9 was elevated on day 4, with HPS-10% higher than NS-10/40% and FCS-10%. The expression of the cartilage remodelling marker MMP13 was comparable across all culture conditions. These findings implicate the potential of HPS-10% to improve conventional FCS-based ACI culture protocols by promoting the proliferation and chondrogenic phenotype of chondrocytes during in vitro expansion.

The Epidemiology of Platelet-Rich Plasma Injections From 2010 to 2020 in a Large US Commercial Insurance Claims Database: A Recent Update

INTRODUCTION

The popularity of platelet-rich plasma (PRP) injections for the treatment of orthopaedic conditions has grown markedly. We sought to better define the trends in the usage of orthopaedic PRP injections across an insured US population over the past decade.

METHODS

The PearlDiver M91Ortho commercial administrative claims database was queried for all patients receiving PRP injections for orthopaedic conditions from 2010 through the first quarter of 2020 (Q1.2020). Trends in PRP use, reimbursement charges, demographics, joints injected, and administering physicians were assessed over time and reported as year-over-year (YOY) changes.

RESULTS

Over the study period, 14,096 unique patients had 17,759 orthopaedic PRP injections. The number of PRP injections administered had a YOY increase of 7.1% (144 injections/year, 95% confidence interval [CI] = 89 to 199, Ptrend = 0.0009). A YOY increase of 895% was observed in total nonsurgical charges ($683,974/yr, 95% CI 441,504 to 926,444, Ptrend = 0.0009). The median age of PRP recipients increased (YOY change = +0.6 years, 95% CI 0.4 to 0.8, Ptrend = 0.0005). Injections to the elbow (YOY change = -0.8%, 95% CI -0.10% to [-0.06%], Ptrend = 0.005) and foot/ankle (YOY change = -1.0%, 95% CI -1.4% to [-0.06%], Ptrend = 0.002) decreased, whereas hip (YOY change = +0.4%, 95% CI 0.2% to 0.6%, Ptrend = 0.019), knee (YOY change = +0.9%, 95% CI 0.3% to 1.2%, Ptrend = 0.016), and spine (YOY change = +0.2%, 95% CI 0.0% to 0.4%, Ptrend = 0.033) injections increased. PRP injections given by sports medicine orthopaedic surgeons (YOY change = +0.8%, 95% CI 0.6% to 1.2%, Ptrend <0.0001) increased over time, whereas those by general orthopaedic surgeons decreased (YOY change = -0.9, 95% CI -1.2 to [-0.6%], Ptrend = 0.001).

CONCLUSION

PRP injections quadrupled in prevalence from 2010 to Q1.2020, with a projected increase in annual usage in this data set of 66% by 2030. As greater evidence-based indications for PRP use are identified, more specialists and insurance providers may consider expanding their involvement in this growing field.

LEVEL OF EVIDENCE

III, retrospective cohort study.

Surgical Versus Non-Surgical Treatments for the Knee: Which Is More Effective?

Osteoarthritis is a degenerative joint disease that is extremely prevalent in society. It affects more than 25% of Americans above the age of 18 years. According to July 2020 publication by the Centers for Disease Control (CDC), osteoarthritis affects approximately 325 million Americans. One of the organs that is most affected by osteoarthritis is the knee. Over the years, we have developed non-surgical treatments, such as physical therapy (PT) and injections, and surgical treatments, such as total knee arthroplasty (TKA) and arthroscopic lavage, for knee osteoarthritis (KOA). If a patient fails with non-surgical options, which are tried first to avoid the risks of surgery, the patient may be considered for knee surgery. This article will investigate the different non-surgical options and TKA as treatment options for KOA based on current literature. The goal of this paper is to be a comprehensive resource for physicians and patients with KOA to make an informed decision. A systematic literature search was conducted using PubMed. The search terms were based on the type of treatments for KOA. To find articles that compared TKA to non-surgical treatments, the terms included "osteoarthritis", "total knee", and "non-surgical treatments," in combination. For other non-surgical treatments such as PT, weight reduction, and injections, a combination of the treatment, "osteoarthritis", and "knee" were included in the search. For the tier 1 process, any randomized controlled trials were included. Any case reports, observational studies, and cross-sectional studies were eliminated from the search. For the tier 2 review process, any articles that did not have relevance to the topic were eliminated after reading the abstracts of the articles. After review of the literature, the data seem to suggest that TKA with 12 weeks of non-surgical treatment improved pain and functionality of the knee more than just 12 weeks of non-surgical treatment when followed up at 12 and 24 months. However, non-surgical treatment before TKA delays the need for surgery. Supervised PT, either in a group or individual format, has been shown to delay TKA in 95% patients in the group that received PT at the end of one year. In addition, weight reduction has been shown as an effective strategy to improve pain and functionality in KOA patients, which decreases the urgency for surgery. Furthermore, platelet-rich plasma (PRP) injections have been shown to have long-term symptomatic relief for KOA compared to hyaluronic acid (HA) and corticosteroid injections. However, HA and corticosteroid injections are beneficial in treating KOA more than receiving no treatment. Physicians often have difficulty deciding whether to pursue conservative or surgical treatment for patients with KOA. The non-surgical treatments explored in this review - PT, injections, and weight reduction - can provide symptomatic relief and, in some cases, delay the need for surgical intervention. However, based on some randomized clinical trials mentioned in the article, patients receiving TKA have more relief, better quality of life, and improved functionality compared to non-surgical therapy. However, a critical review of this important field of debate shows that there are limited randomized controlled studies comparing the effectiveness of TKA and non-surgical treatments for KOA. We believe that this controversial topic needs further clinical investigation.

Osteoarthritis today: Lost in translation?

Osteoarthritis (OA) is a highly prevalent joint disease that is associated with pain, loss of function, and high direct and indirect economic costs. The current therapeutic options are inadequate, providing only a moderate symptom relief without the possibility of disease modification. While treatment options and personalized medicines are increasing for many complex diseases, OA drug development has been impeded by the advanced state of disease at the time of diagnosis and intervention, heterogeneity in both symptoms and rates of progression, and a lack of validated biomarkers and relevant outcome measures. This review article summarizes the OA landscape, including therapies in development as potential OA treatments, potential biomarkers undergoing evaluation by the US Food and Drug Administration, and a summary of current OA treatment guidelines, with a particular focus on the knee OA.

The Influence of Body Mass Index on Growth Factor Composition in the Platelet-Rich Plasma in Patients with Knee Osteoarthritis

BACKGROUND

An abnormally high body mass index is strongly associated with knee osteoarthritis. Usually, obese patients are excluded from clinical trials involving PRP intra-articular injections. Growth factors have been demonstrated to have a disease-modifying effect on KOA treatment, even though data on their influence on treatment effectiveness in obese patients are lacking.

PURPOSE

To prospectively compare the level of selected growth factors including transforming growth factor-b (TGF-β), epidermal growth factor (EGF), fibroblast growth factor, insulin-like growth factor-1 (IGF-1), platelet-derived growth factor (PDGF), vascular endothelial growth factor (VEGF), and fibroblast growth factor-2 (FGF-2) in platelet-rich plasma (PRP) in obese patients and patients with normal BMI.

METHODS

A total of 49 patients were included in the study according to inclusion and exclusion criteria. The groups strongly differed in body mass index (median values 21.6 vs. 32.15). Concentrations of growth factors were measured with an enzyme-linked immunosorbent assay. Statistical significance was determined with the Mann-Whitney U test. The compliance of the distribution of the results with the normal distribution was checked using the Shapiro-Wilk test separately for both groups.

