The use of PRP in ligament and meniscal healing

Addressing radiotherapy-induced fibrosis: the potential of platelet-rich plasma and infliximab for improved breast cancer management

Breast cancer treatment encompasses various therapeutic modalities, including surgery, radiotherapy, and chemotherapy. Breast-conserving surgery has been an integral part of breast cancer management. However, radiotherapy, an important component of breast cancer management, can lead to complications, particularly fibrosis, affecting reconstructive surgery outcomes. We conducted an in vivo study using 48 female Wistar Albino rats, employing segmental mastectomy and radiotherapy to simulate post-mastectomy conditions. The rats were divided into six groups: control, mastectomy, mastectomy + radiotherapy, mastectomy + platelet-rich plasma (PRP) + radiotherapy, mastectomy + infliximab + radiotherapy, and mastectomy + infliximab + PRP + radiotherapy. Edema, hyperemia, inflammation, and fibrosis were assessed as indicators of tissue response. Histopathological analysis revealed that mastectomy + infliximab and mastectomy + infliximab + PRP groups showed significant reductions in fibrosis compared to other groups. Edema, hyperemia, and inflammation were also less severe in these groups compared to the control group. Radiotherapy-induced fibrosis is a major concern in breast reconstruction. Our study suggests that local PRP application and systemic infliximab administration, either alone or in combination, could mitigate the adverse effects of radiotherapy. This approach has the potential to improve reconstructive outcomes in patients undergoing or having the possibility to undergo radiotherapy. This is the first study showing the effectiveness of infliximab and PRP combination on wound healing. The provided experimental rat model might offer guidance for further research. This study provides insights into optimizing outcomes in reconstructive breast surgery, paving the way for further research and clinical studies.

Platelets-rich-plasma in management of non operative post cruciate ligament injury

Posterior cruciate ligament (PCL) injury is a rare ligamentous knee injury which most commonly occurs due to direct trauma; it represents only 0.65% of knee injuries. On the basis of magnetic resonance imaging (MRI), PCL injury is divided into surgical and non-surgical. In the last few years we have witnessed an increasing interest in regenerative medicine. The use of innovative techniques allow the reduction of rehabilitation times in sports injuries. Platelet-Rich-Plasma (PRP) is a plasma-derived which stimulate the tissue repair. The objective of our work is to compare the rehabilitation times in PCL non-operative injuries treated with standard conservative treatment and PCL injuries treated with autologous PRP followed by rehabilitation program. We divided patients into two different groups: Group A formed by patients who underwent a standard conservative rehabilitation program and Group B which included patients treated by ultrasound guided PRP injection and following physiotherapy program. Both groups of patients resumed sports activities; however the rehabilitation times for patients which had undergone treatment with autologous PRP injection were reduced compared to patients who underwent a standard conservative treatment.

Applications and prospects of different functional hydrogels in meniscus repair

The meniscus is a kind of fibrous cartilage structure that serves as a cushion in the knee joint to alleviate the mechanical load. It is commonly injured, but it cannot heal spontaneously. Traditional meniscectomy is not currently recommended as this treatment tends to cause osteoarthritis. Due to their good biocompatibility and versatile regulation, hydrogels are emerging biomaterials in tissue engineering. Hydrogels are excellent candidates in meniscus rehabilitation and regeneration because they are fine-tunable, easily modified, and capable of delivering exogenous drugs, cells, proteins, and cytokines. Various hydrogels have been reported to work well in meniscus-damaged animals, but few hydrogels are effective in the clinic, indicating that hydrogels possess many overlooked problems. In this review, we summarize the applications and problems of hydrogels in extrinsic substance delivery, meniscus rehabilitation, and meniscus regeneration. This study will provide theoretical guidance for new therapeutic strategies for meniscus repair.

Creating an Optimal In Vivo Environment to Enhance Outcomes Using Cell Therapy to Repair/Regenerate Injured Tissues of the Musculoskeletal System

Following most injuries to a musculoskeletal tissue which function in unique mechanical environments, an inflammatory response occurs to facilitate endogenous repair. This is a process that usually yields functionally inferior scar tissue. In the case of such injuries occurring in adults, the injury environment no longer expresses the anabolic processes that contributed to growth and maturation. An injury can also contribute to the development of a degenerative process, such as osteoarthritis. Over the past several years, researchers have attempted to use cellular therapies to enhance the repair and regeneration of injured tissues, including Platelet-rich Plasma and mesenchymal stem/medicinal signaling cells (MSC) from a variety of tissue sources, either as free MSC or incorporated into tissue engineered constructs, to facilitate regeneration of such damaged tissues. The use of free MSC can sometimes affect pain symptoms associated with conditions such as OA, but regeneration of damaged tissues has been challenging, particularly as some of these tissues have very complex structures. Therefore, implanting MSC or engineered constructs into an inflammatory environment in an adult may compromise the potential of the cells to facilitate regeneration, and neutralizing the inflammatory environment and enhancing the anabolic environment may be required for MSC-based interventions to fulfill their potential. Thus, success may depend on first eliminating negative influences (e.g., inflammation) in an environment, and secondly, implanting optimally cultured MSC or tissue engineered constructs into an anabolic environment to achieve the best outcomes. Furthermore, such interventions should be considered early rather than later on in a disease process, at a time when sufficient endogenous cells remain to serve as a template for repair and regeneration. This review discusses how the interface between inflammation and cell-based regeneration of damaged tissues may be at odds, and outlines approaches to improve outcomes. In addition, other variables that could contribute to the success of cell therapies are discussed. Thus, there may be a need to adopt a Precision Medicine approach to optimize tissue repair and regeneration following injury to these important tissues.

