Can platelet-rich plasma (PRP) improve bone healing? A comparison between the theory and experimental outcomes

[Treatment regimen for deep sternal wound infections after cardiac surgical interventions in an interdisciplinary approach]

The aim of this article is to present the importance of a structured and situation-adapted approach based on the diagnostic and therapeutic strategy in the interdisciplinary treatment of 54 patients with deep sternal wound infections (DSWI) after cardiac surgical interventions and the results achieved. The patients were 41 men and 13 women with an average age of 65.1 years, who developed a DSWI after a cardiac surgical intervention during the period 2003-2016. The treatment strategy included a thorough debridement including the removal of indwelling foreign material, the reconstruction with a stable re-osteosynthesis after overcoming the infection and if necessary, situation-related surgical flaps for a defect coverage with a good blood supply and mandatory avoidance of dead spaces. A total of 146 operations were necessary (average 2.7 operations/patient, range 1-7 operations). In 24.1 % of the cases a one-stage approach could be carried out. In 41 patients negative pressure wound therapy (NPWT) with programmed sponge changing was used for wound conditioning (mean 5 changes, standard deviation, SD± 5.6 changes over 22 days, SD± 23.9 days, change interval every 3-4 days in 40.7% of the cases). In 33 patients a bilateral myocutaneous pectoralis major flap was used, in 4 patients a vertical rectus abdominis myocutaneous (VRAM) flap and in 7 patients both were carried out. A total of 43 osteosynthesis procedures were carried out on the sternum with fixed-angle titanium plates. Of the patients 7 died during intensive care unit treatment (total mortality 13 %, n = 5, 9.3 % ≤ 30 days) or in the later course. Of the patients 47 (87.1 %) could be discharged with a cleansed infection. In 2 patients the implant was removed after 2 years due to loosening.

Core decompression combined with platelet-rich plasma-augmented bone grafting for femur head necrosis: a systematic review and meta-analysis

BACKGROUND

The clinical potential of biologic augmentation in core decompression and bone grafting for femoral head necrosis is widely acknowledged, with platelet-rich plasma (PRP) being a frequently employed biologic adjunct. However, its clinical application is not standardized, and high-level evidence is lacking. This study aimed to evaluate the efficacy and safety of core decompression and bone grafting combined with PRP for femur head necrosis.

METHODS

Several databases were systematically retrieved for randomized controlled trials comparing core decompression and bone grafting combined with or without PRP. A systematic review and meta-analysis were conducted following the PRISMA 2020 and AMSTAR 2 guidelines. The study is registered with PROSPERO under the code CRD42022361007, and it is also listed in the research registry under the identification number reviewregistry1537.

RESULTS

Eleven studies with 642 participants (742 hips) were included. The pooled estimates revealed that when core decompression and bone grafting were combined with PRP, the Harris hip score (mean difference: 7.98; 95% CI: 5.77-10.20; P <0.001), visual analog scale (SMD: -0.68; 95% CI: -0.96 - -0.40; P <0.001) and the pain component of Harris hip score (SMD: 8.4; 95% CI: 4.12-12.68; P <0.001), and reduction of radiographic progression [risk ratio (RR): 0.40; 95% CI: 0.27-0.59; P <0.001] were superior to core decompression and bone grafting alone. Fewer patients with treatment failure (RR: 0.27; 95% CI: 0.14-0.52; P <0.001) and higher good-to-excellent results (RR: 1.48; 95% CI: 1.17-1.86; P <0.001) were observed in treatment groups than control groups. Meanwhile, the pooled analysis substantiated the superior safety profile of PRP (RR: 0.29; 95% CI: 0.11-0.77; P =0.01).

CONCLUSIONS

The combination of core decompression and bone grafting with PRP is superior to the approach without PRP, demonstrating enhanced effectiveness in terms of function, pain relief, and radiographic progression. Additionally, it results in lower rates of treatment failure and adverse events. However, further high-quality RCTs are needed to evaluate their effectiveness due to methodological and implementation limitations observed in the existing evidence.

A Comprehensive Review of Platelet-Rich Plasma and Its Emerging Role in Accelerating Bone Healing

This comprehensive review delves into the emerging role of platelet-rich plasma (PRP) in accelerating bone healing. PRP, a blood-derived product rich in platelets and growth factors, has garnered attention for its regenerative potential. The review begins by defining PRP and providing a historical background, highlighting its significance in expediting bone healing. PRP's composition and preparation methods, including centrifugation techniques and commercial kits, are explored. Mechanistically, PRP operates by releasing growth factors, chemotaxis, and angiogenesis, elucidating its cellular effects. Applications in fracture healing and orthopaedic surgeries, such as joint arthroplasty and spinal fusion, are discussed, emphasising the promising outcomes in clinical trials. Safety considerations, patient selection criteria, and the need for PRP preparation and application standardisation are underscored. The review outlines ongoing research trends, potential technological advancements, and unexplored areas in paediatric applications and inflammatory bone disorders. The implications for clinical practice involve informed decision-making, optimised protocols, and interdisciplinary collaboration. In conclusion, the future of PRP in bone healing holds exciting prospects, with the potential for precision medicine, integration with emerging therapies, expanded applications, and enhanced technological innovations shaping its trajectory in orthopaedics and regenerative medicine.

Long-term outcomes of atrophic/oligotrophic non-unions in dogs and cats treated with autologous iliac corticocancellous bone graft and circular external skeletal fixation: 19 cases (2014-2021)

OBJECTIVES

To determine the short- and long-term outcomes and complications in dogs and cats undergoing surgical treatment for viable oligotrophic and nonviable atrophic non-unions using circular external skeletal fixation and autologous corticocancellous bone graft.

MATERIALS AND METHODS

In this case series, the medical records and radiographs of all dogs and cats with radius/ulna and tibia/fibula viable oligotrophic and nonviable atrophic non-unions treated with corticocancellous bone graft and circular external skeletal fixation at two referral veterinary hospitals between 2014 and 2021 were retrospectively reviewed. The long-term follow-up was 1 year or greater.

RESULTS

Thirteen dogs and six cats with 19 non-union fractures met the inclusion criteria for the study. Eighteen non-union fractures (94.7%) healed and one did not. Five patients (26%) had minor perioperative period complications (<3 months). The patient that did not achieve bone union underwent revision surgery with internal fixation (plate and screws) and autologous cancellous bone graft. Fifteen (78.9%) cases returned to full function and three (15.8%) cases returned to acceptable function in the long-term follow-up period.

CLINICAL SIGNIFICANCE

The use of circular external skeletal fixation associated with autologous corticocancellous bone graft for the treatment of radius/ulna and tibia/fibula atrophic/oligotrophic non-union fractures in dogs and cats was considered successful in the majority of patients and was free of major or catastrophic complications.

Autologous concentrated growth factor mediated accelerated bone healing in root-end microsurgery: A multicenter randomized clinical trial

Introduction

Concentrated growth factor (CGF) is a new-generation autologous platelet concentrate that promotes tissue regeneration and has anti-inflammatory properties. This randomized multicenter trial aimed to evaluate the effects of CGF on bone healing in combination with root-end microsurgery.

Methods

Healthy adult patients indicated for root-end microsurgery were randomly assigned to either the CGF or control (no CGF implantation) groups. CGF was implanted into the bone cavity after root-end filling with mineral trioxide aggregate. Clinical and periapical radiographic evaluations were conducted at 1, 3, 6, and 12 months postoperatively, with follow-up cone-beam computed tomography (CBCT) at 6 months. The lesion volume reduction rate was calculated based on data from the preoperative and follow-up CBCT images.

