Efficacy of autologous platelet-rich plasma use for orthopaedic indications: a meta-analysis

Autologous Platelet Concentrates for Pulp and Dentin Regeneration: A Literature Review of Animal Studies

INTRODUCTION

The purpose of this study was to evaluate the effectiveness of autologous platelet concentrates (APCs) in promoting pulp and dentin regeneration in animal models.

METHODS

An electronic search was performed on MEDLINE, Embase, Scopus, SciELO, LILACS, and CENTRAL. Animal studies using APC as a root filling material after pulpectomy in mature or immature teeth were included. Articles underwent risk of bias assessment. Histologic evaluation of intracanal neoformed tissue was the primary outcome; root development, root wall thickening, apical closure, and periapical healing in apical periodontitis were the secondary outcomes.

RESULTS

Seven articles were included. Platelet-rich plasma (PRP) was used as root filling material during regenerative procedures in the experimental group in either mature or immature teeth. After revascularization with PRP alone or in conjunction with stem cells of a different source, the histologic analyses revealed that, in addition to an odontoblastic cell layer or dentinlike structure, the neoformed intracanal tissues were mainly cementumlike, bonelike, and connective tissues.

CONCLUSIONS

True regeneration of necrotic pulp may not be achieved with current techniques using PRP, all of which stimulated tissue repair. Benefits of PRP adjunct for pulp tissue regeneration in preclinical studies remain unclear. Further studies with standardized protocols are necessary to assess the actual contribution of PRP in endodontic regenerative therapies.

Can Platelet rich plasma stimulate human ACL growth in culture? A preliminary experience

INTRODUCTION

Platelet Rich Plasma (PRP) contains numerous growth factors; Platelet poor plasma (PPP) is plasma proteins without platelets, containing growth factors other than platelet derived. We planned to evaluate the effect of both autologous PRP & PPP on human ACL cell growth characteristics in culture conditions to see if one was better than the other.

METHODS

ACL remnants were collected from eleven patients during ACL reconstruction surgery; PPP and PRP were prepared from blood of these patients. Cells were isolated, identified and cultured and were then divided into six groups. Groups A-D had Fetal Bovine Serum (FBS) added to them along with different concentrations of PRP and PPP. Groups E and F had 5% and 10% PRP respectively but lacked FBS. Cell viability was assayed by MTT and Annexin V assay, and DNA content was evaluated by propidium iodide staining and flow cytometry.

RESULTS

analysis of cultured cells showed that addition of PRP (5 or 10%) increased the viability of ACL cells in 4 out of 11 and promoted cell proliferation in 8 of 11 donor samples; 10% PRP was more effective than 5% PRP. However, the difference in effectiveness of 10% PRP was not significantly better than 5% PRP. 5% PPP had no significant effect on cell viability, but it led to an increase in DNA content in 5 of 11. There was no statistically significant effect of either PRP or PPP in preventing cell death (depicted by apoptosis rate).

CONCLUSION

PRP may have an enhancing effect on ACL cell viability and promotion of cell proliferation but the ideal concentration of PRP for these positive effects needs to be determined before it could be used in clinical settings for enhancing primary repair of torn ACL. Also larger, more controlled and better studies are needed to confirm its clinical utility.

Efficacy of autologous platelet-rich plasma for the treatment of muscle rupture with haematoma: a multicentre, randomised, double-blind, placebo-controlled clinical trial

BACKGROUND

The goals of the treatment of muscle injuries are to shorten the time of healing and to avoid relapses. The aim of this study was to assess the efficacy of autologous platelet-rich plasma (PRP) in the healing of muscle injuries.

MATERIALS AND METHODS

A multicentre, randomised, double-blind, parallel, controlled clinical trial was conducted in 71 patients (81.8% males) aged 45.6 (SD=10.0) years with muscle tears in the legs and haematoma. The haematoma was evacuated in all patients. Thirty-three patients were randomised to a single dose of autologous PRP and 38 patients to simulation of PRP administration. The primary end-point was time to complete recovery of muscle injury. Secondary end-points were pain, relapses, ultrasound parameters, and adverse events. The total follow-up per patient was 12 months.