RESULTS

There were no statistically significant differences in median marker levels between groups. Statistically significant Pearson correlations were observed between IGF-1 serum level and age (weak negative, r = -0.294, p = 0.041) and gender (moderate positive, r = 0.392, 0.005).

CONCLUSIONS

BMI does not influence the level of selected growth factors in patients with knee osteoarthritis. Obese and non-obese patients had similar compositions of PDGF, TGF-β, EGF, FGF-2, IGF-1, and VEGF. PRP can be used in both groups with similar effects associated with growth factors' influence on articular cartilage.

Intra-articular injections of platelet-rich plasma decrease pain and improve functional outcomes than sham saline in patients with knee osteoarthritis

PURPOSE

To compare the long-term clinical efficacy provided by intra-articular injections of either Pure Platelet-rich Plasma (P-PRP) or sham saline to treat knee osteoarthritis (KOA).

METHODS

This prospective, parallel-group, double-blind, multi-center, sham-controlled randomized clinical trial recruited participants with KOA from orthopedic departments at nine public hospitals (five tertiary medical centers, four secondary medical units) starting January 1, 2014, with follow-up completed on February 28, 2021. Participants were randomly allocated to interventions in a 1:1 ratio. Data were analyzed from March 1, 2021, to July 15, 2021. Three sessions (1 every week) of P-PRP or sham saline injected by physicians. The primary outcome was the Western Ontario and McMaster Universities Arthritis Index (WOMAC) at 3, 6, 12, 24, 60 months of follow-up. Secondary outcomes included the International Knee Documentation Committee (IKDC) subjective score, visual analogue scale (VAS) score, intra-articular biochemical marker concentrations, cartilage volume, and adverse events. Laboratory of each hospital analyzed the content and quality of P-PRP.

RESULTS

610 participants (59% women) with KOA who received three sessions of P-PRP (n = 308, mean age 53.91 years) or sham saline (n = 302, mean age 54.51 years) injections completed the trial. The mean platelet concentration in PRP is 4.3-fold (95% confidence interval 3.6-4.5) greater than that of whole blood. Both groups showed significant improvements in IKDC, WOMAC, and VAS scores at 1 month of follow-up. However, only the P-PRP group showed a sustained improvement in clinical outcome measurements at month 24 (P < 0.001). There were statistically significant differences between the P-PRP and sham saline groups in all clinical outcome measurements at each follow-up time point (P < 0.001). The benefit of P-PRP was clinically better in terms of WOMAC-pain, WOMAC-physical function and WOMAC-total at 6, 12, 24, and 60 months of follow-up. No clinically significant differences between treatments were documented in terms of WOMAC-stiffness at any follow-up. A clinically significant difference favoring P-PRP group against saline in terms of IKDC and VAS scores was documented at 6, 12, 24 and 60 months of follow-up. At 6 months after injection, TNF-α and IL-1β levels in synovial fluid were lower in the P-PRP group (P < 0.001). Tibiofemoral cartilage volume decreased by a mean value of 1171 mm³ in the P-PRP group and 2311 mm³ in the saline group over 60 months and the difference between the group was statistically significant (intergroup difference, 1140 mm³, 95% CI - 79 to 1320 mm³; P < 0.001).

CONCLUSIONS

In this randomized clinical trial of patients with KOA, P-PRP was superior to sham saline in treating KOA. P-PRP was effective for achieving at least 24 months of symptom relief and slowing the progress of KOA, with both P-PRP and saline being comparable in safety profiles.

Adjunctive platelet-rich plasma and hyaluronic acid injection after arthroscopic debridement in Kellgren-Lawrence grade 3 and 4 knee osteoarthritis

BACKGROUND

Osteoarthritis (OA) is the most common cause of pain and disability, predominantly affecting the knee. The current management of knee OA falls short of completely stopping disease progression, particularly in Kellgren-Lawrence (KL) grade 3 and 4 knee OA. As such, joint replacement is often recommended, although only 15%-33% of candidates accept it. Alternative therapeutic options are still needed to prevent the progression of joint damage and delay the need for knee arthroplasty.

AIM

To investigate the effect of adjunctive platelet rich plasma (PRP) and hyaluronic acid (HA) after arthroscopic debridement in KL grade 3 and 4 knee OA.

METHODS

This retrospective cohort study used the Western Ontario and McMaster Universities Osteoarthritis Index (WOMAC) score and WOMAC sub-scores (pain, stiffness, and function) to assess 21 patients, grouped according to medical record data of treatment received: Arthroscopic debridement (n = 7); arthroscopic debridement with PRP (n = 7); or arthroscopic debridement with HA (n = 7). WOMAC scores and sub-scores at baseline and at 3 mo and 5 mo posttreatment were recorded. The three-group data were statistically analyzed using the tests of paired t, one-way analysis of variance, and post hoc least significant difference.

RESULTS

All three treatment groups showed significant improvements in WOMAC score and sub-scores from before treatment to 3 mo and 5 mo after treatment. However, the arthroscopic debridement with PRP treatment group, in particular, showed a significantly lower WOMAC pain score than the group who received arthroscopic debridement alone at 5 mo after the procedure (P = 0.03).

CONCLUSION

Compared to arthroscopic debridement alone, adjunctive PRP after arthroscopic debridement significantly lessened the patients’ pain symptom.

Multiple platelet-rich plasma injections are superior to single PRP injections or saline in osteoarthritis of the knee: the 2-year results of a randomized, double-blind, placebo-controlled clinical trial

INTRODUCTION

The primary purposes of this study were to prove the efficacy of PRP injection therapy on knee pain and functions by comparing patients with mild to moderate OA with a placebo control group, and also to understand the effectiveness of multiple doses compared to a single dose. It was hypothesized that PRP would lead to more favorable results than the placebo at 1, 3, 6, 12 and 24 months after treatment.

MATERIALS AND METHODS

237 patients diagnosed with OA were randomly separated into 4 groups, who were administered the following: single dose of PRP (n: 62), single dose of sodium saline (NS) (n: 59), three doses of PRP (n: 63), and three doses of NS (n: 53). Clinical evaluations were made pre-treatment and at 1, 3, 6, 12 and 24 months post-treatment, using the Knee Injury and Osteoarthritis Result Score (KOOS), Kujala Patellofemoral Score, knee joint range of motion (ROM), measurements of knee circumference (KC), and mechanical axis angle (MAA) and a Visual Analog Scale (VAS) for the evaluation of pain.

RESULTS

The better score values in the groups were recorded at 3 and 6 months. Patients treated with PRP maintained better scores at 3, 6 and 12 months compared to the NS groups (p < 0.05). Multiple doses of PRP were seen to be more effective than single-dose PRP at 6 and 12 months (p < 0.05). At the end of 24 months, there was no significant score difference across all the groups. The most positive change in scores was found in stage 2 OA, and the most positive change in ROM was in stage 3 OA patients. In the PRP groups, KC decreased more at 1 and 6 months (p < 0.05). Compared to other age groups, patients aged 51-65 years scored better at 6 months (p < 0.05). A negative correlation was determined with MAA scores (r = - 0.508, p < 0.001).

CONCLUSION

In comparison to the placebo (NS), leukocyte-rich PRP treatment was determined to be effective in the treatment of OA. Multiple doses of PRP increase the treatment efficacy and duration. Of all the patients treated with PRP, the best results were obtained by patients aged 51-65 years, with lower MAA, and by K/L stage 2 OA patients.

