Platelet-rich plasma for the replenishment of bone

Formation of Hydroxyapatite-Based Hybrid Materials in the Presence of Platelet-Poor Plasma Additive

Biomaterials based on hydroxyapatite with controllable composition and properties are promising in the field of regenerative bone replacement. One approach to regulate the phase composition of the materials is the introduction of biopolymer-based additives into the synthesis process. The purpose of present study was to investigate the formation of hydroxyapatite-based hybrid materials in the presence of 6-24% platelet-poor plasma (PPP) additive, at a [Ca2+]/[PO43-] ratio of 1.67, pH 11, and varying maturing time from 4 to 9 days. The mineral component of the materials comprised 53% hydroxyapatite/47% amorphous calcium phosphate after 4 days of maturation and 100% hydroxyapatite after 9 days of maturation. Varying the PPP content between 6% and 24% brought about the formation of materials with rather defined contents of amorphous calcium phosphate and biopolymer component and the desired morphology, ranging from typical apatitic conglomerates to hybrid apatite-biopolymer fibers. The co-precipitated hybrid materials based on hydroxyapatite, amorphous calcium phosphate, and PPP additive exhibited increased solubility in SBF solution, which defines their applicability for repairing rhinoplastic defects.

Advances in the Clinical Application of Platelet-Rich Plasma in the Foot and Ankle: A Review

Autologous and recombinant biologic substances have been generated as a result of the research into the cellular features of the healing process. Orthobiologics are increasingly being used in sports medicine and musculoskeletal surgery. Nevertheless, clinical data are limited; consequently, further studies are required, particularly in foot and ankle pathologies. This review aims to provide evidence of the most recent literature results and ignite the interest of orthopedic specialists eager for an update about the most current discussion on platelet-rich plasma (PRP) clinical applications in the foot and ankle fields. Previous studies have shown that platelet-rich plasma can be beneficial in treating various conditions, such as chronic foot ulcers, osteoarthritis, Achilles tendinopathy, etc. Despite the positive effects of PRP on various musculoskeletal conditions, more prospective studies are needed to confirm its effectiveness at treating ankle and foot pathologies. In addition to clinical trials, other factors, such as the quality of the research and the procedures involved, must be considered before they can be used in patients. More long-term evaluations are needed to support or oppose its application in treating foot and ankle disorders. We present the most extensive review of PRP's clinical applications in the foot and ankle field.

Application of platelet-rich plasma in spinal surgery

With the aging of the population and changes in lifestyle, the incidence of spine-related diseases is increasing, which has become a major global public health problem; this results in a huge economic burden on the family and society. Spinal diseases and complications can lead to loss of motor, sensory, and autonomic functions. Therefore, it is necessary to identify effective treatment strategies. Currently, the treatment of spine-related diseases includes conservative, surgical, and minimally invasive interventional therapies. However, these treatment methods have several drawbacks such as drug tolerance and dependence, adjacent spondylosis, secondary surgery, infection, nerve injury, dural rupture, nonunion, and pseudoarthrosis. Further, it is more challenging to promote the regeneration of the interstitial disc and restore its biomechanical properties. Therefore, clinicians urgently need to identify methods that can limit disease progression or cure diseases at the etiological level. Platelet-rich plasma (PRP), a platelet-rich form of plasma extracted from venous blood, is a blood-derived product. Alpha granules contain a large number of cytokines, such as platelet-derived growth factor (PDGF), vascular endothelial growth factor (VEGF), epidermal growth factor, platelet factor 4 (PF-4), insulin-like growth factor-1 (IGF-1), and transforming growth factor-β (TGF-β). These growth factors allow stem cell proliferation and angiogenesis, promote bone regeneration, improve the local microenvironment, and enhance tissue regeneration capacity and functional recovery. This review describes the application of PRP in the treatment of spine-related diseases and discusses the clinical application of PRP in spinal surgery.

