Introduction. Platelet Rich Plasma (PRP) is widely used in clinical praxis. Especially the effects in musculoskeletal repair studies are diverse and an augmentation of healing processes stays questionable. However, diverse cell culture studies reported promising results, which seem not be transferable into the clinical situation. We therefore performed a cell culture study which better reflects the clinical situation: the autologous stimulation of human tendon cells with PRP. Materials and Methods. Human tenocyte-like cells (hTLCs) from 24 donors (12 male/female) with supraspinatus tendon tears were isolated and characterized. The donors were grouped into 4 groups according to their age (</> 65 years) and sex. During follow up, approximately 2.5 years after initial surgery, the patients donated blood for PRP preparation (Ethic vote and written informed consent). Growth factors and platelets were quantified and the effect of autologous stimulation of the hTLCs was measured by analysis of cell proliferation, Collagen I synthesis and expression of Collagen I, III and Osteocalcin. Results. The platelet concentration for the 4 groups was between 3.6–4.5 × 10. 5. platelets/µl (reference level: 1.5–3×10. 5. platelets/µl blood). PRP contained high amounts of IGF-1, lower amounts of TGF-β1 and PDGF-AB. PDGF-AB concentration significantly correlated with platelet concentration and the TGF-β1 concentration. The amounts of BMP-7 and −12 were underneath the detection limits of the assays. Cell proliferation was positively affected by PRP exposure when compared to controls (2% FCS and 10% FCS) (p<0.05). However, the expression and synthesis of Collagen I was significantly reduced compared to controls. Collagen III expression was partly increased, while Osteocalcin expression was not affected. Discussion. PRP is a source of growth factors such as IGF-1, TGF-β and PDGF-AB. It has a high potential to stimulate cell proliferation, which might have a positive effect in clinical applications. However, the decreased expression and synthesis of Collagen I, the most important Collagen in the tendon, might explain the, to date, less satisfactory clinical results. PRPs might have their potential in chronic situation with pain reducing function rather than in acute healing situations. Further studies are necessary to better understand these mechanisms

Introduction and Objective. Platelet-Rich-plasma (PRP) has been used in combination with stem cells, from different sources, with encouraging results both in vitro and in vivo in osteochondral defects management. Adipose-derived Stem Cells (ADSCs) represents an ideal resource for their ease of isolation, abundance, proliferation and differentiation properties into different cell lineages. Furthermore, Stem Cells in the adipose tissue are more numerous than from other sources. Aim of this study was to evaluate the potential of ADSCs in enhancing the effect of arthroscopic mesenchymal stimulation combined with infiltration of PRP. Materials and Methods. The study includes 82 patients. 41 patients were treated with knee arthroscopy, Steadman microfractures technique and intraoperative PRP infiltration, Group A. In the Group B, 41 patients were treated knee arthroscopy, Steadman microfractures and intraoperative infiltration of PRP and ADSCs (Group B). Group A was used as a control group. Inclusion criteria were: Age between 40 and 65 years, Outerbridge grade III-IV chondral lesions, Kellegren-Lawrence Grade I-II. Patient-reported outcome measures (PROMs) evaluated with KOOS, IKDC, VAS, SF-12 were assessed pre-operatively and at 3 weeks, 6 months, 1-year post-operative. 2 patients of Group A and 3 patients of Group B, with indication of Puddu plate removal after high tibial osteotomy (HTO), underwent an arthroscopic second look, after specific informed consent obtained. On this occasion, a bioptic sample was taken from the repair tissue of the chondral lesion previously treated with Steadman microfractures. Results. PROMs showed statistically significant improvement (p <0.05) with comparable results in both groups. The histological examination of the bioptic samples in Group B showed a repair tissue similar to hyaline cartilage, according to the International Cartilage Repair Society (ICRS) Visual Histological Assessment Scale. In Group A, the repair tissue was fibrocartilaginous. Conclusions. According to the PROMs and the histological results, showing repair tissue after Steadman microfractures qualitatively similar to hyaline cartilage, the combination of ADSCs and PRP could represent an excellent support to the arthroscopic treatment of focal chondral lesions and mild to moderate osteoarthritis

We investigated the effect of Platelet Rich Plasma (PRP) in tendon healing. The aim was to assess the effect of an application of PRP on angiogenesis and immunohistochemical expression of TGF-b1 and IGF-I during tendon healing. We used a patellar tendon defect model after resecting its central portion. 48 skeletally mature New Zealand White rabbits were divided into the respective group and each group they were randomised into controls and PRP treated cases. The rabbits were sacrificed at weekly intevals and histological and immunohistological assessments were performed. The results showed a faster healing rate, increased vascularity, and higher expression of the growth factors in the PRP group. We conclude that the mixture of growth factors present in PRP gel improved the rate and quality of tendon healing

Introduction. Whilst most cases of plantar fasciitis can be resolved with existing conservative established treatment options, a few intractable cases can be difficult to resolve. New biologic treatments have been proposed for a variety of soft tissue tendon problems. We evaluated the results of PRP in the treatment of recalcitrant chronic cases of plantar fasciitis. Methods. Patients with plantar fasciitis that had not responded to a minimum of 8 months standard conservative management (eccentric stretching, physiotherapy, cortisone injection, night splints) were offered PRP therapy. The injection into the tender spot at the proximal plantar fascial insertion was performed in theatre as a day case. Roles Maudsley (RM) scores, Visual analogue scores (VAS) for pain, AOFAS scores and ‘would have injection again’ were collated pre-operatively, at three and six months. Results. Prospective data was collected on 39 patients (44 heels – 15 males, 24 females; mean age 51 years, range 25–79 years). No complications were noted. At six months review RM score improved from 3.8 to 2.5 (p<0.001), VAS improved from 7.7 to 4.2 (p<0.001) and AOFAS improved from 61 to 82 (p<0.001). 21 patients had complete relief of symptoms on 3 months review. 25 patients were very satisfied with the clinical improvement and would have the injection again. Whilst there was a slight improvement in scores from 3 to 6 months, this was not significant. 3 patients with bilateral injections on the same sitting did not improve, though 2 patients with bilateral injections on separate sittings did improve. Conclusion. In this series of chronic intractable cases, PRP injection produced a 64% satisfaction rate from patients. The procedure was safe with no reported complications. The authors feel PRP for plantar fasciitis may have some role in treatment and merits further study with a prospective randomised trial

Aims. The present study investigates the effectiveness of platelet-rich plasma (PRP) gel without adjunct to induce cartilage regeneration in large osteochondral defects in a rabbit model. Methods. A bilateral osteochondral defect was created in the femoral trochlear groove of 14 New Zealand white rabbits. The right knees were filled with PRP gel and the contralateral knees remained untreated and served as control sides. Some animals were killed at week 3 and others at week 12 postoperatively. The joints were harvested and assessed by Magnetic Resonance Observation of Cartilage Repair Tissue (MOCART) MRI scoring system, and examined using the International Cartilage Repair Society (ICRS) macroscopic and ICRS histological scoring systems. Additionally, the collagen type II content was evaluated by the immunohistochemical staining. Results. After 12 weeks post-surgery, the defects of the PRP group were repaired by hyaline cartilage-like tissue. However, incomplete cartilage regeneration was observed in the PRP group for three weeks. The control groups showed fibrocartilaginous or fibrous tissue, respectively, at each timepoint. Conclusion. Our study proved that the use of PRP gel without any adjuncts could successfully produce a good healing response and resurface the osteochondral defect with a better quality of cartilage in a rabbit model. Cite this article: Bone Joint Res 2021;10(3):192–202

Platelet Rich Plasma (PRP) has shown to be a general stimulation for repair and 1 year results showed promising success percentages. To determine the effectiveness of PRP compared with corticosteroid injections in patients with chronic lateral epicondylitis with a two-year follow-up. A double-blind randomized controlled trial was conducted between May 2006 and January 2008. The trial was conducted in two Dutch teaching hospitals. 100 patients with chronic lateral epicondylitis were randomly assigned to a leucocyte-enriched PRP group (n=51) or in the corticosteroid group (n=49). Randomization and allocation to the trial group were carried out by a central computer system. Patients received either a corticosteroid injection or an autologous platelet concentrate injection through a peppering needling technique. The primary analysis included Visual Analogue Scale (VAS) pain scores and Disabilities of the Arm, Shoulder, and Hand Outcome (DASH) scores. The PRP group was more often successfully treated than the corticosteroid group (p<.0001). Success was defined as a reduction of 25% on VAS or DASH scores without a re-intervention after 2 years. When baseline VAS and DASH scores were compared with the scores at 2 years follow-up, both groups significantly improved across time (intention-to-treat principle). However, the DASH scores of the corticosteroid group returned back to baseline levels, while the PRP significantly improved (as-treated principle). There were no complications related to the use of PRP. Treatment of patients with chronic lateral epicondylitis with PRP reduces pain and increases function significantly, exceeding the effect of corticosteroid injection even after a follow-up of two years. Future decisions for application of PRP for lateral epicondylitis should be confirmed by further follow-up from this trial and should take into account possible costs and harms as well as benefits

Following the recognition of platelet rich plasma (PRP) as an interventional procedure by NICE, patients who had failed standard conservative treatment for chronic elbow tendinitis and referred for surgery were recruited prospectively into a PRP injection study. 52 patients at Torbay Hospital, Devon, UK received PRP injections in 18 months and 37 had a minimum of 6 months follow up. The outcomes in these patients are summarised. There were 16 males and 21 females. 30 had tennis elbow and 7 had golfers elbow. All patients had their symptoms for a minimum of 6 months and had failed to improve with standard conservative treatment. 2 had a failed outcome from previous tennis elbow release surgery. The PRP injections were carried out under ultrasound guidance after correlating the tender spot with neovascularisation on flow Doppler. 31 patients had a single injection; the other 21 patients had 2 injections. Quick DASH score and patients own self-satisfaction was used to measure outcome. 18 patients (48%) were discharged by 6 months. DASH score worsened in 7 patients (19%) and 2 of these patients opted to have surgery, which had no benefit either. No complications were observed with the use of PRP. Overall, by using PRP injections, surgery was avoided in 35 patients (95%) at 18 months and nearly half of the patients were discharged from follow up by 6 months