Results

A total of 24 patients were enrolled. The treatment success rate was 91.7% and 83.3% on 12-month periapical radiography and 6-month CBCT, respectively, without a significant difference between the two groups. The lesion volume reduction rate in the CGF group (75.6%) was significantly higher than that in the control (61.0%) group.

Conclusions

Autologous CGF in conjunction with root-end microsurgery accelerated lesion reduction as observed on CBCT. Administering autologous blood products to stimulate healing in addition to removing the source of infection appears to be a promising treatment option for root-end microsurgery.

Human Mesenchymal Stem Cells and Innovative Scaffolds for Bone Tissue Engineering Applications

Stem cell-based therapy is a significant topic in regenerative medicine, with a predominant role being played by human mesenchymal stem cells (hMSCs). The hMSCs have been shown to be suitable in regenerative medicine for the treatment of bone tissue. In the last few years, the average lifespan of our population has gradually increased. The need of biocompatible materials, which exhibit high performances, such as efficiency in bone regeneration, has been highlighted by aging. Current studies emphasize the benefit of using biomimetic biomaterials, also known as scaffolds, for bone grafts to speed up bone repair at the fracture site. For the healing of injured bone and bone regeneration, regenerative medicine techniques utilizing a combination of these biomaterials, together with cells and bioactive substances, have drawn a great interest. Cell therapy, based on the use of hMSCs, alongside materials for the healing of damaged bone, has obtained promising results. In this work, several aspects of cell biology, tissue engineering, and biomaterials applied to bone healing/regrowth will be considered. In addition, the role of hMSCs in these fields and recent progress in clinical applications are discussed. Impact Statement The restoration of large bone defects is both a challenging clinical issue and a socioeconomic problem on a global scale. Different therapeutic approaches have been proposed for human mesenchymal stem cells (hMSCs), considering their paracrine effect and potential differentiation into osteoblasts. However, different limitations are still to be overcome in using hMSCs as a therapeutic opportunity in bone fracture repair, including hMSC administration methods. To identify a suitable hMSC delivery system, new strategies have been proposed using innovative biomaterials. This review provides an update of the literature on hMSC/scaffold clinical applications for the management of bone fractures.

Multifactorial assessment of leukocyte reduced platelet rich plasma injection in dogs undergoing tibial plateau leveling osteotomy: A retrospective study

This study assessed the effects of concurrent intra-articular injection and Tibial Plateau Leveling Osteotomy (TPLO) plate surface treatment with leukoreduced platelet rich plasma (lPRP) on outcomes of dogs undergoing TPLO. A retrospective study of medical records for cases presenting from January 2018 to December 2020 was performed. Client-owned dogs with naturally occurring cranial cruciate ligament rupture that underwent TPLO surgery were divided into two groups. The lPRP group included cases that underwent intra-articular injection and plate surface treatment at the time of their TPLO. The control group (C) underwent TPLO without PRP treatment. Data analyzed included: presence of surgical site infection, implant removal rate, degree of change in OA progression score, lameness score progression and radiographic bone healing. The short- and long-term complication rate, hospitalization and antibiotic therapy were also compared between the groups. Descriptive statistics, comparison analyses (Chi square test, t-test, Fisher's exact test) and multi-level logistic regression models were used for statistical analysis. A total of 110 cases met the study inclusion criteria: 54 = lPRP, 56 = C. There were no significant differences between groups with regard to gender, age, presence of meniscal tear, weight, or body condition score. Significant findings included: improved radiographic healing of the osteotomy in the lPRP group, improved global OA scores in the lPRP group, and improved lameness score at recheck examination in the lPRP group. There was no significant difference between the lPRP and C group with regard to surgical site infection and implant removal rate. Concurrent intra-articular injection and plate surface treatment with leukocyte reduced PRP at the time of TPLO, is beneficial in slowing the progression of OA, hastening the radiographic evidence of osteotomy healing, and improved lameness score on recheck examination. Leukocyte reduced PRP was not a significant factor in reducing SSI or implant removal rate.

Regenerative medicine for the treatment of chronic low back pain: a narrative review

Low back pain (LBP) is a common and important clinical problem. In addition to pain, patients are also affected by personal, social, and economic burdens. Intervertebral disc (IVD) degeneration is a common cause of LBP, further increasing the patient's morbidity and medical costs. The limitations of current treatment strategies for long-term pain relief mean that increasing attention has been paid to regenerative medicine. We carried out a narrative review to explore the roles of four types of regenerative medicine for treating LBP: marrow-derived stem cells, growth factors, platelet-rich plasma, and prolotherapy. Marrow-derived stem cells are regarded as an ideal cell source for IVD regeneration. Growth factors may stimulate the synthesis of extracellular matrix and attenuate or reverse the degenerative process in IVD, while platelet-rich plasma, which contains multiple growth factors, is thought to be a promising alternative therapy for IVD degeneration. Prolotherapy can initiate the body's inflammatory healing response to repair injured joints and connective tissues. This review summarizes the mechanisms, in vitro and in vivo studies, and clinical applications of these four types of regenerative medicine in patients with LBP.

Freeze-dried Platelet-rich Plasma and Stem Cell-conditioned Medium for Therapeutic Use in Horses

This study investigated platelet-rich plasma (PRP) and adipose stem cell-conditioned medium (ASC-CM) use as a strategy to accelerate tissue healing. Platelet-derived growth factor (PDGF) and vascular endothelial growth factor (VEGF) were quantified in fresh and freeze-dried PRP and ASC-CM, and a stability test was performed in the freeze-dried samples (90 and 180 days of storage). A cell proliferation test was performed using equine mesenchymal stem cell culture in reconstituted PRP gel mesh after freeze-drying. In vivo PRP, ASC-CM applications, or their association were performed in induced wounds at 15 and 9-day intervals, according to the treatments: saline solution (control), PRP, ASC-CM, or ASC-CM + PRP. Horses were monitored through photographs and wound area measurements on days 5, 7, 15, and 24 after lesion induction. Skin biopsies were obtained on days 15 and 24 of the experiment. PDGF and VEGF quantification did not differ between fresh or freeze-dried treatments, was similar after freeze-drying or 90 days of storage, but showed a significant reduction after 180 days of storage. Comparing all treatments, no differences were observed in the histopathological analyses. For inflammation, fibroplasia, and collagen formation, only the time effect between the first and second biopsies was significant. The cell proliferation test revealed intense multiplication in the PRP gel mesh. Healing time was similar among all treatments. In conclusion, our results showed the possibility to produce and maintain freeze-dried PRP and ASC-CM for 90 days. Further studies are needed to better explore the in vivo therapeutic PRP and ASC-CM effects.

Orthobiologic Use in Sports Injuries

Orthobiologics have gained much popularity in recent years but there has not been a large amount of clinical evidence to support their use. In the limited research that has been published, they have been shown to be effective and safe. They can assist in earlier return to activity with the avoidance of surgery. They can also augment current surgical practice to aid in healing and return to sport with few complications. With new medical innovation, there is unfortunately a higher cost for these products. The use of orthobiologics will only grow and so will the need for high-level clinical evidence.