RESULTS

Time to complete recovery after the treatment was 31.63 days (SD=15.38) in the PRP group, and 38.43 days (SD=18.58) in the control group (p=0.261). Pain decreased over time in both groups without statistical differences between them. Eight patients relapsed (seven in the control group, and one in the PRP group). There were no adverse effects related to the interventions.

DISCUSSION

Autologous PRP did not significantly improve the time to healing compared to that in the control group.

Does platelet-rich plasma have a role in the treatment of osteoarthritis?

Platelet-rich plasma (PRP) has been generating considerable attention as an intra-articular treatment to alleviate the symptoms of osteoarthritis. Activated platelets release a host of soluble mediators such as growth factors and cytokines, thereby inducing complex interactions that vary across tissues within the joint. In vivo, PRP may promote chondrocyte proliferation and differentiation. The available data are somewhat conflicting regarding potential effects on synovial cells and angiogenesis modulation. PRP probably exerts an early anti-inflammatory effect, which may be chiefly mediated by inhibition of the NF-κB pathway, a hypothesis that requires confirmation by proof-of-concept studies. It is far too early to draw conclusions about the efficacy of PRP as a treatment for hip osteoarthritis. The only randomized trial versus hyaluronic acid showed no significant difference in effects, and no placebo-controlled trials are available. Most of the randomized trials in knee osteoarthritis support a slightly greater effect in alleviating the symptoms compared to visco-supplementation, most notably at the early stages of the disease, although only medium-term data are available. Many uncertainties remain, however, regarding the best administration regimen. Serious adverse effects, including infections and allergies, seem rare, although post-injection pain is more common than with other intra-articular treatments for osteoarthritis.

Platelet-Rich Plasma Promotes Axon Regeneration, Wound Healing, and Pain Reduction: Fact or Fiction

Platelet-rich plasma (PRP) has been tested in vitro, in animal models, and clinically for its efficacy in enhancing the rate of wound healing, reducing pain associated with injuries, and promoting axon regeneration. Although extensive data indicate that PRP-released factors induce these effects, the claims are often weakened because many studies were not rigorous or controlled, the data were limited, and other studies yielded contrary results. Critical to assessing whether PRP is effective are the large number of variables in these studies, including the method of PRP preparation, which influences the composition of PRP; type of application; type of wounds; target tissues; and diverse animal models and clinical studies. All these variables raise the question of whether one can anticipate consistent influences and raise the possibility that most of the results are correct under the circumstances where PRP was tested. This review examines evidence on the potential influences of PRP and whether PRP-released factors could induce the reported influences and concludes that the preponderance of evidence suggests that PRP has the capacity to induce all the claimed influences, although this position cannot be definitively argued. Well-defined and rigorously controlled studies of the potential influences of PRP are required in which PRP is isolated and applied using consistent techniques, protocols, and models. Finally, it is concluded that, because of the purported benefits of PRP administration and the lack of adverse events, further animal and clinical studies should be performed to explore the potential influences of PRP.

Tendinopathies and platelet-rich plasma (PRP): from pre-clinical experiments to therapeutic use

OBJECTIVES

The restorative properties of platelets, through the local release of growth factors, are used in various medical areas. This article reviews fundamental and clinical research relating to platelet-rich plasma applied to tendinous lesions.

MATERIALS AND METHOD

Articles in French and English, published between 1 January 2012 and 31 December 2014. dealing with PRP and tendons were searched for using the Medline and Scopus data bases.

RESULTS

Forty-seven articles were identified which addressed pre-clinical and clinical studies: 27 relating to in vitro and in vivo animal studies and 20 relating to human studies. Of these, five addressed lateral epicondylitis, two addressed rotator cuff tendinopathies, ten dealt with patellar tendinopathies and three looked at Achilles tendinopathies.

CONCLUSIONS

The majority of pre-clinical studies show that PRP stimulates the tendon's healing process. However, clinical series remain more controversial and level 1, controlled, randomised studies are still needed.

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.