Introduction. Ostochondral lesion of the knee is a common cause of chronic knee pain. Arthroscopic treatment with subcondral microfracture is a widespread technique leading to noticeable improvement of knee function and pain. To improve the effectiveness of this treatment options, we thought to add intra (PRF) or post-operative (PRP) growth factors. Platelet rich plasma (PRP) is obtained by centrifugation of the blood to produce a plasma with high concentration of platelets and growth factors. This latter represents a promising method to manage degenerative cartilage lesion and can be used postoperatively to improve clinical results of patients treated arthroscopically. Platelet Rich Fibrin (PRF) has been presented as a second-generation platelet concentrate, and it is used intraoperatively to cover the microfracuteres’ holes. No literature was found about using of PRF intraoperative in association with arthroscopic microfracture technique. The aim of this study is to compare clinical outcomes of the treatment of knee osteochondral lesion using arthroscopic microfracture technique alone or in association with PRF Intraoperative application using “Vivostat” system or with PRP “ReGen Lab” postoperative injection. Patients & Methods. 90 patients with clinical and radiographic evidence of osteochondral lesion of the medial or lateral compartment of the knee were enrolled. All patients received arthroscopic debridement and Microfractures and were randomised into 3 groups: 30 patients received microfractures and intraoperative PRF “Vivostat” injection(Group A), 30 patients received microfracture and 3 intra-articular injections of 5.5 mL PRP “Regen”(Group B), 30 patients received microfracture only. IKDC, KOOS and VAS score were administered to all patients before starting the treatment, at 1, 6 and 12 months from the end of the management. Results. Patients who received microfracture and PRF intraoperative application provided the best outcomes, showing a significant higher clinical scores (P<0.001) compared to the other two groups. Patients underwent PRP postoperative administration reported significant higher score than those undergoing arthroscopic microfracture alone (P<0.005), but lesser than Intraoperative PRF group at 6 months and 1 year follow up. Discussion/Conclusion. Treatment of osteochondral lesions of the knee using microfracture technique significantly improved functional and pain scores from the pre- to postoperatively time in the overall cohort. Intraoperative application of PRF shows significantly better outcome than postoperative PRP injections. However, additional treatment with intra-articular PRP injection as an adjunct to microfracture technique may offer better clinical outcomes over microfracture technique alone

Aims

The aim of this study was to prepare a scoping review to investigate the use of biologic therapies in the treatment of musculoskeletal injuries in professional and Olympic athletes.

Aims

The use of biologics in the treatment of musculoskeletal injuries in Olympic and professional athletes appears to be increasing. There are no studies which currently map the extent, range, and nature of existing literature concerning the use and efficacy of such therapies in this arena. The objective of this scoping review is to map the available evidence regarding the use of biologics in the treatment of musculoskeletal injuries in Olympic and professional sport.

Lateral epicondylitis, or ’tennis elbow’, is a common condition that usually affects patients between 35 and 55 years of age. It is generally self-limiting, but in some patients it may continue to cause persistent symptoms, which can be refractory to treatment. This review discusses the mechanism of disease, symptoms and signs, investigations, current management protocols and potential new treatments.

Cite this article: Bone Joint J 2013;95-B:1158–64.

Aims. To determine whether platelet-rich plasma (PRP) injection improves outcomes two years after acute Achilles tendon rupture. Methods. A randomized multicentre two-arm parallel-group, participant- and assessor-blinded superiority trial was undertaken. Recruitment commenced on 28 July 2015 and two-year follow-up was completed in 21 October 2019. Participants were 230 adults aged 18 years and over, with acute Achilles tendon rupture managed with non-surgical treatment from 19 UK hospitals. Exclusions were insertion or musculotendinous junction injuries, major leg injury or deformity, diabetes, platelet or haematological disorder, medication with systemic corticosteroids, anticoagulation therapy treatment, and other contraindicating conditions. Participants were randomized via a central online system 1:1 to PRP or placebo injection. The main outcome measure was Achilles Tendon Rupture Score (ATRS) at two years via postal questionnaire. Other outcomes were pain, recovery goal attainment, and quality of life. Analysis was by intention-to-treat. Results. A total of 230 participants were randomized, 114 to PRP and 116 to placebo. Two-year questionnaires were sent to 216 participants who completed a six-month questionnaire. Overall, 182/216 participants (84%) completed the two-year questionnaire. Participants were aged a mean of 46 years (SD 13.0) and 25% were female (57/230). The majority of participants received the allocated intervention (219/229, 96%). Mean ATRS scores at two years were 82.2 (SD 18.3) in the PRP group (n = 85) and 83.8 (SD 16.0) in the placebo group (n = 92). There was no evidence of a difference in the ATRS at two years (adjusted mean difference -0.752, 95% confidence interval -5.523 to 4.020; p = 0.757) or in other secondary outcomes, and there were no re-ruptures between 24 weeks and two years. Conclusion. PRP injection did not improve patient-reported function or quality of life two years after acute Achilles tendon rupture compared with placebo. The evidence from this study indicates that PRP offers no patient benefit in the longer term for patients with acute Achilles tendon rupture. Cite this article: Bone Joint J 2022;104-B(11):1256–1265

There are a number of patients in whom hip preservation surgery is not indicated as they have developed signs of early osteoarthritis, and nor can they have a hip replacement as they are too early in the disease process. The use of PRP in OA of the hip has not been studied systematically and this study concisely collates all the available data in the use of PRP in Hip OA. This systematic review and meta-analysis aimed to assess intra-articular platelet-rich plasma as a therapeutic intervention for hip osteoarthritis, including the duration of efficacy, influence of dose and composition of PRP, and the incidence of adverse effects. We performed literature searches on the MEDLINE, EMBASE, CINHAL, WEB OF SCIENCE, COCHRANE and SCOPUS databases, and PRSIMA guidelines were followed. Data was pooled using random effects meta-analysis. We assessed quality of the included studies using the Methodological Index for Non-Randomised Studies (MINORS) instrument, with an additional assessment for Randomised Controlled Trials with the Revised Cochrane risk-of-bias tool for randomized trials (RoB 2). Eight studies were included in the analysis, with data from a total of 331 patients. PRP significantly reduced pain compared to baseline at multiple timepoints, with the greatest effect at 1–2mo follow-up. PRP only significantly improved function at the 1–2mo follow-up. A significantly larger reduction in pain was achieved with a single injection or PRP compared to multiple injections, a total injected dose of PRP <15mL compared to ≥15mL or using a leukocyte-poor PRP preparation compared to leukocyte-rich PRP. There were no lasting adverse effects. Low and moderate quality evidence suggests that PRP reduces pain and improves function at endpoint compared to baseline. Moderate quality evidence suggests a larger reduction in pain is achieved with a single injection of PRP compared to multiple injections, and low quality evidence attributes a larger reduction of pain with a total injected dose of PRP <15mL compared to ≥15mL or using leukocyte-poor PRP compared to leukocyte-rich PRP

Abstract. Introduction. This study aimed to assess the effect of PRP on knee articular cartilage content (thickness and/or volume) and establish if there is a correlation between changes in cartilage and clinical outcomes in patients with knee osteoarthritis. Methodology. A systematic review was performed following the Cochrane methodology. Studies were included if they reported on cartilage content with MRI or Ultrasound before and after the injection. A random-effects model meta-analysis was performed. Results. 11 studies (n=786) from 1,453 records met the inclusion criteria, with five (n=444) being RCTs. The PRP treatment protocol varied widely. Follow-up ranged from 6–12 months. Eight studies reported increase in cartilage content in the PRP group as compared to control (four showing significant difference). In meta-analysis: PRP treatment was not associated with a significant increase in cartilage thickness in medial and lateral femoral condyle, or in the overall cartilage content (4 studies, n=187, Hedges’ g: 0.079; 95%CI: 0.358-0.516; p=0.723). Meta-analysis of 3 RCTs (n=112) showed no significant difference in increasing cartilage content overall with PRP injections compared with no PRP (Hedges’ g: 0.217; 95%CI: -0.177 – 0.611; P=0.281). There was no correlation between changes in cartilage and clinical outcomes following PRP treatment. Conclusion. Treatment of knee osteoarthritis with PRP is not associated with a significant increase in articular cartilage content and any effect on cartilage is not associated with better clinical outcomes. A multi-centre, adequately powered RCT, with a standardized preparation / administration protocol assessing long-term effect of PRP in knee osteoarthritis is needed to guide clinical care

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

Background. Disability and slow return to sport and work after tendon rupture are major challenges. Platelet Rich Plasma (PRP) is an autologous supraphysiological concentration of platelets from whole blood that has demonstrated positive cellular and physiological effects on healing in laboratory conditions but evidence from adequately powered robust clinical trials is lacking. We aimed to determine the clinical efficacy of PRP for treatment of acute Achilles tendon rupture. Methods. In a placebo-controlled, participant- and assessor-blinded, trial at 19 NHS hospitals we randomly assigned 230 adults starting acute Achilles rupture non-surgical management to PRP injection or dry-needle insertion (placebo) to the rupture gap under local anaesthetic. Patients with confounding or contraindicated concurrent medical conditions were excluded. The primary outcome was muscle-tendon function, assessed by the limb symmetry index (LSI, uninjured limb/injured limb × 100, higher scores better) of the work (Joules) performed during the heel-rise endurance test at 24 weeks. Secondary outcomes were: Achilles Tendon Rupture Score (ATRS, 0–100, higher scores better), quality of life (SF-12), pain, and goal attainment. Trial registration: ISRCTN54992179. Results. Participants were aged mean 46 years and 57 (25%) were female. 103/114 (90%) of the PRP group and all (n=116) in the placebo group received allocated treatment. At 24 weeks, mean LSI was 34.4 for the PRP group and 38.8 for placebo (adjusted mean difference −4.4 95% CI −11.2 to 2.5, n=201) and ATRS was mean 65.2 PRP vs 65.8 (adjusted mean difference −0.6, 95% CI −4.9 to 3.7, n=224). There were no differences between groups in the other secondary outcomes. Conclusion. We found no evidence of PRP efficacy for improving muscle-tendon function or patient-reported recovery after acute Achilles tendon rupture. Our findings challenge the increasing global use of PRP for acute tendon injury and indicate that robust evaluations are required in other applications