Cell therapies for chondral defects of the talus: a systematic review

Background

This systematic review investigated the efficacy and safety of surgical procedures augmented with cell therapies for chondral defects of the talus.

Methods

The present systematic review was conducted according to the 2020 PRISMA guidelines. PubMed, Google scholar, Embase, and Scopus databases were accessed in March 2022. All the clinical trials investigating surgical procedures for talar chondral defects augmented with cell therapies were accessed. The outcomes of interest were to investigate whether surgical procedures augmented with cell therapies promoted improvement in patients reported outcomes measures (PROMs) with a tolerable rate of complications.

Results

Data from 477 procedures were retrieved. At a mean follow-up of 34.8 ± 9.7 months, the Visual Analogic Scale (VAS) improved of 4.4/10 (P = 0.002) and the American Orthopaedic Foot and Ankle Score (AOFAS) of 31.1/100 (P = 0.0001) points. No improvement was found in Tegner score (P = 0.4). Few articles reported data on complications. At last follow-up, the rate of reoperation and failure were 0.06% and 0.03%, respectively. No graft delamination or hypertrophy was observed.

Conclusion

The current evidence suggests that cell therapies may be effective and safe to enhance surgical procedures for chondral defects of the talus. These results should be considered within the limitations of the present study. The current literature should be enriched with randomized controlled clinical trials with larger population size and longer follow-up.

Cellular Augmentation of Anterior Cruciate Ligament Surgery Is Not Currently Evidence Based: A Systematic Review of Clinical Studies

PURPOSE

To perform a systematic review of clinical outcome studies exploring cellular augmentation of anterior cruciate ligament (ACL) surgery, including stem cell techniques.

METHODS

A systematic search was performed according to the Preferred Reporting Items of Systematic Reviews and Meta-analyses (PRISMA) guidelines using the Cochrane, PubMed, MEDLINE, SPORTDiscus, and CINAHL (Cumulative Index to Nursing and Allied Health Literature) databases from 2000 to 2019. The inclusion criteria were clinical studies that reported on ACL surgery augmented with stem cells or cellular therapy and patient-reported outcome measures or graft healing. Risk of bias was assessed using the Cochrane risk-of-bias tool for randomized clinical trials, and nonrandomized trials were assessed using the Methodological Items for Non-randomized Studies (MINORS) tool. Methodologic assessment was performed according to the Modified Coleman Methodology Score.

RESULTS

Four studies were found: 2 randomized clinical trials, 1 cohort study with a matched historical control group, and 1 case series. The mean Modified Coleman Methodology Score in these studies was 59, and there was a low risk of bias in 1 study. One study reported outcomes of augmented ACL repair, and 3 studies reported the results of augmented ACL reconstruction. Cellular therapies varied and included concentrated bone marrow aspirate, collagenase/centrifuge processed adipose, and marrow stimulation combined with platelet-rich plasma, as well as cells cultured from allograft bone marrow aspirate. The concentrated bone marrow aspirate and adipose tissue study results did not support their use. The marrow stimulation technique combined with repair led to promising clinical results. The use of allograft cultured cells improved patient-reported outcomes and postoperative radiographic findings.

CONCLUSIONS

Augmentation of ACL surgery with cellular therapy is not supported by clinical evidence at this time.

LEVEL OF EVIDENCE

Level IV.

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

AIMS

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

METHODS

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

RESULTS

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

CONCLUSION

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

Efficiency of platelet-rich plasma therapy for healing sports injuries in young athletes

In recent years, platelet-rich plasma (PRP) therapy has been a subject of controversy in orthopedics field. Our objective was to assess the efficiency of PRP therapy for patients who have suffered grade 2 meniscal lesions and grade 2 anterior cruciate ligament (ACL) lesions, graded by magnetic resonance imaging (MRI). A retrospective observational study was conducted, which included 72 young recreational athletes who had been diagnosed with grade 2 meniscal injury, graded using MRI, that benefited from PRP therapy as an enhancement of the primary treatment, after cast immobilization. The Lysholm score, the pain intensity and the resuming of the physical activity before the PRP treatment and one month after were analyzed. Our study revealed that patients had an improved subjective perception of pain after PRP therapy and an improvement of the Lysholm score. Concurrently, 83.3% of patients could return to sports and daily physical activity. It can be concluded that PRP therapy is a safe, easy to manage treatment, efficient for pain relief and in resuming of sports activities for young recreational athletes who have sustained partial meniscal or ACL tears. In terms of pain relief, it appears that the PRP therapy could be more efficient for young patients with ACL injuries.