Overview of First-Line and Second-Line Pharmacotherapies for Osteoarthritis with Special Focus on Intra-Articular Treatment

Osteoarthritis (OA) can be defined as the result of pathological processes of various etiologies leading to damage to the articular structures. Although the mechanism of degenerative changes has become better understood due to the plethora of biochemical and genetic studies, the drug that could stop the degenerative cascade is still unknown. All available forms of OA therapy are based on symptomatic treatment. According to actual guidelines, comprehensive treatment of OA should always include a combination of various therapeutic options aimed at common goals, which are pain relief in the first place, and then the improvement of function. Local treatment has become more common practice, which takes place between rehabilitation and pharmacological treatment in the hierarchy of procedures. Only in the case of no improvement and the presence of advanced lesions visible in imaging tests, should surgery be considered. Currently, an increasing number of studies are being published suggesting that intra-articular injections may be as effective or even more effective than non-steroidal anti-inflammatory drugs (NSAIDs) and result in fewer systemic adverse events. The most commonly used preparations are hyaluronic acid (HA), glucocorticosteroids (GS), and also platelet-rich plasma (PRP) in recent years. This review aims to present the mechanism of action and clinical effectiveness of different pharmacological options in relieving pain and improving functions in OA as well as the emerging approach in intra-articular treatment with PRP.

Clinical Effectiveness of Platelet-Rich Plasma for Long-Bone Delayed Union and Nonunion: A Systematic Review and Meta-Analysis

Background

More recently, there was a series of clinical studies focusing on local administration of platelet-rich plasma (PRP) in long-bone fracture patients suffering from delayed union and nonunion. Therefore, we performed a systematic review to evaluate the effectiveness of PRP injection for treatment of patients with long-bone delayed union and nonunion.

Methods

Relevant clinical trials were selected by the main bibliographic databases, including Medline, PubMed, Embase, Web of Science, and the Cochrane library, to evaluate the effectiveness of PRP for long-bone fracture patients diagnosed with delayed union or nonunion by two reviewers independently. The main outcomes included healing rate, healing duration, pain relief, functional outcome, and complications.

Results

Finally, thirteen studies including four hundred and fifty-nine participants met the selection criteria and were included in this systematic review. These articles included three randomized controlled studies, one prospective study, and nine retrospective studies. 146 out of 155 (94.19%) patients treated with PRP during operation, and 144 out of 183 (78.69%) patients treated with PRP injection alone, exhibited bone consolidation. The healing rate of the PRP group (85.80%) was higher than that of the control group (60.76%). The mean bony union time of patients treated and untreated with PRP, were, respectively, 4.64 and 5.15 months. Four papers reported that PRP was effective in pain relief of patient with delayed union and nonunion. Complications, including small subcutaneous hematoma, subcutaneous swelling, and postoperative infection, were also reported in enrolled studies.

Conclusions

PRP is a promising alternative treatment for patients with long-bone delayed union and nonunion. PRP could successfully promote the healing rate and relieve the pain of patients with delayed union and nonunion. However, the long-term adverse side and functional outcome in application of PRP still need further large-scale trials and long-term follow-up.

Systematic Review Registration

https://www.researchregistry.com/browse-the-registry#home/registrationdetails/61dbd2f837e948001e68d5c5/, The identifying number is research registry 7525.

The Impact of Nano-Crystal Hydroxyapatites on the Regeneration of Bone Defects

Calcium hydroxyapatite is a widely used material for replacing bone defects. However, the effectiveness of nano-crystalline calcium hydroxyapatite produced from eggshells in the replacement of bone defects has not been investigated yet. The study aimed to evaluate the effectiveness of using nano-crystalline calcium hydroxyapatite made from eggshell for the healing of bone defect of the femur in rats. Forty-eight (n=48) rats underwent a surgical procedure to simulate femoral defect. The animals were sub-divided into 4 groups (each with n=12) depending on the methods of bone defect replacement: I control group (CG) (without bone defect replacement); II intervention group (the bone defect was replaced by PRP (PRP); III intervention group (the bone defect was replaced by nano-crystalline hydroxyapatite obtained from eggshell) (HA) and IV interventional group (the bone defect was replaced by a combination of hydroxyapatite and PRP) (HA+PRP). The degree of effectiveness of studied methods was assessed using radiological (on the 14th day), histological (on the 61st day), and biomechanical analysis (on the 61st day). According to radiographic data, the CG group had the lowest level of bone regeneration after 14 days (4.2 ±1.7%). In the HA + PRP group, the level of bone regeneration was 22.1±7.1 %, which was higher in comparison with the rates of consolidation of bone defects in the HA group (20.7± 9.3) (p = 0.023). According to the histo-morphometry data, the rates of bone tissue regeneration in the PRP group (19.8 ±4.2%) were higher in comparison with the CG group (12.7 ± 7.3%), (p>0.05). In the HA+PRP group, bone regeneration rates (48.9±9.4 %) were significantly higher (p=0.001) than in the HA group (35.1±9.8%). According to the results of biomechanical assessment under the maximum stress (121.0722), the maximum bending deformation of the contralateral bone without defect was 0.028746, which was higher than the indicators of the HA+PRP group, where at the maximum stress (90.67979) the bending deformation was 0.024953 (p>0.05). Compared to CG, PRP, and HA, biomechanical bone strength was significantly higher in the HA + PRP group (p≤0.01). At the maximum stress (51.81391), the maximum bending strain in the CG group was 0.03869, which was lower than in the PRP group, where the maximum stress and bending strain were 59.45824 and 0.055171, respectively (p>0.05). However, the bone strength of the HA group was statistically significantly higher compared to the CG and PRP groups (p<0.01).

The results demonstrated the effectiveness of the use of nanocrystalline calcium hydroxyapatite obtained from eggshell in the healing of a bone defect. The best results were observed in the group of the combined use of nano-crystalline calcium hydroxyapatite and PRP.

Comparison between intra-articular infiltrations of placebo, steroids, hyaluronic and PRP for knee osteoarthritis: a Bayesian network meta-analysis

INTRODUCTION

Regarding the efficacy of intra-articular injections of platelet-rich plasma, hyaluronic acid and corticosteroids, current evidence is controversial. The superiority of one technique over another is questioned and debates are ongoing. The purpose of the present study was to compare and investigate the efficacy of these intra-articular infiltrations in patients with knee osteoarthritis (OA). A Bayesian network meta-analysis of randomized clinical trials (RCTs) was conducted comparing patient outcomes at 3, 6 and 12-months of follow-up.

MATERIALS AND METHODS

This Bayesian network meta-analysis was conducted according to the PRISMA extension statement for reporting systematic reviews incorporating network meta-analyses of health care interventions. All the RCTs comparing the outcomes of two or more intra-articular infiltrations of interest for knee OA were considered for inclusion. The outcomes of interest were the WOMAC and VAS scores. The network meta-analyses were performed using the STATA routine for Bayesian hierarchical random-effects models.

RESULTS

Data from 30 RCTs (3463 patients) were collected. At 3-months follow-up, PRP showed the best WOMAC scores, followed by the Placebo, CCS and HA. At 6-months follow-up, PRP showed the best WOMAC scores, followed by HA, CCS and Placebo. At 12-months follow-up, PRP showed the best WOMAC scores, followed by the Placebo, HA and CCS. At 3-months follow-up, the PRP showed the best VAS scores, followed by CCS, HA and Placebo. At 6-months follow-up, PRP showed the best VAS scores, followed by CCS, Placebo and HA. At 12-months follow-up, the PRP showed the best VAS scores, followed by CCS, Placebo and HA.