Background. The PATH-2 trial found no evidence of a benefit of Platelet Rich Plasma (PRP) injection versus a placebo after Achilles tendon rupture (ATR) at six-months. ATR often leave longer-term functional deficiencies beyond six-months. This study aim is to determine if PRP affect tendon functional outcomes at two-years after rupture. Study design. Randomised multi-centre two-arm parallel-group, participant- and assessor-blinded, superiority trial. Methods. Adults with acute ATR managed non-surgically were recruited in 19 UK hospitals from 2015 to 2019. Exclusions were insertion or musculotendinous injuries, leg injury or deformity, diabetes, haematological disorder, corticosteroids and anticoagulation therapy. Participants were randomised via an online system 1:1 to PRP or placebo. Primary outcome was Achilles Tendon Rupture Score (ATRS) at two-years. Secondary outcomes were pain, Patient-Specific Functional Scale (PSFS), SF-12 and re-rupture. Assessors were blinded. Intention-to-treat and Compliance Average Causal effects (CACE) analyses were carried out. Consistency of effects across subgroups age, BMI, smoking and gender were assessed using Forest plots. Pearson's correlation was used to explore ATRS correlation with blood and growth factors. Results. 216/230 (94%) participants completed the 6-months follow-up were contacted. 182/216 (84%) completed the two-year follow-up. Participants were aged mean 46 (SD 13.0), 57 female/159 male. 96% received the allocated intervention. Two-years ATRS scores were 82.2 (SD 18.3) in the PRP group (n=85) and 83.8 (SD 16.0) in the placebo group (n=92). There was no evidence of a difference in the two-years ATRS (adjusted-mean difference −0.752 95%CI −5.523 to 4.020, p=0.757), or in any secondary outcome, and no re-rupture between at two-years. Neither PRP cellular or growth factors correlated with the two-year ATRS. Conclusion. PRP did not improve patient-reported function or quality of life two-years after acute Achilles tendon rupture, compared with placebo, indicating that PRP offers no patient benefit in the longer term

Platelet-rich plasma (PRP) has been demonstrated to benefit a variety of disciplines. But there exists heterogeneity in results obtained due to lack of standardization of the preparation protocols employed in them. We aim to identify and standardize a preparation protocol for PRP with maximum recovery of platelets to obtain reproducible results across studies. Blood samples were collected from 20 healthy volunteers. The double spin protocol of PRP preparation was analyzed for variables such as centrifugal acceleration, time, and volume of blood processed and final product utilized. The final PRP prepared was investigated for platelet recovery, concentration, integrity, and viability. We noted maximum platelet recovery (86-99%) with a mean concentration factor of 6-times baseline, with double centrifugation protocol at 100xg and 1600xg for 20 minutes each. We also noted that 10 ml of blood in a 15 ml tube was the ideal volume of blood to be processed to maximize platelet recovery. We demonstrated that the lower 1/3rd is the ideal volume to be utilized for clinical application. We did not note a loss of integrity or viability of the platelets in the final product from the above-said protocol. Preparation of PRP by the double spin protocol of 10 ml of blood at 100xg and 1600xg for 20 minutes each in a 15ml tube and using the lower 1/3rd of the final product demonstrated consistent high platelet recovery (86-99%) and concentration (6x) without disturbing the platelet integrity or viability

There is good scientific rationale to support the use of growth factors to promote musculoskeletal tissue regeneration. However, the clinical effectiveness of platelet-rich plasma (PRP) and other blood-derived products has yet to be proven. Characterization and reporting of PRP preparation protocols utilized in clinical trials for the treatment of musculoskeletal disease is highly inconsistent, and the majority of studies do not provide sufficient information to allow the protocols to be reproduced. Furthermore, the reporting of blood-derived products in orthopaedics is limited by the multiple PRP classification systems available, which makes comparison of results between studies challenging. Several attempts have been made to characterize and classify PRP; however, no consensus has been reached, and there is lack of a comprehensive and validated classification. In this annotation, we outline existing systems used to classify preparations of PRP, highlighting their advantages and limitations. There remains a need for standardized universal nomenclature to describe biological therapies, as well as a comprehensive and reproducible classification system for autologous blood-derived products. Cite this article: Bone Joint J 2019;101-B:891–896

Degenerative disc disease, associated to low back pain, afflicts more than 50% of humans, and represents a major healthcare problem, especially for the pathology initiation. Current treatments range from conservative strategies to more invasive surgical techniques, such as disc removal and vertebral fusion. In the Intervertebral Disease (IVD) the nucleus pulposus (NP) degeneration is a key factor for the pathology initiation. Several tissue engineering approaches aiming to restore the appropriate NP cell (NPCs) and matrix content, were attempted by using adult stromal cells either from bone marrow or adipose tissue, chondrocytes, notochordal cells and more recently also pluripotent stem cells. However, none was fully satisfactory since the NP acid and a-vascularized environment appeared averse to the implanted heterologous cells. Several studies demonstrated the efficacy of platelet derivatives such as platelet rich plasma (PRP) in promoting the regeneration of connective tissues. We investigated the efficacy of PRP on NPCs proliferation and differentiation with the goal to propose the direct stimulation of resident cells (stimulation of endogenous cells – less invasive surgical procedure) or the implantation of NPCs expanded in vitro in the presence of PRP as therapeutic agents in IVD degeneration. NPCs were isolated from small fragments of NP explants, cultivated in medium supplemented with PRP or FCS (standard condition control) and characterized by FACS analysis for the expression of the typical mesenchymal stem cells markers CD34, CD44, CD45, CD73, CD90 and CD105. NPCs cultured in PL showed a phenotypic profile like the cells cultured in FCS. However, compared to NPCs expanded in the presence of FCS, NPCs expanded in PRP showed a much better proliferation and differentiation capacity. NPCs differentiation was evaluated by the cell ability to produce an organized metachromatic cartilaginous matrix, confirmed by the positive immunohistochemical staining for chondrogenic markers

Aims. For cementless implants, stability is initially attained by an interference fit into the bone and osteo-integration may be encouraged by coating the implant with bioactive substances. Blood based autologous glue provides an easy, cost-effective way of obtaining high concentrations of growth factors for tissue healing and regeneration with the intention of spraying it onto the implant surface during surgery. The aim of this study was to incorporate nucleated cells from autologous bone marrow (BM) aspirate into gels made from the patient’s own blood, and to investigate the effects of incorporating three different concentrations of platelet rich plasma (PRP) on the proliferation and viability of the cells in the gel. Methods. The autologous blood glue (ABG) that constituted 1.25, 2.5, and 5 times concentration PRP were made with and without equal volumes of BM nucleated cells. Proliferation, morphology, and viability of the cells in the glue was measured at days 7 and 14 and compared to cells seeded in fibrin glue. Results. Overall, 2.5 times concentration of PRP in ABG was capable of supporting the maximum growth of cells isolated from the BM aspirate and maintain their characteristics. Irrespective of PRP concentration, cells in ABG had statistically significantly higher viability compared to cells in fibrin glue. Conclusion. In vitro this novel autologous gel is more capable of supporting the growth of cells in its structure for up to 14 days, compared to commercially available fibrin-based sealants, and this difference was statistically significant. Cite this article: Bone Joint Res 2020;9(7):402–411

Aims. This study investigates the effects of intra-articular injection of adipose-derived mesenchymal stem cells (AdMSCs) and platelet-rich plasma (PRP) on lameness, pain, and quality of life in osteoarthritic canine patients. Methods. With informed owner consent, adipose tissue collected from adult dogs diagnosed with degenerative joint disease was enzymatically digested and cultured to passage 1. A small portion of cells (n = 4) surplus to clinical need were characterized using flow cytometry and tri-lineage differentiation. The impact and degree of osteoarthritis (OA) was assessed using the Liverpool Osteoarthritis in Dogs (LOAD) score, Modified Canine Osteoarthritis Staging Tool (mCOAST), kinetic gait analysis, and diagnostic imaging. Overall, 28 joints (25 dogs) were injected with autologous AdMSCs and PRP. The patients were followed up at two, four, eight, 12, and 24 weeks. Data were analyzed using two related-samples Wilcoxon signed-rank or Mann-Whitney U tests with statistical significance set at p < 0.05. Results. AdMSCs demonstrated stem cell-like characteristics. LOAD scores were significantly lower at week 4 compared with preinjection (p = 0.021). The mCOAST improved significantly after three months (p = 0.001) and six months (p = 0.001). Asymmmetry indices decreased from four weeks post-injection and remained significantly lower at six months (p = 0.025). Conclusion. These improvements in quality of life, reduction in pain on examination, and improved symmetry in dogs injected with AdMSCs and PRP support the effectiveness of this combined treatment for symptom modification in canine OA for six months. Cite this article: Bone Joint Res 2021;10(10):650–658

Platelet Rich Plasma (PRP), either rich (L-PRP) or poor (P-PRP) of leukocytes, is frequently used as an anti-inflammatory and regenerative tool in osteoarthritis (OA). PRP contains proteins but not genes as it is derived from megakaryocytes. Proteomics but not metabolomics of PRP was recently studied. Metabolomics is a field of ‘omics’ research involved in comprehensive portrayal of the small molecules, metabolites, in the metabolome. These small molecules can be endogenous metabolites or exogenous compounds found in an organism (1). Our aim was to determine the difference between L-PRP and P-PRP. A cross-sectional clinical study was designed in six recreational male athletes between the ages of 18 and 35 years. 3 mL P-PRP and 3 mL -LPRP was prepared from 60 mL of venous blood after treating with 9 mL of sodium citrate and centrifugation at 2.700 rpm for 10 min. Half of the prepared PRP's were frozen at −20°C for a week. Fresh and frozen samples were analyzed at the Q-TOF LC/MS device after thawing to room temperature. Untargeted metabolomic results revealed that the metabolomic profile of the L-PRP and P-PRP were significantly different from each other. A total of 33.438 peaks were found. Statistically significant (p<0.05) peaks were uploaded to the MetaboAnalyst 5.0 platform. Exogenous out of 2.308 metabolites were eliminated and metabolites found significant for our study were subjected to pathway analysis. Steroid biosynthesis, sphingolipid metabolism and metabolism of lipid pathways were affected. In the L-PRP samples, Nicotinamide riboside (FC: 2.2), MHPG (FC: 3.0), estrone sulfate (FC: 7.5), thiamine diphosphate (FC: 2.0), leukotriene E4 (FC: 7.5), PC(18:1 (9Z)e/2:0) (FC: 9.8) and Ap4A (FC: 2.1) were higher compared to P-PRP. C24 sulfatide (FC: −11.8), 3-hexaprenyl-4,5-dihydroxybenzoic acid (FC: −2.8) metabolites were furthermore lower in P-PRP. Clinical outcomes of PRP application should consider these metabolic pathways in future studies (2)