Platelet-rich plasma (PRP) augmentation does not result in more favourable outcomes in arthroscopic meniscal repair: a meta-analysis

Background

The efficacy and safety of platelet-rich plasma (PRP) augmentation for arthroscopic meniscal repair is controversial. This meta-analysis compared arthroscopic meniscal repair performed in isolation or augmented with PRP.

Methods

The present study was conducted according to PRISMA 2020 guidelines. Pubmed, Web of Science, Google Scholar and Embase were accessed in August 2021. All the clinical trials which compared arthroscopic meniscal repair performed in isolation or augmented with PRP were included.

Results

Eight hundred thirty-seven patients were included: 38% (318 of 837 patients) were women; the mean age of the patients was 35.6 (range, 20.8–64.3) years; the mean follow-up was 26.2 (range, 6–54) months. Similarity was found in analogue scale (VAS) (P = 0.5) and Lysholm (P = 0.9), and International Knee Documentation Committee (IKDC) scores (P = 0.9). Similarity was found in the rate of failure (P = 0.4) and rate of revision (P = 0.07).

Conclusion

The current published scientific evidence does not support PRP augmentation for arthroscopic meniscal repair.

Clinical Outcomes of Meniscus Repair with or without Multiple Intra-Articular Injections of Platelet Rich Plasma after Surgery

Preservation of the meniscal volume is crucial in meniscus repair. The goal of this study was to evaluate the clinical outcome of repeated intra-articular platelet-rich plasma (PRP) injections after arthroscopic repair of a traumatic meniscal tear. We retrospectively reviewed 61 primary meniscal repairs in 61 patients (PRP group: 30; non-PRP: 31) from 2017 to 2018. Patients in the PRP group received repeated intra-articular PRP injections in week 2,4,6 after the primary meniscus repair. Subsequent meniscal repair treatment or meniscectomy, knee arthroplasty, and IKDC changes of less than 11.5 points were defined as healing failures. After following up for at least 24 months, the IKDC score was 75.1 ± 13.6, and the Lysholm score was 80.6 ± 14.9 in the PRP group and 72.6 ± 15.8 (IKDC) and 77.7 ± 17.2 (Lysholm) in the non-PRP group. Healing rates of the PRP and the non-PRP groups were 93.3% (Kaplan-Meier 91.6%) and 87.1% (Kaplan-Meier 84.7%), respectively (log rank test p = 0.874). Our study is the first to use multiple intra-articular PRP injections to facilitate meniscal healing after meniscal repair. Though selection bias may be present in this study, the PRP group had similar functional outcome and healing rate compared to non-PRP group.

Preparation Methods and Clinical Outcomes of Platelet-Rich Plasma for Intra-articular Hip Disorders: A Systematic Review and Meta-analysis of Randomized Clinical Trials

Background:

Despite its increasing use in the management of musculoskeletal conditions, questions remain regarding the preparation methods of platelet-rich plasma (PRP) and its clinical applications for intra-articular hip disorders, including femoroacetabular impingement syndrome (FAIS), labral pathology, and osteoarthritis (OA).

Purpose:

To systematically review and assess the preparation methods and clinical outcomes from randomized clinical trials (RCTs) on the use of PRP for intra-articular hip disorders.

Study Design:

Systematic review; Level of evidence, 2.

Methods:

A systematic review in accordance with the 2009 PRISMA (Preferred Reporting Items for Systematic Reviews and Meta-Analyses) guidelines was performed in September 2019. The Cochrane Database of Systematic Reviews, Cochrane Central Register of Controlled Trials, PubMed, Ovid Medline, and Embase were queried for studies regarding the use of PRP to treat intra-articular hip disorders. Qualifying articles were English-language RCTs describing the use of PRP for intra-articular hip disorders, either as standalone treatment or surgical augmentation. Two authors independently assessed article eligibility. Data pertaining to patient characteristics, indication for treatment, PRP preparation method, follow-up period, and clinical outcomes were extracted. Study results were qualitatively reported and quantitatively compared using meta-analysis when appropriate.

Results:

Seven RCTs met inclusion criteria. Four studies described the use of PRP for hip OA and 3 utilized PRP at arthroscopy for FAIS and labral tears. Outcomes after PRP for OA demonstrated improvement in validated patient-reported outcome measures for up to 1 year; however, pooled effect sizes found no statistically significant difference between PRP and hyaluronic acid (HA) regarding pain visual analog scale scores at short-term (≤2 months; P = .27), midterm (4-6 months; P = .85), or long-term (1 year; P = .42) follow-up. When injected at arthroscopy, 1 study reported improved outcomes, 1 reported no difference in outcomes, and 1 reported worse outcomes compared with controls. The meta-analysis demonstrated no statistically significant difference on the modified Harris Hip Score (mHHS) between PRP and control cohorts at a minimum 1-year follow-up. There were considerable deficiencies and heterogeneity in the reporting of PRP preparation methods for both indications.

Conclusion:

Treatment of OA with PRP demonstrated reductions in pain and improved patient-reported outcomes for up to 1 year. However, there was no statistically significant difference between PRP and HA in pain reduction. Likewise, for FAIS and labral surgery there was no statistically significant difference in mHHS outcomes between patients treated with PRP and controls. Given the limited number of studies and variability in PRP preparations, additional high-quality randomized trials are warranted.