STUDY DESIGN

Randomized controlled trial; Level of evidence, 1.

REGISTRATION

NCT04454164 (ClinicalTrials.gov identifier).

Microfragmented Adipose Tissue Versus Platelet-Rich Plasma for the Treatment of Knee Osteoarthritis: A Prospective Randomized Controlled Trial at 2-Year Follow-up

BACKGROUND

Intra-articular microfragmented adipose tissue (MF-AT) injections have been proposed for the treatment of knee osteoarthritis (OA).

PURPOSE

To compare a single injection of MF-AT or platelet-rich plasma (PRP) in terms of clinical outcomes and OA progression.

STUDY DESIGN

Randomized controlled trial; Level of evidence, 1.

METHODS

A total of 118 patients with symptomatic knee OA were randomized to receive a single intra-articular injection of MF-AT or PRP. Patients were evaluated before the injection and at 1, 3, 6, 12, and 24 months with the International Knee Documentation Committee (IKDC) subjective score, Knee injury and Osteoarthritis Outcome Score (KOOS) subscales, EuroQol visual analogue scale (EQ-VAS), EuroQol 5 dimensions (EQ-5D), and visual analogue scale (VAS) for pain. Primary outcomes were the IKDC subjective score and the KOOS pain subscore at 6 months. Knees were evaluated at baseline and at 6, 12, and 24 months with radiography and high-resolution magnetic resonance imaging (MRI) using the Whole-Organ Magnetic Resonance Imaging Score (WORMS).

RESULTS

Both MF-AT and PRP provided a statistically and clinically significant improvement up to 24 months. The improvement in the IKDC subjective score from baseline to 6 months was similar in both MF-AT (41.1 ± 16.3 to 57.3 ± 18.8) and PRP (44.8 ± 17.3 to 58.4 ± 18.1) groups (P < .0005). The improvement in the KOOS pain subscore from baseline to 6 months was similar in both the MF-AT (58.4 ± 15.9 to 75.8 ± 17.4) and PRP (63.5 ± 17.8 to 75.5 ± 16.1) groups (P < .0005). Overall, no differences were found between the MF-AT and PRP groups in terms of clinical outcomes, adverse events (18.9% and 10.9%, respectively), and failures (15.1% and 25.5%, respectively). Radiographic and MRI findings did not show changes after the injection. As a secondary outcome, more patients in the MF-AT group with moderate/severe OA reached the minimal clinically important difference for the IKDC score at 6 months compared with the PRP group (75.0% vs 34.6%, respectively; P = .005).

CONCLUSION

A single intra-articular injection of MF-AT was not superior to PRP, with comparable low numbers of failures and adverse events and without disease progression. No differences were found in clinical and imaging results between the 2 biological approaches.

The effectiveness of leucocyte-poor platelet-rich plasma injections on symptomatic early osteoarthritis of the knee: the PEAK randomized controlled trial

AIMS

Platelet-rich plasma (PRP) intra-articular injections may provide a simple and minimally invasive treatment for early-stage knee osteoarthritis (OA). This has led to an increase in its adoption as a treatment for knee OA, although there is uncertainty about its efficacy and benefit. We hypothesized that patients with early-stage symptomatic knee OA who receive multiple PRP injections will have better clinical outcomes than those receiving single PRP or placebo injections.

METHODS

A double-blinded, randomized placebo-controlled trial was performed with three groups receiving either placebo injections (Normal Saline), one PRP injection followed by two placebo injections, or three PRP injections. Each injection was given one week apart. Outcomes were prospectively collected prior to intervention and then at six weeks, three months, six months, and 12 months post-intervention. Primary outcome measures were Knee Injury and Osteoarthritis Outcome Score (KOOS) and EuroQol five-dimension five-level index (EQ-5D-5L). Secondary outcomes included visual analogue scale for pain and patient subjective assessment of the injections.

RESULTS

A total of 102 patients were recruited. The follow-up period was 12 months, at intervals of six weeks, 12 weeks, six months, and 12 months. KOOS-Total significantly improved in all groups at these time intervals compared to pre-injection. There was an improvement in EQ-5D-5L index scores in saline and single injection groups, but not in the multiple injection group. Comparison of treatment groups showed no additional beneficial effect of single or multiple PRP injections above that displayed in the saline injection group. Subjective patient satisfaction and recommendation of treatment received demonstrated a similar pattern in all the groups. There was no indication of superiority of either single or multiple PRP injections compared to saline injections.

CONCLUSION

There is no evidence that single or multiple PRP had any additional beneficial effect compared to saline injection up to 12 months, follow-up after treatment of early stage symptomatic OA of the knee. Cite this article: Bone Joint J 2022;104-B(6):663-671.

Platelet Rich Plasma Injections for Knee Osteoarthritis Treatment: A Prospective Clinical Study

Background: The aim of this prospective study was to evaluate the efficacy and safety of Platelet Rich Plasma (PRP) injections in patients affected by knee osteoarthritis (KOA). An autologous blood product containing a high percentage of various growth factors (GFs), cytokines and modulating factors as PRP has shown promising results in achieving this goal. Methods: One hundred and fifty-three patients (72 males, mean age 59.06 ± 8.78, range 40−81 years old) from January 2018 to January 2020 received three consecutive PRP injections and completed the follow ups. Western Ontario and McMaster University Osteoarthritis index (WOMAC), Knee society score (KSS) and Visual Analogic Scale (VAS) were evaluated before PRP injection (T0), one month (T1), three months (T2) and six months (T3) after the treatment. All patients underwent baseline and at 6 months MRI and X-ray evaluation. Results: A statistically significant VAS, KSS and WOMAC reduction emerged in the comparison between evaluations (p < 0.05), MRI demonstrated non-statistically significant improvement in cartilage thickness for both tibial plate and femoral plate (p = 0.46 and p = 0.33 respectively), and no radiographic changes could be seen in any patients. Conclusions: PRP injection represents a valid conservative treatment to reduce pain, improve quality of life and functional scores even at midterm of 6 months follow-up.

Double-Spin Leukocyte-Rich Platelet-Rich Plasma Is Predominantly Lymphocyte Rich With Notable Concentrations of Other White Blood Cell Subtypes

Purpose

To comprehensively characterize a double-spin leukocyte-rich platelet-rich plasma (LR-PRP) formulation and to compare it with whole blood (WB) by quantitatively assessing platelet and WB cell subtype concentrations in each.

Methods

Prospective human ex vivo analysis with 12 healthy adult men with ages ranging from 25 to 31 was performed in a controlled laboratory setting. The main outcome measure was the leukocyte profile of human LR-PRP.

Results

In LR-PRP, lymphocytes were the predominant WB cell type (11.94 ± 2.97 × 10³ cells/μL) followed by neutrophils (3.72 ± 1.28 × 10³ cells/μL). The mean cumulative percentage of granulocytes was 23% ± 8% and agranulocytes was 77% ± 18%. There was a significant difference observed between granulocyte and agranulocyte percentage within both WB (P = .004, [95% CI: (7%,31%)]) and LR-PRP (P < .0001, [95% CI: (42%,66%)]) groups. In addition, there was a significant difference observed between the WB and LR-PRP granulocyte percentages (P < .0001, [95% CI: (29%,43%)]) and between the WB and LR-PRP agranulocyte percentages (P < .0001, [95% CI: (30%,42%)]).