CONCLUSION

Intra-articular injections of PRP demonstrated the best overall outcome compared to steroids, hyaluronic acid and placebo for patients with knee osteoarthrosis at 3, 6 and 12-months follow-up. Among CCS, hyaluronic acid and placebo, no discrepancies were detected.

LEVEL OF EVIDENCE

I, Bayesian network meta-analysis of RCTs.

Classification and coding of platelet-rich plasma derived from New Zealand white rabbits for tissue engineering and regenerative medicine applications

BACKGROUND AND OBJECTIVE

Platelet-rich plasma (PRP) is a category of platelet concentrate that has been widely used as a therapeutic modality in musculoskeletal medicine. The present study was conducted to classify and code the non-activated platelet-rich plasma (nPRP) derived from New Zealand white rabbits for tissue engineering and other regenerative medicine applications.

METHODS

PRP was prepared from the whole blood by double centrifugation protocol using a laboratory centrifuge. The prepared nPRP was characterized using the parameters such as platelet dose, the relative composition of platelets, WBC, and RBC. The production protocol was described using the parameters such as platelet enrichment factor, factor increase in WBC concentration, platelet capture efficiency, WBC-reducing efficiency, and RBC-reducing efficiency. The nPRP was also classified and coded using the most recent and universally accepted classification and coding systems.

RESULTS

The non-activated leukocyte-poor red cell-rich PRP had an average platelet count of 1875.75 × 10⁹/L, which is higher than the basal platelet concentration in the whole blood. Furthermore, the protocol used in this study has a mean platelet capture efficiency of 47.43 ± 6.42%.

CONCLUSION

The protocol described in this study can be used to prepare non-activated leukocyte-poor red cell-rich PRP (Red-PRP IC1) from rabbits that can be coded as 318-00-00.

Platelet Concentrate In Lumbar Interbody Cage Fusion: A New Era of Modality Of Fusion

AIM: This was a prospective double-blinded randomized comparative study. Several authors have reported the efficacy of platelets derivatives for spinal union. However, the use of PRP and PRF for bone fusion with TLIF has not been fully explored. METHODS: Standard open TLIF surgery was performed on 80 patients, randomized in three groups, TLIF and local bone were used in 40 patients (control group) and TLIF, local bone, and PRP were used in 20 patients (PRP group) and PRF was used in 20 patients (PRF group). Radiological parameters were assessed by X-ray after 3 months post-operative to evaluate the position of the screws and cage migration and by CT scans at 6 months and 12 months postoperatively. Patients, surgeons, and post-surgical analysis were blinded. RESULTS: VAS scores for lower back pain and leg pain were statistically significant between the three groups preoperatively. The VAS scores of back pain improved after 12 months and were statistically significant (p < 0.001) and the VAS score of leg pain improved compared with preoperatively in the three groups during the 6- and 12-month follow-up postoperatively, however, the three groups, VAS scores for leg pain were not significantly different. After 1-year follow-up, significantly more patients achieved definite fusion, when implanted platelets derivatives compared with the control group, but with no significance regarding fusion rates. CONCLUSION: We advocated using platelet derivative as a fusion enhancer modality which is cost and time saving. It appears to be a complementary step that ensures better outcome for the patients.

Application of a collagen scaffold saturated with platelet-rich plasma in prevention of bisphosphonate-related osteonecrosis of the jaw in the rat animal model

BACKGROUND

Among the myriad adverse events of drugs in the oral cavity, Bisphosphonate-related osteonecrosis of the jaw (BRONJ) is one of the most detrimental drug reactions that have ever been known.

OBJECTIVE

This study was aimed to investigate the success of applying collagen scaffold alone and platelet-rich plasma (PRP)+collagen scaffold in prevention of zoledronic acid-induced BRONJ in the rat.

METHODS

A total of 17 male Wistar-rats were treated with 4 weekly doses of zoledronic acid. All rats were undergone bilateral tooth extraction of mandibular first molars and divided into three groups of scaffold + PRP + suture, scaffold + suture, and suture only. All rats were scarified and clinical, radiological, histological and histomorphomerical evaluations were made on week 8 post-treatment. The soft tissue healing, bone mineralized density (BMD), number of osteoclasts and osteoblasts, necrotic bone (NB), intensity of inflammation and new bone formation (NBF) were analyzed.

RESULTS

BMD, number of osteoblasts and NBF variables proved to be statistically were higher in the treatment groups than the control group. In addition, the PRP + scaffold group showed the better results in terms of BMD, number of osteoblasts and NBF than that of the scaffold alone group. Number of osteoclasts, inflammation intensity and osteonecrosis were also significantly different in the PRP + scaffold group compared to the scaffold alone and the control groups.

CONCLUSION

Application of a PRP-enriched collagen scaffold appeared to be a successful preventive treatment for BRONJ by effecting of the number of osteoblasts and osteoclasts, BMD, NBF, inflammation, and osteonecrosis.

Platelet-rich plasma: a narrative review

The aim of this article was to synopsize platelet-rich plasma (PRP) use in musculoskeletal pathologies through evidence-based assessment of the preparation, classification, mechanism of action and applications of PRP, thereby answering which PRP type is best for each clinical indication.

The literature search was performed using Medline, EMBASE and Cochrane Reviews databases for papers containing the key terms “platelet-rich plasma” AND “orthopaedics” AND (“classification” OR “mechanism of action” OR “preparation” OR “clinical application”). Generated papers were evaluated for pertinence in following areas: preparation, classification, mechanism of action, clinical application within orthopaedics. Non-English papers were excluded. Included studies were evaluated for quality.

Sixty studies were included in our review. There are many commercial PRP preparation kits with differing component concentrations. There is no consensus on optimal component concentrations. Multiple PRP classifications exist but none have been validated. Platelet-rich plasma acts via growth factors (GFs) released from α-granules within platelets. Growth factors have been shown to be beneficial in healing. Grossly elevated concentrations of GFs may have inhibitory effects on healing. Multiple systematic reviews show efficacy of PRP in tendinopathies, early osteoarthritis, acute muscle injuries and in combination with rotator cuff repair and anterior cruciate ligament reconstruction.

The literature suggests leukocyte-rich PRP (L-PRP) is more beneficial in tendinopathies and pure PRP (P-PRP) is more beneficial in cartilage pathology. However, different PRP preparations have not been directly compared in any pathology. Classification of PRP type is frequently not stated in research. Standardization of PRP research parameters is needed to streamline findings and generate clear indications for PRP types to yield maximum clinical benefit.

Cite this article: EFORT Open Rev 2021;6:225-235. DOI: 10.1302/2058-5241.6.200017

Percutaneous injection of platelet-rich plasma to treat atrophic nonunion after internal fixation of ulnar fracture: a case report

Non-union is a serious postoperative complication of fracture. Early detection and intervention can avoid revision surgery. Platelet-rich plasma releases many active tissue factors and has potential to promote fracture healing. Percutaneous injection of platelet-rich plasma at the fracture site may avoid surgical treatment when non-union occurs. We present a case of atrophic non-union of an ulna fracture treated conservatively with percutaneous injection of platelet-rich plasma.