Objectives. Platelet-rich plasma (PRP) is being used increasingly often in the clinical setting to treat tendon-related pathologies. Yet the optimal PRP preparations to promote tendon healing in different patient populations are poorly defined. Here, we sought to determine whether increasing the concentration of platelet-derived proteins within a derivative of PRP, platelet lysate (PL), enhances tenocyte proliferation and migration in vitro, and whether the mitogenic properties of PL change with donor age. Methods. Concentrated PLs from both young (< 50 years) and aged (> 50 years) donors were prepared by exposing pooled PRP to a series of freeze-thaw cycles followed by dilution in plasma, and the levels of several platelet-derived proteins were measured using multiplex immunoassay technology. Human tenocytes were cultured with PLs to simulate a clinically relevant PRP treatment range, and cell growth and migration were assessed using DNA quantitation and gap closure assays, respectively. Results. Platelet-derived protein levels increased alongside higher PL concentrations, and PLs from both age groups improved tenocyte proliferation relative to control conditions. However, PLs from aged donors yielded a dose-response relationship in tenocyte behaviour, with higher PL concentrations resulting in increased tenocyte proliferation and migration. Conversely, no significant differences in tenocyte behaviour were detected when increasing the concentration of PLs from younger donors. Conclusion. Higher PL concentrations, when prepared from the PRP of aged but not young donors, were more effective than lower PL concentrations at promoting tenocyte proliferation and migration in vitro. Cite this article: D. R. Berger, C. J. Centeno, N. J. Steinmetz. Platelet lysates from aged donors promote human tenocyte proliferation and migration in a concentration-dependent manner. Bone Joint Res 2019;8:32–40. DOI: 10.1302/2046-3758.81.BJR-2018-0164.R1

Aims. Bone marrow-derived mesenchymal stem cells obtained from bone marrow aspirate concentrate (BMAC) with platelet-rich plasma (PRP), has been used as an adjuvant to hip decompression. Early results have shown promise for hip preservation in patients with osteonecrosis (ON) of the femoral head. The purpose of the current study is to examine the mid-term outcome of this treatment in patients with precollapse corticosteroid-induced ON of the femoral head. Methods. In all, 22 patients (35 hips; 11 males and 11 females) with precollapse corticosteroid-induced ON of the femoral head underwent hip decompression combined with BMAC and PRP. Mean age and BMI were 43 years (SD 12) and 31 kg/m² (SD 6), respectively, at the time of surgery. Survivorship free from femoral head collapse and total hip arthroplasty (THA) and risk factors for progression were evaluated at minimum five-years of clinical follow-up with a mean follow-up of seven years (5 to 8). Results. Survivorship free from femoral head collapse and THA for any reason was 84% and 67% at seven years postoperatively, respectively. Risk factors for conversion to THA included a high preoperative modified Kerboul angle (grade 3 or 4) based on preoperative MRI (hazard ratio (HR) 3.96; p = 0.047) and corticosteroid use at the time of decompression (HR 4.15; p = 0.039). The seven-year survivorship for patients with grade 1 or 2 Kerboul angles for conversion to THA for articular collapse, and THA for any reason, were 96% and 72%, respectively, versus THA for articular collapse and THA for any reason in patients with grade 3 or 4 Kerboul angles of 40% (p = 0.003) and 40% (p = 0.032). Conclusion. At seven years, hip decompression augmented with BMAC and PRP provided a 67% survivorship free from THA in patients with corticosteroid-induced ON. Ideal candidates for this procedure are patients with low preoperative Kerboul angles and can stop corticosteroid treatment prior to decompression. Cite this article: Bone Jt Open 2021;2(11):926–931

Objectives. Triamcinolone acetonide (TA) is widely used for the treatment of rotator cuff injury because of its anti-inflammatory properties. However, TA can also produce deleterious effects such as tendon degeneration or rupture. These harmful effects could be prevented by the addition of platelet-rich plasma (PRP), however, the anti-inflammatory and anti-degenerative effects of the combined use of TA and PRP have not yet been made clear. The objective of this study was to determine how the combination of TA and PRP might influence the inflammation and degeneration of the rotator cuff by examining rotator cuff-derived cells induced by interleukin (IL)-1ß. Methods. Rotator cuff-derived cells were seeded under inflammatory stimulation conditions (with serum-free medium with 1 ng/ml IL-1ß for three hours), and then cultured in different media: serum-free (control group), serum-free + TA (0.1mg/ml) (TA group), serum-free + 10% PRP (PRP group), and serum-free + TA (0.1mg/ml) + 10% PRP (TA+PRP group). Cell morphology, cell viability, and expression of inflammatory and degenerative mediators were assessed. Results. Exposure to TA significantly decreased cell viability and changed the cell morphology; these effects were prevented by the simultaneous administration of PRP. Compared with the control group, expression levels of inflammatory genes and reactive oxygen species production were reduced in the TA, PRP, and TA+PRP groups. PRP significantly decreased the expression levels of degenerative marker genes. Conclusions. The combination of TA plus PRP exerts anti-inflammatory and anti-degenerative effects on rotator cuff-derived cells stimulated by IL-1ß. This combination has the potential to relieve the symptoms of rotator cuff injury. Cite this article: T. Muto, T. Kokubu, Y. Mifune, A. Inui, R. Sakata, Y. Harada, F. Takase, M. Kurosaka. Effects of platelet-rich plasma and triamcinolone acetonide on interleukin-1ß-stimulated human rotator cuff-derived cells. Bone Joint Res 2016;5:602–609. DOI: 10.1302/2046-3758.512.2000582

Biofabrication is a popular technique to produce personalized constructs for tissue engineering. In this study we combined laponite (Lap), gellan gum (GG) with platelet-rich plasma (PRP) aiming to enhance the endothelial regeneration through the synergistic effects of their individual properties. Laponite has the ability to form porous three-dimensional networks mimicking the extracellular matrix structure, and PRP delivery of growth factors stimulates the endothelial cell proliferation and migration, offering a composite bioink for cell growth and support. The sustained release of these growth factors from the GG-laponite-PRP composite material over time provides a continuous source of stimulation for the cells, leading to more effective tissue engineering strategies for endothelial tissue regeneration. Four blend compositions comprising 1% w/v GG and 0.5 or 1% w/v Lap and 25% v/v PRP were combined with Wharton jelly mesenchymal stem cells (WJ-MSCs) and bioprinted into vessel-like structures with an inner diameter of 3 mm and a wall thickness of 1 mm. Stress/strain analysis revealed the elastomeric properties of the hydrogels with Young modulus values of 10 MPa. Increasing the Lap concentration led to a non-significant decrease of swelling ratio from 93 to 91%. Live/dead assay revealed cell viability of at least 76%, with the 0.5%Lap-GG viability exceeding 99% on day 21. Gradual increase of glycosaminoglycans accumulation and collagen production indicate promotion of ECM formation. The expression and membranous localization of PECAM-1 from day 7 and the granular intracellular localization of vWF after 2 weeks demonstrate in vitro endothelial functionality. In vivo subcutaneous implantation indicated the absence of any adverse immunological reactions. The results reveal the expression of both vWF and PECAM-1 by WJ-MSCs entrapped in all four construct compositions with significantly higher expression of vWF in the presence of PRP

Various approaches have been implemented to enhance bone regeneration, including the utilization of autologous platelet-rich plasma and bone morphogenetic protein-2. The objective of this study was to evaluate the impact of Marburg Bone Bank-derived bone grafts in conjunction with platelet-rich plasma (PRP), recombinant human bone morphogenetic protein-2 (rhBMP-2), and zoledronic acid (ZA) on osteogenesis within rabbit bone defects. Methodology. Bone defects (5mm in diameter) were created in the femurs of 96 male rabbits. The animals were allocated into five groups: (1) bone graft + PRP (BG + PRP), (2) bone graft + 5μg rhBMP-2 (BG + rhBMP-2), (3) bone graft + 5μg ZA (BG + ZA), (4) bone graft + 10μg rhBMP-2 + 5μg ZA (BG + rhBMP-2 + ZA), and (5) bone graft (BG). Marburg Bone Bank-processed human femoral head allografts were utilized for bone grafting. The rabbits were euthanized at 14-, 30-, and 60-days post-surgery, and their femurs underwent histopathological and histomorphometric assessments. Results. Histomorphometric analysis revealed significantly enhanced de novo osteogenesis within the bone allografts in the BG + PRP and BG + rhBMP-2 groups compared to the BG, BG + ZA, and BG + rhBMP-2 + ZA groups at 14 and 30 days (p < 0.05). However, on day 60, the BG + rhBMP-2 group exhibited elevated osteoclastic activity (early resorption). The local co-administration of ZA with thermally treated grafts impeded both bone graft resorption and new bone formation within the bone defect across all time points. The addition of ZA to BG + rhBMP-2 resulted in diminished osteogenic activity compared to the BG + rhBMP-2 group (p < 0.000). Conclusion. The study findings indicated that the combination of PRP and rhBMP-2 with Marburg bone grafts facilitates early-stage osteogenesis in bone defect healing. Incorporating ZA into the thermally treated bone graft hinders both graft resorption and de novo bone formation

