Platelet-rich plasma use in anterior cruciate ligament surgery: systematic review of the literature

Platelet-rich plasma augmentation in anterior cruciate ligament reconstruction: Evidence is still too scattered. A scoping review of randomised controlled trials

PURPOSE

Platelet-rich plasma (PRP) augmentation has been proposed to improve the results of anterior cruciate ligament reconstruction (ACLR). The present study aims to quantify the available evidence to support the use of PRP as biological augmentation in ACLR surgery.

METHODS

A systematic literature search was conducted on the PubMed, Cochrane, Web of Science and Embase databases on 10 March 2023. Inclusion criteria were randomised controlled trials (RCTs), written in English, addressing PRP augmentation in ACLR surgery, with no time limitation. A scoping review was performed to map the body of literature by examining the evidence related to specific aspects of patients' treatment and evaluation. Risk of bias evaluation was performed with the Cochrane risk-of-bias tool for randomised trials Version 2 (RoB 2), while the quality assessment was performed with the use of the Coleman Score.

RESULTS

Out of 983 articles retrieved, 23 RCTs on 943 knees were included in this scoping review. PRP was administered in a liquid form in nine studies and clotted in 11 studies, while in three studies both liquid and clotted PRP were used. Hamstring auto/allografts were used in 14 studies, patellar tendon auto/allografts were used in eight studies and one study described ACLR with peroneus longus allografts. The map of the evidence documented high heterogeneity also in terms of surgical technique, objective and subjective outcome measures and radiological assessment, as well as follow-up times ranging from 1 day to 2 years, with virtually no overlapping data among studies neither in terms of treatments nor evaluations. Risk of bias evaluation showed an overall low quality of the included studies.

CONCLUSIONS

The available literature addressing PRP augmentation in ACLR is largely scattered. PRP was produced and applied following different procedures, and high variability was detected across the included studies for every aspect of ACLR surgery and evaluation. Currently, a meaningful comparison of the available studies is not possible as the quantification of the literature results is biased by their heterogeneity. Future studies should provide more standardisation to investigate the benefits of biological augmentation in ACL surgery and confirm the promising yet weak evidence of PRP potential as well as the most suitable application modality, before routine use in clinical practice.

LEVEL OF EVIDENCE

Levels I and II, scoping review.

Nanosurgical and Bioengineering Treatment of Human Anterior Cruciate Ligament Tears with Ultrasound-Guided Injection of Modified Platelet-Rich Plasma Using Human Cell Memory Based on Clinical, Ultrasound, MRI, and Nanoscope Analyses: A Double-Blind Randomized Trial

Background: Anterior cruciate ligament (ACL) tears account for 40% to 50% of all ligamentous knee injuries. Most patients with ACL ruptures undergo surgical treatment. There is currently no objective, well-documented, repeatable, and standardized nonsurgical method for ACL tear treatment. This study aimed to investigate ACL outcomes in patients who underwent a novel nanosurgery and bioengineering treatment (NSBT) for an ACL tear. Methods: This was a double-blind randomized trial including 44 patients with a history of traumatic knee injury and a confirmed ACL tear. The final sample comprised 40 patients who met all the eligibility criteria. The patients were divided into two groups: the treatment group (n = 30) and the control group (n = 10). The treatment group underwent nanosurgery with an ultrasound-guided injection of modified platelet-rich plasma (PRP) using human cell memory (RP-hCM). The control group was treated with an ultrasound-guided PRP injection into the joint capsule. At baseline and post-treatment, all patients underwent both ultrasonography and magnetic resonance imaging (MRI), and the following clinical variables were assessed: the WOMAC score, the Lysholm knee score, the visual analog scale score, and knee instability. In most patients, the clinical outcome was verified using nanoscopy. Results: The median WOMAC, VAS, and LKS scores, as well as knee instability, improved significantly 12 weeks after the procedure in the treatment group (p < 0.001). We found a significantly larger improvement in the assessed parameters in the treatment group compared to the control group (p < 0.001). In the treatment group, all the patients had good and very good clinical outcomes, while 90% of the patients had a normal ACL signal in a follow-up MRI scan. In the control group, a physical examination revealed no changes in knee stability after treatment. Conclusions: This study showed that there is a significant difference in patient experience and the duration of recovery for patients with ACL tears treated with NSBT. The novel nonsurgical method was shown to be repeatable, objective, well documented, standardized, and highly effective.

Cells Remain Viable When Collected With an In-Line-Suction Tissue Collector From Byproducts of Anterior Cruciate Ligament Reconstruction Surgery

Purpose

To investigate the viability of cells collected with an in-line-suction autologous tissue collector from the tissue byproducts of arthroscopic anterior cruciate ligament (ACL) reconstruction, to characterize cells from different tissue types, and to identify mesenchymal stem cells.

Methods

Patients aged 14 to 50 years with ACL injuries requiring arthroscopic reconstruction surgery were offered enrollment and screened for participation. In total, 12 patients were enrolled in the descriptive laboratory study. Arthroscopic byproduct tissue was collected with an in-line-suction autologous tissue collector from 4 intraoperative collection sites for each patient: ACL stump, ACL fat pad, notchplasty debris, and tunnel drilling debris. All tissue samples were digested using collagenase, and the derived cellular populations were analyzed in vitro, characterizing cellular viability, proliferative potential, qualitative multipotent differentiation capacity, and cell-surface marker presence.

Results

An equivalent mass of arthroscopic byproduct tissue was taken from each of the 4 intraoperative collection sites (1.12-1.61 g, P = .433), which all showed an average viability of at least 99.95% and high average total nucleated cells (≥1.37 × 107 cells/mL). No significant differences in collected mass (P = .433), cellular viability (P = .880), or total nucleated cells (P = .692) were observed between the 4 byproduct tissues. The byproduct tissues did exhibit significant differences in monocyte (P = .037) and red blood cell (P = .038) concentrations, specifically with greater values present in the ACL stump tissue. Cells from all byproduct tissues adhered to plastic cell culture flasks. Significant differences were found between colony-forming unit fibroblast counts of the 4 byproduct tissues when plated at 106 (P = .003) and 103 (P = .016) cells as the initial seeding density. There was a significant relationship found between both the starting concentration (χ2 = 32.7, P < .001) and the byproduct tissue type (χ2 = 30.4, P < .001) to the presence of ≥80% confluency status at 10 days. Cells obtained from all 4 byproduct tissues qualitatively showed positive tri-lineage (adipocyte, osteoblast, chondroblast) differentiation potential compared with negative controls under standardized in vitro differentiation conditions. Cells derived from all 4 byproduct tissues expressed cell-surface antigens CD105+, CD73+, CD90+, CD45-, CD14-, and CD19- (>75%), and did not express CD45 (<10%). There were no statistically significant differences in cell-surface antigens between the four byproduct tissues.

Conclusions

This descriptive laboratory study demonstrated that cells derived from arthroscopic byproduct tissues of ACL reconstruction remain viable when collected with an in-line-suction autologous tissue collector and these cells meet the ISCT criteria to qualify as mesenchymal stem cells.

Clinical Relevance

It is known that viable mesenchymal stem cells reside in byproduct tissue of anterior cruciate ligament reconstruction surgery (ACLR). Practical methods to harvest these cells at the point of care require further development. This study validates the use of an in-line-suction autologous tissue collector for the harvest of viable mesenchymal stem cells after ACLR.

Remnant tissue enhances early postoperative biomechanical strength and infiltration of Scleraxis-positive cells within the grafted tendon in a rat anterior cruciate ligament reconstruction model

When ruptured, ligaments and tendons have limited self-repair capacity and rarely heal spontaneously. In the knee, the Anterior Cruciate Ligament (ACL) often ruptures during sports activities, causing functional impairment and requiring surgery using tendon grafts. Patients with insufficient time to recover before resuming sports risk re-injury. To develop more effective treatment, it is necessary to define mechanisms underlying ligament repair. For this, animal models can be useful, but mice are too small to create an ACL reconstruction model. Thus, we developed a transgenic rat model using control elements of Scleraxis (Scx), a transcription factor essential for ligament and tendon development, to drive GFP expression in order to localize Scx-expressing cells. As anticipated, Tg rats exhibited Scx-GFP in ACL during developmental but not adult stages. Interestingly, when we transplanted the flexor digitorum longus (FDP) tendon derived from adult Scx-GFP+ rats into WT adults, Scx-GFP was not expressed in transplanted tendons. However, tendons transplanted from adult WT rats into Scx-GFP rats showed upregulated Scx expression in tendon, suggesting that Scx-GFP+ cells are mobilized from tissues outside the tendon. Importantly, at 4 weeks post-surgery, Scx-GFP-expressing cells were more frequent within the grafted tendon when an ACL remnant was preserved (P group) relative to when it was not (R group) (P vs R groups (both n = 5), p<0.05), and by 6 weeks, biomechanical strength of the transplanted tendon was significantly increased if the remnant was preserved (P vsR groups (both n = 14), p<0.05). Scx-GFP+ cells increased in remnant tissue after surgery, suggesting remnant tissue is a source of Scx+ cells in grafted tendons. We conclude that the novel Scx-GFP Tg rat is useful to monitor emergence of Scx-positive cells, which likely contribute to increased graft strength after ACL reconstruction.