Augmentation of Meniscal Repair With Platelet-Rich Plasma: A Systematic Review of Comparative Studies

Background:

The effect of platelet-rich plasma (PRP) augmentation for meniscal repair (MR) is unclear, as current evidence is limited to small, mostly nonrandomized studies.

Purpose:

To systematically review the literature to evaluate the efficacy and safety of MR with PRP augmentation.

Study Design:

Systematic review; Level of evidence, 3.

Methods:

A systematic review was performed by searching PubMed, the Cochrane Library, and Embase to identify studies (level of evidence 1-3) that compared the clinical efficacy of MR performed with versus without PRP. The search phrase used was platelet-rich plasma meniscus. Patients were assessed based on the Western Ontario and McMaster Universities Osteoarthritis Index (WOMAC), the visual analog scale (VAS) for pain, the Lysholm score, the Knee injury and Osteoarthritis Outcome Score (KOOS), the subjective International Knee Documentation Committee (IKDC) score, and treatment failure.

Results:

We identified 6 studies (2 studies with level 1 evidence; 4 studies with level 3 evidence) that met inclusion criteria, for a total of 309 patients undergoing MR with PRP (mean age, 31.9 years) and 445 patients without PRP augmentation (mean age, 29.6 years). The mean follow-up was 32.8 months (range, 12-72 months). Overall, 17.0% of PRP patients experienced MR failure compared with 22.1% of non-PRP patients. No differences in VAS, Lysholm, or subjective IKDC scores were found between groups except in 1 study, in which postoperative subjective IKDC scores were significantly better in the PRP group (P < .01). Another study found significantly better postoperative WOMAC scores among PRP patients, and 2 studies found significantly better KOOS subscores among PRP patients.

Conclusion:

There are a limited number of high-quality studies comparing outcomes and healing rates between patients undergoing MR with versus without PRP augmentation. Based on the available evidence, patients undergoing MR with PRP augmentation experience similar clinical outcomes at midterm follow-up when compared with conventional MR, and additional studies are needed to determine the efficacy of MR augmented with PRP.

American Society for Bone and Mineral Research-Orthopaedic Research Society Joint Task Force Report on Cell-Based Therapies - Secondary Publication

Cell-based therapies, defined here as the delivery of cells in vivo to treat disease, have recently gained increasing public attention as a potentially promising approach to restore structure and function to musculoskeletal tissues. Although cell-based therapy has the potential to improve the treatment of disorders of the musculoskeletal system, there is also the possibility of misuse and misrepresentation of the efficacy of such treatments. The medical literature contains anecdotal reports and research studies, along with web-based marketing and patient testimonials supporting cell-based therapy. Both the American Society for Bone and Mineral Research (ASBMR) and the Orthopaedic Research Society (ORS) are committed to ensuring that the potential of cell-based therapies is realized through rigorous, reproducible, and clinically meaningful scientific discovery. The two organizations convened a multidisciplinary and international Task Force composed of physicians, surgeons, and scientists who are recognized experts in the development and use of cell-based therapies. The Task Force was charged with defining the state-of-the art in cell-based therapies and identifying the gaps in knowledge and methodologies that should guide the research agenda. The efforts of this Task Force are designed to provide researchers and clinicians with a better understanding of the current state of the science and research needed to advance the study and use of cell-based therapies for skeletal tissues. The design and implementation of rigorous, thorough protocols will be critical to leveraging these innovative treatments and optimizing clinical and functional patient outcomes. In addition to providing specific recommendations and ethical considerations for preclinical and clinical investigations, this report concludes with an outline to address knowledge gaps in how to determine the cell autonomous and nonautonomous effects of a donor population used for bone regeneration. © 2020 Orthopaedic Research Society. Published by Wiley Periodicals, Inc. J Orthop Res 38:485-502, 2020.

American Society for Bone and Mineral Research-Orthopaedic Research Society Joint Task Force Report on Cell-Based Therapies

Cell-based therapies, defined here as the delivery of cells in vivo to treat disease, have recently gained increasing public attention as a potentially promising approach to restore structure and function to musculoskeletal tissues. Although cell-based therapy has the potential to improve the treatment of disorders of the musculoskeletal system, there is also the possibility of misuse and misrepresentation of the efficacy of such treatments. The medical literature contains anecdotal reports and research studies, along with web-based marketing and patient testimonials supporting cell-based therapy. Both the American Society for Bone and Mineral Research (ASBMR) and the Orthopaedic Research Society (ORS) are committed to ensuring that the potential of cell-based therapies is realized through rigorous, reproducible, and clinically meaningful scientific discovery. The two organizations convened a multidisciplinary and international Task Force composed of physicians, surgeons, and scientists who are recognized experts in the development and use of cell-based therapies. The Task Force was charged with defining the state-of-the art in cell-based therapies and identifying the gaps in knowledge and methodologies that should guide the research agenda. The efforts of this Task Force are designed to provide researchers and clinicians with a better understanding of the current state of the science and research needed to advance the study and use of cell-based therapies for skeletal tissues. The design and implementation of rigorous, thorough protocols will be critical to leveraging these innovative treatments and optimizing clinical and functional patient outcomes. In addition to providing specific recommendations and ethical considerations for preclinical and clinical investigations, this report concludes with an outline to address knowledge gaps in how to determine the cell autonomous and nonautonomous effects of a donor population used for bone regeneration. © 2019 American Society for Bone and Mineral Research.

