The effect of platelet-rich plasma on Achilles tendon healing in a rabbit model

Effect of platelet-rich plasma in Achilles tendon allograft in rabbits

BACKGROUND

Achilles tendon is composed of dense connective tissue and is one of the largest tendons in the body. In veterinary medicine, acute ruptures are associated with impact injury or sharp trauma. Healing of the ruptured tendon is challenging because of poor blood and nerve supply as well as the residual cell population. Platelet-rich plasma (PRP) contains numerous bioactive agents and growth factors and has been utilized to promote healing in bone, soft tissue, and tendons.

OBJECTIVE

The purpose of this study was to evaluate the healing effect of PRP injected into the surrounding fascia of the Achilles tendon after allograft in rabbits.

METHODS

Donor rabbits (n = 8) were anesthetized and 16 lateral gastrocnemius tendons were fully transected bilaterally. Transected tendons were decellularized and stored at -80°C prior to allograft. The allograft was placed on the partially transected medial gastrocnemius tendon in the left hindlimb of 16 rabbits. The allograft PRP group (n = 8) had 0.3 mL of PRP administered in the tendon and the allograft control group (n = 8) did not receive any treatment. After 8 weeks, rabbits were euthanatized and allograft tendons were transected for macroscopic, biomechanical, and histological assessment.

RESULTS

The allograft PRP group exhibited superior macroscopic assessment scores, greater tensile strength, and a histologically enhanced healing process compared to those in the allograft control group.

CONCLUSIONS

Our results suggest administration of PRP on an allograft tendon has a positive effect on the healing process in a ruptured Achilles tendon.

Platelet-rich plasma injections as a treatment for Achilles tendinopathy and plantar fasciitis in athletes

Platelet-rich plasma (PRP) injections represent a growing interest in the use of biologic therapies for treatment of musculoskeletal injuries. One possible application of PRP is in the management of overuse injuries commonly experienced by athletes. The aim of this review is to evaluate and summarize existing evidence regarding the efficacy of PRP in the treatment of Achilles tendinopathy and plantar fasciitis in athletes. Although many lower quality single-armed studies have demonstrated clinical improvement in athletes treated for Achilles tendinopathy with PRP, higher quality randomized controlled trials (RCTs) have shown no clear benefit in athletes. Existing data suggest PRP significantly improves clinical outcomes for plantar fasciitis in the general population, but very few studies and no RCTs are available that specifically analyze outcomes in athletic populations. More research is needed to evaluate how platelet concentration, leukocyte and erythrocyte presence, and sport type may interact to affect clinical outcomes in athletes.

Aging and injury affect nuclear shape heterogeneity in tendon

Tissue level properties are commonly studied using histological stains assessed with qualitative scoring methods. As qualitative evaluation is typically insensitive, quantitative analysis provides additional information about pathological mechanisms, but cannot capture structural heterogeneity across cell subpopulations. However, molecular analyses of cell and nuclear behavior have identified that cell and more recently also nuclear shape are highly associated with cell function and malfunction. This study combined a Visually Aided Morpho-Phenotyping Image Recognition analysis that automatically segments cells based on their shape with an added capacity to further discriminate between cells in certain protein-rich extracellular matrix regions. We used tendon as a model system given the enormous changes in organization and cell and nuclear shape they undergo during aging and injury. Our results uncover that multiple shape modes of nuclei exist during maturity and aging in rat tendon and that distinct subgroups of cell nuclei shapes exist in proteoglycan-rich regions during aging. With injury, several immunomarkers (αSMA, CD31, CD146) were associated with more rounded shape modes. In human tendons, the cell nuclei at sites of injury were found to be more rounded relative to uninjured tissues. To conclude, the tendon tissue changes occurring during aging and injury could be associated with a variation in cell nuclear morphology and the appearance of various region-specific subpopulations. Thus, the methodologies developed allow for a deeper understanding of cell heterogeneity during tendon aging and injury and may be extended to study further clinical applications.