Nanofibrous scaffolds for the healing of the fibrocartilaginous enthesis: advances and prospects

With the current developmental advancements in nanotechnology, nanofibrous scaffolds are being widely used. The healing of fibrocartilaginous enthesis is a slow and complex process, and while existing treatments have a certain effect on promoting their healing, these are associated with some limitations. The nanofibrous scaffold has the advantages of easy preparation, wide source of raw materials, easy adjustment, easy modification, can mimic the natural structure and morphology of the fibrocartilaginous enthesis, and has good biocompatibility, which can compensate for existing treatments and be combined with them to promote the repair of fibrocartilaginous enthesis. The nanofibrous scaffold can promote the healing of fibrocartilaginous enthesis by controlling the morphology and ensuring controlled drug release. Hence, the use of nanofibrous scaffold with stimulative response features in the musculoskeletal system has led us to imagine its potential application in fibrocartilaginous enthesis. Therefore, the healing of fibrocartilaginous enthesis based on a nanofibrous scaffold may be a novel therapeutic approach.

Orthobiologics: a review

PURPOSE

The use of biologic materials in orthopaedics (orthobiologics) has gained significant attention over the past years. To enhance the body of the related literature, this review article is aimed at summarizing these novel biologic therapies in orthopaedics and at discussing their multiple clinical implementations and outcomes.

METHODS

This review of the literature presents the methods, clinical applications, impact, cost-effectiveness, and outcomes, as well as the current indications and future perspectives of orthobiologics, namely, platelet-rich plasma, mesenchymal stem cells, bone marrow aspirate concentrate, growth factors, and tissue engineering.

RESULTS

Currently available studies have used variable methods of research including biologic materials as well as patient populations and outcome measurements, therefore making comparison of studies difficult. Key features for the study and use of orthobiologics include minimal invasiveness, great healing potential, and reasonable cost as a nonoperative treatment option. Their clinical applications have been described for common orthopaedic pathologies such as osteoarthritis, articular cartilage defects, bone defects and fracture nonunions, ligament injuries, and tendinopathies.

CONCLUSIONS

Orthobiologics-based therapies have shown noticeable clinical results at the short- and mid-term. It is crucial that these therapies remain effective and stable in the long term. The optimal design for a successful scaffold remains to be further determined.

Strategies to promote tendon-bone healing after anterior cruciate ligament reconstruction: Present and future

At present, anterior cruciate ligament (ACL) reconstruction still has a high failure rate. Tendon graft and bone tunnel surface angiogenesis and bony ingrowth are the main physiological processes of tendon-bone healing, and also the main reasons for the postoperative efficacy of ACL reconstruction. Poor tendon-bone healing has been also identified as one of the main causes of unsatisfactory treatment outcomes. The physiological process of tendon-bone healing is complicated because the tendon-bone junction requires the organic fusion of the tendon graft with the bone tissue. The failure of the operation is often caused by tendon dislocation or scar healing. Therefore, it is important to study the possible risk factors for tendon-bone healing and strategies to promote it. This review comprehensively analyzed the risk factors contributing to tendon-bone healing failure after ACL reconstruction. Additionally, we discuss the current strategies used to promote tendon-bone healing following ACL reconstruction.

Strategies for promoting tendon-bone healing: Current status and prospects

Tendon-bone insertion (TBI) injuries are common, primarily involving the rotator cuff (RC) and anterior cruciate ligament (ACL). At present, repair surgery and reconstructive surgery are the main treatments, and the main factor determining the curative effect of surgery is postoperative tendon-bone healing, which requires the stable combination of the transplanted tendon and the bone tunnel to ensure the stability of the joint. Fibrocartilage and bone formation are the main physiological processes in the bone marrow tract. Therefore, therapeutic measures conducive to these processes are likely to be applied clinically to promote tendon-bone healing. In recent years, biomaterials and compounds, stem cells, cell factors, platelet-rich plasma, exosomes, physical therapy, and other technologies have been widely used in the study of promoting tendon-bone healing. This review provides a comprehensive summary of strategies used to promote tendon-bone healing and analyses relevant preclinical and clinical studies. The potential application value of these strategies in promoting tendon-bone healing was also discussed.

Return to sport soccer after anterior cruciate ligament reconstruction: ISAKOS consensus

INTRODUCTION

Many factors can affect the return to pivoting sports, after an Anterior Cruciate Ligament Reconstruction. Prehabilitation, rehabilitation, surgical and psychological aspects play an essential role in the decision to return to sports. The purpose of this study is to reach an international consensus about the best conditions for returning to sports in soccer-one of the most demanding level I pivoting sports after anterior cruciate ligament (ACL) reconstruction.

METHODS

34 International experts in the management of ACL injuries, representing all the Continents were convened and participated in a process based on the Delphi method to achieve a consensus. 37 statements related to ACL reconstruction were reviewed by the experts in three rounds of surveys in complete anonymity. The statements were prepared by the working group based on previous literature or systematic reviews. Rating agreement through a Likert Scale: strongly agree, agree, neither agree or disagree, disagree and strongly disagree was used. To define consensus, it was established that the assertions should achieve a 75% of agreement or disagreement.

RESULTS

Of the 37 statements, 10 achieved unanimous consensus, 18 non-unanimous consensus and 9 did not achieve consensus. In the preoperative, the correction of the range of motion deficit, the previous high level of participation in sports and a better knowledge of the injury by the patient and compliance to participate in Rehabilitation were the statements that reached unanimous consensus. During the surgery, the treatment of associated injuries, as well as the use of autografts, and the addition of a lateral extra-articular tenodesis in some particular cases (active young athletes, <25 years old, hyperlaxity, high rotatory laxity and revision cases) obtained also 100% consensus. In the postoperative period, psychological readiness and its validation with scales, adequate physical preparation, as well as not basing the RTSS purely on the time of evolution after surgery, were the factors that reached unanimous Consensus.

CONCLUSIONS

The consensus statements derived from this international ISAKOS leaders, may assist clinicians in deciding when to return to sports soccer in patients after an ACL reconstruction. Those statements that reached 100% consensus have to be strongly considered in the final decision to RTS soccer.

Rehabilitation And Advances In Surgical Reconstruction For Anterior Cruciate Ligament Insufficiency: What Has Changed Since The 1960s? - State Of The Art

Anterior cruciate ligament (ACL) insufficiency can be disabling, given the physical and sports activity constraints that negatively impact the quality of life. Consequently, surgery is the main approach for most active patients. Nonetheless, ACL reconstruction (ACLR) cannot be successful without adequate preoperative and postoperative rehabilitation. Since the 1960s, post-ACLR rehabilitation has evolved, mainly from advances in surgery, coupled with a better understanding of the biological concepts of graft revascularization, maturation and integration, which have impacted ACL postoperative rehabilitation protocols. However, new technologies do involve a definite learning curve which could affect rehabilitation programs and produce inconsistent results. The development of rehabilitation protocols cannot be defined without an accurate diagnosis of ACL injury and considering the patient's main physical demands and expectations. This article discusses how postoperative rehabilitation following ACLR has changed from the 1960s to now, focussing on surgical technique (type of tendon graft, fixation devices, and graft tensioning), biological concepts (graft maturation and integration), rehabilitation protocols (prevention of ACL injuries, preoperative rehabilitation, postoperative rehabilitation), criteria to return to sports, patient's reported outcomes and outcome. Although rehabilitation plays an essential role in managing ACL injuries, it cannot be fully standardised preoperatively or postoperatively. Preoperative and postoperative rehabilitation should be based on an accurate clinical diagnosis, patients' understanding of their injury, graft tissue biology and biomechanics, surgical technique, the patient's physical demands and expectations, geographical differences in ACL rehabilitation and future perspectives.