Conclusions

Our study found that LR-PRP is predominantly lymphocyte rich with notable concentrations of other WB cell subtypes, including neutrophils, monocytes, eosinophils, basophils, and large unstained cells. While these subtypes are not routinely reported, they may play a role in modulating the local inflammatory environment. We also found significant differences in WB cell subtype concentrations between WB and LR-PRP.

Clinical Relevance

PRP has been routinely used in many clinical practices without clear indications for its use and lacks standardization in its formulation. This study provides a comprehensive characterization of a broadly used PRP, LR-PRP, and further characterizes subtypes of WBC cells present in LR-PRP that have not been previously reported. Comprehensively reporting these subtypes in clinical trials of PRP is crucial to understanding how these cells participate in PRP’s therapeutic potential. This type of data can help standardize future PRP formulations and improve patient outcomes.

Role of Triple Injection Platelet-Rich Plasma for Osteoarthritis Knees: A 2 Years Follow-Up Study

PURPOSE

To assess the clinical outcomes of intra-articular Platelet-rich plasma (PRP) injection in knee osteoarthritis (OA) at 2 year follow-up.

METHODS

This was a prospective interventional study. 68 cases (105 knees) with Kellgren-Lawrence (KL) grades I, II and III knee OA received 3 intra-articular injections of PRP 1 month apart. The cases were followed up for 2-years. Outcomes were measured using Western Ontario and McMaster Universities Arthritis Index (WOMAC) score and Visual analog scale (VAS) scores.

RESULTS

The mean age was 51.7 years. 18 knees had KL grade I, 55 had grade II and 32 had grade III OA. The mean pre-treatment VAS score decreased significantly at 1 year (mean difference - 5.3, p = 0.003) and 2 year follow-up (mean difference - 6, p = 0.007). The mean pre-treatment WOMAC score decreased significantly at 1 year (mean difference - 45.9, p = 0.011) and at 2 year (mean difference - 52.4, p = 0.009). The WOMAC and VAS scores improved significantly from baseline to final follow-up across all KL grades (p = 0.001 and 0.001, 0.009 and 0.007, 0.021 and 0.017 for WOMAC and VAS across KL grade I, II and III, respectively). There was no significant differences in WOMAC and VAS scores between three KL grades at final follow-up (p = 0.17 and 0.09, respectively), although the baseline scores had significant difference (p = 0.001 for both VAS and WOMAC) with worse scores in higher KL grades. The variables like age, sex, BMI, KL grade, baseline VAS and baseline WOMAC did not predict the final VAS and WOMAC scores.

CONCLUSION

Triple injection of intra-articular PRP given one month apart significantly relieves the symptoms of knee OA till 2 years in KL grade I, II and III. The improvement in symptoms at 2-year follow-up did not differ across different KL grades.

Single versus multi-dose intra-articular injection of platelet rich plasma in early stages of osteoarthritis of the knee: A single-blind, randomized, superiority trial

Objectives

This study aims to compare the effectiveness of single, double, and triple doses of intra-articular (IA) platelet rich plasma (PRP) in early stages of osteoarthritis (OA) of the knee.

Patients and methods

This single-blind, randomized, superiority trial included a total of 180 knees of 90 patients (22 males, 68 females; mean age: 47.9 years; range, 36 to 60 years) with bilateral OA knee of Kellgren-Lawrence Grade 1-2 between May 2017 and December 2018. The patients were randomized (30 in each group) to receive single, double, or triple doses of IA PRP (two weeks apart in repeat injections). The outcome measures were Visual Analog Scale, International Knee Documentation Committee Score, Knee Injury and Osteoarthritis Outcome Score, and Tegner Lysholm Knee Score. The assessor of outcome was blinded. The scores were collected before intervention and at six weeks, three months, six months, and one year after the intervention.

Results

All patients completed the study. All three groups were comparable with respect to demographic and disease characteristics. All four scores were comparable among the three groups before intervention and at six weeks, three months, and six months. However, at one-year follow-up, the three-dose group showed superiority to others in terms of all four scores. All three groups showed improvement until six months and deterioration thereafter, which was only marginal in the three-dose group. All groups showed a statistically significant improvement of scores compared to baseline scores at one year. There were no major complications.

Conclusion

The IA administration of three doses of PRP yields superior outcome to single and double doses at the end of one year. Repeat doses are probably needed to sustain the benefit achieved at one year.

Evaluation of the influence of platelet-rich plasma (PRP), platelet lysate (PL) and mechanical loading on chondrogenesis in vitro

The aim of this work is to investigate the capability of PRP as an adjuvant therapy to autologous chondrocyte implantation (ACI) in combination with multi-axial load with respect to cartilage regeneration. Articular cartilage shows poor repair capacity and therapies for cartilage defects are still lacking. Well-established operative treatments include ACI, and growing evidence shows the beneficial effects of PRP. Platelets contain numerous growth factors, among them transforming growth factor beta (TGF-β). Dynamic mechanical loading is known to be essential for tissue formation, improving extracellular matrix (ECM) production. For our ACI model monolayer expanded human chondrocytes were seeded into polyurethane scaffolds and embedded in fibrin (hChondro), in PRP-Gel (PRP), or in fibrin with platelet lysate (PL), which was added to the media once a week with a concentration of 50 vol%. The groups were either exposed to static conditions or multi-axial forces in a ball-joint bioreactor for 1 h per day over 2 weeks, mimicking ACI under physiological load. The culture medium was collected and analyzed for glycosaminoglycan (GAG), nitrite and transforming growth factor beta 1 (TGF-β1) content. The cell-scaffold constructs were collected for DNA and GAG quantification; the expression of chondrogenic genes, TGF-β and related receptors, as well as inflammatory genes, were analyzed using qPCR. Loading conditions showed superior chondrogenic differentiation (upregulation of COL2A1, ACAN, COMP and PRG4 expression) than static conditions. PRP and PL groups combined with mechanical loading showed upregulation of COL2A1, ACAN and COMP. The highest amount of total TGF-β1 was quantified in the PL group. Latent TGF-β1 was activated in all loaded groups, while the highest amount was found in the PL group. Load increased TGFBR1/TGFBR2 mRNA ratio, with further increases in response to supplements. In general, loading increased nitrite release into the media. However, over time, the media nitrite content was lower in the PL group compared to the control group. Based on these experiments, we conclude that chondrogenic differentiation is strongest when simulated ACI is performed in combination with dynamic mechanical loading and PRP-gel or PL supplementation. An inflammatory reaction was reduced by PRP and PL, which could be one of the major therapeutic effects. Loading presumably can enhance the action of TGF-β1, which was predominantly activated in loaded PL groups. The combination of load and PRP represents an effective and promising synergy concerning chondrocyte-based cartilage repair.

Platelets and Adipose Stroma Combined for the Treatment of the Arthritic Knee

Knee osteoarthritis (OA) leads to significant pain and disability, prompting new cell-based injections to lessen the symptoms. Biological therapies such as autologous microfragmented adipose tissue (AMAT) and a stromal vascular fraction (SVF) are a common source for harvesting mesenchymal and progenitor cells. Platelet-rich plasma (PRP) is associated with cytokines and growth factors. Recent studies have reported good clinical outcomes with AMAT, SVF, and PRP in knee osteoarthritis treatment. However, the preparation, processing, and application technique are vital to achieving satisfactory results. Many studies have examined outcomes after AMAT, SVF, or PRP injection, with encouraging results. Still, there is a lack of studies describing a technique that combines both methods, the timing, and the amount of SVF or PRP injected. This technical note's objective was to describe a standardized new technique composed of platelet and adipose stroma to treat knee osteoarthritis (OA) and the processing method.