Intra-articular and extra-articular platelet-rich plasma injections for knee osteoarthritis: A 26-week, single-arm, pilot feasibility study

AIM

Platelet Rich Plasma (PRP) is an emerging therapy for knee osteoarthritis (KOA). Studies have evaluated the effectiveness of intra-articular PRP, which ignores extra-articular tissue dysfunction and may provide incomplete treatment of KOA. The study aimed to pilot test a leukocyte-rich (mononuclear cells) PRP injection protocol for primary KOA, which consisted of single intra-articular injection and extra-articular injections on the medial coronary and medial collateral ligaments.

METHODS

A prospective 26-week single-arm uncontrolled feasibility pilot study. Patients (N = 12) with primary KOA as defined by the American Rheumatology Association, with moderate to severe medial knee pain which failed conservative management, were recruited in a university primary care clinic and received a single session of PRP injection in week 1. The primary outcome was the feasibility of the protocol at 26 weeks as defined by rates of recruitment, compliance, retention, dropout, side effects or adverse events; and treatment satisfaction. Secondary outcomes included the Western Ontario McMaster University Osteoarthritis Index, the Intermittent and Constant Osteoarthritis Pain total and subscales, objective physical function tests and EuroQol-5D.

RESULTS

Twelve of 40 potential patients were recruited in 3 months period (recruitment rate 30%, x2 = 3.33, P = 0.068). All participants adhered to the protocol and completed the follow up assessment with no dropouts (dropout rate 0%, X2= 2.67, P = 0.103). Satisfaction was high; no related adverse events were reported. Most secondary outcomes showed statistically significant improvement.

CONCLUSIONS

Concomitant intra-articular and extra-articular PRP injections were feasible and produced preliminary favourable outcomes.

The Effectiveness of Autologous Platelet-Rich Plasma for Osteoarthritis of the Hip: A Retrospective Analysis

Background

Platelet-rich plasma (PRP) is a minimally invasive treatment option to reduce pain and promote tissue healing. At the time this study was performed, there was limited published literature analyzing outcomes for patients treated with PRP for hip osteoarthritis.

Methods

Thirty-six patients aged 49–85 (66.0 ± 12.1) years with chronic hip pain who met inclusion criteria underwent image-guided intra-articular hip PRP injection. Outcomes were measured at baseline, two weeks, three months, and up to six months using the visual analog scale (VAS) for pain and the Hip Disability and Osteoarthritis Outcome Score (HOOS). The proportion of responders, as defined by a ≥50% reduction in VAS pain score, was assessed at three and six months.

Results

At two weeks, there was a significant improvement (P < 0.05) of function in two HOOS subscales: Symptoms and Activities of Daily Living. There was a significant improvement in all HOOS categories at six months. A significant improvement in VAS was observed at six months (baseline VAS = 6.9 ± 0.7 &→ 4.3 ± 1.8, 95% confidence interval = 2.0 to 3.2, P < 0.05). Sixty-seven percent (24/36) of the patients reported a ≥50% improvement in pain at three months; 58% (21/36) reported a ≥50% improvement in pain at six months. Stratification by Kellgren-Lawrence grades revealed that 86% and 82% of the KL grades 1 and 2 were responders at six months, respectively.

Conclusions

In patients with mild/moderate hip osteoarthritis, PRP may provide pain relief and functional improvement for up to six months.

Clinical Update: Why PRP Should Be Your First Choice for Injection Therapy in Treating Osteoarthritis of the Knee

PURPOSE OF REVIEW

The purpose of this review is to update the reader on the current applications of platelet-rich plasma (PRP) in the treatment of knee osteoarthritis (KOA). This review will focus on PRP's effect on the osteoarthritic joint, how PRP compares to traditional treatments of KOA, and provide clinical feedback on the use of PRP in an orthopedic and sports medicine practice.

RECENT FINDINGS

Recent research into the applications of PRP for KOA has further indicated both the efficacy and safety of PRP treatment. Although research has shown a tendency toward better efficacy at earlier stages of osteoarthritis (OA), evidence exists to indicate positive effects at all stages of OA. In summary, since KOA is an extremely prevalent condition that can be a challenge to treat, it is imperative that safe and effective nonoperative treatment methods be available to individuals that are suffering from this condition.