Knee Cartilage Change within 5 Years after Aclr Using Hamstring Tendons with Preserved Tibial-Insertion: A Prospective Randomized Controlled Study Based on Magnetic Resonance Imaging

Background: Comparing to anterior cruciate ligament reconstructions (ACLR) with free hamstring tendon (FHT), ACLR with preserved tibial-insertion hamstring tendon (HT-PTI) could ensure the blood supply of the graft and avoid graft necrosis. Yet, whether HT-PTI could protect the cartilage and clinical outcomes in mid-long period after ACLR was still unclear. Purpose: To compare the cartilage change and clinical results between the HT-PTI and FHT in 5 years after ACLR. Study design: Randomized controlled trial; Level of evidence, 2. Methods: A total of 45 patients who underwent isolated ACLR with the autograft of hamstring tendons were enrolled and randomized into 2 groups. The study group undertook ACLR with HT-PTI, whereas the control group had FHT. At pre-operation, and 6, 12, 24, and 60 months post-operation, all cases underwent evaluation with Knee Injury and Osteoarthritis Outcome Score (KOOS), and MR examination. The knee cartilage was divided into 8 sub-regions of which the T2 value and cartilage volume on MRI were measured and documented. The data of two groups were compared and their correlations were analyzed. Results: A total of 18 patients in the HT-PTI group and 19 patients in the FHT group completed the follow-up. The KOOS scores were improved at each follow-up time point (p < 0.001), reached the most superior at 12 months and maintained until 60 months but had no significant difference between the two groups. At 60 months, the cartilage in most subregions in FHT group had higher T2 values than those of pre-operation (p < 0.05) and also higher than HT-PTI group; The cartilage volume changes (CV%) are positive at 6 months and negative from 12 to 60 months in the FHT group, while being negative at all time points in the HT-PTI group. The values of absolute CV% in most subregions in FHT group were significantly higher than those in the HT-PTI group at 6 and 60 months (p < 0.05). Conclusion: The improvement of KOOS score peaked at 12 months in all cases and had no difference between the two groups. The cartilage in the FHT group had more volume loss, earlier and wider damage than that in the HT-PTI group within 5 years. No significant correlation was found among KOOS score, CV%, and T2 value.

Platelet-rich plasma therapy or arthroscopic surgery on repair of anterior cruciate ligament rupture

The Anterior Cruciate Ligament (ACL) rupture reduces knee stability. In old patients with ACL rupture, surgery is not recommended due to the person's low level of activity and knee osteoarthritis. Platelet-rich plasma (PRP) is a good treatment option in inflammatory cases in orthopedics. Hence, the aim of this study was to assess and comparison of the effect of PRP and arthroscopic surgery on anterior cruciate ligament rupture. This is a clinical trial that was performed in 2020-2021 in Tehran. 100 patients were randomly divided into two groups. The first group of patients underwent ACL tendon repair surgery by arthroscopy and tendon graft. The second group were treated by PRP injection. Both groups of patients were visited from 3 months to 14 months after surgery or PRP treatments. The pain was assessed by Visual Analogue Scale (VAS), we also used Knee Score by the Oxford Score Knee Outcome Scale (OKS) to assess patient's functions. The mean VAS score was 3.05 ± 2.47 in patients in surgery group and mean VAS score was 4.39± 2.66 in patients in the PRP group (p = 0.03). These data showed significant improvements in VAS score in both groups with higher improvements in surgical group. After procedures, the ROM was 120.33 ± 19.60º in surgery group and 109.31 ± 17.22º in PRP group (p = 0.03). Patients in both groups had significantly decreased pain severity after 14 months, but the patients in the surgical treatment group had significantly lower pain and higher ROM compared to PRP group.

Infrapatellar Fat Pad Mesenchymal Stromal Cell-Derived Exosomes Accelerate Tendon-Bone Healing and Intra-articular Graft Remodeling After Anterior Cruciate Ligament Reconstruction

BACKGROUND

Exosomes derived from mesenchymal stromal cells (MSCs) reportedly enhance the healing process. However, no studies have investigated the effect of exosomes from infrapatellar fat pad (IPFP) MSCs on tendon-bone healing and intra-articular graft remodeling after anterior cruciate ligament reconstruction (ACLR).

PURPOSE

To evaluate the in vivo effect of exosomes from IPFP MSCs on tendon-bone healing and intra-articular graft remodeling in a rat model of ACLR.

STUDY DESIGN

Controlled laboratory study.

METHODS

A total of 90 skeletally mature male Sprague Dawley rats underwent unilateral ACLR using an autograft. All rats were randomly divided into 3 groups: sham injection (SI) group (n = 30), control injection (CI) group (n = 30), and IPFP MSC-derived exosome injection (IMEI) group (n = 30). At 2, 4, and 8 weeks postoperatively, tendon-bone healing and intra-articular graft remodeling were evaluated via biomechanical testing, micro-computed tomography, and histological analysis; macrophage polarization was evaluated using immunohistochemical staining.

RESULTS

Biomechanical testing demonstrated a significantly higher failure load and stiffness in the IMEI group than in the SI and CI groups at 4 and 8 weeks postoperatively. Moreover, a thinner graft-to-bone healing interface with more fibrocartilage was observed in the IMEI group at both time points. Micro-computed tomography revealed greater new bone ingrowth in the IMEI group than in the other groups, as demonstrated by smaller mean bone tunnel areas and a larger bone volume/total volume ratio. Additionally, more cellular infiltration was observed in the intra-articular graft in the IMEI group than in the other groups at 4 weeks, followed by more regularly organized fibers with mature collagen at 8 weeks. Notably, similar trends of macrophage polarization were found at both the graft-to-bone interface and the intra-articular graft in the IMEI group, with significantly fewer proinflammatory M1 macrophages and larger numbers of reparative M2 macrophages than in the SI and CI groups.

CONCLUSION

IPFP MSC-derived exosomes accelerated tendon-bone healing and intra-articular graft remodeling after ACLR, which may have resulted from the immunomodulation of macrophage polarization.

CLINICAL RELEVANCE

The IPFP can be easily harvested by most orthopaedic surgeons. Exosomes from IPFP MSCs, constituting a newly emerging cell-free approach, may represent a treatment option for improving tendon-bone healing and intra-articular graft remodeling after ACLR.

Current trends in the anterior cruciate ligament part 1: biology and biomechanics

A trend within the orthopedic community is rejection of the belief that "one size fits all." Freddie Fu, among others, strived to individualize the treatment of anterior cruciate ligament (ACL) injuries based on the patient's anatomy. Further, during the last two decades, greater emphasis has been placed on improving the outcomes of ACL reconstruction (ACL-R). Accordingly, anatomic tunnel placement is paramount in preventing graft impingement and restoring knee kinematics. Additionally, identification and management of concomitant knee injuries help to re-establish knee kinematics and prevent lower outcomes and registry studies continue to determine which graft yields the best outcomes. The utilization of registry studies has provided several large-scale epidemiologic studies that have bolstered outcomes data, such as avoiding allografts in pediatric populations and incorporating extra-articular stabilizing procedures in younger athletes to prevent re-rupture. In describing the anatomic and biomechanical understanding of the ACL and the resulting improvements in terms of surgical reconstruction, the purpose of this article is to illustrate how basic science advancements have directly led to improvements in clinical outcomes for ACL-injured patients.Level of evidenceV.

Cell and Cell Free Therapies in Osteoarthritis

Osteoarthritis (OA) is the most common articular disease in adults and has a current prevalence of 12% in the population over 65 years old. This chronic disease causes damage to articular cartilage and synovial joints, causing pain and leading to a negative impact on patients' function, decreasing quality of life. There are many limitations regarding OA conventional therapies-pharmacological therapy can cause gastrointestinal, renal, and cardiac adverse effects, and some of them could even be a threat to life. On the other hand, surgical options, such as microfracture, have been used for the last 20 years, but hyaline cartilage has a limited regeneration capacity. In recent years, the interest in new therapies, such as cell-based and cell-free therapies, has been considerably increasing. The purpose of this review is to describe and compare bioregenerative therapies' efficacy for OA, with particular emphasis on the use of mesenchymal stem cells (MSCs) and platelet-rich plasma (PRP). In OA, these therapies might be an alternative and less invasive treatment than surgery, and a more effective option than conventional therapies.

Has platelet-rich plasma any role in partial tears of the anterior cruciate ligament? Prospective comparative study

BACKGROUND

Partial tears of the anterior cruciate ligament (ACL) are frequent, and there is still considerable controversy surrounding their diagnosis, natural history and treatment.

AIM

To examine patient-reported outcomes, physical examination and magnetic resonance imaging (MRI) findings of partial ACL tears treated with an intraarticular injection of platelet-rich plasma (PRP) compared to a control group.