A Practical Guide for the Current Use of Biologic Therapies in Sports Medicine

Over the past decade, there has been an increased interest in the use of biologic therapies in sports medicine. Although these technologies are in relatively early stages of development, there have been substantial increases in marketing, patient demand, and clinical utilization of biologics, including platelet-rich plasma, bone marrow aspirate concentrate, and other cell-derived therapies. Direct-to-consumer marketing of biologics has also proliferated but is largely unregulated, and clinicians must accurately convey the safety and efficacy profiles of these therapies to patients. Because most insurance companies consider biologic treatments to be experimental or investigational for orthopaedic applications given the lack of high-quality evidence to support their efficacy, patients receiving these treatments often make substantial out-of-pocket payments. With a range of treatment costs among centers offering biologics, there is a need for appropriate and sustainable pricing and reimbursement models. Clinicians utilizing biologics must also have a thorough understanding of the recently clarified Food and Drug Administration guidelines that regulate the clinical use of cell and tissue products. There is a lack of consensus on the optimal preparation, source, delivery method, and dosing of biologic therapies, which has been exacerbated by a lack of sufficient experimental detail in most published studies. Future research must better identify the biologic target of treatment, adhere to better standards of reporting, and better integrate researchers, industry, and regulatory bodies to optimize applications.

Platelet-rich plasma in the foot and ankle

PURPOSE OF REVIEW

Platelet-rich plasma has become an increasingly popular treatment option within the orthopedic community to biologically enhance and stimulate difficult-to-heal musculoskeletal tissues. This review evaluates the recent literature on platelet-rich plasma use in the treatment of foot and ankle pathologies.

RECENT FINDINGS

Recent literature has demonstrated platelet-rich plasma to have a possible benefit in the treatment of Achilles pathology, chronic plantar fasciitis, osteochondral lesions of the talus, ankle osteoarthritis, and diabetic foot ulcers. However, given the lack of standardization of platelet-rich plasma preparations and protocols and the predominance of low-quality studies, no definitive treatment indications exist. Platelet-rich plasma is a promising treatment option, but at present, there is only limited clinical evidence supporting its use in foot and ankle applications.

Platelet-rich plasma does not reduce skeletal muscle fibrosis after distraction osteogenesis

Background

Skeletal muscle fibrosis caused by an increase in collagen deposition often occurs after distraction osteogenesis. Although studies are available reporting the effects of platelet-rich plasma (PRP) on tissue healing following injury, current findings remain controversial. This study focused on determining whether PRP reduces skeletal muscle fibrosis caused by distraction osteogenesis.

Methods

Tibial osteotomies were performed on 8-week-old wild type mice, and tibiae were distracted at a rate of 0.42 mm/day for 2 weeks, starting 1 week after osteotomy. Immediately after distraction was completed (3 weeks after osteotomy), PRP or phosphate buffered saline (as a sham) was injected into the gastrocnemius (GC) muscle. The GC muscles were harvested and analyzed.

Results

The amount and area of collagenous tissue increased in both the PRP and control groups following distraction osteogenesis, but the changes were not significantly different between both groups at all time points (p = 0.89, 0.45, 0.33 and 0.52 at 4, 6, 8 and 10 weeks).

Conclusion

From this study, our results suggest that PRP did not significantly reduce skeletal muscle fibrosis due to distraction osteogenesis.

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.

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.

Autologous blood preparations rich in platelets, fibrin and growth factors

OBJECTIVES

Bone regeneration is often needed prior to dental implant treatment due to the lack of adequate quantity and quality after infectious diseases. The greatest regenerative power was obtained with autologous tissue, primarily the bone alive, taken from the same site or adjacent sites, up to the use centrifugation of blood with the selection of the parts with the greatest potential regenerative. In fact, various techniques and technologies were chronologically successive to cope with an ever better preparation of these concentrates of blood. Our aim is to review these advances and discuss the ways in which platelet concentrates may provide such unexpected beneficial therapeutic effects.

METHODS

The research has been carried out in the MEDLINE and Cochrane Central Register of Controlled Trials database by choosing keywords as "platelet rich plasma", "platelet rich fibrin", "platelet growth factors", and "bone regeneration" and "dentistry".

RESULTS

Autologous platelet rich plasma is a safe and low cost procedure to deliver growth factors for bone and soft tissue healing.

CONCLUSION

The great heterogeneity of clinical outcomes can be explained by the different PRP products with qualitative and quantitative difference among substance.

Biologic Treatments for Sports Injuries II Think Tank-Current Concepts, Future Research, and Barriers to Advancement, Part 2: Rotator Cuff

Rotator cuff tears are common and result in considerable morbidity. Tears within the tendon substance or at its insertion into the humeral head represent a considerable clinical challenge because of the hostile local environment that precludes healing. Tears often progress without intervention, and current surgical treatments are inadequate. Although surgical implants, instrumentation, and techniques have improved, healing rates have not improved, and a high failure rate remains for large and massive rotator cuff tears. The use of biologic adjuvants that contribute to a regenerative microenvironment have great potential for improving healing rates and function after surgery. This article presents a review of current and emerging biologic approaches to augment rotator cuff tendon and muscle regeneration focusing on the scientific rationale, preclinical, and clinical evidence for efficacy, areas for future research, and current barriers to advancement and implementation.