Injectable gelatin microspheres loaded with platelet rich plasma improve wound healing by regulating early inflammation

We investigated the potential of gelatin microspheres (GMs) loaded with platelet-rich plasma (PRP) to enhance their wound healing effect. Platelets from the PRP were immobilized onto GMs to form biomimetic bioreactor GM+PRP. The therapeutic effect of this agent was further investigated in vivo on a wound-healing model in rats. Wounds were locally injected with phosphate buffered saline (PBS), GM, PRP, and GM+PRP. Wound healing rate, vessel density, and inflammation level were measured histologically, by RT-PCR, and by Western blotting at days 3, 7, 14, and 21. Platelets on GM caused a continuous high release in both interleukin-10 and metalloproteinase-3 compared with PRP alone. Both GM+PRP and PRP successfully accelerated the wound healing process, while GM alone did not improve the wound healing process compared with the untreated control. Wounds treated with GM+PRP resulted in shorter healing period and improved dermal structure. GM+PRP improved angiogenesis in the wound by increasing expression of angiogenic factors. GM+PRP prolonged and enhanced the cytokine release profile compared with PRP. By promoting the inflammatory and angiogenic responses, GM+PRP has the potential to improve wound healing. Our findings demonstrate that GMs are an injectable carrier that enhanced the therapeutic effects of PRP.

Allogeneic Platelet-Rich Plasma: Is It Safe and Effective for Wound Repair?

BACKGROUND

Platelet-rich plasma (PRP) and its derivatives are an emerging biotechnology whereby concentrated platelets provide damaged tissue with growth factors, cytokines, and other mediators to improve healing outcomes. Although there is strong evidence in the benefits of autologous PRP for both acute and chronic wounds, allogeneic PRP has been studied far less in comparison.

SUMMARY

In this mini-review, we discuss critical steps of allogenic PRP (and its derivatives) preparation. We performed a non-systematic review of the literature to identify animal and human subject studies testing allogenic PRP for wound treatment. We searched OVID Medline and PubMed for articles using the keywords "wound, ulcer, lesion, skin, and cutaneous" and "PRP, or platelet-rich plasma, or platelet-rich fibrin, or PRF, or platelet releasate" and "homologous, allogeneic or allogenic," which were limited to non-review articles and English language. Two studies in animal models and 8 studies in patients were reviewed. There were inconsistencies in preparation methods, treatment regimens, and some lacked a control group in their studies. Despite these variations, none of the studies identified any major side effects or adverse events. The treatment resulted in a reduced time to heal and/or reduced wound size in most cases. Key Messages: In situations where autologous PRP is not available or suitable, allogeneic PRP appears to provide a safe alternative. Its efficacy, however, requires larger-scale studies with appropriate controls. Standardization in PRP preparation and treatment regime are also needed to be able to interpret allogenic PRP efficacy.

The platelet-rich plasma and mesenchymal stem cell milieu: A review of therapeutic effects on bone healing

Platelet-rich plasma is autologous plasma that contains concentrated platelets compared to whole blood. It is relatively inexpensive to produce, can be easily isolated from whole blood, and can be administered while the patient is in the operating room. Further, because platelet-rich plasma is an autologous therapy, there is minimal risk for adverse reactions to the patient. Platelet-rich plasma has been used to promote bone regeneration due to its abundance of concentrated growth factors that are essential to wound healing. In this review, we summarize the methods for producing platelet-rich plasma and the history of its use in bone regeneration. We also summarize the growth factor profiles derived from platelet-rich plasma, with emphasis on those factors that play a direct role in promoting bone repair within the local fracture environment. In addition, we discuss the potential advantages of combining platelet-rich plasma with mesenchymal stem cells, a multipotent cell type often obtained from bone marrow or fat, to improve craniofacial and long bone regeneration. We detail what is currently known about how platelet-rich plasma influences mesenchymal stem cells in vitro, and then highlight the clinical outcomes of administering platelet-rich plasma and mesenchymal stem cells as a combination therapy to promote bone regeneration in vivo.

The effect of platelet-rich plasma on fracture healing in long-bone pseudoarthrosis

PURPOSE

The aim of this study was to investigate the effects of platelet-rich plasma (PRP) on fracture union rate and fracture union time in pseudoarthrosis surgery and to evaluate the clinical and functional results of the patients.

METHODS

The patients who were undergone pseudoarthrosis surgery between 2011 and 2014 were evaluated retrospectively. Twenty-four patients were included in the study. Patients were divided into two groups with used PRP and not used PRP during surgery. There were 14 patients in the PRP group and 10 patients in the control group. The two groups were compared in terms of demographic characteristics, fracture union time, and functional scores of the Lower Extremity Functional Scale and Upper Extremity Functional Index.

RESULTS

Fractures were healed in both groups, and no complications were encountered. A statistically significant difference was found between the two groups in terms of fracture union time. The mean time of union was 5.3 months in the PRP group and 11.3 months in the control group (p: 0.000). There was no statistically significant difference between the two groups in terms of functional scores (p: 0.250).

CONCLUSION

As a result of our study, we concluded that PRP is an effective and safe method in pseudoarthrosis surgery that reduces fracture union time. Controlled studies with more patient numbers are needed.

Allogenic Bone Graft Enriched by Periosteal Stem Cell and Growth Factors for Osteogenesis in Critical Size Bone Defect in Rabbit Model: Histopathological and Radiological Evaluation

Background & Objective:

This study aimed to investigate the effect of decellularized allogeneic bone graft enriched by periosteal stem cells (PSCs) and growth factors on the bone repair process in a rabbit model, which could be used in many orthopedic procedures.

Methods:

In this experimental study, a critical size defect (CSD) (10 mm) was created in the radial diaphysis of 40 rabbits. In group A, the defect was left intact with no medical intervention. In group B, the defect was filled by a decellularized bone graft. In group C, the defect was implanted by a decellularized bone graft enriched with platelet growth factors. In group D, the defect was treated by a decellularized bone graft seeded by periosteal mesenchymal stem cells (MSCs). Also, in group E, the defect was filled by a decellularized bone graft enriched with platelet growth factors and periosteal MSCs. Radiological evaluation was done on the first day and then in the second, fourth, and eighth weeks after the operation. The specimens were harvested on the 28th and 56th postoperative days and evaluated for histopathological criteria.

Results:

The radiologic and microscopic analysis of the healing process in bone defects of the treated groups (C, D, and E) revealed more advanced repair criteria than those of groups A and B significantly (P<0.05).

Conclusion:

Based on this study, it appears that implantation of concentrated PSCs in combination with growth factors and allogeneic cortical bone graft is an effective therapy for the repair of large bone defects.

Emerging Options for Biologic Enhancement of Stress Fracture Healing in Athletes

In an era of continual single-sport specialization and year-round training, overuse injuries, including stress injuries of bone, are increasingly common. These injuries can be season- or even career-ending. For many elite and professional athletes, the traditional treatment strategy of immobilization and extended rest from sports participation is often not practical or acceptable. An understanding of modern strategies for evaluating and treating stress fractures is paramount for maintaining athletic participation and optimal athletic performance. This begins with the ability to categorize and stratify bony stress injuries by both severity and risk of fracture progression. Surgical procedures such as open reduction and internal fixation or intramedullary fixation with possible bone grafting remain the standard of care for chronic or severe stress fractures. However, emerging techniques to augment the biologic environment are a minimally invasive adjunct for stimulating and supporting bone healing in elite-level athletes to optimize bone health, expedite recovery, and decrease the risk of nonunion or catastrophic fracture.