METHODS

From January 2015 to November 2017, consecutive patients from a single institution with partial ACL tears treated nonoperatively were prospectively evaluated. Partial tears were defined as a positive Lachman test with a clear end-point, a negative pivot-shift and less than 3 mm of side-to-side difference using the KT1000 arthrometer. Patients in group 1 were treated with one intraarticular injection of PRP and specific physical therapy protocol. Control group consisted of patients treated only with physical therapy. Prospective analyzed data included physical examination, Tegner activity level and Lysholm and International Knee Documentation Committee scores. Baseline MRI findings and at 6 mo follow-up were reviewed. Failure was defined as those patients with clinical instability at follow-up that required a subsequent ACL reconstruction.

RESULTS

A total of 40 patients where included, 21 treated with PRP injection with a mean follow-up of 25 mo [standard deviation (SD): 3.6] and 19 in the control group with a mean follow-up of 25 mo (SD: 5.68). Overall failure rate was 32.0% (n = 13). No significant differences were observed between groups regarding subjective outcomes, return to sport and failure rate. MRI findings revealed an improvement in the ACL signal in half of the patients of both groups. However, we did not find a significant relationship between MRI findings and clinical outcomes.

CONCLUSION

Overall, 95.0% of patients returned to sports at a mean follow-up of 25 mo. Mean time to return to sports was 4 mo. Out of these patients, almost 30.0% in each group had a new episode of instability and required surgery at a median time of 5 mo in group 1 and 8 mo in group 2. The addition of PRP alone was not sufficient to enhance any of the outcome measures evaluated, including MRI images, clinical evaluation and failure rate.

Return to sport following anterior cruciate ligament reconstruction: the argument for a multimodal approach to optimise decision-making: current concepts

Existing literature is varied in the methods used to make this determination in the treatment of athletes who have undergone recent anterior cruciate ligament (ACL) reconstruction. Some authors report using primarily time-based criteria, while others advocate for physical measures and kinematic testing to inform decision-making. The goal of this paper is to elucidate the most current medical evidence regarding identification of the earliest point at which a patient may safely return to sport. The present review therefore seeks to examine the evidence from a critical perspective-breaking down the biology of graft maturation, effect of graft choice, potential for image-guided monitoring of progression and results associated with time-based versus functional criteria-based return to play-to justify a multifactorial approach to effectively advance athletes to return to sport. The findings of the present study reaffirm that time is a prerequisite for the biological progression that must occur for a reconstructed ligament to withstand loads demanded by athletes during sport. Modifications of surgical techniques and graft selection may positively impact the rate of graft maturation, and evidence suggests that imaging studies may offer informative data to enhance monitoring of this process. Aspects of both functional and cognitive testing have also demonstrated utility in prior studies and consequently have been factored into modern proposed methods of determining the athlete's readiness for sport. Further work is needed to definitively determine the optimal method of clearing an athlete to return to sport after ACL reconstruction. Evidence to date strongly suggests a role of a multimodal algorithmic approach that factors in time, graft biology and functional testing in return-to-play decision-making after ACL reconstruction.Level of evidence: level V.

The 2020 NBA Orthobiologics Consensus Statement

This 2020 NBA Orthobiologics Consensus Statement provides a concise summary of available literature and practical clinical guidelines for team physicians and players. We recognize that orthobiologic injections are a generally safe treatment modality with a significant potential to reduce pain and expedite early return to play in specific musculoskeletal injuries. The use of orthobiologics in sports medicine to safely reduce time loss and reinjury is of considerable interest, especially as it relates to the potential effect on a professional athlete. While these novel substances have potential to enhance healing and regeneration of injured tissues, there is a lack of robust data to support their regular use at this time. There are no absolutes when considering the implementation of orthobiologics, and unbiased clinical judgment with an emphasis on player safety should always prevail. Current best evidence supports the following: Key Points There is support for the use of leukocyte-poor platelet-rich plasma in the treatment of knee osteoarthritis. There is support for consideration of using leukocyte-rich platelet-rich plasma for patellar tendinopathy. The efficacy of using mesenchymal stromal cell injections in the management of joint and soft tissue injuries remains unproven at this time. There are very few data to suggest that current cell therapy treatments lead to any true functional tissue regeneration. Meticulous and sterile preparation guidelines must be followed to minimize the risk for infection and adverse events if these treatments are pursued.Given the high variability in orthobiologic formulations, team physicians must stay up-to-date with the most recent peer-reviewed literature and orthobiologic preparation protocols for specific injuries.Evidence-based treatment algorithms are necessary to identify the optimal orthobiologic formulations for specific tissues and injuries in athletes.Changes in the regulatory environment and improved standardization are required given the exponential increase in utilization as novel techniques and substances are introduced into clinical practice.

Texture analysis to differentiate anterior cruciate ligament in patients after surgery with platelet-rich plasma

BACKGROUND

Platelet-rich plasma (PRP) has been used to favor anterior cruciate ligament (ACL) healing after reconstruction surgeries. However, clinical data are still inconclusive and subjective about PRP. Thus, we propose a quantitative method to demonstrate that PRP produced morphological structure changes.

METHODS

Thirty-four patients undergoing ACL reconstruction surgery were evaluated and divided into control group (sixteen patients) without PRP application and experiment group (eighteen patients) with intraoperative application of PRP. Magnetic resonance imaging (MRI) scans were performed 3 months after surgery. We used Matlab® and machine learning (ML) in Orange Canvas® to texture analysis (TA) features extraction. Experienced radiologists delimited the regions of interest (RoIs) in the T2-weighted images. Sixty-two texture parameters were extracted, including gray-level co-occurrence matrix and gray level run length. We used the algorithms logistic regression (LR), naive Bayes (NB), and stochastic gradient descent (SGD).

RESULTS

The accuracy of the classification with NB, LR, and SGD was 83.3%, 75%, 75%, respectively. For the area under the curve, NB, LR, and SGD presented values of 91.7%, 94.4%, 75%, respectively. In clinical evaluations, the groups show similar responses in terms of improvement in pain and increase in the IKDC index (International Knee Documentation Committee) and Lysholm score indices differing only in the assessment of flexion, which presents a significant difference for the group treated with PRP.

CONCLUSIONS

Here, we demonstrated quantitatively that patients who received PRP presented texture changes when compared to the control group. Thus, our findings suggest that PRP interferes with morphological parameters of the ACL.

TRIAL REGISTRATION

Protocol no. CAAE 56164316.6.0000.5411.

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

Treatment of Partial Posterior Cruciate Ligament Injuries with Platelet-Rich Plasma in Growth Factors (PRGF) Intraligamentous Infiltration and a Specific Knee Brace

Posterior cruciate ligament (PCL) injuries are not as common as other knee ligament injuries, but may present a challenging scenario for even skilled knee surgeons. Complete PCL tears are typically encountered in the setting of multiligament knee injuries and require surgical treatment. Isolated complete PCL injuries are uncommon and the best treatment is debated, and likely depends on the degree of symptoms and objective instability. However, many PCL injuries will be partial tears (grade I or II). The purpose of this chapter is to describe our treatment of choice for partial PCL injuries through a conservative approach.

Level of evidence  Level IV.

Patellar Bone-Tendon-Bone Autografts versus Quadriceps Tendon Allograft with Synthetic Augmentation in a Canine Model

Patellar bone-tendon-bone (pBTB) autografts are often considered the "gold standard" for complete anterior cruciate ligament (ACL) reconstruction and are also associated with significant complications and early-onset knee osteoarthritis (OA). A novel quadriceps tendon allograft with synthetic augmentation, or "internal brace" (QTIB), has been reported to have potential advantages for ACL reconstruction based on animal model data. In this preclinical canine comparison study, we hypothesized that QTIB allograft compared with pBTB autograft would provide superior durability for knee stability, function, and prevention of OA. Under approval from our Institutional Animal Care and Use Committee, adult purpose-bred research hounds (n = 10) underwent arthroscopic complete transection of the ACL followed by either an arthroscopic-assisted all-inside ACL reconstruction using the QTIB allograft (n = 5) or pBTB autograft (n = 5). Contralateral knees were used as nonoperated controls (n = 10). Radiographic and arthroscopic assessments were performed at 2 and 6 months, respectively, after surgery. Anterior drawer, internal rotation, lameness, kinetics, pain, effusion, and comfortable range of knee motion were measured at 2, 3, and 6 months. Biomechanical and histologic assessments were performed at 6 months. All reconstructed knees were stable and had intact ACL grafts 6 months after surgery. At 6 months, QTIB reconstructed knees had significantly less lameness, lower pain, less effusion, and increased range of motion when compared with BTB knees (p < 0.05). BTB knees had significantly higher radiographic OA scores than QTIB knees at 6 months (p < 0.05). Superior outcomes associated with QTIB allograft may be due to the lack of donor site morbidity, the use of a robust tendon graft, and/or protection of the graft from the synthetic augmentation. Robust tendon grafts combined with a synthetic internal brace and platelet-rich plasma (PRP) may allow for more rapid and robust tendon-bone healing and graft "ligamentization," which protects the graft from early failure and rapid OA development that can plague commonly-used allografts.