Development of a Micronized Meniscus Extracellular Matrix Scaffold for Potential Augmentation of Meniscal Repair and Regeneration

Decellularized scaffolds composed of extracellular matrix (ECM) hold promise for repair and regeneration of the meniscus, given the potential for ECM-based biomaterials to aid in stem cell recruitment, infiltration, and differentiation. The objectives of this study were to decellularize canine menisci to fabricate a micronized, ECM-derived scaffold and to determine the cytocompatibility and repair potential of the scaffold ex vivo. Menisci were decellularized with a combination of physical agitation and chemical treatments. For scaffold fabrication, decellularized menisci were cryoground into a powder and the size and morphology of the ECM particles were evaluated using scanning electron microscopy. Histologic and biochemical analyses of the scaffold confirmed effective decellularization with loss of proteoglycan from the tissue but no significant reduction in collagen content. When washed effectively, the decellularized scaffold was cytocompatible to meniscal fibrochondrocytes, synoviocytes, and whole meniscal tissue based on the resazurin reduction assay and histologic evaluation. In an ex vivo model for meniscal repair, radial tears were augmented with the scaffold delivered with platelet-rich plasma as a carrier, and compared to nonaugmented (standard-of-care) suture techniques. Histologically, there was no evidence of cellular migration or proliferation noted in any of the untreated or standard-of-care treatment groups after 40 days of culture. Conversely, cellular infiltration and proliferation were noted in scaffold-augmented repairs. These data suggest the potential for the scaffold to promote cellular survival, migration, and proliferation ex vivo. Further investigations are necessary to examine the potential for the scaffold to induce cellular differentiation and functional meniscal fibrochondrogenesis.

Biological treatment of the knee with platelet-rich plasma or bone marrow aspirate concentrates

- Knee pathologies including focal cartilage injuries, osteoarthritis (OA), and ligament injuries are common. The poor regeneration and healing potential of cartilage has led to the search for other treatment modalities with improved healing capacity. Furthermore, with an increasing elderly population that desires to remain active, the burden of knee pathologies is expected to increase. Increased sports participation and the desire to return to activities faster is also demanding more effective and minimally invasive treatment options. Thus, the use of biologic agents in the treatment of knee pathologies has emerged as a potential option. Despite the increasing use of biologic agents for knee pathology, there are conflicting results on the efficacy of these products. Furthermore, strong data supporting the optimal preparation methods and composition for widely used biologic agents, such as platelet-rich plasma (PRP) and bone marrow aspirate concentrate (BMAC), largely remain absent from the literature. This review presents the literature on the most commonly employed biologic agents for the different knee pathologies.

Platelet-Rich Plasma as an Autologous and Proangiogenic Cell Delivery System

Angiogenesis is a key factor in early stages of wound healing and is crucial for the repair of vascularized tissues such as the bone. However, supporting timely revascularization of the defect site still presents a clinical challenge. Tissue engineering approaches delivering endothelial cells or prevascularized constructs may overcome this problem. In the current study, we investigated platelet-rich plasma (PRP) gels as autologous, injectable cell delivery systems for prevascularized constructs. PRP was produced from human thrombocyte concentrates. GFP-expressing human umbilical vein endothelial cells (HUVECs) and human bone marrow-derived mesenchymal stem cells (MSCs) were encapsulated in PRP gels in different proportions. The formation of cellular networks was assessed over 14 days by time-lapse microscopy, gene expression analysis, and immunohistology. PRP gels presented a favorable environment for the formation of a three-dimensional (3D) cellular network. The formation of these networks was apparent as early as 3 days after seeding. Networks increased in complexity and branching over time but were only stable in HUVEC-MSC cocultures. The high cell viability together with the 3D capillary-like networks observed at early time points suggests that PRP can be used as an autologous and proangiogenic cell delivery system for the repair of vascularized tissues such as the bone.

The Use of Platelet-Rich and Platelet-Poor Plasma to Enhance Differentiation of Skeletal Myoblasts: Implications for the Use of Autologous Blood Products for Muscle Regeneration

BACKGROUND

Platelet-rich plasma (PRP) has been used to augment tissue repair and regeneration after musculoskeletal injury. However, there is increasing clinical evidence that PRP does not show a consistent clinical effect. Purpose/Hypothesis: This study aimed to compare the effects of the following non-neutrophil-containing (leukocyte-poor) plasma fractions on human skeletal muscle myoblast (HSMM) differentiation: (1) PRP, (2) modified PRP (Mod-PRP), in which transforming growth factor β1 (TGF-β1) and myostatin (MSTN) were depleted, and (3) platelet-poor plasma (PPP). The hypothesis was that leukocyte-poor PRP would lead to myoblast proliferation (not differentiation), whereas certain modifications of PRP preparations would increase myoblast differentiation, which is necessary for skeletal muscle regeneration.

STUDY DESIGN

Controlled laboratory study.

METHODS

Blood from 7 human donors was individually processed to simultaneously create leukocyte-poor fractions: PRP, Mod-PRP, PPP, and secondarily spun PRP and Mod-PRP (PRP_ss and Mod-PRP_ss, respectively). Mod-PRP was produced by removing TGF-β1 and MSTN from PRP using antibodies attached to sterile beads, while a second-stage centrifugal spin of PRP was performed to remove platelets. The biologics were individually added to cell culture groups. Analysis for induction into myoblast differentiation pathways included Western blot analysis, reverse-transcription polymerase chain reaction, and immunohistochemistry, as well as confocal microscopy to assess polynucleated myotubule formation.