Adult Stem Cells for Bone Regeneration and Repair

The regeneration of bone fractures, resulting from trauma, osteoporosis or tumors, is a major problem in our super-aging society. Bone regeneration is one of the main topics of concern in regenerative medicine. In recent years, stem cells have been employed in regenerative medicine with interesting results due to their self-renewal and differentiation capacity. Moreover, stem cells are able to secrete bioactive molecules and regulate the behavior of other cells in different host tissues. Bone regeneration process may improve effectively and rapidly when stem cells are used. To this purpose, stem cells are often employed with biomaterials/scaffolds and growth factors to accelerate bone healing at the fracture site. Briefly, this review will describe bone structure and the osteogenic differentiation of stem cells. In addition, the role of mesenchymal stem cells for bone repair/regrowth in the tissue engineering field and their recent progress in clinical applications will be discussed.

Platelet-rich plasma decreases fibroblastic activity and woven bone formation with no significant immunohistochemical effect on long-bone healing: An experimental animal study with radiological outcomes

PURPOSE

This study aimed to analyze the immunohistochemical effect of platelet-rich plasma (PRP) on healing of long-bone fractures in terms of bone morphogenetic protein-2 (BMP-2), vascular endothelial growth factor (VEGF), the Ki-67 proliferation index, and radiological and histological analyses.

METHODS

Sixteen adult rabbits, whose right femoral diaphysis was fractured and fixed with Kirschner wires, were randomly divided into two groups, control and PRP (groups A and B, respectively). PRP was given to group B at 1 week postoperatively, and all animals were euthanized after 12 weeks. Radiographic evaluations were performed periodically. Cortical callus formation, chondroid and woven bone area percentages, osteoblastic and fibroblastic activities, and mature bone formation were examined. The depths of BMP-2 and VEGF staining were measured. The Ki-67 proliferation index was also calculated.

RESULTS

The mean radiological union score of group B was significantly higher than that of group A. There were also statistically significant differences between groups A and B in terms of cortical callus formation, woven bone area percentage, fibroblast proliferation, and mature bone formation. Group B had significantly more cortical callus and mature bone formation with less woven bone and fibroblast proliferation. Immunohistochemical analysis revealed no statistically significant difference between the groups in terms of BMP-2 and VEGF staining and the Ki-67 index.

CONCLUSIONS

PRP had no effect on BMP-2 or VEGF levels with no increase in the Ki-67 proliferation index, although its application had a positive effect on bone healing by increasing callus and mature bone formation with decreased woven bone and fibroblast proliferation.

In Vivo Evaluation of the Genotoxic Effects of Poly (Butylene adipate-co-terephthalate)/Polypyrrole with Nanohydroxyapatite Scaffolds for Bone Regeneration

Here, butylene adipate-co-terephthalate/polypyrrole with nanohydroxyapatite (PBAT/PPy/nHAp) scaffolds were fabricated and characterized. The electrospinning process was carried out using 12 kV, a needle of 23 G, an infusion pump set at 0.3 mL/h, and 10 cm of distance. Afterwards, nHAp was directly electrodeposited onto PBAT/PPy scaffolds using a classical three-electrode apparatus. For in vivo assays (comet assay, acute and chronic micronucleus), 60 male albino Wistar rats with 4 groups were used in each test (n = 5): PBAT/PPy; PBAT/PPy/nHAp; positive control (cyclophosphamide); and the negative control (distilled water). Peripheral blood samples were collected from the animals to perform the comet test after 4 h (for damage) and 24 h (for repair). In the comet test, it was shown that the scaffolds did not induce damage to the % DNA tail and neither for tail length. After the end of 48 h (for acute micronucleus) and 72 h (for chronic micronucleus), bone marrow was collected from each rat to perform the micronucleus test. All of the produced scaffolds did not present genotoxic effects, providing strong evidence for the biological application of PBAT/PPy/nHAp scaffolds.

Hyaluronic acid hydrogels incorporating platelet lysate enhance human pulp cell proliferation and differentiation

The restoration of dentine-pulp complex remains a challenge for dentists; nonetheless, it has been poorly addressed. An ideal system should modulate the host response, as well as enable the recruitment, proliferation and differentiation of relevant progenitor cells. Herein was proposed a photocrosslinkable hydrogel system based on hyaluronic acid (HA) and platelet lysate (PL). PL is a cocktail of growth factors (GFs) and cytokines involved in wound healing orchestration, obtained by the cryogenic processing of platelet concentrates, and was expected to provide the HA hydrogels specific biochemical cues to enhance pulp cells' recruitment, proliferation and differentiation. Stable HA hydrogels incorporating PL (HAPL) were prepared after photocrosslinking of methacrylated HA (Met-HA) previously dissolved in PL, triggered by the Ultra Violet activated photoinitiator Irgacure 2959. Both the HAPL and plain HA hydrogels were shown to be able to recruit cells from a cell monolayer of human dental pulp stem cells (hDPSCs) isolated from permanent teeth. The hDPCs were also seeded directly over the hydrogels (5 × 10⁴ cells/hydrogel) and cultured in osteogenic conditions. Cell metabolism and DNA quantification were higher, in all time-points, for PL supplemented hydrogels (p < 0,05). Alkaline phosphatase (ALPL) activity and calcium quantification peaks were observed for the HAPL group at 21 days (p < 0,05). The gene expression for ALPL and COLIA1 was up-regulated at 21 days to HAPL, compared with HA group (p < 0,05). Within the same time point, the gene expression for RUNX2 did not differ between the groups. Overall, data demonstrated that the HA hydrogels incorporating PL increased the cellular metabolism and stimulate the mineralized matrix deposition by hDPSCs, providing clear evidence of the potential of the proposed system for the repair of damaged pulp/dentin tissue and endodontics regeneration.

Influence of Absorbable Calcium Sulfate-Based Bone Substitute Materials on Human Haemostasis-In Vitro Biological Behavior of Antibiotic Loaded Implants

Calcium sulfate (CS) formulations are frequently implanted as antibiotically impregnated bone substitutes in orthopedic and trauma surgery to prevent or treat bone infections. Calcium ions have been discussed as candidates to accelerate blood coagulation. The goal of this study is to evaluate substance-specific influences of CS formulations on blood coagulation. Specific ELISAs were conducted to determine markers of activated blood coagulation after incubation of human blood with CS beads. Additionally, wettability with freshly drawn human blood was measured. Three different types of CS bone substitute beads were compared (CS dihydrate with tripalmitin, containing Gentamicin (Herafill^®-G: Group A) or Vancomycin (CaSO₄-V: Group B); and a CS hemihydrate with Tobramycin (Osteoset^®: Group C)). Examinations were performed by ELISA assays for F₁₊₂, FXIIa and C3a. Our results prove that none of the CS preparations accelerated single specific assays for activated coagulation markers. This allows the conclusion that neither Herafill^®-G (CaSO₄-G) nor CaSO₄-V alter haemostasis negatively. Blood samples incubated with Osteoset^® display an elevated F₁₊₂-activity. The addition of tripalmitin in Herafill^®-G shifts the original into a significantly hydrophobic formulation. This was additionally proven by contact angle examination of the three substances with freshly drawn human blood, showing that acceleration of plasmatic coagulation is hindered by lipids and induced by surface effects caused by presence of rapidly soluble calcium ions in the Osteoset^® preparation.