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

PURPOSE

To systematically review the current literature for evidence that would substantiate the use of platelet-rich plasma (PRP) in the treatment of anterior cruciate ligament (ACL) ruptures.

METHODS

We performed a systematic search in PubMed and Embase of studies written in the English and Spanish languages that compared the use of PRP with a control group in patients with ACL injuries assessing graft-to-bone healing, graft maturation, and/or clinical outcomes and were randomized controlled trials or prospective cohort studies.

RESULTS

Eleven studies fulfilled the inclusion criteria, comprising 516 patients (266 ACL reconstructions using PRP and 250 ACL reconstructions without PRP). Six studies reported a statistically significant difference (4 studies) or tendency toward faster graft maturation in the platelet group (2 studies). One study found no differences. Regarding tunnel healing/widening, 1 study showed faster healing in the PRP group and 5 studies showed no differences between the 2 groups. Considering clinical outcomes, 1 study showed better clinical outcomes with PRP use and 5 studies showed no benefits with the use of PRP.

CONCLUSIONS

Concerning ACL graft maturation, there is promising evidence that the addition of PRP could be a synergic factor in acquiring maturity more quickly than grafts with no PRP, with the clinical implication of this remaining unclear. Regarding tunnel healing, it appears that there is not an improvement with the addition of PRP. There is no proof that clinical outcomes of ACL surgery are enhanced by the use of PRP.

LEVEL OF EVIDENCE

Level III, systematic review of Level I through III studies.

Platelet-rich plasma in orthopedic therapy: a comparative systematic review of clinical and experimental data in equine and human musculoskeletal lesions

BACKGROUND

This systematic review aimed to present and critically appraise the available information on the efficacy of platelet rich plasma (PRP) in equine and human orthopedic therapeutics and to verify the influence of study design and methodology on the assumption of PRP's efficacy. We searched Medline, PubMed, Embase, Bireme and Google Scholar without restrictions until July 2013. Randomized trials, human cohort clinical studies or case series with a control group on the use of PRP in tendons, ligaments or articular lesions were included. Equine clinical studies on the same topics were included independently of their design. Experimental studies relevant to the clarification of PRP's effects and mechanisms of action in tissues of interest, conducted in any animal species, were selected.

RESULTS

This review included 123 studies. PRP's beneficial effects were observed in 46.7% of the clinical studies, while the absence of positive effects was observed in 43.3%. Among experimental studies, 73% yielded positive results, and 7.9% yielded negative results. The most frequent flaws in the clinical trials' designs were the lack of a true placebo group, poor product characterization, insufficient blinding, small sampling, short follow-up periods, and adoption of poor outcome measures. The methods employed for PRP preparation and administration and the selected outcome measures varied greatly. Poor study design was a common feature of equine clinical trials. From studies in which PRP had beneficial effects, 67.8% had an overall high risk of bias. From the studies in which PRP failed to exhibit beneficial effects, 67.8% had an overall low risk of bias.

CONCLUSIONS

Most experimental studies revealed positive effects of PRP. Although the majority of equine clinical studies yielded positive results, the human clinical trials' results failed to corroborate these findings. In both species, beneficial results were more frequently observed in studies with a high risk of bias. The use of PRP in musculoskeletal lesions, although safe and promising, has still not shown strong evidence in clinical scenarios.

Increased platelet concentration does not improve functional graft healing in bio-enhanced ACL reconstruction

PURPOSE

The use of an extracellular matrix scaffold (ECM) combined with platelets to enhance healing of an anterior cruciate ligament (ACL) graft ("bio-enhanced ACL reconstruction") has shown promise in animal models. However, the effects of platelet concentration on graft healing remain unknown. The objectives of this study were to determine whether increasing the platelet concentration in the ECM scaffold would (1) improve the graft biomechanical properties and (2) decrease cartilage damage after surgery.

METHODS

Fifty-five adolescent minipigs were randomized to five treatment groups: untreated ACL transection (n = 10), conventional ACL reconstruction (n = 15) and bio-enhanced ACL reconstruction using 1× (n = 10), 3× (n = 10) or 5× (n = 10) platelet-rich plasma. The graft biomechanical properties, anteroposterior (AP) knee laxity, graft histology and macroscopic cartilage integrity were measured at 15 weeks.