Injured skeletal muscle repairs spontaneously via regeneration, however, this process is often incomplete because of fibrotic tissue formation. In our study we wanted to show improved efficiency of regeneration process induced by antifibrotic agent decorin in a combination with Platelet Rich Plasma (PRP)-derived growth factors. A novel human myoblast cell (hMC) culture, defined as CD56 (NCAM)+ developed in our laboratory, was used for evaluation of potential bioactivity of PRP and decorin. To determine the their effect on the viability of hMC we performed a MTT assay. To perform the cell proliferation assay, hMCs were separately seeded on plates at a concentration of 30 viable cells per well. Cell growth medium prepared with different concentrations of PRP exudates (5%, 10%, and 20%) and decorin (10 ng/mL, 25 ng/mL, and 50 ng/mL) were added and incubated for 7 days. After incubation we stained the cells with crystal-violet and measured the absorbance. To study the expression of Transforming Growth Factor Beta (TGF-β) and myostatin (MSTN), two main fibrotic factors in the process of muscle regeneration we performed several ELISA assays in groups treated with all therapeutic agents (PRP, decorin and their combination). Further, we have studied the ability of these agents to influence the differential cascade of dormant myoblasts towards fully differentiated myotubes by monitoring step wise activation of single nuclear factors like MyoD and Myogenin via multicolor flow cytometry. We stained the cells simultaneously with antibodies against CD56, MyoD and myogenin. We acquired cell images of 5,000 events per sample at 40 x magnification using 488 nm and 658 nm lasers and fluorescence was collected using three spectral detection channels. We analysed the cells populations according to expression of single or multiple markers and their ratios. Finally, we examined the treated cell populations using a multicolour laser microscope after staining for desmin (a key marker of myogenic differentiation of hMC), α-tubulin, and nuclei. Optical images were acquired at the center of chamber slides where the cell density is at its highest using a Leica TCS SP5 II confocal microscope and analysed using Photoshop CS6, where a “Color Range” tool was used in combination with a histogram palette to count the pixels that correspond to desmin-positive areas in an image. The mitochondrial activity of cells, as determined by the MTT assay, was significantly increased (p < 0 .001) after exposure to tested concentrations of PRP exudate. Similarly, viability was elevated in all tested concentrations of decorin. PRP exudate enhanced the viability of cells to more than 400% when compared to the control (p < 0 .001). The viability of cells treated with PRP exudates was also significantly higher when compared to decorin (p < 0 .001). Decorin did not show a significant effect on cell proliferation compared to the control, however, cultivation with PRP exudate leads to a 5-fold increase in cell proliferation (p < 0 .001). Decorin was shown to down-regulate the expression of TGF-β when compared to the control by more than 15% (p < 0 .001) but significantly less than PRP exudate p < 0 .005). PRP significantly down-regulated TGF-β expression by more than 30% (p < 0 .001). Similarly, the MSTN expression levels were significantly down-regulated by decorin and PRP. MSTN levels of cells treated with decorin were decreased by 28.4% (p < 0 .001) and 23.1% by PRP (p < 0 .001) when compared to the control group. Using flow cytometry we detected a 39.1% increase in count of myogenin positive cells in the PRP-treated group compared to the control. Moreover, there was a 3.09% increase in cells positive only for myogenin, whereas no such cells were found in the control cell population. The population of cells positive only for myogenin is considered as fully differentiated and capable of fusion into myotubes as well as future mucle fibers and is thus of great importance for muscle regeneration. At the same time 20.6% fewer cells remained quiescent (positive only for CD56). Cells positive for both MyoD and myogenin represent the population that shifted significantly towards mature myocites during myogenesis but are not yet fully committed. Finally, a statistically significant up-regulation of desmin expression (p < 0 .01 for the PRP treated group, p < 0 .005 for the decorin and PRP + decorin treated groups) was present in all therapeutic groups when compared to the control. While no significant difference was found between the PRP and decorin-treated groups, their combination led to a more than 3-fold increase (p < 0 .005) of desmin expression when compared to single bioactives. PRP can be a highly potential therapeutic agent for skeletal muscle regeneration and repair, especially if in combination with a TGF-β antagonis decorin. Achieving better healing could likely result in faster return to play and lower reinjury rate

Aims. Intra-articular (IA) injection may be used when treating hip osteoarthritis (OA). Common injections include steroids, hyaluronic acid (HA), local anaesthetic, and platelet-rich plasma (PRP). Network meta-analysis allows for comparisons between two or more treatment groups and uses direct and indirect comparisons between interventions. This network meta-analysis aims to compare the efficacy of various IA injections used in the management of hip OA with a follow-up of up to six months. Methods. This systematic review and network meta-analysis used a Bayesian random-effects model to evaluate the direct and indirect comparisons among all treatment options. PubMed, Web of Science, Clinicaltrial.gov, EMBASE, MEDLINE, and the Cochrane Library were searched from inception to February 2023. Randomized controlled trials (RCTs) which evaluate the efficacy of HA, PRP, local anaesthetic, steroid, steroid+anaesthetic, HA+PRP, and physiological saline injection as a placebo, for patients with hip OA were included. Results. In this meta-analysis of 16 RCTs with a total of 1,735 participants, steroid injection was found to be significantly more effective than placebo injection on reported pain at three months, but no significant difference was observed at six months. Furthermore, steroid injection was considerably more effective than placebo injection for functional outcomes at three months, while the combination of HA+PRP injection was substantially more effective at six months. Conclusion. Evidence suggests that steroid injection is more effective than saline injection for the treatment of hip joint pain, and restoration of functional outcomes. Cite this article: Bone Joint J 2024;106-B(6):532–539

Aims. Platelet concentrates, like platelet-rich plasma (PRP) and platelet lysate (PL), are widely used in regenerative medicine, especially in bone regeneration. However, the lack of standard procedures and controls leads to high variability in the obtained results, limiting their regular clinical use. Here, we propose the use of platelet-derived extracellular vesicles (EVs) as an off-the-shelf alternative for PRP and PL for bone regeneration. In this article, we evaluate the effect of PL-derived EVs on the biocompatibility and differentiation of mesenchymal stromal cells (MSCs). Methods. EVs were obtained first by ultracentrifugation (UC) and then by size exclusion chromatography (SEC) from non-activated PL. EVs were characterized by transmission electron microscopy, nanoparticle tracking analysis, and the expression of CD9 and CD63 markers by western blot. The effect of the obtained EVs on osteoinduction was evaluated in vitro on human umbilical cord MSCs by messenger RNA (mRNA) expression analysis of bone markers, alkaline phosphatase activity (ALP), and calcium (Ca. 2+. ) content. Results. Osteogenic differentiation of MSCs was confirmed when treated with UC-isolated EVs. In order to disprove that the effect was due to co-isolated proteins, EVs were isolated by SEC. Purer EVs were obtained and proved to maintain the differentiation effect on MSCs and showed a dose-dependent response. Conclusion. PL-derived EVs present an osteogenic capability comparable to PL treatments, emerging as an alternative able to overcome PL and PRP limitations. Cite this article: Bone Joint Res 2020;9(10):667–674

Introduction and Objective. The early pro-inflammatory hematoma phase of bone healing is characterized by platelet activation followed by growth factor release. Bone marrow mesenchymal stromal cells (MSC) play a critical role in bone regeneration. However, the impact of the pro-inflammatory hematoma environment on the function of MSC is not fully understood. We here applied platelet-rich plasma (PRP) hydrogels to study how platelet-derived factors modulate functional properties of MSC in comparison to a non-inflammatory control environment simulated by fibrin (FBR) hydrogels. Materials and Methods. MSC were isolated from acetabular bone marrow of patients undergoing hip arthroplasty. PRP was collected from pooled apheresis thrombocyte concentrates. The phenotype of MSC was analyzed after encapsulation in hydrogels or exposure with platelet-derived factors with regards to gene expression changes, cell viability, extracellular vesicle (EV) release and immunomodulatory effects utilizing cellular and molecular, flow cytometry, RT-PCR, western blot and immunofluorescence stainings. Results. Our results showed that encapsulation of MSC in PRP induced changes in cell metabolism increasing lactate production and reducing mitochondria membrane potential. This was followed by significantly decreased mTOR phosphorylation and differential gene regulation. While PRP-released factors could support EV-biogenesis and immunoregulation-related gene expression, FBR hydrogel reduced CD63+ and CD81+ EV release by MSC. In co-cultures with mitogen stimulated PBMC, pre-exposure of MSC with PRP reduced the proliferation rate and frequency of peripheral blood CD4. +. and favored the persistence of FOXP3. +. regulatory T lymphocytes (32±4.7% compared to 9±2.3% in control co-cultures where MSC were exposed to FBR). Conclusions. Our data indicate that exposure of MSC with a hematoma environment causes metabolic adaptation of MSC followed by increased immune regulatory functions, which in turn might contribute to resolution of inflammation required for successful bone healing

Greater trochanteric pain syndrome is a painful condition characterised by pain around the greater trochanter usually affecting middle-aged women. The majority of patients will improve with conservative management such as physiotherapy and non-steroidal anti-inflammatory drugs (NSAIDs); however, if this fails then more invasive treatments including corticosteroids and surgery may be required. Platelet-rich plasma (PRP) is an autologous blood product, which has a higher concentration of growth factors postulated to provide enhanced healing and anti-inflammatory properties. The Hip Injections PRP Vs Placebo (HIPPO) trial aims to assess the ability of ultrasound-guided PRP injections to improve symptoms and function in patients with GTPS. 64 patients were enrolled and randomised to either the PRP or placebo (normal saline) treatment arm. Two patients decided to drop out of the trial. Clinical outcomes in both groups were evaluated and compared using the International Hip Outcome Tool-12 (iHOT12), Visual Analogue Scale (VAS) of pain, the modified Harris Hip Score (mHHS) and the presence or absence of complications at 3 and six months. The level of significance was set at p<0.05. Both groups received physiotherapy after the injections. The mean age was 57.5. There were 6 males and 56 females with M:F ratio of 1:9.3. Both groups were similar in terms of demography and preoperative scores. The iHOT12 score improved from 28.23 to 45.42 at three-months and decreased slightly to 42.44 at six-months in the Placebo group. The iHOT12 in the PRP group improved from 35.51 to 44.47 at three-months and decreased to 39.78 at six-months. Both groups showed improved VAS and mHHS at three-months compared to the baseline with no statistically significant difference between the two groups (p >0.05). The scores decreased at six-months however remained above the baseline. No complications were reported. Gender and age had no effect on outcomes. Both groups similarly improved from baseline. Physiotherapy can be considered as an important factor in patients' treatment. Further research should be conducted to investigate the role of physiotherapy in the treatment of GTPS

Although mechanical stabilisation has been a hallmark of orthopaedic surgical management, orthobiologics are now playing an increasing role. Platelet-rich plasma (PRP) is a volume of plasma fraction of autologous blood having platelet concentrations above baseline. The platelet α granules are rich in growth factors that play an essential role in tissue healing, such as transforming growth factor-β, vascular endothelial growth factor, and platelet-derived growth factor. PRP is used in various surgical fields to enhance bone and soft-tissue healing by placing supraphysiological concentrations of autologous platelets at the site of tissue damage. The easily obtainable PRP and its possible beneficial outcome hold promise for new regenerative treatment approaches. The aim of this literature review was to describe the bioactivities of PRP, to elucidate the different techniques for PRP preparation, to review animal and human studies, to evaluate the evidence regarding the use of PRP in trauma and orthopaedic surgery, to clarify risks, and to provide guidance for future research