Orthopaedic regenerative tissue engineering en route to the holy grail: disequilibrium between the demand and the supply in the operating room

Orthopaedic disorders are very frequent, globally found and often partially unresolved despite the substantial advances in science and medicine. Their surgical intervention is multifarious and the most favourable treatment is chosen by the orthopaedic surgeon on a case-by-case basis depending on a number of factors related with the patient and the lesion. Numerous regenerative tissue engineering strategies have been developed and studied extensively in laboratory through in vitro experiments and preclinical in vivo trials with various established animal models, while a small proportion of them reached the operating room. However, based on the available literature, the current strategies have not yet achieved to fully solve the clinical problems. Thus, the gold standards, if existing, remain unchanged in the clinics, notwithstanding the known limitations and drawbacks. Herein, the involvement of regenerative tissue engineering in the clinical orthopaedics is reviewed. The current challenges are indicated and discussed in order to describe the current disequilibrium between the needs and solutions made available in the operating room. Regenerative tissue engineering is a very dynamic field that has a high growth rate and a great openness and ability to incorporate new technologies with passion to edge towards the Holy Grail that is functional tissue regeneration. Thus, the future of clinical solutions making use of regenerative tissue engineering principles for the management of orthopaedic disorders is firmly supported by the clinical need.

[Recent advances in treatment of aseptic femoral shaft nonunion]

Objective

To review the recent advances in treatment of aseptic femoral shaft nonunion.

Methods

The clinical studies about the treatments of aseptic femoral shaft nonunion in recent years were widely reviewed and analyzed.

Results

There are several surgical methods for aseptic femoral shaft nonunion. Due to uncertain clinical outcome, dynamization of nail should be carefully selected. The exchange nailing is suitable for the hypertrophic nonunion of the isthmal femoral shaft fracture. The exchange lateral plating is suitable for nonunion with obvious malformation. However, wave plate or dual plate should be chosen when the bone nonuinon is combined with the medial defect. The augmentation plating improves the success rate of nailing for femoral shaft nonunion, but it should be carefully selected for patients with obvious deformity or bone defect. Ilizarov technique is suitable for various bone nonunion, especially with complicated or large segmental bone defects. Induced membrane technique is also an important method for the treatment of bone nonunion with large bone defects. The clinical efficacy of the blocking screw remains to be supported by further evidence. Biological stimulants are mainly used for atrophic nonunion, and the clinical efficacy of them alone are still controversial.

Conclusion

Due to lack of comparative studies between different surgical methods, the orthopedist should choose the appropriate treatment according to the individual situations of the patient and the types of bone nonunion.

Efficacy of platelet concentrates in pulpotomy - a systematic review

The main purpose of the present systematic review was to evaluate the efficacy of platelet concentrates in pulpotomy of human teeth. Our systematic search included Medline, Embase, CINAHL, PsycINFO, Scopus, key journals, and review articles; the date of the last search was July 30, 2017. We graded the methodological quality of the studies by Cochrane Risk of Bias tool. Four randomized controlled trails were included in the present systematic review. The number of study participants ranged from 28 to 50, with a mean of 45.5. The age of study participants ranged between 4 and 25 years. In three of the included studies, platelet-rich fibrin (autologous) was used and in one study lyophilized freeze-dried platelet (allogenic) was used as pulpotomy material. Calcium hydroxide and mineral trioxide aggregate were used in control groups. The quality assessment rated three studies as being of fair quality and one study as poor quality. Two of the included studies showed a 100% success of pulpotomy with platelet concentrates and two studies showed more than 80% of success, but the difference between control group and platelet concentrates group was not statistically significant. To conclude, the number of publications that met all inclusion criteria was found to be very limited and no significant difference was reported in the studies comparing platelet concentrates with other materials in pulpotomy. The present results point to the need for high-quality randomized controlled trials in further research.

Efficacy of platelet concentrates in bone healing: A systematic review on animal studies - Part B: Large-size animal models

In the presence of large bone defects, delayed bone union, or nonunion and fractures, bone reconstruction may be necessary. Different strategies have been employed to enhance bone healing among which the use of autologous platelet concentrates (APCs). Due to the high content of platelets and platelet-derived bioactive molecules (e.g., growth factors, antimicrobial peptides), they are promising candidates to enhance bone healing. However, both preclinical and clinical studies produced contrasting results, mainly due to a high heterogeneity in study design, objectives, techniques adopted, and outcomes assessed. The aim of the present systematic review was to evaluate the efficacy of APCs in animal models of bone regeneration, considering the possible factors that might affect the outcome. An electronic search was performed on MEDLINE and Scopus databases. Comparative animal studies with a minimum follow up of 2 weeks, at least five subjects per group and using APCs for regeneration of bone defects were included. Articles underwent risk of bias assessment and quality evaluation. Fifty studies performed on six animal species (rat, rabbit, dog, sheep, goat, mini-pig) were included. The present part of the review considers studies performed on small ruminants, dogs, and mini-pigs (14 articles). The majority of the studies were considered at low risk of bias. In general, APCs' adjunct positively affected bone regeneration. Animal species, platelet and growth factors concentration, type of bone defect and of platelet concentrate used seemed to influence their efficacy in bone healing. However, sound conclusions were not drawn since too few studies for each large-size animal model were included. In addition, characterization of APCs' content was performed only in a few studies. Further studies with a standardized protocol including characterization of the final products will provide useful information for translating the results to clinical application of APCs in bone surgery.

Biological Facet of Segmental Bone Loss Reconstruction

The management of long bone defects continues to be associated with significant challenges for optimum and timely bone repair. When bone grafting is needed, essential parameters to be addressed include adequate volume, optimum density, and structural capacity as well as potent biological properties. Although the autologous iliac crest bone graft remains the gold standard, its reduced availability and donor site morbidity have made the clinicians to seek for other alternative options. Reamer irrigator aspirator graft with materials used as graft expanders along with inductive molecules and cellular augmentation constitute the current trend for optimum bone regeneration. This article presents the contemporary thinking of the biological facet of segmental bone loss reconstruction.

Effects of platelet rich plasma and chondrocyte co-culture on MSC chondrogenesis, hypertrophy and pathological responses

Regarding the inadequate healing capability of cartilage tissue, cell-based therapy is making the future of cartilage repair and regeneration. Mesenchymal stem cells (MSC) have shown great promise in cartilage regeneration. However, a yet-unresolved issue is the emergence of hypertrophic and pathologic markers during in vitro MSC chondrogenesis. Articular chondrocytes (AC) can suppress the undesired hypertrophy when co-cultured with MSC. On the other hand, platelet rich plasma (PRP), is considered potentially effective for cartilage repair and in-vitro chondrogenesis. We thus aimed to harness chondro-promotive effects of PRP and hypertrophic-suppressive effects of AC:MSC co-culture to achieve a more functional cartilage neo-tissue. We used PRP or conventional-differentiation chondrogenic media (ConvDiff) in MSC mono-cultures and AC:MSC co-cultures. We assessed gene expression of chondrogenic and hypertrophic markers using real-time RT-PCR and immunostaining. Alkaline-phosphatase activity (ALP) and calcium content of the pellets were quantified. We also measured VEGF and TNF-α secretion via ELISA. We showed PRP had higher chondrogenic potential (in mRNA and protein level) and hypertrophic-suppressive effects than Conv-Diff (mRNA level). Co-culturing reduced ALP while PRP increased calcium deposition. In all four groups, TNF-α was down-regulated compared to MSC controls, with co-cultures receiving ConvDiff media secreting the least. Meanwhile, the only group with increased VEGF secretion was PRP-mono-cultures. We observed synergistic effects for PRP and AC:MSC co-culture in enhancing chondrogenesis. Inclusion of AC reduced hypertrophic markers and angiogenic potential in PRP groups. We thus propose that combination of PRP and co-culture would favor chondrogenesis while alleviate but not totally eradicate undesired hypertrophic and pathologic responses.