RESULTS

HSMMs cultured with PRP showed an increase in proliferation but no evidence of differentiation. Western blot analysis confirmed that MSTN and TGF-β1 could be decreased in Mod-PRP using antibody-coated beads, but this modification mildly improved myoblast differentiation. However, cell culture with PPP, PRP_ss, and Mod-PRP_ss led to a decreased proliferation rate but a significant induction of myoblast differentiation verified by increased multinucleated myotubule formation and myosin heavy chain expression (mean 8-fold change in mRNA level; P < .05), which was comparable with 2% horse serum, the positive control.

CONCLUSION

PPP and leukocyte-poor PRP preparations subjected to a second spin to remove the platelets led to induction of myoblast cells into the muscle differentiation pathway, whereas unmodified leukocyte-poor PRP led to myoblast proliferation.

CLINICAL RELEVANCE

These results indicate that traditionally formulated PRP may not be appropriate to induce muscle regeneration. Laboratory evidence suggests that PPP or non-neutrophil-containing PRP_ss, subjected to an additional spin to remove platelets, should be used to stimulate myoblast differentiation, which is necessary for skeletal muscle regeneration. Clinical studies will be required to confirm the effect of these biologics on muscle regeneration.

Platelet-rich plasma in meniscal repair: does augmentation improve surgical outcomes?

BACKGROUND

Increased contact stresses after meniscectomy have led to an increased focus on meniscal preservation strategies to prevent articular cartilage degeneration. Platelet-rich plasma (PRP) has received attention as a promising strategy to help induce healing and has been shown to do so both in vitro and in vivo. Although PRP has been used in clinical practice for some time, to date, few clinical studies support its use in meniscal repair.

QUESTIONS/PURPOSES

We sought to (1) evaluate whether PRP augmentation at the time of index meniscal repair decreases the likelihood that subsequent meniscectomy will be performed; (2) determine if PRP augmentation in arthroscopic meniscus repair influenced functional outcome measures; and (3) examine whether PRP augmentation altered clinical and patient-reported outcomes.

METHODS

Between 2008 and 2011, three surgeons performed 35 isolated arthroscopic meniscus repairs. Of those, 15 (43%) were augmented with PRP, and 20 (57%) were performed without PRP augmentation. During the study period, PRP was used for patients with meniscus tears in the setting of no ACL reconstruction. Complete followup at a minimum of 2 years (mean, 4 years; range, 2-6 years) was available on 11 (73%) of the PRP-augmented knees and 15 (75%) of the nonaugmented knees. Clinical outcome measures including the International Knee Documentation Committee (IKDC) score, Tegner Lysholm Knee Scoring Scale, and return to work and sports/activities survey tools were completed in person, over the phone, or through the mail. Range of motion data were collected from electronic patient charts in chart review. With the numbers available, a post hoc power calculation demonstrated that we would have expected to be able to discern a difference using IKDC if we treated 153 patients with PRP and 219 without PRP assuming an alpha rate of 5% and power exceeding 80%. Using the Lysholm score as an outcome measure, post hoc power estimate was 0.523 and effect size was -1.1 (-2.1 to -0.05) requiring 12 patients treated with PRP and 17 without to find statistically significant differences at p = 0.05 and power = 80%.

RESULTS

There was no difference in the proportion of patients who underwent reoperation in the PRP group (27% [four of 15]) compared with the non-PRP group (25% [five of 20]; p = 0.89). Functional outcome measures were not different between the two groups based on the measures used (mean IKDC score, 69; SD, 26 with PRP and 76; SD, 17 without PRP; p = 0.288; mean, Tegner Lysholm Knee Scoring Scale, 66, SD, 32 with PRP and 89; SD, 10 without PRP; p = 0.065). With the numbers available there was no difference in the proportion of patients who returned to work in the PRP group (100% [six of six]) compared with the non-PRP group (100% [nine of nine]) or in the patients who returned to their regular sports/activities in the PRP group (71% [five of seven]) compared with the non-PRP group (78% [seven of nine]; p = 0.75).

CONCLUSIONS

Patients who sustain meniscus injuries should be counseled at the time of injury about the outcomes after meniscus repair. With our limited study group, outcomes after meniscus repair with and without PRP appear similar in terms of reoperation rate. However, given the lack of power and nature of the study, modest size differences in outcome may not have been detected. Future larger prospective studies are needed to definitively determine whether PRP should be used with meniscal repair. Additionally, studies are needed to determine if PRP and other biologics may benefit complex tear types.

LEVEL OF EVIDENCE

Level III, therapeutic study.

Sonographically Guided Anterior Cruciate Ligament Injection: Technique and Validation

OBJECTIVE

To describe and validate a practical technique for sonographically guided anterior cruciate ligament (ACL) injections.

DESIGN

Prospective, cadaveric laboratory investigation.

SETTING

Procedural skills laboratory in a tertiary medical center.

SUBJECTS

Ten unembalmed, cadaveric mid-thigh-knee-ankle foot specimens (5 left knees and 5 right knees; 5 male and 5 female) from 10 donors aged 76 to 93 years (mean 85.6 years) with body mass indices of 17.6 to 42.2 kg/m(2) (mean 28.8 kg/m(2)).