Objectives. After an injury, the biological reattachment of tendon to bone is a challenge because healing takes place between a soft (tendon) and a hard (bone) tissue. Even after healing, the transition zone in the enthesis is not completely regenerated, making it susceptible to re-injury. In this study, we aimed to regenerate Achilles tendon entheses (ATEs) in wounded rats using a combination of kartogenin (KGN) and platelet-rich plasma (PRP). Methods. Wounds created in rat ATEs were given three different treatments: kartogenin platelet-rich plasma (KGN-PRP); PRP; or saline (control), followed by histological and immunochemical analyses, and mechanical testing of the rat ATEs after three months of healing. Results. Histological analysis showed well organised arrangement of collagen fibres and proteoglycan formation in the wounded ATEs in the KGN-PRP group. Furthermore, immunohistochemical analysis revealed fibrocartilage formation in the KGN-PRP-treated ATEs, evidenced by the presence of both collagen I and II in the healed ATE. Larger positively stained collagen III areas were found in both PRP and saline groups than those in the KGN-PRP group. Chondrocyte-related genes, SOX9 and collagen II, and tenocyte-related genes, collagen I and scleraxis (SCX), were also upregulated by KGN-PRP. Moreover, mechanical testing results showed higher ultimate tensile strength in the KGN-PRP group than in the saline control group. In contrast, PRP treatment appeared to have healed the injured ATE but induced no apparent formation of fibrocartilage. The saline-treated group showed poor healing without fibrocartilage tissue formation in the ATEs. Conclusions. Our results show that injection of KGN-PRP induces fibrocartilage formation in the wounded rat ATEs. Hence, KGN-PRP may be a clinically relevant, biological approach to regenerate injured enthesis effectively. Cite this article: J. Zhang, T. Yuan, N. Zheng, Y. Zhou, M. V. Hogan, J. H-C. Wang. The combined use of kartogenin and platelet-rich plasma promotes fibrocartilage formation in the wounded rat Achilles tendon entheses. Bone Joint Res 2017;6:231–244. DOI: 10.1302/2046-3758.64.BJR-2017-0268.R1

Rotator cuff disease encompasses a spectrum from partial to full thickness tears. Despite being 2–3 times more common than full–thickness tears, effective non-operative treatment for partial thickness tears has remained elusive. Platelet enriched plasma (PRP) has been proposed to enhance rotator cuff healing by enhancing the natural healing cascade. However, its utility in rotator cuff disease remains controversial. The purpose of this study was to compare the patient reported outcomes between PRP and corticosteroid injection in patients with symptomatic partial thickness tears. This double blind randomized controlled trial enrolled patients with symptomatic, partial thickness rotator cuff tears or rotator cuff tendinopathy proven on ultrasound or MRI. Patients were randomized to either corticosteroid or PRP ultrasound-guided injection of the affected shoulder. Patients completed patient reported outcomes at 6 weeks and 12 weeks. The primary outcome was Visual Analog Scale (VAS) pain scores. Secondary outcomes included the Western Ontario Rotator Cuff (WORC) index, American Shoulder and Elbow Surgeons (ASES) score, and failure of non-operative management as determined by consent for surgery or progression to operative intervention. Ninety-nine patients were enrolled in the study with equal demographics between the two groups. Taking into account pre-injection scores, patients with PRP injections demonstrated a statistically significant improvement in VAS scores compared to patients receiving corticosteroid injections at 12 weeks (p=0.045) but not at 6 weeks (p=0.704). There was no difference in other outcome measures or progression of the two groups to surgical intervention. The use of PRP in the management of partial thickness rotator cuff tears demonstrates significant improvement of pain scores at 12 week follow up compared to corticosteroid injections. However, this did not affect the rate of progression to surgical intervention. Continued study is required to determine the utility of PRP in this patient population

The use of platelet-rich plasma (PRP) as an adjuvant to tissue repair is gaining favour in orthopaedic surgery. Tunnel widening after anterior cruciate ligament (ACL) reconstruction is a recognised phenomenon that could compromise revision surgery. The purpose of this study was to determine whether PRP might prevent tunnel widening in ACL reconstruction. Patients undergoing ACL reconstruction using a hamstring graft were randomly allocated either to have PRP introduced into the tunnels peri-operatively or not. CT scanning of the knees was carried out on the day after surgery and at three months post-operatively and the width of the tunnels was measured. Patients were also evaluated clinically at three months, when laxity was also measured. Each group comprised 25 patients, and at three months post-operatively all were pain-free with stable knees, a negative Lachman test and a good range of movement. Arthrometric results had improved significantly in both groups (p < 0.001). Despite slightly less tunnel widening in the PRP group, there was no significant difference between the groups at the femoral opening or the mid-tunnel (p = 0.370 and p = 0.363, respectively) nor at the tibial opening or mid-tunnel (p = 0.333 and p = 0.177, respectively). We conclude that PRP has no significant effect in preventing tunnel widening after ACL reconstruction. Cite this article: Bone Joint J 2013;95-B:65–9

The use of stem cells transplanted into the intervertebral disc (IVD) is a promising regenerative approach to treat intervertebral disc degeneration (IDD). The aim of this study was to assess the effect of a hydrogel composed of hyaluronic acid (HA) and platelet-rich plasma (PRP) loaded with human mesenchymal stem cells (hMSCs), on IVD extracellular matrix synthesis and nucleus pulposus (NP) marker expression in a whole IVD culture model. HA was blended with batroxobin (BTX), a gelling agent activated in presence of PRP to construct a hydrogel. Bovine IVDs (n=25) were nucleotomised and filled with 1×10. 6. or 2×10. 6. hMSCs suspended in ∼150 mL of the PRP/HA/BTX hydrogel. IVDs harvested at day 0 and nucleotomised IVDs with no hMSCs and/or hydrogel were used as controls. hMSCs alone or encapsulated in the hydrogel were also cultured in well plates to examine the effect of the IVD microenvironment on hMSCs. After 1 week, tissue structure, scaffold integration and gene expression of anabolic (collagen type I, collagen type II and aggrecan), catabolic (matrix metalloproteinase 3 – MMP-3 –, MMP-13 and a disintegrin and metalloproteinase with thrombospondin motifs 4) and NP cell (cytokeratin 19, carbonic anhydrase 12, cluster of differentiation 24) markers were assessed. Histological analysis showed a good integration of the scaffold within the NP area with cell repopulation. At the gene expression level, the hMSC-loaded hydrogels demonstrated to increase disc cell anabolic and catabolic marker expression and promoted hMSC differentiation towards a NP cell phenotype. This study demonstrated that the HA/PRP/BTX may represent a valid carrier for hMSCs being capable of stimulating cell activity and NP marker expression as well as achieving a good integration with the surrounding tissues

Osteoarthritis (OA) is a debilitating disease characterised by degradation of articular cartilage and subchondral bone remodeling. Current therapies for early or midstage disease do not regenerate articular cartilage, or fail to integrate the repair tissue with host tissue, and therefore there is great interest in developing biological approaches to cartilage repair. We have shown previously that platelet-rich plasma (PRP) can enhance cartilage tissue formation. PRP is obtained from a patient's own blood, and is an autologous source of many growth factors and other molecules which may aid in healing. This raised the question as to whether PRP could enhance cartilage integration. We hypothesise that PRP will enhance integration of bioengineered cartilage with native cartilage. Chondrocytes were isolated from bovine metacarpal-phalangeal joints, seeded on a porous bone substitute (calcium polyphosphate) and grown in the presence of FBS to form an in vitro model of osteochondral-like tissue. After 7 days, the biphasic constructs were soaked in PRP for 30 minutes prior to implantation into the core of a ring-shaped biphasic explant of native bovine cartilage and bone. Controls were not soaked in PRP. The resulting implant-explant construct was cultured in a stirring bioreactor in serum free conditions for 2 weeks. The integration zone was visualised histologically. A push-out test was performed to assess the strength of integration. Matrix accumulation at the zone of integration was assessed biochemically and the gene expression of the cells in this region was assessed by RT-PCR. Significance (p<0.05) was assessed by a student's t-test or one-way ANOVA with tukey's post hoc. PRP soaked bioengineered implants, integrated with the host tissue in 73% of samples, whereas control bioengineered implants only integrated in 19% of samples based on macroscopic evaluation (p<0.05). The integration strength, as determined by the normalised maximum force to failure, was significantly increased in the PRP soaked implant group compared to controls (219 +/− 35.4 kPa and 72.0 +/− 28.5 kPa, respectively, p<0.05). This correlated with an increase in glycosaminoglycan and collagen accumulation in the region of integration in the PRP treated implant group, compared to untreated controls after 2 weeks (p<0.05). Immunohistochemical studies revealed that the integration zone was rich in collagen type II and aggrecan. The cells at the zone of integration in the PRP soaked group had a 2.5 fold increase in aggrecan gene expression (p=0.05) and a 3.5 fold increase in matrix metalloproteinase 13 expression (p<0.05) compared to controls. PRP soaked bio-engineered cartilage implants showed improved integration with native cartilage compared to non-treated implants, perhaps due to the increased matrix accumulation and remodeling at the interface. Further evaluation is required to determine if PRP improves integration in vivo

Introduction. The use of stem cell and platelet-rich plasma (PRP) injections for knee osteoarthritis (OA) is extremely controversial and at best experimental. These treatments are being given to patients across the nation for “cash only payments”. Our objectives were (1) to determine the proportion of board certified orthopedic surgeons who offer stem cell or PRP treatment for knee OA, (2) how much the practices charge for those treatments and (3) if members of the knee society use these therapies. Methods. Board certified orthopedic surgeons’ offices in our county were identified by their AAOS active membership. Knee society membership roll was also utilized. Offices were contacted by telephone and presented with a hypothetical patient with end stage knee osteoarthritis searching for specific treatment (stem cells or PRP injections). T-test was used to compare the Dade county board certified orthopedists to knee society members. Results. A total of 186 board certified orthopedic surgeons’ offices were contacted. 17.6% of all contacted orthopedics offices offered PRP and 12.5% offered stem cell treatments. 61.2% of the offices were transparent on the pricing of PRP while 31.8% gave a price for stem cell therapy. The remaining practices stated that pricing would be “determined or discussed” during a scheduled visit. Mean cost for a PRP injection was $887 (SE 101; range: $350–$1700) and for a stem cell injection was $2800 (SE 852; range: $1000–$6000). Usage of these therapies amongst general AAOS members and Knee Society members was found to be significantly different for both PRP and stem cells (17% vs. 10%; p<0.001 and 26% vs. 13%; p<0.001, respectively). No practice had a “free” research protocol to study the treatments. Conclusions. Biological injectables as a treatment for knee OA has theoretical potential promise in the management of arthritis but continues to be at best investigational. Knee Society members demonstrated significantly more caution using these treatments