Leucocyte-poor-platelet-rich plasma intra-operative injection in chondral knee injuries improve patients outcomes. A prospective randomized trial

PURPOSE

Evaluate the effects of intra-operative leucocyte-poor-platelet-rich plasma (PRP) (type P3-Bβ with endogenous activation) injection in International Cartilage Repair Society (ICRS) grade III knee chondral injuries treated by chondroplasties, to increase and ameliorate the repair tissue.

METHODS

Patients were divided into two groups. Group A (control) consisted of 31 patients and Group B (PRP) 33 patients, totaling 64 patients analyzed. Patients also could had associated injuries (meniscal and/or ACL) being equally divided between both groups to avoid bias. PRP was injected at the end of surgery in group B. The patient outcomes were assessed using subjective International Knee Documentation Committee (IKDC) form, Knee Injury and Osteoarthritis Outcome Score (KOOS), and Tegner activity forms, prior to the surgery and three, six, 12, and 24 months after surgery (medium-term follow up).

RESULTS

IKDC and KOOS scores showed increase at each evaluation time points after surgery in both groups, but the treated Group (B) showed a higher increase with statistically significant difference. The Tegner activity scores were higher for the treated group only at six and 12 months.

CONCLUSION

Based on the subjective IKDC, KOOS, and Tegner scores, those patients affected by ICRS grade III chondral injuries undergoing arthroscopic chondroplasty who were also treated with PRP showed better and faster outcomes than the control group. Independently from the associated injury (meniscal or ACL). This difference could be measured for up to two years.

Higher Physiologic Platelet Counts in Whole Blood Are Not Associated With Improved ACL Cross-sectional Area or Signal Intensity 6 Months After Bridge-Enhanced ACL Repair

Background:

A bridge-enhanced anterior cruciate ligament (ACL) repair (BEAR) procedure places an extracellular matrix implant, combined with autologous whole blood, in the gap between the torn ends of the ligament at the time of suture repair to stimulate healing. Prior studies have suggested that white blood cell (WBC) and platelet concentrations significantly affect the healing of other musculoskeletal tissues.

Purpose/Hypothesis:

The purpose of this study was to determine whether concentrations of various blood cell types placed into a bridging extracellular matrix implant at the time of ACL repair would have a significant effect on the healing ligament cross-sectional area or tissue organization (as measured by signal intensity). We hypothesized that patients with higher physiologic platelet and lower WBC counts would have improved healing of the ACL on magnetic resonance imaging (MRI) (higher cross-sectional area and/or lower signal intensity) 6 months after surgery.

Study Design:

Cohort study; Level of evidence, 2.

Methods:

A total of 61 patients underwent MRI at 6 months after bridge-enhanced ACL repair as part of the BEAR II trial. The normalized signal intensity and average cross-sectional area of the healing ligament were measured from a magnetic resonance stack obtained using a gradient echo sequence. The results were stratified by sex, and univariate and multivariate regression analyses determined significant correlations between blood cell concentrations on these 2 magnetic resonance parameters.

Results:

In unadjusted analyses, older age and male sex were associated with greater healing ligament cross-sectional area (P < .04) but not signal intensity (P > .15). Adjusted multivariable analyses indicated that in female patients, a higher monocyte concentration correlated with a higher ACL cross-sectional area (β = 1.01; P = .049). All other factors measured, including the physiologic concentration of platelets, neutrophils, lymphocytes, basophils, and immunoglobulin against bovine gelatin, were not significantly associated with either magnetic resonance parameter in either sex (P > .05 for all).

Conclusion:

Although older age, male sex, and monocyte concentration in female patients were associated with greater healing ligament cross-sectional area, signal intensity of the healing ligament was independent of these factors. Physiologic platelet concentration did not have any significant effect on cross-sectional area or signal intensity of the healing ACL at 6 months after bridge-enhanced ACL repair in this cohort. Given these findings, factors other than the physiologic platelet concentration and total WBC concentration may be more important in the rate and amount of ACL healing after bridge-enhanced ACL repair.

Effectiveness of platelet-rich plasma in the management of hip osteoarthritis: a systematic review and meta-analysis

The effectiveness of platelet-rich plasma (PRP) injections for osteoarthritis (OA) is still controversial. Previous research supports the use of intra-articular PRP injections to promote a favorable environment for joint tissue healing and to delay the progression of OA. The purpose of this review is to investigate the effectiveness of PRP in the management of hip osteoarthritis (HOA). Five electronic databases were searched from inception to May 2019: Medline (via PubMed), SportDiscus via EBSCO, ProQuest Health & Medical Complete, CINAHL, and Cochrane. Risk of bias was assessed with the Cochrane risk of bias tool. The GRADE method was used to assess the level of evidence for the studies included in this review. Clinical trials evaluate PRP injections among adult patients diagnosed with HOA according to the American College of Rheumatology criteria. At least one outcome measure for pain or function must have been reported. A total of 4 trials (334 participants, 340 hips) were included, all marked as "moderate risk of bias". Pain and function were assessed throughout the studies with visual analogue scale (VAS), Western Ontario and McMaster Universities Osteoarthritis Index (WOMAC), and Harris Hip Score (HHS) tools. Intra-articular PRP injections were more effective at stages earlier than 3 months for both treatment groups with the exception of WOMAC score in one study. The superiority of PRP against comparative treatments was only reported in one study; longer-term evaluations from 4 to 12 months showed diverse results, with only one study reporting significantly better results for PRP. PRP may be beneficial and safe for patients with HOA at mid-term follow-up. However, its superiority over other procedures such as hyaluronic acid remains unclear. Further researches with high-quality designs and larger samples become imperative.

The effect of perioperative platelet-rich plasma injections on postoperative failure rates following rotator cuff repair: a systematic review with meta-analysis

BACKGROUND

Platelet-rich plasma (PRP) has gained significant interest in recent years to potentially add biological augmentation of healing to surgical repairs of soft-tissue injuries. We sought to determine whether perioperative PRP injection influences the risk of failure following rotator cuff repair.

METHODS

A systematic search was performed in the Embase and PubMed databases and identified 16 randomized controlled trials or prospective cohort studies (1045 participants) reporting rates of failure, defined as a subsequent tear on postoperative imaging, after rotator cuff repair with or without perioperative PRP administration. A random-effects meta-analysis of the included studies was performed to determine the pooled effect of PRP administration on the postoperative failure risk.

RESULTS

Among the 16 studies investigating rotator cuff repairs, PRP augmentation resulted in a 25% reduction in the risk of repair failure, with low heterogeneity among the included studies. A significant protective effect was seen for studies of only small to medium tears (7 studies) (P = .007) and studies including large or massive tears (9 studies) (P < .001).

CONCLUSIONS

Intraoperative PRP reduces the failure risk following rotator cuff repair and has a consistent effect regardless of tear size. However, because of the variability in PRP preparations, a specific recommendation cannot be made.

Anterior Cruciate Ligament Reconstruction with Platelet-Rich Plasma: A Systematic Review of Randomized Control Trials

PURPOSE

To perform a systematic review of the randomized controlled trials (RCTs) evaluating the efficacy of platelet-rich plasma (PRP) to augment anterior cruciate ligament (ACL) reconstruction.

METHODS

Two independent reviewers screened the MEDLINE, The Cochrane Library, and EMBASE databases using Preferred Reporting for Systematic Reviews and Meta-Analyses guidelines for applicable RCTs evaluating the efficacy of PRP in ACL reconstruction. A meta-analysis was performed on the papers involving bone-patellar tendon-bone (BPTB) grafting.

RESULTS

Thirteen RCTs fulfilled the inclusion criteria involving 765 patients. There was no clinical improvement (Tegner, Lysholm, Knee Injury and Osteoarthritis Outcome Score, or International Knee Documentation Committee scores) in any of the 7 studies evaluating PRP alongside the hamstring tendon autograft ACL reconstructions versus the control. Two studies evaluating PRP for hamstring tendon autograft demonstrated significantly improved magnetic resonance imaging findings. Two studies analyzed the use of PRP with allograft ACL reconstruction showed no clinical, biochemical, or radiologic improvements in postoperative follow-up. No functional improvements were found when PRP was used alongside BPTB in 4 studies. There was no significant difference in visual analog scale score in the BPTB group (1.1 vs 1.5, P = .18), or tibial filling defects (P = .30).