Novel assessment of leukocyte-rich platelet-rich plasma on functional and patient-reported outcomes in knee osteoarthritis: a pilot study

Background: Leukocyte-rich platelet-rich plasma (LR-PRP) has demonstrated to be beneficial for patients with knee osteoarthritis (KOA); however, reliable objective end points to accurately assess its therapeutic effects is lacking. Aim: To investigate the efficacy of LR-PRP as assessed by functional and patient-reported outcomes at early time points (6 weeks). Materials & methods: We conducted a prospective cohort study in 12 patients with diagnosed KOA (Kellgren Lawrence score of II-III), who underwent a single ultrasound-guided LR-PRP injection. Results: There was significant improvement in timed up and go, pain and quality of life scales and balance parameters. There were nonsignificant improvements in range of motion and gait parameters. Conclusion: LR-PRP demonstrates efficacy in meaningful end points for functional and patient-reported outcomes at early time points in patients with KOA.

Cultured Horse Articular Chondrocytes in 3D-Printed Chitosan Scaffold With Hyaluronic Acid and Platelet Lysate

Three-dimensional (3D) printing has gained popularity in tissue engineering and in the field of cartilage regeneration. This is due to its potential to generate scaffolds with spatial variation of cell distribution or mechanical properties, built with a variety of materials that can mimic complex tissue architecture. In the present study, horse articular chondrocytes were cultured for 2 and 4 weeks in 3D-printed chitosan (CH)-based scaffolds prepared with or without hyaluronic acid and in the presence of fetal bovine serum (FBS) or platelet lysate (PL). These 3D culture systems were analyzed in terms of their capability to maintain chondrocyte differentiation in vitro. This was achieved by evaluating cell morphology, immunohistochemistry (IHC), gene expression of relevant cartilage markers (collagen type II, aggrecan, and Sox9), and specific markers of dedifferentiated phenotype (collagen type I, Runx2). The morphological, histochemical, immunohistochemical, and molecular results demonstrated that the 3D CH scaffold is sufficiently porous to be colonized by primary chondrocytes. Thereby, it provides an optimal environment for the colonization and synthetic activity of chondrocytes during a long culture period where a higher rate of dedifferentiation can be generally observed. Enrichment with hyaluronic acid provides an optimal microenvironment for a more stable maintenance of the chondrocyte phenotype. The use of 3D CH scaffolds causes a further increase in the gene expression of most relevant ECM components when PL is added as a substitute for FBS in the medium. This indicates that the latter system enables a better maintenance of the chondrocyte phenotype, thereby highlighting a fair balance between proliferation and differentiation.

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.

Efficacy of different platelet-rich plasma injections in the treatment of mild-moderate knee osteoarthritis: A systematic review and meta-analysis

AIMS

This study aimed to compare the efficacy of different numbered sets of injections of platelet-rich plasma (PRP) in the treatment of mild-moderate knee osteoarthritis (OA).

METHODS

A comprehensive search in three databases of Cochrane Library, Embase, and PubMed was conducted to find relevant articles that investigated the efficacy of PRP injection therapies in the treatment of mild-moderate knee OA through August 2020. The Western Ontario and McMaster Universities Osteoarthritis Index (WOMAC) pain and function scores were the primary outcomes and visual analogue scale (VAS) was the secondary outcome. The pooled improvements amongst different injection therapies were compared.

RESULTS

No significant differences in the improvement of WOMAC pain were observed amongst 1-, 2-, and 3-injection therapies at 3- (P = .26) and 6-month (P = .13) follow-ups. For a 12-month follow-up, the difference amongst different therapies reached borderline significance (P = .05) in which 3-injection therapy had a significantly better improvement than 2-injection therapy (P = .02) and reached borderline significance compared with 1-injection (P = .07). However, no significant differences in the improvement of VAS scores were observed amongst three injection therapies for all the follow-up visits (P > .05). For WOMAC function score, 3-injection therapy performed significantly better than 1-injection (P < .00001) or 2-injection therapy (P < .0001) only at 12-month follow-up visit.

CONCLUSIONS

Our results demonstrated that 3-injection therapy of PRP in the treatment of mild-moderate knee OA had the best efficacy in pain relief and function improvement compared with 1- and 2-injection therapies.

A Prospective Study Comparing Leukocyte-Poor Platelet-Rich Plasma Combined with Hyaluronic Acid and Autologous Microfragmented Adipose Tissue in Patients with Early Knee Osteoarthritis

The objective of this study was to compare the clinical efficacy of repeated doses of leucocyte-poor platelet-rich plasma (LP-PRP) plus hyaluronic acid (HA) to a single dose of autologous microfragmented adipose tissue (AMAT) injections in patients with early osteoarthritis (OA) symptoms. Eighty knees in 50 patients (mean age: 61.3 years) were randomly allocated into two equal groups in a nonblinded design and prospectively followed for 12 months. Group 1 received three intra-articular injections (1 month apart) using autologous LP-PRP+HA. Group 2 received a single dose of AMAT injection. Outcomes were measured by PROMs Tegner, Marx, visual analog scale, and Knee Injury and Osteoarthritis Outcome Score (KOOS) at 6 and 12 months. Both groups had significant clinical and functional improvement at 6 and 12 months. The differences between groups were statistically significant in Tegner score and KOOS symptoms (both P < 0.05) at 6 months in group 2. The test with statistically significant differences (P < 0.05) at 12 months was Tegner (P < 0.001), with group 2 having a higher median than group 1. LP-PRP+HA and AMAT lead to clinical and functional improvement at 6 and 12 months. AMAT showed better clinical results in Tegner and KOOS symptoms at 6 months and Tegner at 12 months. Understanding which therapy offers the most benefits with the least risk can significantly improve the quality of life for millions of people affected by OA. Long-term randomized controlled studies are needed to verify differences in efficacy.

Platelet-Rich Plasma versus Corticosteroid Intra-Articular Injections for the Treatment of Trapeziometacarpal Arthritis: A Prospective Randomized Controlled Clinical Trial

Various systematic reviews have recently shown that intra-articular platelet-rich plasma (IA-PRP) can lead to symptomatic relief of knee osteoarthritis for up to 12 months. There exist limited data on its use in small joints, such as the trapeziometacarpal joint (TMJ) or carpometacarpal joint (CMCJ) of the thumb. A prospective, randomized, blind, controlled, clinical trial of 33 patients with clinical and radiographic osteoarthritis of the TMJ (grades: I-III according to the Eaton and Littler classification) was conducted. Group A patients (16 patients) received 2 ultrasound-guided IA-PRP injections, while group B patients (17 patients) received 2 ultrasound-guided intra-articular methylprednisolone and lidocaine injections at a 2-week interval. Patients were evaluated prior to and at 3 and 12 months after the second injection using the visual analogue scale (VAS) 100/100, shortened Disabilities of the Arm, Shoulder, and Hand Questionnaire (Q-DASH), and patient's subjective satisfaction. No significant differences between the baseline clinical and demographic characteristics of the 2 groups were identified. After 12 months' follow-up, the IA-PRP treatment has yielded significantly better results in comparison with the corticosteroids, in terms of VAS score (P = 0.015), Q-DASH score (P = 0.025), and patients' satisfaction (P = 0.002). Corticosteroids offer short-term relief of symptoms, but IA-PRP might achieve a lasting effect of up to 12 months in the treatment of early to moderate symptomatic TMJ arthritis.