Platelet-rich plasma in the pathologic processes of tendinopathy: a review of basic science studies

Tendinopathy is a medical condition that includes a spectrum of inflammatory and degenerative tendon changes caused by traumatic or overuse injuries. The pathological mechanism of tendinopathy has not been well defined, and no ideal treatment is currently available. Platelet-rich plasma (PRP) is an autologous whole blood derivative containing a variety of cytokines and other protein components. Various basic studies have found that PRP has the therapeutic potential to promote cell proliferation and differentiation, regulate angiogenesis, increase extracellular matrix synthesis, and modulate inflammation in degenerative tendons. Therefore, PRP has been widely used as a promising therapeutic agent for tendinopathy. However, controversies exist over the optimal treatment regimen and efficacy of PRP for tendinopathy. This review focuses on the specific molecular and cellular mechanisms by which PRP manipulates tendon healing to better understand how PRP affects tendinopathy and explore the reason for the differences in clinical trial outcomes. This article has also pointed out the future direction of basic research and clinical application of PRP in the treatment of tendinopathy, which will play a guiding role in the design of PRP treatment protocols for tendinopathy.

Effectiveness of platelet-rich plasma in the treatment of Achilles tendon disease

BACKGROUND

The effectiveness of Platelet-Rich Plasma (PRP) in the treatment of patients with Achilles tendon rupture (ATR) and Achilles tendinopathy (AT) has been controversial.

AIM

To assess PRP injections’ effectiveness in treating ATR and AT.

METHODS

A comprehensive review of relevant literature was conducted utilizing multiple databases such as Cochrane Library, PubMed, Web of Science, Chinese Science and Technology Journal, EMBASE, and China Biomedical CD-ROM. The present investigation integrated randomized controlled trials that assessed the effectiveness of platelet-rich plasma injections in managing individuals with Achilles tendon rupture and tendinopathy. The eligibility criteria for the trials encompassed publications that were published within the timeframe of January 1, 1966 to December 2022. The statistical analysis was performed utilizing the Review Manager 5.4.1, the visual analogue scale (VAS), Victorian Institute Ankle Function Scale (VISA-A), and Achilles Tendon Thickness were used to assess outcomes.

RESULTS

This meta-analysis included 13 randomized controlled trials, 8 of which were randomized controlled trials of PRP for AT and 5 of which were randomized controlled trials of PRP for ATR. PRP for AT at 6 wk [weighted mean difference (WMD) = 1.92, 95%CI: -0.54 to 4.38, I² = 34%], at 3 mo [WMD = 0.20, 95%CI: -2.65 to 3.05, I² = 60%], and 6 mo [WMD = 2.75, 95%CI: -2.76 to 8.26, I² = 87%) after which there was no significant difference in VISA-A scores between the PRP and control groups. There was no significant difference in VAS scores between the PRP group and the control group after 6 wk [WMD = 6.75, 95%CI: -6.12 to 19.62, I² = 69%] and 6 mo [WMD = 10.46, 95%CI: -2.44 to 23.37, I² = 69%] of treatment, and at mid-treatment at 3 mo [WMD = 11.30, 95%CI: 7.33 to 15.27, I² = 0%] after mid-treatment, the PRP group demonstrated better outcomes than the control group. Post-treatment patient satisfaction [WMD = 1.07, 95%CI: 0.84 to 1.35, I² = 0%], Achilles tendon thickness [WMD = 0.34, 95%CI: -0.04 to 0.71, I² = 61%] and return to sport [WMD = 1.11, 95%CI: 0.87 to 1.42, I² = 0%] were not significantly different between the PRP and control groups. The study did not find any statistically significant distinction between the groups that received PRP treatment and those that did not, regarding the Victorian Institute of Sport Assessment - Achilles scores at 3 mo [WMD = -1.49, 95%CI: -5.24 to 2.25, I² = 0%], 6 mo [WMD = -0.24, 95%CI: -3.80 to 3.32, I² = 0%], and 12 mo [WMD = -2.02, 95%CI: -5.34 to 1.29, I² = 87%] for ATR patients. Additionally, no significant difference was observed between the PRP and the control groups in improving Heel lift height respectively at 6 mo [WMD = -3.96, 95%CI: -8.61 to 0.69, I² = 0%] and 12 mo [WMD = -1.66, 95%CI: -11.15 to 7.83, I² = 0%] for ATR patients. There was no significant difference in calf circumference between the PRP group and the control group after 6 mo [WMD = 1.01, 95%CI: -0.78 to 2.80, I² = 54%] and 12 mo [WMD = -0.55, 95%CI: -2.2 to 1.09, I² = 0%] of treatment. There was no significant difference in ankle mobility between the PRP and control groups at 6 mo of treatment [WMD = -0.38, 95%CI: -2.34 to 1.58, I² = 82%] and after 12 mo of treatment [WMD = -0.98, 95%CI: -1.41 to -0.56, I² = 10%] there was a significant improvement in ankle mobility between the PRP and control groups. There was no significant difference in the rate of return to exercise after treatment [WMD = 1.20, 95%CI: 0.77 to 1.87, I² = 0%] and the rate of adverse events [WMD = 0.85, 95%CI: 0.50 to 1.45, I² = 0%] between the PRP group and the control group.