CONCLUSIONS

This study found that the current level I evidence does not support the use of PRP to improve graft healing, improve donor-site morbidity, reduce postoperative pain levels, or improve functional outcomes following ACL reconstruction.

LEVEL OF EVIDENCE

Level I; systematic review of level I evidence.

Editorial Commentary: Use of Platelet-Rich Plasma in Anterior Cruciate Ligament Reconstruction: Should We Abandon?

The advantages of using platelet-rich plasma application in anterior cruciate ligament reconstruction remains controversial. However, I think further long-term and better design studies are needed to identify whether the administration of platelet-rich plasma could truly play a beneficial role during anterior cruciate ligament reconstruction.

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.

Use of Biologics as an Adjunct Therapy to Arthroscopic Surgery for the Treatment of Femoroacetabular Impingement: A Systematic Review

BACKGROUND

There has been a recent increase in the use of biologics in hip arthroscopy to assist in the management of femoroacetabular impingement (FAI).

PURPOSE

To analyze the current use of biologics for the treatment of FAI and its associated lesions.

STUDY DESIGN

Systematic review; Level of evidence, 4.

METHODS

A search of the PubMed, Medline, and EMBASE databases was performed in March 2019 with use of the PRISMA (Preferred Reporting Items for Systematic Reviews and Meta-Analyses) guidelines. The criterion for inclusion was observational, published research articles studying the therapeutic use of biologics as an adjuvant therapy during arthroscopic surgery for FAI; treatments included bone marrow aspirate concentrate, mesenchymal stem cells (MSCs), platelet-rich plasma (PRP), hyaluronic acid, growth factors, and autologous chondrocyte implantation (ACI) or autologous matrix-induced chondrogenesis (AMIC).

RESULTS

There were 9 studies that met the inclusion criteria, and a total of 674 patients were included across all studies. FAI was studied in all articles. Further, 7 studies (78%) also analyzed chondral injuries, and 3 studies also analyzed labral tears (33%). ACI or AMIC was used in 56% of studies and showed superior functional outcomes at short- and midterm follow-up versus debridement or microfracture. PRP did not improve the outcome of labral repairs at short-term follow-up.

CONCLUSION

The current literature regarding biologic adjuncts in hip arthroscopy is varied in quality, with only one level 1 study. The use of ACI/AMIC for medium-sized chondral lesions showed promising results in individual studies; however, these were of lower quality. To enable comparisons among future studies, investigators must ensure accuracy in the reporting of biologic preparations and formulations used and homogeneity in the type and severity of lesion treated.

Editorial Commentary: Platelet-Rich Plasma: The Devil Is in the Details, and the Details Need to Be Better Reported

The use of biologics may be the next big revolution in sports medicine since the use of the arthroscope. However, we are currently in the infancy of both the understanding of biologics in sports medicine and in the methods we are employing to evaluate their efficacy. As surgeons undertake further studies to elucidate the efficacy of platelet-rich plasma in the treatment of a variety of sports medicine pathologies, adherence to minimum guidelines such as the minimum information for studies evaluating biologics in orthopedics will help to clarify the true benefits of platelet-rich plasma and allow colleagues to reproduce these therapies in their respective practices.

Classification systems for platelet-rich plasma

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

Cite this article: Bone Joint J 2019;101-B:891–896.

Impact of Platelet-Rich Plasma Use on Pain in Orthopaedic Surgery: A Systematic Review and Meta-analysis

CONTEXT

Amid extensive debate, evidence surrounding the use of platelet-rich plasma (PRP) for musculoskeletal injuries has rapidly proliferated, and an overall assessment of efficacy of PRP across orthopaedic indications is required.

OBJECTIVES

(1) Does PRP improve patient-reported pain in musculoskeletal conditions? and (2) Do PRP characteristics influence its treatment effect?

DATA SOURCES

MEDLINE, EMBASE, Cochrane, CINAHL, SPORTDiscus, and Web of Science libraries were searched through February 8, 2017. Additional studies were identified from reviews, trial registries, and recent conferences.

STUDY SELECTION

All English-language randomized trials comparing platelet-rich therapy with a control in patients 18 years or older with musculoskeletal bone, cartilage, or soft tissue injuries treated either conservatively or surgically were included. Substudies of previously reported trials or abstracts and conference proceedings that lacked sufficient information to generate estimates of effect for the primary outcome were excluded.

STUDY DESIGN

Systematic review and meta-analysis.

LEVEL OF EVIDENCE

Level 1.

DATA EXTRACTION

All data were reviewed and extracted independently by 3 reviewers. Agreement was high between reviewers with regard to included studies.

RESULTS

A total of 78 randomized controlled trials (5308 patients) were included. A standardized mean difference (SMD) of 0.5 was established as the minimum for a clinically significant reduction in pain. A reduction in pain was associated with PRP at 3 months (SMD, -0.34; 95% CI, -0.48 to -0.20) and sustained until 1 year (SMD, -0.60; 95% CI, -0.81 to -0.39). Low- to moderate-quality evidence supports a reduction in pain for lateral epicondylitis (SMD, -0.69; 95% CI, -1.15 to -0.23) and knee osteoarthritis (SMD, -0.91; 95% CI, -1.41 to -0.41) at 1 year. PRP characteristics did not influence results.

CONCLUSION

PRP leads to a reduction in pain; however, evidence for clinically significant efficacy is limited. Available evidence supports the use of PRP in the management of lateral epicondylitis as well as knee osteoarthritis.

Effect of Autologous Platelet-Rich Plasma and Gelatin Sponge for Tendon-to-Bone Healing After Rabbit Anterior Cruciate Ligament Reconstruction

PURPOSE

To investigate platelet-rich plasma (PRP) combined with gelatin sponge (GS) to improve tendon-bone interface healing and structure formation.

METHODS

Characterization of the GS scaffold was performed with a scanning electron microscope, and the release curve after loading with PRP was evaluated. A real-time reverse transcription quantitative polymerase chain reaction assay was performed to test the levels of tendon-to-bone healing-related gene expression. Finally, 18 New Zealand white rabbits were randomly divided into 3 groups and underwent semitendinosus autograft anterior cruciate ligament reconstruction: autograft group without PRP, PRP group, and PRP-GS group. All rabbits were killed 8 weeks after the operation. Magnetic resonance imaging scans, biomechanical testing, and histologic evaluation were performed.

RESULTS

An enzyme-linked immunosorbent assay and cell counting kit-8 assay showed that the GS could control the release of PRP and prolong its bioactivity time, as well as promote bone marrow mesenchymal stem cell proliferation. In the PRP-GS group, the levels of related genes were upregulated compared with the PRP group (P < .05). Lower signal in the magnetic resonance images indicated fibrocartilage formation in the 2 groups with PRP. In addition, histologic staining showed that the tendon-bone connection had a greater fibrocartilaginous transition region in the PRP-GS group, and the histologic scores were higher (vs the PRP group, P = .039). The maximum failure load and stiffness were higher in the PRP-GS group than in the other 2 groups.

CONCLUSIONS

GS loading with PRP could prolong the bioactivity time of PRP and promote bone marrow mesenchymal stem cell proliferation and osteogenic gene expression in vitro. It also promoted the early healing process at the tendon-bone junction in a rabbit anterior cruciate ligament reconstruction model.

CLINICAL RELEVANCE

GS is a natural material and offers satisfactory biocompatibility. Using GS as a scaffold to control the release of bioactive factors in bone tunnels may be useful, but additional studies in human subjects will be necessary to evaluate its clinical prospects.

ACL Reconstruction with Augmentation: a Scoping Review

PURPOSE OF REVIEW

We reviewed the recent literature to identify and summarize new research surrounding anterior cruciate ligament reconstruction (ACLR) with augmentation in the form of additional soft tissue procedures or biologic augmentation. Specifically, we wanted to review the failure rates of these procedures in both the primary and revision settings.

METHODS

The databases Embase, PubMed, and Medline were searched on August 13, 2018, for English-language studies that reported on the use of anterior cruciate ligament reconstruction (primary and revision) in conjunction with either soft tissue or biologic augmentation. The studies were systematically screened and data abstracted in duplicates.