Intra-articular injection with Autologous Conditioned Plasma does not lead to a clinically relevant improvement of knee osteoarthritis: a prospective case series of 140 patients with 1-year follow-up

Background and purpose - Platelet-rich plasma (PRP) is broadly used in the treatment of knee osteoarthritis, but clinical outcomes are highly variable. We evaluated the effectiveness of intra-articular injections with Autologous Conditioned Plasma (ACP), a commercially available form of platelet-rich plasma, in a tertiary referral center. Second, we aimed to identify which patient factors are associated with clinical outcome. Patients and methods - 140 patients (158 knees) with knee osteoarthritis (Kellgren and Lawrence grade 0-4) were treated with 3 intra-articular injections of ACP. The Knee Injury and Osteoarthritis Outcome Score (KOOS), pain (Numeric Rating Scale; NRS), and general health (EuroQol 5 Dimensions; EQ5D) were assessed at baseline and 3, 6, and 12 months' follow-up. The effect of sex, age, BMI, Kellgren and Lawrence grade, history of knee trauma, and baseline KOOS on clinical outcome at 6 and 12 months was determined using linear regression. Results - Mean KOOS increased from 37 at baseline to 44 at 3 months, 45 at 6 months, and 43 at 12 months' follow-up. Mean NRS-pain decreased from 6.2 at baseline to 5.3 at 3 months, 5.2 at 6 months, and 5.3 at 12 months. EQ5D did not change significantly. There were no predictors of clinical outcome. Interpretation - ACP does not lead to a clinically relevant improvement (exceeding the minimal clinically important difference) in patients suffering from knee osteoarthritis. None of the investigated factors predicts clinical outcome.

Osteo-core Plasty: A Minimally Invasive Approach for Subchondral Bone Marrow Lesions of the Knee

"Bone marrow lesion" (BML) is a common term used to describe the presence of fluid in the bone marrow. Although various pathologies can cause BMLs seen on magnetic resonance imaging, in this Technical Note we focus on treating the lesions associated with osteoarthritis in the knee joint. The role of the subchondral bone in transferring loads within the knee joint, as well as in cartilage homeostasis, is well established. In addition, cartilage and subchondral bone are increasingly considered as an osteochondral unit, rather than as 2 separate structures. Knee osteoarthritis, along with insufficiency fracture, is one of the main indications for the treatment of painful BMLs. Nowadays, there is a growing interest in this field, and new approaches are being developed. Our technique can be defined as a surgical procedure aimed directly at pathology within the subchondral bone and is named "osteo-core plasty." It consists of 2 parts: The first is decompression of bone marrow to decrease intraosseous pressure, and the second is administration of bone marrow aspirate concentrate for better healing potential and bone autograft to deliver supportive tissue. It should be noted that the cause of BMLs must be known before this kind of treatment is performed.

Efficacy of Autologous Conditioned Serum (ACS), Platelet-Rich Plasma (PRP), Hyaluronic Acid (HA) and Steroid for Early Osteoarthritis Knee: A Comparative Analysis

BACKGROUND

Intra-articular injection therapy constituting corticosteroids, viscosupplements and blood-derived products are considered to have a key role in non-operative management of osteoarthritis knee. While corticosteroids and viscosupplements have proven short-term efficacy in early osteoarthritis; orthobiologics are gaining increased attention in osteoarthritis management. The aim of present study was thus to compare two commonly used biologics (platelet-rich plasma/PRP and autologous conditioned serum/ACS) to each other and to established therapies.

METHODS

After required institutional clearances, all patients presenting with early primary osteoarthritis knee who had failed initial conservative management and received only unilateral knee injection were included. Patients in the PRP group were compared to the other groups (comprising the HA/hyaluronic acid group, steroid group, and a matched cohort who had been administered ACS for the same indication earlier). Clinical outcome was evaluated using the Western Ontario and McMaster Universities Arthritis Index (WOMAC) questionnaire and Visual Analogue scale (VAS) pre-injection and at 6 months.

RESULTS

ACS and PRP did not have any significant difference in terms of either WOMAC score (p = 0.154) or VAS score at 6 months (p = 0.850). The scores for both these orthobiologics were better than the control groups (HA group and Steroid group). Between the two control groups, HA group had better VAS scores as compared to the Steroid group (p = 0.008).

CONCLUSION

The clinical outcomes following intra-articular injection of ACS and PRP are better than controls (HA and steroid), but a difference between the two orthobiologics could not be demonstrated.

LEVEL OF EVIDENCE

3b.

Platelet lysate reduces the chondrocyte dedifferentiation during in vitro expansion: Implications for cartilage tissue engineering

In vitro studies have demonstrated that platelet lysate (PL) can serve as an alternative to platelet-rich plasma (PRP) to sustain chondrocyte proliferation and production of extracellular matrix components in chondrocytes. The present study aimed to evaluate the direct effects of PL on equine articular chondrocytes in vitro in order to provide a rationale for in vivo use of PL. An in vitro cell proliferation and de-differentiation model was used: primary articular chondrocytes isolated from horse articular cartilage were cultured at low density under adherent conditions to promote cell proliferation. Chondrocytes were cultured in serum-free medium, 10% foetal bovine serum (FBS) supplemented medium, or in the presence of alginate beads containing 5%, 10% and 20% PL. Cell proliferation and gene expression of relevant chondrocyte differentiation markers were investigated. The proliferative capacity of cultured chondrocytes, was sustained more effectively at certain concentrations of PL as compared to that with FBS. In addition, as opposed to FBS, PL, particularly at percentages of 5% and 10%, could maintain the gene expression pattern of relevant chondrocyte differentiation markers. In particular, 5% PL supplementation showed the best compromise between chondrocyte proliferation capacity and maintenance of differentiation. The results of the present study provide a rationale for using PL as an alternative to FBS for in vitro expansion of chondrocytes for matrix-assisted chondrocyte implantation, construction of 3D scaffolds for tissue engineering, and treatment of damaged articular cartilage.

Lack of standardization among clinical trials of injection therapies for knee osteoarthritis: a systematic review

Purpose: Osteoarthritis (OA) of the knee is a debilitating, expensive, and prevalent disease, and interest in the non-surgical management of knee OA has grown recently. Our objective was to systematically assess the level of heterogeneity among all clinical trials and published studies regarding injections for knee osteoarthritis, in terms of treatment of interest, outcomes evaluated, and time points of outcome assessment. Methods: The Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines were utilized to review all published studies and publically available clinical trials from 1 January 2013 to 3 May 2019evaluating intra-articular injections to treat knee OA. Their treatment group and specifics of methodology were scrutinized and compared. Results: 84 published studies and 114 clinical trials were included. Within the 84 published studies, the most common injection treatment studied was hyaluronic acid [N = 22; 26.2%]. In total, 29 different injection treatment groups were utilized. The most common time point for patient evaluation post-injection was 6 months (N = 33 studies; 50.0%), and ranged from 1 week (N = 9 studies; 13.6%) to 7 years (N = 1 study; 1.5%). The most common patient-reported outcome (PRO) measure assessed in the included studies was Western Ontario and McMaster's University Osteoarthritis Index (WOMAC) [N = 44 studies; 66.7%]. For the 114 clinical trials identified, the most common injection treatment studied is platelet-rich plasma in isolation (N = 19; 16.7%). Forty-two different injection treatment types/groups are utilized. The most common PRO measure assessed was WOMAC (N = 77 trials; 67.5%). Overall there were 34 different patient-reported outcome measures used. Conclusions: Research efforts to find the most effective injection therapy for knee OA continue with a tremendous number of injection therapies still being evaluated. Substantial heterogeneity exists in these completed and ongoing trials in terms of patient demographics, OA grades, outcome scores and relatively short-term timing of assessments, with no clear standardization of testing protocol despite proposing to answer the same clinical question. We recommend that studies of this genre going forward be standardized in terms of outcome measures and longer-term follow-up time points, and should incorporate functional assessment evaluations and imaging studies.