CONCLUSION

The use of PRP for AT improved the patient’s immediate VAS scores but not VISA-A scores, changes in Achilles tendon thickness, patient satisfaction, or return to sport. Treatment of ATR with PRP injections alone improved long-term ankle mobility but had no significant effect on VISA-A scores, single heel lift height, calf circumference or return to sport. Additional research employing more extensive sampling sizes, more strict experimental methods, and standard methodologies may be necessary to yield more dependable and precise findings.

Hyaluronic acid/platelet rich plasma-infused core-shell nanofiber membrane to prevent postoperative tendon adhesion and promote tendon healing

An anti-adhesive barrier membrane incorporating hyaluronic acid (HA) can reduce fibroblasts attachment and impart lubrication effect for smooth tendon gliding during management of post-surgical tendon adhesion. On the other hand, as numerous growth factors are required during tendon recovery, growth factors released by platelets in platelet-rich plasma (PRP) can provide beneficial therapeutic effects to facilitate tendon recovery post tendon injury. Furthermore, PRP is reported to be associated with anti-inflammatory properties for suppressing postoperative adhesion. Toward this end, we fabricate core-shell nanofiber membranes (NFM) with HA/PRP-infused core and polycaprolactone shell in this study. Different NFM with 100 % (H-P), 75 % (HP31-P), 50 % (HP11-P) and 25 % (H31-P) HA in the core was fabricated through coaxial electrospinning and analyzed through microscopic, pore size, mechanical, as well as HA and growth factor release studies. In vitro study with fibroblasts indicates the NFM can act as a barrier to prevent cell penetration and reduce cell attachment/focal adhesion, in addition to promoting tenocyte migration in tendon healing. In vivo studies in a rabbit flexor tendon rupture model indicates the HP11-P NFM shows improved efficacy over H-P NFM and control in reducing tendon adhesion formation and inflammation, while promoting tendon healing, from functional assays and histological analysis.

Effectiveness of topical administration of platelet-rich plasma on the healing of methicillin-resistant Staphylococcus aureus-infected full-thickness wound model

This study aimed to investigate the wound-healing activity of animal platelet-rich plasma (PRP) in wounds infected with methicillin-resistant Staphylococcus aureus (MRSA) in rats. After wound induction, the rats were divided into three groups: noninfected animals treated with PRP (PRP group), MRSA-infected animals treated with mupirocin (standard control group), and MRSA-infected animals treated with PRP (MRSA+PRP group). Scratch assays, MTT test, and live/dead cells were also investigated. Total bacterial count, parameters of wound area, histopathological assessment, and expressions of IL-1β, TNF-α, iNOS, PDGF, FGF-2, and TGF-β mRNA levels and immunofluorescent staining of CD31 and collagen type 1 were assessed. The results showed that culture with PRP increased migration. PRP only showed cytotoxicity in a concentration of 100%. Topical application of PRP (50 µL) reduced the wound area and total bacterial count compared with the control group (P<0.05). The mRNA levels of IL-1β, TNF-α, and iNOS expression on days 7 and 14 (P<0.05) decreased in the treated groups compared with control rats. The mRNA levels of PDGF and TGF-β expression (P<0.05) increased in the treatment groups compared with control rats on days 3 and 7 (P<0.05). FGF-2 expression was significantly higher in the treated groups compared with the control group on days 7 and 14 (P<0.05). Moreover, positive expressions of macrophage colony-stimulating factor (M-CSF), CD31, collagen type 1 and cytokeratin proteins keratinocyte proliferation, and re-epithelization were significantly (P<0.05) increased in both PRP and MRSA+PRP-treated groups compared with the control groups on days 7 and 14. Topical administration of PRP accelerated the wound healing in MRSA-infected wound by decreasing the inflammation and improving the proliferative phase.