RECENT FINDINGS

Advancements in ACLR surgery, including soft tissue augmentation, may decrease primary and revision surgery failure rates for high-risk patients. The use of biological augmentation has shown histologic and radiographic improvements. These differences, however, have failed to be statistically significant and have not resulted in clinically significant improvements in outcome. The limited body of evidence has shown that the addition of soft tissue procedures may in fact lower the risk of graft re-rupture rates particularly in revision or in patients wishing to return to high-risk sports and activities. The use of biologic augmentation although promising in laboratory studies has yet to show any significant clinical results and therefore will require further studies to prove any efficacy.

Efficacy and Tolerability of Progen, a Nutritional Supplement Based on Innovative Plasma Proteins, in ACL Reconstruction: A Multicenter Randomized Controlled Trial

Background:

New biologic strategies are arising to enhance healing and improve the clinical outcome of anterior cruciate ligament (ACL) reconstruction.

Purpose:

To evaluate the efficacy of a new oral nutritional supplement (Progen) that contains hydrolyzed collagen peptides and plasma proteins, a hyaluronic acid–chondroitin sulfate complex, and vitamin C.

Study Design:

Randomized controlled trial; Level of evidence, 2.

Methods:

The study included patients who underwent ACL reconstruction with hamstring autografts using the same fixation method. All patients received the same analgesia and physical therapy (PT) protocol and were randomized to receive either the nutritional supplement (supplemented group) or no additional therapy (control group). Patients were followed up at days 7, 30, 60, and 90. Pain was assessed by use of a visual analog scale (VAS) and by analgesic consumption. Clinical outcome was assessed via International Knee Documentation Committee (IKDC) score and the number of PT sessions. Perceived efficacy and tolerability were rated on a 5-point Likert scale. Graft maturation was assessed by a blinded musculoskeletal radiologist using magnetic resonance imaging. The number of adverse events (AEs) was recorded.

Results:

The intention-to-treat analysis included 72 patients, 36 allocated to the supplemented group and 36 to the control group, with no significant differences regarding demographic and preoperative characteristics. Both groups showed significant improvement in pain and function (measured by VAS and IKDC scores) during the 90-day follow-up period (P < .001 for both), without significant differences between groups. The supplemented group had fewer patients that needed analgesics (8.5% vs 50.0%; P < .05) and attended fewer PT sessions (38.0 vs 48.4 sessions; P < .001) at 90 days and had a higher IKDC score at 60 days (62.5 vs 55.5; P = .029) compared with the control group. Patient- and physician-perceived efficacy was considered significantly higher in the supplemented group at 60 and 90 days (P < .05). Perceived tolerability of the overall intervention was better in the supplemented group at 30, 60, and 90 days (P < .05). Graft maturation showed more advanced degrees (grades 3 and 4) in the supplemented group at 90 days (61.8% vs 38.2%; P < .01). No intolerance or AEs associated with the nutritional supplement treatment were reported.

Conclusion:

The combination of the nutritional supplement and PT after ACL reconstruction improved pain, clinical outcome, and graft maturation. Nutritional supplementation showed higher efficacy during the second month of recovery, without causing AEs.

Registration:

NCT03355651 (ClinicalTrials.gov identifier).

Platelet-Rich Plasma: Review of Current Literature on its Use for Tendon and Ligament Pathology

PURPOSE OF REVIEW

Platelet-rich plasma (PRP) contains numerous growth factors and cytokines that potentially offer an alternative treatment modality to assist in the healing of multiple musculoskeletal issues. The purpose of this review was to examine the latest literature on the use of PRP for various ligament and tendon pathologies.

RECENT FINDINGS

Recent literature has shown moderate- to high-quality evidence that PRP can have positive clinical effects in certain conditions such as lateral epicondylitis and rotator cuff tendinopathy. Prospective studies have shown that it can also be useful in the treatment of patella tendinopathy. In summary, we found PRP to have variable success in ligament and tendon pathology; however, it should be considered a viable option in chronic musculoskeletal disease that has failed other treatments. Patient selection, duration of symptoms, and combining with other modalities such as physical therapy should all be taken into consideration in treatment with PRP.

Time From Injury to Surgery Affects Graft Maturation Following Posterior Cruciate Ligament Reconstruction With Remnant Preservation: A Magnetic Resonance Imaging-Based Study

PURPOSE

To evaluate the clinical outcomes and graft maturation following posterior cruciate ligament reconstruction (PCLR) with preserved remnant and further analyze the correlated factors affecting graft maturation.

METHODS

Consecutive patients who underwent unilateral single-bundle PCLR with remnant preservation from January 2011 to October 2014 by the same senior doctor using tibialis anterior allografts and same surgical technique were included. At a follow-up of more than 2 years, range of motion (ROM) and posterior laxity assessed by posterior drawer test and the KT-1000 arthrometer were examined. Tegner, Lysholm, and International Knee Documentation Committee scores were evaluated. The graft maturation was assessed by a 3.0-T magnetic resonance imaging. Overall correlation analyses and multivariate regression analysis were performed to identify correlated factors of graft maturation, and then subgroups were divided and analyzed according to significant risk factor.

RESULTS

Forty-three (84.3%) of 51 enrolled patients were successfully followed up (38.4 months, 24-54 months). All clinical scores improved significantly, and there were no complications. The results of KT-1000 difference revealed significant decline of posterior laxity (9.4 ± 1.5 vs 2.2 ± 1.5 mm; P < .001). The MRI evaluation confirmed no ligament retears. Both correlation and regression analyses showed time from injury to surgery had a positive, statistically significant weak correlation with the signal intensity score (R = 0.38, P = .012; coefficient = 0.10; P = .036). Subgroup (group 1: time from injury to surgery <3 months; group 2: 3-6 months; group 3: 6-12 months; group 4: ≥12 months) analysis showed there were no significant differences of clinical outcomes between subgroups, while MRI signal intensity was significantly lower in the group with shorter time from injury to surgery (P = .02).

CONCLUSIONS

The remnant-preserved PCLR resulted in satisfactory clinical outcomes and graft maturation at a mean follow-up of 38.4 months. The time from injury to surgery showed a weak positive correlation with postoperative graft signal intensity on MRI.

LEVEL OF EVIDENCE

Level III, retrospective comparative study.

Biologically Augmented Quadriceps Tendon Autograft With Platelet-Rich Plasma for Anterior Cruciate Ligament Reconstruction

Anterior cruciate ligament (ACL) reconstruction is one of the most common procedures studied in the orthopaedic literature. In this regard, graft preparation is a key factor for successful outcomes. Although current methods to reconstruct the ACL are generally perceived to be successful, recent studies indicate that normal structure and function of the knee are fully restored in less than half of the patients. Therefore, biologically augmenting these scaffolds could provide a potential solution for improving healing times and biomechanical properties of the graft. The purpose of this Technical Note is to describe our preferred technique for an ACL graft preparation (quadriceps tendon) augmented with platelet-rich plasma.

Platelet-rich plasma: myth or reality?

Platelet-rich plasma (PRP) is a preparation for therapeutic purposes that is increasingly accepted for various musculoskeletal disorders, due to its theoretical potential to repair tissues with poor healing capacity. Several randomised clinical trials have investigated the capacity of PRP to repair tendons, ligaments, muscles and cartilage, and to date there is level 1a evidence to support its use for lateral epicondylitis, osteoarthritis of the knee, plantar fasciitis and rotator cuff tendinopathy; and level 1b for patellar tendinopathy and osteoarthritis of the hip. Retrospective cohort studies and case series describe promising results with PRP for treating other musculoskeletal disorders. Since its side effects are fewer than those of the control groups, the treatment is considered practically harmless and is being increasingly used. Further randomised clinical trials are necessary to establish future indications, and to confirm effectiveness and safety.

Effect of Intraoperative Platelet-Rich Plasma Treatment on Postoperative Donor Site Knee Pain in Patellar Tendon Autograft Anterior Cruciate Ligament Reconstruction: A Double-Blind Randomized Controlled Trial

BACKGROUND

Donor site morbidity in the form of anterior knee pain is a frequent complication after bone-patellar tendon-bone (BPTB) autograft anterior cruciate ligament (ACL) reconstruction. Hypothesis/Purpose: The purpose was to examine the effect of the intraoperative administration of platelet-rich plasma (PRP) on postoperative kneeling pain. It was hypothesized that PRP treatment would reduce knee pain.

STUDY DESIGN

Randomized controlled trial; Level of evidence, 2.