Meta-analysis Comparing Platelet-Rich Plasma vs Hyaluronic Acid Injection in Patients with Knee Osteoarthritis

PURPOSE

The purpose of this meta-analysis was to compare platelet-rich plasma (PRP) and hyaluronic acid (HA) in patients with knee osteoarthritis (KOA).

METHODS

Randomized controlled trials (RCTs) comparing the use of PRP and HA in KOA patients were retrieved from each database from the establishment date to April 2018. Outcome measurements were the Western Ontario and McMaster Universities Arthritis Index (WOMAC), visual analog scale (VAS), International Knee Documentation Committee, and Lequesne Index scores and adverse events. The pooled data were evaluated with Review Manager 5.3.5.

RESULTS

Fifteen RCTs (N = 1,314) were included in our meta-analysis. The present meta-analysis indicated that PRP injections reduced pain more effectively than HA injections in patients with KOA at six and 12 months of follow-up, as evaluated by the WOMAC pain score; the VAS pain score showed a significant difference at 12 months. Moreover, better functional improvement was observed in the PRP group, as demonstrated by the WOMAC function score at three, six, and 12 months. Additionally, PRP injections did not display different adverse event rates compared with HA injections.

CONCLUSION

In terms of long-term pain relief and functional improvement, PRP injections might be more effective than HA injections as a treatment for KOA. The optimal dosage, the timing interval and frequency of injections, and the ideal treatment for different stages of KOA remain areas of concern for future investigations.

Platelet-rich plasma injections delay the need for knee arthroplasty: a retrospective study and survival analysis

PURPOSE

The biological action of platelet-rich plasma (PRP) could slow down the osteoarthritis progression, resulting in a delay of joint replacement. This work aims to evaluate the ability of PRP to postpone and even avoid knee replacement in patients with knee osteoarthritis (KOA) analyzing, on the one hand, the time of delay and on the other hand the percentage of patients without undergoing total knee arthroplasty (TKA).

METHODS

A retrospective analysis and a survival analysis were conducted. KOA patients who underwent knee replacement between 2014 and 2019 and previously received PRP infiltrations were included in the retrospective analysis. Regarding survival analysis, KOA patients who received PRP treatment during 2014 and with follow-up until 2019 were included. The dates of PRP treatment and TKA, KOA severity, age of the patients, number of PRP cycles, and administration route were analyzed.

RESULTS

This work included 1084 patients of which 667 met the inclusion criteria. 74.1% of the patients in the retrospective study achieved a delay in the TKA of more than 1.5 years, with a median delay of 5.3 years. The survival analysis showed that 85.7% of the patients did not undergo TKA during the five year follow-up. The severity degree, age, PRP cycles, and administration route had a statistically significant influence on the efficacy of PRP in delaying surgery.

CONCLUSION

These data suggest that the application of PRP in KOA patients is a treatment that could delay TKA, although further studies are needed to understand and improve this therapy.

Intra-articular Injection of Pure Platelet-Rich Plasma Is the Most Effective Treatment for Joint Pain by Modulating Synovial Inflammation and Calcitonin Gene-Related Peptide Expression in a Rat Arthritis Model

BACKGROUND

Platelet-rich plasma (PRP) has emerged as a treatment for osteoarthritis (OA). However, the effect that leukocyte concentrations in PRP have on OA remains unclear.

PURPOSE

To clarify the optimal PRP formulation for OA treatment by comparing pure PRP, leukocyte-poor PRP (LP-PRP), and leukocyte-rich PRP (LR-PRP) in a rat arthritis model.

STUDY DESIGN

Controlled laboratory study.

METHODS

Knee arthritis was induced bilaterally in male Wistar rats with intra-articular injections of monosodium iodoacetate (MIA) on day 0. Rats were randomly assigned to 1 of 3 treatment groups (pure PRP, LP-PRP, and LR-PRP). On day 1, allogenic PRP was injected into the right knee of rats and phosphate-buffered saline was injected into the left knee as a control. Weight distribution on the hindlimbs was measured for 14 days to assess pain behavior. Rats were euthanized at day 5 or 14 for histological assessment of synovial tissue and cartilage. Immunohistochemical staining of calcitonin gene-related peptide (CGRP) and α-smooth muscle actin was performed to determine the mechanism of pain relief induced by the PRP preparations.

RESULTS

In all groups, PRP increased the load-sharing ratio on PRP-injected knees, with pure PRP eliciting the largest effect among the 3 kinds of PRP (P < .05). Structural changes in the synovial tissue were significantly inhibited in the pure-PRP group compared with the control group after both 5 and 14 days (P < .001 and P = .025, respectively), whereas no significant difference was found between the control, LP-PRP, and LR-PRP groups. An inhibitory effect on cartilage degeneration was observed only in the pure-PRP group on day 14. Pure PRP also significantly inhibited expression of CGRP-positive nerve fibers in the infrapatellar fat pad compared with the other groups (P < .05).

CONCLUSION

In an MIA-induced arthritis model, pure PRP injection was the most effective treatment for reduction of pain-related behavior and inhibition of synovial inflammation and pain sensitization.

CLINICAL RELEVANCE

PRP formulations should be optimized for each specific disease. This study shows the superiority of pure PRP for treatment of arthritis and joint pain.

Enhanced vascularization and biocompatibility of rat pancreatic decellularized scaffolds loaded with platelet-rich plasma

The ultimate goal of pancreatic tissue engineering is to create a long-lived substitute organ to treat diabetes. However, the lack of neovascularization and the occurrence of immune response limit the efficacy of tissue-engineered pancreas after in vivo transplantation. Platelet-rich plasma (PRP) is an autologous platelet concentrate containing a large number of growth factors and immunoregulatory factors. The aim of this study was to evaluate rat pancreatic decellularized scaffold (PDS) loaded with PRP for vascularization, host inflammatory response and macrophage polarization in an animal model. The study results indicated that compared to PDS, PRP-loading PDS exhibited the enhanced mechanical properties and released growth factors in a slow and sustained manner to supplement the loss of growth factors during decellularization. In vitro, human umbilical vein endothelial cells (HUVECs) were seeded in PDS and PRP-loading PDS, and cultured in the circular perfusion system. When compared with PDS, PRP-loading PDS significantly promoted the colonization, proliferation and pro-angiogenic genes expression of cells on scaffolds. In vivo, PDS loaded with PRP then re-endothelialized with HUVECs were implanted subcutaneously in rats, which enhanced the angiogenesis of scaffolds, inhibited the host inflammatory response, and induced the polarization dominated by pro-regenerative M2 macrophages that also facilitated tissue vascular regeneration. Thus, the re-endothelialized PRP-loading PDS may represent a promising bioengineered pancreas with sustained vascularization and excellent biocompatibility.