Morphology of the asymptomatic Αchilles tendon: Measurement of tendon length and shape using magnetic resonance imaging, and investigation of related factors

BACKGROUND

One of the severe complications of Achilles tendon (AT) rupture is muscle weakness due to tendon lengthening. It is very important to prevent tendon lengthening during treatment; however, data on the length, thickness, and width of normal ATs are scarce. Furthermore, no studies have investigated the factors related to the AT length and shape. We aimed to determine the normal AT length and shape and to investigate any correlating factors.

METHODS

We measured the AT length, thickness, and width of 100 asymptomatic patients using magnetic resonance imaging. We also investigated the correlation between the AT length, thickness, and width and factors including age, sex, height, body weight, body mass index, history of sports activities, and the area of Kager's fat pad.

RESULTS

The mean AT length was 42.1 ± 12.9 mm. The AT length in 73% of the patients was within the range of 30-55 mm. Individual differences in the tendon length were large, but there was no correlation between the tendon length and patient height (P = 0.505). There was a strong correlation between the AT length and area of Kager's fat pad on magnetic resonance imaging (r = 0.734, P < 0.001). Furthermore, the correlation coefficient between the area of Kager's fat pad on magnetic resonance imaging and the area of Kager's triangle on radiography was extremely high (r = 0.851, P < 0.001).

CONCLUSIONS

The AT length can be predicted based on the area of Kager's triangle of the unaffected ankle on radiography. If the AT length is > 55 mm or longer than the length measured directly or calculated from the estimated area of Kager's triangle, tendon lengthening should be suspected. Our findings could provide an important indicator for the evaluation of AT lengthening not only in daily clinical situations but also in clinical studies.

Comparison of the Effects of Open Surgery and Minimally Invasive Surgery on the Achilles Tendon Rupture Healing Based on Angiogenesis

Objective

To compare the effect of three different surgical methods on rabbit Achilles tendon rupture.

Methods

The Achilles tendon transection model was constructed by cutting off the inner half of the Achilles tendon. Rabbits were divided into 4 groups: model group, open surgery (OS) group, minimally invasive surgery (MS) group, and conservative treatment (CT) group. Biomechanical evaluation, H&E, and Picrosirius Red staining were applied to evaluate the histological changes and healing. RT-qPCR, Western blot, ELISA, and IHC staining were used to detect the expression of COLIII, IL-1β, TNF-α, IL-6, CD31, VEGF, bFGF, and TGF-β1.

Results

Different surgery treatments significantly alleviated the histological changes in rabbits. The tension and elasticity of the Achilles tendon were significantly increased after surgery. In addition, surgery treatments notably alleviated the inflammatory responses in vivo via downregulation of IL-1β, TNF-α, and IL-6 and promoted the tube formation in tissues through upregulating VEGF, bFGF, TGF-β1, and CD31. Furthermore, MS exhibited best therapeutic efficiency on Achilles tendon rupture healing, compared with OS or CT.

Conclusions

Our research revealed the superiority of MS in Achilles tendon rupture treatment at the molecular level compared with OS or CT.