Angiogenesis is a key factor in early stages of wound healing and is crucial for tissue regeneration. Gold standard for large bone defect treatment is the transplantation of autologous bone grafts, but is not entirely satisfying (e.g. limited amount). Cell therapies and tissue engineering approaches may overcome these problems by using cells and autologous blood components obtainable by less invasive procedures. Pre-clinical studies previously showed promising results combining endothelial progenitor cells (EPCs) and mesenchymal stem cell (MSCs) in polyurethane scaffolds in presence of PRP (1). A systemic investigation of the chemical and mechanical characteristics of different PRP gels formulations suggested their potential use as sustained autologous growth factor delivery system (2). Here we investigate PRP hydrogels as autologous injectable cell delivery systems for EPCs and MSCs and their efficacy in promoting fast neo-vascularization for bone repair applications. PRP hydrogel and corresponding platelet lysate (PL) were produced from platelet concentrates as described before (3). MSCs were isolated by Ficoll-Paque centrifugation from human bone marrow (EK_regensburg12-101-0127), and cultured in alpha MEM containing 10% FCS and 5 ng/mL basic-FGF (GIBCO). EPCs (CD133+/CD34+) were isolated from MSC fractions using magnetic-activated cell sorting (MACS®) and further cultured in IMDM (GIBCO) containing 5% FCS and 5% PL. GFP positive HUVECs are from Angio-Proteomie, (Boston, USA). Prior to gel encapsulation, MSC and EPCs were pre-stained using PKH26-red® and PKH67-green® respectively. Cells in different proportions were encapsulated in 3D PRP gels, in FDA approved Fibrin gels and in Matrigel®. The gels were cultured in Ibidi microwells placed in an onstage incubator linked to an EVOS Auto Cell Imaging System. The cellular network formation capacity of HUVEC or EPCs and MSC in different proportions was analyzed for the 3 types of hydrogels using time lapse movies recorded over a period of 14 days. Parallel cultures were performed in a classical cell culture CO. 2. incubator and sample gels were taken at different time points for additional immunostaining and gene expression analysis. Preliminary results indicate high cell viability in all of the three tested gels. PRP hydrogels present a favorable environment for the formation of a 3 dimensional cellular network in cell co-culture. The formation of these networks was apparent as early as 4 days after seeding. Networks increase in complexity and branching over time. The same was observed when cells were embedded in Matrigel®, which is known for its pro-angiogenic properties. Further experiments are currently in process looking at the involvement of MSCs in this process and the effect of PRP 3D co-culture on their differentiation. PRP was previously shown as a potent growth factor delivery system for tissue engineering. In the present work, the high cell viability together with the 3 dimensional capillary-like networks observed at early time points suggest that PRP can also be used as an autologous cell delivery and pro-angiogenic system for bone tissue repair

Summary Statement. An autologous thrombin activated 3-fold PRP, mixed with a biphasic calcium phosphate at a 1mL:1cc ratio, is beneficial for early bone healing in older age sheep. Introduction. The management of bone defects continues to present challenges. Upon activation, platelets secrete an array of growth factors that contribute to bone regeneration. Therefore, combining platelet rich plasma (PRP) with bone graft substitutes has the potential to reduce or replace the reliance on autograft. The simple, autologous nature of PRP has encouraged its use. However, this enthusiasm has failed to consistently translate to clinical expediency. Lack of standardisation and improper use may contribute to the conflicting outcomes reported within both pre-clinical and clinical investigations. This study investigates the potential of PRP for bone augmentation in an older age sheep model. Specifically, PRP dose is controlled to provide clearer indications for its clinical use. Methods. Eighty 11mm diameter defects of 20mm in depth were created in the cancellous bone within the epiphyseal region of the medial proximal tibia and distal femur of twenty five-year-old sheep. The defects were treated with three doses of an autologous thrombin activated PRP combined with a biphasic calcium phosphate (BCP). Activated platelet poor plasma (PPP) and the BCP alone provided reference groups, while the autograft and empty defects served as controls. All animals were sacrificed at four weeks post-operatively for radiographic assessment, micro-computed tomography quantification, histological assessment, histomorphometric quantification of new bone area and bone ingrowth, and weekly fluorochrome bone label quantification. TGF-β1 concentrations were quantified using enzyme-linked immunosorbent assays. Results. The PRP had a 2.9-fold (0.4) increase in platelet concentration, a 0.57-fold (0.09) decrease in leukocytes, and a 0.65-fold (0.11) decrease in fibrinogen. After activation, the PRP had an 8.9-fold (1.5) increase in TGF-β1 serum concentration above baseline. Eleven (11) mm diameter cancellous bone defects in the hind legs of five-year-old sheep do not spontaneously heal within four weeks. PRP dose had a significant effect on the radiographic grade. The highest dose of PRP treatment had a significantly greater micro-CT BV/TV over the BCP alone (PRP: 30.6±1.8%; BCP: 24.5±0.1%). All doses of PRP treatment were significantly greater than the BCP alone for both the histomorphometric new bone area (PRP: 14.5±1.3%; BCP: 9.7±1.5%) and bone ingrowth depth (PRP: 2288±210µm; BCP:1151±268µm). From week two onwards, PRP had a significant effect on the weekly bone ingrowth over BCP, however, autograft had the greatest amount of fluorescently labelled bone within the first three weeks. PRP has a significant effect on the shape and density of osteoblasts within the central region of the defect compared to the BCP alone, however, was not significantly different to autograft. TGF-β1 appeared a better predictor of healing outcomes than platelet concentration, however both had relatively weak correlations (r<.324). Conclusion. PRP induces new bone formation with a dose dependant response at four weeks when used with a biphasic calcium phosphate in older age sheep

Background. A cell-based tissue-engineered construct can be employed for treating meniscal lesions occurring in the non-vascularized inner two-thirds. The objective of this study was to test the hypothesis that both pre-differentiation of human bone marrow derived stromal cells (hBMSCs) into chondrogenic lineage before cell seeding and platelet-rich plasma (PRP) pretreatment on a PLGA mesh scaffold enhances the healing capacity of the meniscus with hBMSCs-seeded scaffolds in vivo. Methods. PRP of 5 donors was mixed and used for the experiments. The woven PLGA mesh scaffold (VicrylTM, Ethicon) measuring 20×8 mm (thickness, 0.2 mm) was prepared. The scaffolds were immersed into 1,000 μl of PRP and were centrifuged at 150g for 10 min. Then, the scaffold was flipped 180° and the same procedure was done for the other side. After washing, the scaffolds were soaked into 1,000 μl of DMEM media. hBMSCs from an iliac crest of 10 patients after informed consent and approval of our IRB were induced into chondrogenic differentiation with chondrogenic media containing 10 ng/ml rhTGF-ß3 in 1.2% alginate bead culture system for 7 days. Then, 2×10. 5. hBMSCs were recovered, seeded onto the scaffold, and cultured under dynamic condition. Based on the presence of pre-differentiation into chondrogenic lineage and the PRP pretreatment, 4 study groups were prepared. (no differentiation without PRP, no differentiation with PRP, chondrogenic differentiation without PRP, chondrogenic differentiation with PRP) Cell number for each cell-seeded scaffold was determined at 24 hours after seeding. Then, scaffolds were placed between human meniscal discs and were implanted subcutaneously in nude mice for 6 weeks (n=10 per group). Results. Cell attachment analysis revealed no significant difference among groups (p>0.05). The average cell number attached on the scaffold was ranged 1.1×10. 5. to 1.2×10. 5. among groups after 24 hours, so the initial cell seeding efficiency was ranged 55 to 60%. Histologic results from the 10 constructs containing hBMSCs undifferentiated and seeded onto non-PRP treated scaffolds revealed none had healed at all. Of the constructs containing hBMSCs undifferentiated and seeded onto PRP-pretreated scaffolds, three menisci healed and seven did not heal. Of the constructs containing hBMSCs pre-differentiated into chondrogenic lineage and seeded onto non-PRP treated scaffolds, six menisci healed and four did not heal. Of the constructs containing hBMSCs pre-differentiated into chondrogenic lineage and seeded onto PRP-pretreated scaffolds, seven menisci healed and three did not heal. Histological evaluation demonstrated a continuous hypercellular new fibrous tissue integrating into the native devitalized meniscus disc tissue in healed samples. The histological outcome between the groups was significant (p<0.05) (Table 1) (Figure 1). Conclusion. hBMSCs, which were differentiated into chondrogenic lineage before cell seeding and attached PRP-pretreated PLGA mesh scaffolds, demonstrated enhanced healing capacity of human meniscus in a meniscal repair mouse model. These findings demonstrate that both pre-differentiation of hBMSCs into chondogenesis and the PLGA scaffold modified by PRP pretreatment provides more biomimetic and biocompatible strategy for cell-mediated meniscal repair. Acknowledgements. This study was supported by Basic Science Research Program through the National Research Foundation of Korea (#2015-01004099)

Objectives. This study was conducted to evaluate the cytokine-release kinetics of platelet-rich plasma (PRP) according to different activation protocols. Methods. Two manual preparation procedures (single-spin (SS) at 900 g for five minutes; double-spin (DS) at 900 g for five minutes and then 1500 g for 15 minutes) were performed for each of 14 healthy subjects. Both preparations were tested for platelet activation by one of three activation protocols: no activation, activation with calcium (Ca) only, or calcium with a low dose (50 IU per 1 ml PRP) of thrombin. Each preparation was divided into four aliquots and incubated for one hour, 24 hours, 72 hours, and seven days. The cytokine-release kinetics were evaluated by assessing PDGF, TGF, VEGF, FGF, IL-1, and MMP-9 concentrations with bead-based sandwich immunoassay. Results. The concentration of cytokine released from PRP varied over time and was influenced by various activation protocols. Ca-only activation had a significant effect on the DS PRPs (where the VEGF, FGF, and IL-1 concentrations were sustained) while Ca/thrombin activation had effects on both SS and DS PRPs (where the PDGF and VEGF concentrations were sustained and the TGF and FGF concentrations were short). The IL-1 content showed a significant increase with Ca-only or Ca/thrombin activation while these activations did not increase the MMP-9 concentration. Conclusion. The SS and DS methods differed in their effect on cytokine release, and this effect varied among the cytokines analysed. In addition, low dose of thrombin/calcium activation increased the overall cytokine release of the PRP preparations over seven days, relative to that with a calcium-only supplement or non-activation. Cite this article: Professor J. H. Oh. Cytokine-release kinetics of platelet-rich plasma according to various activation protocols. Bone Joint Res 2016;5:37–45. doi: 10.1302/2046-3758.52.2000540