Platelet Concentrates in Musculoskeletal Medicine

Platelet concentrates (PCs), mostly represented by platelet-rich plasma (PRP) and platelet-rich fibrin (PRF) are autologous biological blood-derived products that may combine plasma/platelet-derived bioactive components, together with fibrin-forming protein able to create a natural three-dimensional scaffold. These types of products are safely used in clinical applications due to the autologous-derived source and the minimally invasive application procedure. In this narrative review, we focus on three main topics concerning the use of platelet concentrate for treating musculoskeletal conditions: (a) the different procedures to prepare PCs, (b) the composition of PCs that is related to the type of methodological procedure adopted and (c) the clinical application in musculoskeletal medicine, efficacy and main limits of the different studies.

Fire acupuncture for mild to moderate knee osteoarthritis: a protocol for a randomized controlled pilot trial

BACKGROUND

Knee osteoarthritis (KOA) is one of the most common bone and joint diseases. As one of the main non-drug therapies, acupuncture is widely used to treat KOA, although the evidence for its efficacy is inconclusive. The objective of this pilot trial is to clarify the clinical efficacy and safety of fire acupuncture in the treatment of mild to moderate KOA and to provide high-quality data for further research.

METHODS/DESIGN

This study is a prospective randomized controlled pilot trial in which 120 patients with mild to moderate KOA will be randomly allocated in equal proportions to a fire acupuncture group or a general acupuncture group. They will receive acupuncture for six sessions over 2 weeks. The primary end point is success rate, which will be calculated based on the change from baseline of the pain and function scores in the Western Ontario and McMaster Universities Osteoarthritis Index at 4 weeks. Secondary end points include the proportion of patients achieving clinical improvement based on: (1) the OMERACT-OARSI responder criteria, (2) levels of matrix metalloproteinase 3, interleukin 1β, and tumor necrosis factor α in blood, and (3) a subjective efficacy evaluation from patients.

TRIAL REGISTRATION

Chinese Clinical Trial Registry, ChiCTR1800019162. Registered on 29 October 2018.

Cell Therapy-a Basic Science Primer for the Sports Medicine Clinician

PURPOSE OF REVIEW

The emergence of cell-based therapies has brought much excitement to the field of orthopedic sports medicine. However, the significant inconsistency of reporting has led to the poor understanding, misinformation, and false expectations for patients and clinicians alike. In this paper, we aim to clarify the available cell-therapy treatments and summarize some of the latest research.

RECENT FINDINGS

Although this technology is in early development, our understanding of cell biology has grown significantly over the last decade. Furthermore, it is becoming evident that tissue specificity may play a significant role in determining the effectiveness and overall clinical benefit attributed to cell therapy. Cell therapy is an emerging field with tremendous potential for clinically significant benefit. However, in its current state, clinical application of these treatments is limited by federal regulations, variability in formulation, and limited understanding of the biologic activity of various cell formulations.

Single-dose intra-articular corticosteroid injection prior to platelet-rich plasma injection resulted in better clinical outcomes in patients with knee osteoarthritis: A pilot study

BACKGROUND

The synergistic and protective effect of platelet-rich plasma (PRP) added to methlyprednisolone (MP) has been demonstrated via in-vitro studies. However, there is no report in the literature about this issue.

OBJECTIVE

The aim of this study was to evaluate clinical outcomes of intra-articular (IA) MP injection prior to PRP injection in comparison with single-dose MP and PRP injections alone in patients with knee osteoarthritis (OA).

METHODS

The treatment groups were "PRP group" (n= 37) who underwent single-dose IA PRP injection, "PRP + MP group" (n= 40) who underwent MP injection one week prior to single-dose PRP injection, and "MP group" (n= 38) who underwent single-dose MP injection. Visual Analog Scale (VAS) and The Western Ontario and McMaster Universities Arthritis Index (WOMAC) scores were applied at first admission and at 1st, 3rd, 6th, and 12th month follow-ups.

RESULTS

At the end of the 1st month, WOMAC score in PRP + MP group was significantly lower than PRP group. At the 3rd month, WOMAC score in PRP + MP group was significantly lower than PRP and MP groups. At the 6th month, VAS and WOMAC score in PRP + MP group was significantly lower than MP group. At the end of the 12th month, no significant difference was observed among three groups in VAS and WOMAC scores.

CONCLUSION

According to our results, IA MP injection prior to PRP injection resulted in significantly better clinical outcomes compared to PRP and MP injections alone in patients who had mild to moderate knee OA.

Comparison of platelet-rich plasma vs hyaluronic acid injections in patients with knee osteoarthritis: A protocol for a systematic review and meta-analysis

BACKGROUND

Knee osteoarthritis (KOA) is a progressive joint disease involving intraarticular and periarticular structures. In recent years, there has been increasing interest in the use of autologous growth factors, such as intraarticular injections of platelet-rich plasma (PRP), to treat KOA. It is necessary to update the research and reevaluate the efficacy and safety of PRP to provide up-to-date evidence for KOA management. Therefore, we provide a protocol for a systematic review of PRP for KOA.

METHODS

The aim of this study was to retrieve papers on the topic of PRP treatment for KOA in electronic databases including PubMed, Embase, and the Cochrane Library. The search will include studies that were published from the time the databases were established until April 2018. The entire process will include study selection, data extraction, risk of bias assessment, and meta-analyses.

RESULTS

The literature will provide a high-quality analysis of the current evidence supporting PRP for KOA based on various comprehensive assessments including the Western Ontario and McMaster Universities Osteoarthritis Index, visual analog scale scores, International Knee Documentation Committee scores, Lequesne index scores, and adverse events.

CONCLUSION

This proposed systematic review will provide up-to-date evidence to assess the effect of PRP treatment for patients with KOA.

PROSPERO REGISTRATION NUMBER

CRD42018108825.

Combination treatment of captopril and prazosin to treat patients with gestational hypertension

Gestational hypertensive disorder is a complication of pregnancy, which adversely affects mother-child health. Captopril and prazosin are two agents that are frequently applied for the treatment of patients with gestational hypertension. However, the cooperative efficacy of captopril and prazosin has been not investigated in a previous study. In the present study, the comprehensive treatment of captopril and prazosin for the treatment of patients with gestational hypertension was investigated. A total of 324 patients with gestational hypertension were recruited to analyze the therapeutic effects of captopril and prazosin in patients with gestational hypertension. The duration of the treatment, dose-limiting toxicities and maximum tolerated dose of captopril and prazosin were examined in this cohort. Furthermore, the levels of blood pressure and proteinuria were also examined in patients with gestational hypertension who received treatment with captopril and/or prazosin with placebo as a control. Serum levels of vasodilation-converting enzyme and α-adrenergic receptor were also examined prior to and during the 4-week post-treatment period. It was observed that the most common treatment-emergence adverse events were hypertension and proteinuria following 4-week treatments. The data revealed that captopril or prazosin treatments significantly ameliorated gestational hypertension and symptoms compared with placebo (P<0.01). Notably, the combination of captopril and prazosin treatments significantly ameliorated hypertension and proteinuria and reduced the expression levels of vasodilation-converting enzyme and α-adrenergic receptor (all P<0.01), which contributed to beneficial effects on complications and blood coagulation mechanism compared with either captopril or prazosin treatment. In conclusion, the present clinical study indicated that combination treatment of captopril and prazosin exhibited more efficient outcomes than the single agent by improving gestational hypertension, indicating that a comprehensive therapeutic regimen of captopril and prazosin may be a potential clinical opinion for patients with gestational hypertension.