Comparative analysis of Achilles tendon healing outcomes after open tenotomy versus percutaneous tenotomy: An experimental study in rats

There is growing interest in conservative treatment of Achilles tendon rupture. However, the majority of experimental studies of Achilles tendon have been performed by open tenotomy. More appropriate model of conservative treatment of Achilles tendon rupture is required. We performed an experimental study to evaluate whether outcomes differ between open tenotomy and percutaneous tenotomy of the Achilles tendon in rats. The Achilles tendons of 48 rats were transected. The animals were divided into two groups according to surgical technique: open tenotomy or microscopy-assisted percutaneous tenotomy. After 1, 2, and 4 weeks, functional, biomechanical, and histological analyses were performed. Western blot was performed for quantitative molecular analysis at 1 week. The Achilles functional index was superior in the percutaneous tenotomy group, compared with the open tenotomy group, at 1 week. The cross-sectional area was significantly larger in the percutaneous tenotomy group than in the open tenotomy group at 4 weeks. Relative to the native tendons, load to failure and stiffness yielded comparable results at 2 weeks in the percutaneous tenotomy group and at 4 weeks in the open tenotomy group. The histological score was significantly better in the percutaneous tenotomy group than in the open tenotomy group at 1 week. At 1 week, interleukin-1β expression in the open tenotomy group was higher than in the percutaneous tenotomy group. In summary, Achilles tendon healing was substantially affected by the tenotomy method. We presume that our percutaneous tenotomy method might constitute a useful experimental animal model for conservative treatment of Achilles tendon rupture.

The effects of orthobiologics in the treatment of tendon pathologies: a systematic review of preclinical evidence

Purpose

The aim of this systematic review is to explore the current available knowledge about tendon disorders and orthobiologics derived by preclinical experiments to evaluate their role and efficacy in the different stages and conditions related to the tendon healing processes.

Methods

The systematic review was performed according to the PRISMA guidelines. Different electronic databases (MEDLINE, Web of Science, EMBASE) were searched for studies investigating orthobiologics (PRP and cell-based products from adipose tissue or bone marrow) in animal models or veterinary clinical trials for tendon pathologies (complete/partial tendon ruptures, rotator cuff tears, tendinopathy, enthesis-related injuries). Data regarding the specific product used, the treatment site/pathology, the host and the model were collected. The results were classified into the following categories: histological, biomechanical, molecular and imaging.

Results

A large pool of preclinical studies on tendon disorders have been found on platelet-rich plasma (PRP), while data about stromal vascular fraction (SVF) and bone marrow concentrate (BMAC) are still limited and frequently focused on expanded cells, rather than orthobiologics prepared at the point of care.

The effect of PRP is related to an acceleration of the healing process, without improvements in the final structure and properties of repaired tendon. Cell-based products have been reported to produce more durable results, but the level of evidence is currently insufficient to draw clear indications.

Conclusions

The preclinical results about orthobiologics applications to tendon pathologies would support the rationale of their clinical use and encourage the performance of clinical trials aimed to confirm these data in human subjects.

Supplementary Information

The online version contains supplementary material available at 10.1186/s40634-022-00468-w.

Intrinsic Tendon Regeneration After Application of Purified Exosome Product: An In Vivo Study

Background:

Tendons are primarily acellular, limiting their intrinsic regenerative capabilities. This limited regenerative potential contributes to delayed healing, rupture, and adhesion formation after tendon injury.

Purpose:

To determine if a tendon’s intrinsic regenerative potential could be improved after the application of a purified exosome product (PEP) when loaded onto a collagen scaffold.

Study Design:

Controlled laboratory study.

Methods:

An in vivo rabbit Achilles tendon model was used and consisted of 3 groups: (1) Achilles tenotomy with suture repair, (2) Achilles tenotomy with suture repair and collagen scaffold, and (3) Achilles tenotomy with suture repair and collagen scaffold loaded with PEP at 1 × 10¹² exosomes/mL. Each group consisted of 15 rabbits for a total of 45 specimens. Mechanical and histologic analyses were performed at both 3 and 6 weeks.