We performed this systematic overview on the overlapping meta-analyses that analyzed autologous platelet-rich plasma (PRP) as an adjuvant in the repair of rotator cuff tears and identify the studies which provide the current best evidence on this subject and generate recommendations for the same. We conducted independent and duplicate electronic database searches in PubMed, Web of Science, Scopus, Embase, Cochrane Database of Systematic Reviews, and the Database of Abstracts of Reviews of Effects on September 8, 2021, to identify meta-analyses that analyzed the efficacy of PRP as an adjuvant in the repair of rotator cuff tears. Methodological quality assessment was made using Oxford Levels of Evidence, AMSTAR scoring, and AMSTAR 2 grades and used the Jadad decision algorithm to generate recommendations. 20 meta-analyses fulfilling the eligibility criteria were included. The AMSTAR scores of the included studies varied from 6–10 (mean:7.9). All the included studies had critically low reliability in their summary of results due to their methodological flaws according to AMSTAR 2 grades. The initial size of the tear and type of repair performed do not seem to affect the benefit of PRPs. Among the different preparations used, leucocyte poor (LP)-PRP possibly offers the greatest benefit as a biological augment in these situations. Based on this systematic overview, we give a Level II recommendation that intra-operative use of PRPs at the bone-tendon interface can augment the healing rate, reduce re-tears, enhance the functional outcomes and mitigate pain in patients undergoing arthroscopic rotator cuff repair

Autologous injection of platelet rich plasma (PRP) stimulates healing process in degenerated tendons. The purpose of this study is to compare the functional outcome of lateral epicondylitis treated with PRP and steroid injection. Tennis elbow patients who failed conservative medical therapy were included and were allocated randomly steroid group (n=70) and PRP group (n=63). Data were collected before procedure, at 4, 8, 12 weeks, 1 year and 2 years after procedure. The main outcome measures were visual analogue score, Mayo elbow performance score, DASH score and hand grip strength. Successful treatment was defined as more than a 25% reduction in visual analogue score or DASH score and more than 75 score in Mayo elbow performance score. We observed that 35 of the 70 patients (50%) in corticosteroid group and 47 of the 63 patients (75%) in PRP group were successful, which was significantly different (p<.001), according to DASH score 37 of the 70 patients (53%) and 47 of the 63 patients (75%) in the PRP group were successful which was also significantly different (P = .005), Mayo elbow performance score was successful in 36 of the 70 patients (51%) in corticosteroid group and 49 of the 63 patients (78%) in PRP group. The improvement in hand grip strength of hand from 24.7kg (mean) 26kg in corticosteroid group and 23.5kg (mean) to 32.9kg (mean) in PRP group. PRP injection for chronic lateral epicondylitis reduces pain, improve functionality and hand grip strength when compared to steroid injection

The incorporation of platelet rich plasma (PRP) in the treatment of various musculoskeletal conditions has increased exponentially over the past decade. While described most often as an augment or treatment for tendinopathies and acute tendon injuries, more recently, PRP has been described as an adjunct to arthroplasty procedures, mostly with respect to knee arthroplasty. In the shoulder, only a single study has been published, in which Zavadil and colleagues performed a randomised study of 40 patients undergoing total shoulder arthroplasty undergoing either treatment with autologous platelet gel and platelet poor plasma (n=20) or undergoing no biologic treatment (control group, n=20). The authors noted that the treatment group had significantly lower pain scores, less pain medication requirements, and improved internal rotation when compared to controls; in addition, there were no significant differences in post-operative (compared to pre-operative) hemoglobin levels or length of stay. The vast majority of arthroplasty studies discussing PRP analyze the impact of treatment on wound healing, post-operative pain, post-operative range of motion, and need for post-operative blood transfusions. Unfortunately, due to the substantial variability of methodology (not all PRP preparations are the same) in the available studies as well as the variability in outcomes reporting, direct comparison between different studies is not feasible. Here, we discuss the basic science elements of PRP relevant to arthroplasty, the variability of PRP solutions, the specific applications of PRP in arthroplasty, and the latest clinical outcomes analyses of patients undergoing PRP therapy in conjunction with shoulder arthroplasty

Autologous platelet rich plasma (PRP) has an established history of clinical use in dental and orthopaedic procedures. However, there is little scientific data demonstrating a mode of action and conflicting clinical data to support its use. The aim of this study was to determine the cellular and metabolic pathways by which PRP modulates the osteogenic response. PRP is a concentrate of platelets in a small volume of plasma derived from whole blood. Platelets contain pre-packaged growth factors in & #61537;-granules that are released during clotting at the trauma site and are an essential requirement for the hard (bone) and soft tissue healing process. S& N’s Caption ™ device, a standalone disposable device that prepares autologous PRP in 15minutes, was used to prepare human PRP. We determined a platelet concentration factor of 3.4& #61617;1.2 fold and significant increases in the concentration of platelet derived growth factor–AB (PDGF-AB), transforming growth factor-& #61538; (TGF-& #61538;) and vascular endothelial growth factor (VEGF). A 5.9 fold increase in VEGF, 4 fold increase in TGF-& #61538; and 1.5 fold increase in PDGF-AB indicate that PRP has the potential to enhance bone repair as each of these growth factors individually and synergistically affect multiple cell responses essential for tissue repair. An in vitro study was then undertaken to investigate the effect of human PRP compared to human serum on the proliferation and differentiation of human primary osteoblasts (hOBs) and human mesenchymal stem cells (hMSCs). A significant proliferative effect of PRP compared to serum was observed in both cell types. In hMSCs, PRP treatment significantly increased proliferation after 24 hours as determined by Pico green analysis. However, in osteoblasts a proliferative effect of PRP over and above that of serum was not observed until 72 hours. These data indicate that PRP may have specific differing stimulatory effects on each cell type. Quantitative RT-PCR analysis also determined that PRP significantly increased the expression of BMP 2 over and above that of serum in human osteoblasts at both 6 and 12 hour time points. Furthermore, in hMSCs, PRP increased both BMP-2 and alkaline phosphatase gene expression at early time points suggesting the commitment of these cells to the osteoblastic lineage. This hypothesis was consistent with alkaline phosphatase protein expression which was significantly increased at 72hrs in hMSCs and was further confirmed by increased alizarin red staining, indicative of calcium deposition, in long term cultures of hMCSs treated with PRP. In summary, these data demonstrate that PRP initiates proliferation in hMSCs and osteoblasts, enhances BMP-2 mRNA expression and induces osteoblast differentiation and maturation in human MSC cultures. Together these data demonstrate a positive effect of PRP on osteogenesis and highlight the potential for Caption™ derived PRP to enhance bone repair

Purpose. Platelet Rich Plasma (PRP) has been shown to have positive effect in tendon regeneration in in-vitro and limited in-vivo animal studies. We aim to study PRP use in acute Achilles tendon rupture (ATR) regeneration in a purposely designed clinical trial. Methods. This is a prospective double-arm patient-blinded randomized controlled trial. ATR patients were randomized into PRP treatment or control groups. Non-operatively treated patients received PRP or control injection in clinic. In operatively treated patients, PRP gel was applied in the ruptured gap during percutaneous repair. Standard rehabilitation protocol was used and patients were followed up for 24 weeks. ATR, VISA-A and FAOS scores were used as subjective outcome measures. Functional ultrasound Elastography (FUSE) was performed at each follow-up to assess the mechanical properties of tendons. PRP analysis and tendon needle-biopsy were performed to study the histological differences during healing in both groups. Results. 20 patients were recruited with mean age 37.5±8.8 (8males and 7 females). Rupture location was 4.8±2.1 cm from insertion. PRP platelet count 1044±320 × 1000/μL with average platelet CD62p activation 68.42±4.5%. Mixed linear regression analysis revealed PRP treated tendon achieved better ATR and VISA-A outcome scores (p<0.05). FAOS score analysis showed that PRP group had better pain, ADL and symptoms scores with significant difference apparent from week 3 onwards. Strain mapping using FUSE scan in 4 patients showed bigger harder tendons in PRP group. Analysis of the remaining patients is on the way. To achieve the desired statistical power in pragmatic settings, recruitment will continue in a multi-centre trial. Conclusion. Our preliminary findings show that PRP application in Achilles tendon rupture may lead to faster regeneration and return to function as supported by a combination of objective and subjective outcome measures

Intra-articular injections of human mesenchymal stromal cells (MSCs) and platelet-rich plasma (PRP) have been intensively investigated as therapies for knee osteoarthritis (OA) with positive outcomes. In this work we evaluated weather a combination of the treatments (MSCs + PRP) would be beneficial compared to MSCs alone (MSCs) and standard corticosteroid injection (Control group). Forty seven patients (24 males and 23 females; 53.3 ± 10.7 years old) with radiographic symptomatic knee OA (Dejour grades II–IV) were randomized to receive intra-articular injections of MSCs (n = 16), MSCs + PRP (n = 14) or corticosteroid (n=17). MSCs were obtained after mononuclear cells separation from bone marrow aspiration collected from both posterior iliac crests using Sepax automated closed system and expanded in culture until reaching the number of 4 × 10. 7. PRP was obtained by double-centrifugation of whole blood according to a protocol developed in house. After 12 months follow-up, the MSCs and MSCs+PRP groups achieved higher percentages of expected improvement when comparing to the corticosteroid group for the KOOS-symptoms, pain, function and daily living, domains and global score. For the population older or equal to 60 years old the MSCs+PRP group showed significant superiority for the KOOS-ADL domain at 12 months. Cytokines quantification evidenced anti-inflammatory aspects of the treatments. This work evidences the safety and efficacy of intra-articular injection of MSCs for the treatment of early knee OA, with greater improvement with PRP addition particularly to the older population