The collagen component of biological bone graft substitutes promotes ectopic bone formation by human mesenchymal stem cells

Synthetic bone substitutes are attractive materials for repairing a variety of bone defects. They are readily available in unlimited quantities, have a defined composition without batch variability and bear no risk of disease transmission. When combined with mesenchymal stem cells (MSCs), bone healing can be further enhanced due to the osteogenic potential of these cells. However, human MSCs showed considerable donor variability in ectopic bone formation assays on synthetic bone substitutes, which may limit clinical success. This study addresses whether bone formation variability of MSCs is cell-intrinsic or biomaterial-dependent and may be improved using biological bone substitutes with and without collagen. Ectopic bone formation of MSCs from nine donors was tested in immune-deficient mice on biological bone substitutes of bovine and equine origin, containing collagen (bHA-C; eHA-C) or not (bHA; eHA). Synthetic β-TCP was used for comparison. Histology of 8-week explants demonstrated a significant influence of the bone graft substitute (BGS) on donor variability of ectopic bone formation with best results seen for eHA-C (15/17) and β-TCP (16/18). Bone was of human origin in all groups according to species-specific in situ hybridization, but MSCs from one donor formed no bone with any bone substitute. According to histomorphometry, most neo-bone was formed on eHA-C with significant differences to bHA, eHA and β-TCP (p<0.001). Collagen-free biological BGSs were inferior to biological BGSs with collagen (p<0.001), while species-origin was of little influence. In conclusion, BGS composition had a strong influence on ectopic bone formation ability of MSCs, and biological BGSs with a collagen component seem most promising to display the strong osteogenic potential of MSCs.

Reconstruction of unstable, complex proximal humeral fractures with the da Vinci cage: surgical technique and outcome at 2 to 6 years

BACKGROUND

Treatment of displaced proximal humeral fractures remains a challenge for the orthopaedic surgeon. We describe the reconstruction of such fractures with a new device designed to provide good medial cortex support and report treatment outcome.

MATERIALS AND METHODS

The da Vinci device is an open triangular prism made of titanium. It is inserted in the proximal humeral cavity to stabilize the humeral head and tuberosities. Between May 2005 and December 2010, we treated 81 patients with unstable dislocated proximal fractures using this device. We report the outcome of the 69 patients monitored for at least 2 years.

RESULTS

The results, based on the Constant-Murley and Disabilities of the Arm, Shoulder and Hand scores at a minimum of 2 years' follow-up, were excellent in 36 of 69 patients, good in 29, fair in 2, and poor in the remaining 2. Successful fracture healing was obtained in 68 of 69 patients, whereas the cage was removed in 1 patient 80 days after surgery because of infection. Partial vascular osteonecrosis occurred in 5 patients but was clinically symptomatic in only 1 of these. Fragment reduction was maintained during follow-up in all 68 cases.

CONCLUSIONS

The da Vinci cage results in good reduction and stable fixation of displaced proximal humeral fractures, as well as in cases of humeral head dislocation and comminuted fractures. Unlike other devices and screwed plates, it does not invade the subacromial space and osteosynthesis is minimally invasive.

LEVEL OF EVIDENCE

Level IV, Case Series, Treatment Study.

Controlled release strategies for bone, cartilage, and osteochondral engineering--Part II: challenges on the evolution from single to multiple bioactive factor delivery

The development of controlled release systems for the regeneration of bone, cartilage, and osteochondral interface is one of the hot topics in the field of tissue engineering and regenerative medicine. However, the majority of the developed systems consider only the release of a single growth factor, which is a limiting step for the success of the therapy. More recent studies have been focused on the design and tailoring of appropriate combinations of bioactive factors to match the desired goals regarding tissue regeneration. In fact, considering the complexity of extracellular matrix and the diversity of growth factors and cytokines involved in each biological response, it is expected that an appropriate combination of bioactive factors could lead to more successful outcomes in tissue regeneration. In this review, the evolution on the development of dual and multiple bioactive factor release systems for bone, cartilage, and osteochondral interface is overviewed, specifically the relevance of parameters such as dosage and spatiotemporal distribution of bioactive factors. A comprehensive collection of studies focused on the delivery of bioactive factors is also presented while highlighting the increasing impact of platelet-rich plasma as an autologous source of multiple growth factors.