Results:

The load to failure and ultimate tensile stress were found to be similar across all groups (P ≥ .15). The tendon cross-sectional area was significantly smaller for tendons treated with PEP compared with the control groups at 6 weeks, which was primarily related to an absence of external adhesions (P = .04). Histologic analysis confirmed these findings, demonstrating significantly lower adhesion grade both macroscopically (P = .0006) and microscopically (P = .0062) when tendons were treated with PEP. Immunohistochemical staining showed a greater intensity for type 1 collagen for PEP-treated tendons compared with collagen-only or control tendons.

Conclusion:

Mechanical and histologic results suggested that healing in the PEP-treated group favored intrinsic healing (absence of adhesions) while control animals and animals treated with collagen only healed primarily via extrinsic scar formation. Despite a smaller cross-sectional area, treated tendons had the same ultimate tensile stress. This pilot investigation shows promise for PEP as a means of effectively treating tendon injuries and enhancing intrinsic healing.

Clinical Relevance:

The production of a cell-free, off-the-shelf product that can promote tendon regeneration would provide a viable solution for physicians and patients to enhance tendon healing and decrease adhesions as well as shorten the time required to return to work or sports.

Effectiveness of platelet-rich plasma injections for the treatment of acute Achilles tendon rupture: A systematic review and meta-analysis

BACKGROUND

The effect of platelet-rich plasma (PRP) on patients with acute Achilles tendon rupture is still controversial. The purpose of this systematic review is to assess the efficacy of PRP injections treating acute Achilles tendon rupture.

METHODS

A comprehensive electronic literature search was performed in the PubMed, Embase, Cochrane Library, and Web of Science databases to identify relevant studies that were published prior to April 29, 2021. Randomized controlled trials evaluating the efficacy of PRP injections in treating patients with acute Achilles tendon rupture were included. Statistical analyses were conducted using RevMan software.

RESULTS

Five randomized controlled trials were included in this systematic review. The results of the meta-analysis showed that PRP has positive effects on ankle dorsiflexion angle, dorsal extension strength of the ankle, and calf circumference compared with that in controls. However, the current evidence failed to show that PRP effectively improves ankle plantar flexion angle, plantar flexion strength of the ankle, and pain.

CONCLUSIONS

PRP injections for the treatment of acute Achilles tendon rupture significantly improved ankle dorsiflexion angle, dorsal extension strength of the ankle, and calf circumference compared with that in controls. Additional studies with larger sample sizes, more rigorous designs and standardized protocols are needed to draw more reliable and accurate conclusions.

Platelet-rich plasma in non-operative management of mild to moderate carpal tunnel syndrome - A systematic review & meta-analysis of short-term outcomes

Background

To perform an updated systematic review with meta-analysis on trials focusing on patient-reported outcome measures (PROMs), nerve conduction studies (NCS) result and cross sectional area (CSA) measurements of those who underwent PRP injection for mild to moderate CTS, versus a control.

Conclusion

This study indicates that there may be a potential role for the use of PRP in the non-operative management of mild to moderate CTS results in improvements in pain scores, functional outcomes as well as CSA measurements of the MN at short-term follow-up. However, PRP does not result in improvements in NCS.

Level of evidence

II; Systematic Review & Meta-Analysis of Prospective Trials;

Comparison of the Effects of Pulsed Electromagnetic Field and Extracorporeal Shockwave Therapy in a Rabbit Model of Experimentally Induced Achilles Tendon Injury