Current Orthobiologics for Elective Arthrodesis and Nonunions of the Foot and Ankle

A fusion rate of 100% would be ideal. Despite adhering to sound surgical principles, complete compliance, and no adverse comorbidities, that 100% fusion rate goal is elusive. Orthobiologics are a special class of materials developed to enhance the fusion rates in foot and ankle arthrodesis sites. Whether orthobiologics are used for the first fusion or reserved for a nonunion is debatable, especially when considering cost.

Efficacy of platelets in bone healing: A systematic review on animal studies

In presence of large bone defects, delayed bone union, non-union, fractures, and implant surgery, bone reconstruction may be necessary. Different strategies have been employed to enhance bone healing among which the use of autologous platelet concentrates. Due to the high content of platelets and platelet-derived bioactive molecules (e.g., growth factors, antimicrobial peptides), they are promising candidates to increase bone healing. However, a high heterogeneity of both preclinical and clinical studies resulted in contrasting results. Aim of the present systematic review was to evaluate the efficacy of platelet concentrates in animal models of bone regeneration, considering the possible factors which might affect the outcome. An electronic search was performed on MEDLINE and SCOPUS databases. Animal studies with a minimum follow up of 2 weeks and a sample size of five subjects per group, using platelet concentrates for bone regeneration, were included. Articles underwent risk of bias assessment and further quality evaluation was done. Sixty studies performed on six animal species (rat, rabbit, dog, sheep, goat, and mini-pig) were included. The present part of the review considers only studies performed on rats and rabbits (35 articles). The majority of the studies were considered at medium risk of bias. Animal species, healthy models, platelet, growth factors and leukocytes concentration, and type of bone defect seemed to influence the efficacy of platelet concentrates in bone healing. However, final conclusions were not be drawn, since only few included studies evaluated leukocyte, growth factor content, or presence of other bioactive molecules in platelet concentrates. Further studies with a standardized protocol including characterization of the final products will provide useful information for clinical application of platelet concentrates in bone surgery.

The effect of platelet-rich plasma on osseous healing in dogs undergoing high tibial osteotomy

OBJECTIVES

The purpose of this study was to investigate whether platelet-rich plasma (PRP) enhances osseous healing in conjunction with a high tibial osteotomy in dogs.

STUDY DESIGN

Randomized controlled trial.

METHODS

Sixty-four client-owned pet dogs with naturally occurring rupture of the anterior cruciate ligament and that were to be treated with a high tibial osteotomy (tibial plateau leveling osteotomy) were randomized into the treatment or control group. Dogs in the treatment group received autologous platelet-rich plasma activated with calcium chloride and bovine thrombin to produce a well-formed PRP gel that was placed into the osteotomy at the time of surgery. Dogs in the control group received saline lavage of the osteotomy. All dogs had the osteotomy stabilized with identical titanium alloy implants and all aspects of the surgical procedure and post-operative care were identical among dogs of the two groups. Bone healing was assessed at exactly 28, 49, and 70 days after surgery with radiography and ultrasonography and with MRI at day 28. The effect of PRP on bone healing was assessed using a repeated measures analysis of covariance with radiographic and ultrasonographic data and using a t-test with the MRI data.

RESULTS

Sixty dogs completed the study. There were no significant differences in age, weight, or gender distribution between the treatment and control groups. Twenty-seven dogs were treated with PRP and 33 were in the control group. The average platelet concentration of the PRP was 1.37x106 platelets/μL (±489x103) with a leukocyte concentration of 5.45x103/μL (±3.5x103). All dogs demonstrated progressive healing over time and achieved clinically successful outcomes. Time since surgery and patient age were significant predictors of radiographic healing and time since surgery was a significant predictor of ultrasonographic assessment of healing. There was no significant effect of PRP treatment as assessed radiographically, ultrasonographically, or with MRI.

CONCLUSION

The PRP used in this study did not hasten osseous union in dogs treated with a high tibial osteotomy.

The synergistic effect of TiO2 nanoporous modification and platelet-rich plasma treatment on titanium-implant stability in ovariectomized rats

For several decades, titanium and its alloys have been commonly utilized for endosseous implantable materials, because of their good mechanical properties, chemical resistance, and biocompatibility. But associated low bone mass, wear and loss characteristics, and high coefficients of friction have limited their long-term stable performance, especially in certain abnormal bone-metabolism conditions, such as postmenopausal osteoporosis. In this study, we investigated the effects of platelet-rich plasma (PRP) treatment and TiO₂ nanoporous modification on the stability of titanium implants in osteoporotic bone. After surface morphology, topographical structure, and chemical changes of implant surface had been detected by scanning electron microscopy (SEM), atomic force microscopy, contact-angle measurement, and X-ray diffraction, we firstly assessed in vivo the effect of PRP treatment on osseointegration of TiO₂-modified implants in ovariectomized rats by microcomputed tomography examinations, histology, biomechanical testing, and SEM observation. Meanwhile, the potential molecular mechanism involved in peri-implant osseous enhancement was also determined by quantitative real-time polymerase chain reaction. The results showed that this TiO₂-modified surface was able to lead to improve bone implant contact, while PRP treatment was able to increase the implant surrounding bone mass. The synergistic effect of both was able to enhance the terminal force of implants drastically in biomechanical testing. Compared with surface modification, PRP treatment promoted earlier osteogenesis with increased expression of the RUNX2 and COL1 genes and suppressed osteoclastogenesis with increased expression of OPG and decreased levels of RANKL. These promising results show that PRP treatment combined with a TiO₂-nanomodified surface can improve titanium-implant biomechanical stability in ovariectomized rats, suggesting a beneficial effect to support the success of implants in osteoporotic bone.

Stem cell regenerative potential for plastic and reconstructive surgery

Stem cells represent heterogeneous population of undifferentiated cells with unique characteristics of long term self renewal and plasticity. Moreover, they are capable of active migration to diseased tissues, secretion of different bioactive molecules, and they have immunosuppressive potential as well. They occur in all tissues through life and are involved in process of embryogenesis and regeneration. During last decades stem cells attracted significant attention in each field of medicine, including plastic and reconstructive surgery. The main goal of the present review article is to present and discuss the potential of stem cells and to provide information about their safe utilization in chronic wounds and fistulae healing, scar management, breast reconstruction, as well as in bone, tendon and peripheral nerve regeneration.

Calcium Phosphates and Angiogenesis: Implications and Advances for Bone Regeneration

Calcium phosphates (CaPs) are among the most utilized synthetic biomaterials for bone regeneration, largely owing to their established osteoconductive and osteoinductive properties. While angiogenesis is a crucial prerequisite to bone formation, research and applications for CaPs have not appreciated its crucial role. This review discusses how CaPs influence angiogenesis, and highlights promising strategies that address this topic. The objective is to draw attention to the gap in the literature and to highlight the importance of angiogenesis in CaP research, development, and use.