METHODS

Fifty patients (mean ± SD age, 30 ± 12 years) undergoing BPTB ACL autograft reconstruction were randomized to the PRP (n = 27) or sham (n = 23) treatment. In either case, 10 mL of venous blood was drawn before the induction of anesthesia and either discarded (sham) or processed (PRP) for preparation of a PRP gel to be later mixed with donor site bone chips and inserted into the patellar defect. At 12 weeks, 6 months, 1 year, and 2 years after surgery, patients completed International Knee Documentation Committee (IKDC) forms and visual analog scale pain scores for activities of daily living and kneeling. Healing indices at the donor site were assessed by routine noncontrast magnetic resonance imaging (MRI) at 6 months. Mixed-model analysis of variance was used to assess the effect of PRP on patient symptoms and MRI indices of donor site healing, as measured by the width of the donor site defect.

RESULTS

Kneeling pain, pain with activities of daily living, and IKDC scores were not different between treatment groups at any of the time intervals ( P = .08-.83). Kneeling pain improved from 12 weeks to 6 months and from 1 to 2 years ( P < .05). IKDC scores improved substantially from 12 weeks to 6 months ( P < .001) and continued to improve to 2 years (PRP, 86 ± 19; sham, 89 ± 10). MRI indices of donor site healing were not different between treatment groups ( P = .53-.90).

CONCLUSION

Whether randomized to receive PRP in their patellar defect or not, patients continued to have similar levels of kneeling pain and patellar defect sizes after autograft BPTB ACL reconstruction. Registration: NCT01765712 ( ClinicalTrials.gov identifier).

The Effect of Cartilage Fragments on Femoral Tunnel Widening After Anterior Cruciate Ligament Reconstruction: A Prospective Randomized Controlled Study

PURPOSE

To analyze the effect of cartilage fragments on tunnel widening and tendon-bone integration at 2 years' follow-up after anterior cruciate ligament reconstruction (ACLR).

METHODS

A prospective randomized controlled study was performed in 116 patients who underwent ACLR with autologous hamstring tendons augmented with cartilage fragments (study group, n = 56) or without any augmentation (control group, n = 60). All patients were followed up for 25.6 months (range, 24-28 months), and the International Knee Documentation Committee score, Lysholm score, and visual analog scale score were determined. Computed tomography scans of all patients were obtained 2 years after surgery to evaluate the diameter of the femoral tunnel and thereby assess the amount of tunnel widening. Magnetic resonance imaging evaluation was performed 2 years postoperatively to evaluate the status of the graft in the femoral tunnel. In addition, 5 patients underwent biopsy of the tendon-bone interface at 24 months postoperatively with histologic assessment and transmission electron microscopy.

RESULTS

A total of 107 patients completed the follow-up. There were no significant differences between the 2 groups in terms of International Knee Documentation Committee score (P = .07), Lysholm score (P = .10), and visual analog scale score (P = .57) at 24 months' follow-up. The femoral tunnel diameter and the tunnel widening percentage in the study group were significantly smaller than those in the control group (P < .001). The signal-noise quotient value of the graft in the femoral tunnel was 10.4 ± 7.0 in the study group, which was significantly lower than that in the control group (19.5 ± 9.2, P < .001). Histologic studies of the tendon-bone interface showed that there were more bone formations containing chondroid cells with aligned connective tissue in the study group compared with the control group; in addition, the diameter of the collagen fibrils in the study group was considerably thicker than that in the control group (P < .05).

CONCLUSIONS

The use of cartilage fragments was effective in preventing femoral tunnel widening and seemed to promote the tendon-bone integration process after ACLR.

LEVEL OF EVIDENCE

Level II, prospective randomized controlled study.

A Randomized Clinical Trial to Evaluate Attached Hamstring Anterior Cruciate Ligament Graft Maturity With Magnetic Resonance Imaging

BACKGROUND

The hamstring tendons are commonly harvested for anterior cruciate ligament (ACL) reconstruction with detachment of the tibial insertion. Retaining the insertion may help to preserve vascularity and viability of the graft and bypass the stages of avascular necrosis and revascularization, which might be beneficial to graft maturity.

PURPOSE

To investigate and compare graft maturity by magnetic resonance imaging (MRI) after ACL reconstruction with preservation or detachment of hamstring tendon tibial insertion at up to 2 years.

STUDY DESIGN

Randomized controlled trial; Level of evidence, 2.

METHODS

Forty-five patients (age range, 18-45 years) undergoing isolated ACL reconstruction with hamstring tendon were enrolled and randomized to 2 groups. The tibial insertion of the hamstring tendon was preserved in the study group (n = 21) and detached in the control group (n = 24). Patients had follow-up at 3, 6, 12, and 24 months, which consisted of the following: (1) clinical examination and (2) MRI evaluation of graft signal intensity based on signal/noise quotient (SNQ) values. Finally, 18 patients in the study group and 19 in the control group received full follow-up evaluation (ie, at all 4 time points).

RESULTS

All knees acquired full range of motion at 24 months without significant laxity. At each time point, the KT-1000 arthrometer revealed no significant difference between groups; the clinical scores significantly improved in both groups, although the difference between groups was not significant. In the control group, the SNQ value increased from 3 months, peaked at 6 months, and then decreased (3 months, 21.4 ± 12.7; 6 months, 25.6 ± 12; 12 months, 18.3 ± 7.7; 24 months, 15.3 ± 6.3). However, the insertion-preserved graft in the study group maintained relatively lower and unchanged signal intensity throughout all time points (3 months, 15.0 ± 11.2; 6 months, 14.9 ± 6.3; 12 months, 12.6 ± 7.0; 24 months, 14.6 ± 7.0). Between groups, there was no significant difference at 3 or 24 months ( P = .11 and .75, respectively), while the SNQ values were significantly lower in the study group versus the control group at 6 and 12 months ( P = .002 and .02, respectively).

CONCLUSION

The insertion-detached hamstring tendon grafts underwent a significantly increasing change in signal intensity during the first 2 years after ACL reconstruction, while the insertion-preserved grafts kept a relatively lower and unchanged signal intensity. The difference was most significant at 6 and 12 months postoperatively.

Bench-to-bedside: Bridge-enhanced anterior cruciate ligament repair

Anterior cruciate ligament (ACL) injuries are one of the most well-known orthopaedic injuries and are treated with one of the most common orthopaedic procedures performed in the United States. This surgical procedure, ACL reconstruction, is successful at restoring the gross stability of the knee. However, the outcomes of ACL reconstruction can be limited by short and long-term complications, including muscle weakness, graft rupture, and premature osteoarthritis. Thus, new methods of treating this injury are being explored. This review details the pathway of how a tissue engineering strategy can be used to improve the healing of the ACL in preclinical studies and then translated to patients in an FDA-approved clinical study. This review paper will outline the clinical importance of ACL injuries, history of primary repair, the pathology behind failure of the ACL to heal, pre-clinical studies, the FDA approval process for a high risk medical device, and the preliminary results from a first-in-human study. © 2017 Orthopaedic Research Society. Published by Wiley Periodicals, Inc. J Orthop Res 35:2606-2612, 2017.

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.

An evidence-based evaluation on the use of platelet rich plasma in orthopedics - a review of the literature

Within orthopedics, the use of platelet-rich plasma (PRP) has been rapidly increasing in popularity, however, its true effectiveness has yet to be fully established. Several studies find that injecting PRP to the site of injury does not provide any significant benefit with respect to clinical outcomes; however, many others report the contrary. Due to the conflicting evidence and multiple meta-analyses conducted on the topic, a literature review of high-quality evidence on the use of PRP for common orthopaedic conditions was performed. Thus far, the evidence appears to suggest that PRP may provide some benefit in patients who present with knee osteoarthritis or lateral epicondylitis. On the other hand, evidence appears to be inconsistent or shows a minimal benefit for PRP usage in rotator cuff repair, patellar and Achilles tendinopathies, hamstring injuries, anterior cruciate ligament (ACL) repair, and medial epicondylitis. There is limited confidence in the conclusions from the published meta-analyses due to issues with statistical pooling, and limited subgroup analyses exploring the substantial heterogeneity across studies. Evidence-based clinicians considering the use of PRP in their patients with musculoskeletal injuries should be weary that the literature appears to be inconsistent and thus far, inconclusive.

Orthobiologics in Pediatric Sports Medicine

Orthobiologics are biological substances that allow injured muscles, tendons, ligaments, and bone to heal more quickly. They are found naturally in the body; at higher concentrations they can aid in the healing process. These substances include autograft bone, allograft bone, demineralized bone matrix, bone morphogenic proteins, growth factors, stem cells, plasma-rich protein, and ceramic grafts. Their use in sports medicine has exploded in efforts to increase graft incorporation, stimulate healing, and get athletes back to sport with problems including anterior cruciate ligament ruptures, tendon ruptures, cartilage injuries, and fractures. This article reviews orthobiologics and their applications in pediatric sports medicine.