Achilles tendon injuries are a common cause of complications including adhesions and tendon degeneration. As a result of these complications, the biomechanical properties are lost. Extracorporeal shockwave therapy (ESWT) and pulsed electromagnetic field (PEMF) recover the injured tendon structure; however, detailed studies of changes in tendon biomechanical properties are limited. We hypothesized that PEMF application would improve Achilles tendon biomechanical properties similar to ESWT. The curative effects of a PEMF 4-week application (15 Hz, 1 mT, 260 µs, 1 h/day) and ESWT (3 doses/28 days, 1st dose: 0.12 mJ/mm² , 15 Hz, 300 impulses; 2nd dose: 0.14 mJ/mm² , 15 Hz, 500 impulses; 3rd dose: 0.14 mJ/mm² , 15 Hz, 500 impulses) on rabbits with Achilles tendon injury were investigated in terms of histopathological and biomechanical properties. The clinical feasibility of PEMF application was evaluated by comparing the results of both methods. Fifty New Zealand female rabbits were divided into two groups to be used in either biomechanical or immunohistochemical studies. Each of the two groups was further divided into five groups: C (Control), SH (Sham), TI (tendon injury), TI + ESWT, and TI + PEMF. Biomechanical evaluations revealed that maximum load, toughness, and maximum stress averages of the TI + PEMF group significantly increased (P < 0.05). When immunohistochemical images of the TI + PEMF group were compared with those of the TI group, the amount of fibrous tissue was less, the homogeneity of collagen fibers recovered, and collagen organization was more uniform. We conclude that both ESWT and PEMF are equally efficient for Achilles tendon recovery. PEMF application is effective and can be used in the clinic as a painless alternative treatment method. © 2020 Bioelectromagnetics Society.

Role of Mechanical Loading for Platelet-Rich Plasma-Treated Achilles Tendinopathy

There is no consensus on the optimal rehabilitation protocol after platelet-rich plasma (PRP) treatment for tendinopathy despite basic science studies showing the critical role of mechanical loading in the restoration of tendon structure and function posttreatment. In this article, we will review tendon mechanobiology, platelet biology, and review levels I and II Achilles tendon clinical studies paying particular attention to the role of mechanical loading in rehabilitation of injured tendons. Animal studies emphasize the synergistic effect of mechanical tendon loading and PRP to treat tendon injury while clinical studies described minimal details on loading protocols.

Efficacy of platelet-rich plasma injection in mild and moderate carpal tunnel syndrome: randomized control study

Background

Carpal tunnel syndrome (CTS) is the most common peripheral entrapment neuropathy. Typical symptoms and signs include numbness, tingling, pain, or burning sensation in the digits supplied by the median nerve and/or nocturnal paresthesia. Treatments of CTS range from conservative measures to surgical decompression of the median nerve.

Results

The PRP group showed a statistically significant reduction in the visual analog scale, Boston Carpal Tunnel Syndrome Questionnaire, for the severity and the functional capacity scores, and cross-sectional area of the median nerve compared to those of control group 3 months post-treatment (p < 0.05).

Conclusions

Platelet-rich plasma injection in CTS relieves pain and symptom severity and improves functional status but not significantly improve the electrophysiological parameters.

Cytokine and Growth Factor Delivery from Implanted Platelet-Rich Fibrin Enhances Rabbit Achilles Tendon Healing

Tendons are hypocellular and hypovascular tissues, and thus, their natural healing capacity is low. In this study, we sought to evaluate the efficacy of platelet-rich fibrin (PRF) to serve as a bioactive scaffold in promoting the healing of rabbit Achilles tendon injury. For in vitro study, the essence portion of PRF was determined through bioluminescent assay. Furthermore, we analyzed the time-sequential cytokines-release kinetics of PRF and evaluated their effects on tenocytes proliferation and tenogenic gene expressions. In animal study, the rabbit Achilles tendon defect was left untreated or implanted with normal/heat-denatured PRF scaffolds. Six weeks postoperatively, the specimens were evaluated through sonographic imaging and histological analysis. The results revealed significantly more activated platelets on bottom half of the PRF scaffold. Cytokine concentrations released from PRF could be detected from the first hour to six days. For the in vitro study, PRF enhanced cell viability and collagen I, collagen III, tenomodulin, and tenascin gene expression compared to the standard culture medium. For in vivo study, sonographic images revealed significantly better tendon healing in the PRF group in terms of tissue echogenicity and homogeneity. The histological analysis showed that the healing tissues in the PRF group had more organized collagen fiber, less vascularity, and minimal cartilage formation. In conclusion, bioactive PRF promotes in vitro tenocytes viability and tenogenic phenotypic differentiation. Administration of a PRF scaffold at the tendon defect promotes tissue healing as evidenced by imaging and histological outcomes.

Perineural Platelet-Rich Plasma for Diabetic Neuropathic Pain, Could It Make a Difference?