METHODS

A single, experienced operator used a 22-gauge, 63.5-mm stainless steel needle and a 12-3-MHz linear transducer to inject 1.5 mL of diluted colored latex into the ACLs of 10 unembalmed cadaveric specimens via an in-plane, caudad-to-cephalad approach, long axis to the ACL. At a minimum of 24 hours postinjection, specimens were dissected, and the presence and distribution of latex within the ACL assessed by a study co-investigator.

MAIN OUTCOME

Presence and distribution of latex within the ACL.

RESULTS

All 10 injections accurately delivered latex into the proximal (femoral), midsubstance, and distal (tibial) portions of the ACL. No specimens exhibited evidence of needle injury or latex infiltration with respect to the menisci, hyaline cartilage, or posterior cruciate ligament.

CONCLUSIONS

Sonographically guided intra-ligamentous ACL injections are technically feasible and can be performed with a high degree of accuracy. Sonographically guided ACL injections could be considered for research and clinical purposes to directly deliver injectable agents into the healing ACL postinjury or postreconstruction.

Platelet-rich plasma for open meniscal repair in young patients: any benefit?

PURPOSE

Many studies have demonstrated that injection of various growth factors including platelet-derived growth factor could increase meniscal cell activity and stimulate repair. The purpose of this study was to augment repair and promote meniscal healing by the use of platelet-rich plasma (PRP) within horizontal cleavage meniscal tears repaired via an open approach. The hypothesis was that the clinical outcomes and healing process would be improved using this meniscal healing augmentation technique.

METHODS

In this case-control study, 34 consecutive young patients underwent an open meniscal repair to treat symptomatic Grade 2 or Grade 3 horizontal meniscal tears [median age 28 years (13-40)]. The median time between the onset of symptoms and surgery was 11.5 months (6-50). In the first group (17 consecutive patients, Group 1), a standard open meniscal repair was performed. In the second group (17 consecutive patients, Group 2), the same surgical repair was performed, but platelet-rich plasma was introduced into the lesion at the end of the procedure. Clinical outcomes were evaluated using KOOS and IKDC 2000 scores. MRI was performed at 1 year after surgery for objective evaluation.

RESULTS

At a minimum of 24 months postoperatively (mean 32.2 months, 24-40), three patients underwent subsequent meniscectomy (two in Group 1, one in Group 2). The mean KOOS distribution (pain, symptoms, daily activities, sports, quality of life) was 78.4, 86.1, 93.8, 74.4, 74.6 in Group 1, and 93.3, 90.7, 97.1, 88.8, 78.3 in Group 2 (p < 0.05 for pain and sports parameters). MRI revealed five cases with the complete disappearance of any hypersignal within the repaired meniscus in Group 2, and none in Group 1 (p < 0.01).

CONCLUSIONS

Open meniscal repair of horizontal tears extending into the avascular zone was effective at midterm follow-up in young patients. Clinical outcomes were slightly improved by the addition of PRP in this case-control study.

LEVEL OF EVIDENCE

III.

Updates in biological therapies for knee injuries: menisci

The preservation of meniscal tissue is paramount for long-term joint function, especially in younger patients who are athletically active. Many studies have reported encouraging results following the repair of meniscus tears, including both simple longitudinal tears located in the periphery and complex multiplanar tears that extend into the central third avascular region. However, most types of meniscal lesions are managed with a partial meniscectomy. Options to restore the meniscus range from an allograft transplantation to the use of synthetic and biological technologies. Recent studies have demonstrated good long-term outcomes with meniscal allograft transplantation, although the indications and techniques continue to evolve, and the long-term chondroprotective potential of this approach has yet to be determined. Several synthetic implants, most of which are approved in the European market, have shown some promise for replacing part of or the entire meniscus, including collagen meniscal implants, hydrogels, and polymer scaffolds. Currently, there is no ideal implant generated by means of tissue engineering. However, meniscus tissue engineering is a fast developing field that promises to develop an implant that mimics the histologic and biomechanical properties of a native meniscus.

Regenerative repair of damaged meniscus with autologous adipose tissue-derived stem cells

Mesenchymal stem cells (MSCs) are defined as pluripotent cells found in numerous human tissues, including bone marrow and adipose tissue. Such MSCs, isolated from bone marrow and adipose tissue, have been shown to differentiate into bone and cartilage, along with other types of tissues. Therefore, MSCs represent a promising new therapy in regenerative medicine. The initial treatment of meniscus tear of the knee is managed conservatively with nonsteroidal anti-inflammatory drugs and physical therapy. When such conservative treatment fails, an arthroscopic resection of the meniscus is necessary. However, the major drawback of the meniscectomy is an early onset of osteoarthritis. Therefore, an effective and noninvasive treatment for patients with continuous knee pain due to damaged meniscus has been sought. Here, we present a review, highlighting the possible regenerative mechanisms of damaged meniscus with MSCs (especially adipose tissue-derived stem cells (ASCs)), along with a case of successful repair of torn meniscus with significant reduction of knee pain by percutaneous injection of autologous ASCs into an adult human knee.