Objective

To evaluate the clinical effect of perineural platelet-rich plasma (PRP) injection for pain and numbness alleviation in diabetic peripheral neuropathy (DPN).

Study Design

A randomized prospective clinical trial.

Setting

Pain clinic and Rheumatology and Rehabilitation Departments, Assiut University Hospital.

Methods

Sixty adult patients with type II DM accompanied by DPN of at least six months’ duration were assessed by modified Toronto Clinical Neuropathy Score (mTCNS) and randomly allocated into two groups. Group I underwent ultrasound-guided perineural PRP injection and medical treatment, and Group II received medical treatment only. Patients were followed up at months 1, 3, and 6 with regard to pain and numbness visual analog scale (VAS) and mTCNS scores.

Results

Significant improvement was recorded in pain and numbness VAS scale scores in group I vs group II (P ≤ 0.001 during the whole study period for both parameters); at the same time, mTCNS improved in group I in comparison with group II with P = 0.01, 0.001, and &lt;0.001 at months 1, 3, and 6, respectively.

Conclusions

Perineural PRP injection is an effective therapy for alleviation of diabetic neuropathy pain and numbness and enhancement of peripheral nerve function.

Enhancement of abdominal wall defect repair using allogenic platelet-rich plasma with commercial polyester/cotton fabric (Damour) in a canine model

Platelet-rich plasma (PRP) has an important role in musculoskeletal surgery; however, it has been underutilized for accelerating the healing of abdominal wall defects in veterinary practice. Therefore, the aim of this study was to evaluate the use of commercial polyester/cotton fabric (Damour) as a new composite mesh for the repair of experimentally induced abdominal wall defects in canine models, and to investigate the possible role of PRP for improving such repair and reducing allied complications. For this purpose, abdominal wall defects were created in 24 healthy mongrel dogs and then repaired with mesh alone (control group) or mesh and allogenic PRP (PRP group). Dogs were euthanized after 2 or 4 months for gross examination of implantation site, detection of adhesion score and hernia recurrence. Moreover, tissue samples were collected for histological and gene expression analyses for neovascularization, collagen formation and tissue incorporation. Hernia recurrence was not recorded in PRP-treated dogs that also displayed significantly more neovascularization and less severe adhesion to the underlings (1.08 ± 0.51) in comparison to control group (2.08 ± 0.99). Histological and molecular evaluation confirmed the gross findings that collagen deposition, new vessel formation, and overexpression of angiogenic and myofibroplastic genes (COL1α1, COL3α1, VEGF and TGFβ1) were observed more frequently in the PRP group, at both time points. In conclusion, we found that addition of allogenic PRP to Damour mesh enhanced neovessel formation, and increased tissue deposition and incorporation, with subsequent reduction of peritoneal adhesion and recurrence rate.

Six-month efficacy of platelet-rich plasma for carpal tunnel syndrome: A prospective randomized, single-blind controlled trial

Recently, a few small reports with short follow-up period have shown clinical benefits of platelet-rich plasma (PRP) for peripheral neuropathy including one pilot study and one small, non-randomized trial in patients with carpal tunnel syndrome (CTS). Therefore, we conducted a randomized, single-blind, controlled trial to assess the 6-month effect of PRP in patients with CTS. Sixty patients with unilateral mild-to-moderate CTS were randomized into two groups of 30, namely the PRP and control groups. In the PRP group, patients were injected with one dose of 3 mL of PRP using ultrasound guidance and the control group received a night splint through the study period. The primary outcome measure was the visual analog scale (VAS) and secondary outcome measures included the Boston Carpal Tunnel Syndrome Questionnaire (BCTQ) score, the cross-sectional area (CSA) of the median nerve (MN), electrophysiological findings of the MN, and finger pinch strength. The evaluation was performed before treatment and at 1, 3, and 6 months post-injection. The PRP group exhibited a significant reduction in the VAS score, BCTQ score, and CSA of MN compared to the those of control group 6 months post-treatment (p < 0.05). Our study demonstrates that PRP is a safe modality that effectively relieves pain and improves disability in the patients with CTS.