RESULTS

The mean linear stiffness of the bio-enhanced ACL reconstruction procedure using the 1× preparation was significantly greater than traditional reconstruction, while the 3× and 5× preparations were not. The failure loads of all the ACL-reconstructed groups were equivalent but significantly greater than untreated ACL transection. There were no significant differences in the Ligament Maturity Index or AP laxity between reconstructed knees. Macroscopic cartilage damage was relatively minor, though significantly less when the ECM-platelet composite was used.

CONCLUSIONS

Only the 1× platelet concentration improved healing over traditional ACL reconstruction. Increasing the platelet concentration from 1× to 5× in the ECM scaffold did not further improve the graft mechanical properties. The use of an ECM-platelet composite decreased the amount of cartilage damage seen after ACL surgery.

Is intra-articular hyaluronic acid effective in treating osteoarthritis of the hip joint?

Hyaluronic acid (HA) injections are used to treat osteoarthritis of the hip but their efficacy has not been clearly established. The purpose of this meta-analysis was to determine the effect of HA injections on hip pain. There were twenty-three studies that met our criteria and the mean decrease in visual analog scores (VAS) was -1.97 (95% CL, 2.83 to -1.12, P<0.0001). However, the clinical relevance of this change is difficult to determine since the decrease in VAS was only -0.27 in the six randomized trials in the study and the duration of follow-up in most studies was less than six months. Multicenter randomized trials are needed to determine the true efficacy of HA injections in decreasing pain associated with hip osteoarthritis.

The use of autologous platelet-rich plasma in the orthopedic setting

BACKGROUND

Autologous platelet-rich plasma (aPRP) is widely used with orthopedic patients to help treat injuries to tendons, cartilage, ligaments, and muscle. A comprehensive review of the literature was conducted to evaluate aPRP's efficacy and compare available methods. In addition, the production and administration of aPRP were explored.

STUDY DESIGN AND METHODS

A literature search was performed. Randomized controlled clinical trials (RCTs) in orthopedic procedures on adult patients were included and assessed for methodologic quality. The main outcomes were pain relief, increase in function, structural integrity, and "healing" based on various validated scales.

RESULTS

Twelve RCTs and one controlled cohort were included (four lateral epicondylitis, two chronic Achilles tendinopathy, two anterior cruciate ligament injury, and five rotator cuff injuries). Four trials reported some benefit from aPRP versus controls while eight trials found no benefit from aPRP applications versus control. One study had too many patients withdraw from the control arm for acceptable data interpretation. All protocols used a different aPRP formulation or method of delivery or application.

CONCLUSIONS

Despite its popularity, there are no standardized criteria that define aPRP. Different techniques yield wide variability in terms of platelet count and concentration. These variations make it difficult to compare clinical trials that use aPRP or draw conclusions concerning its clinical efficacy in orthopedic procedures. Blood bankers have experience in the production of standardized blood components. This expertise may be used to develop and implement protocols for the production and administration of aPRP, as well as quality control measures.

Advances in biology and mechanics of rotator cuff repair

High initial fixation strength, mechanical stability and biological healing of the tendon-to-bone interface are the main goals after rotator cuff repair surgery. Advances in the understanding of rotator cuff biology and biomechanics as well as improvements in surgical techniques have led to the development of new strategies that may allow a tendon-to-bone interface healing process, rather than the formation of a fibrovascular scar tissue. Although single-row repair remains the most cost-effective technique to address a rotator cuff tear, some biological intervention has been recently introduced to improve tissue healing and clinical outcome of rotator cuff repair. Animal models are critical to ensure safety and efficacy of new treatment strategies; however, although rat shoulders as well as sheep and goats are considered the most appropriate models for studying rotator cuff pathology, no one of them can fully reproduce the human condition. Emerging therapies involve growth factors, stem cells and tissue engineering. Experimental application of growth factors and platelet-rich plasma demonstrated promising results, but has not yet been transferred into standardized clinical practice. Although preclinical animal studies showed promising results on the efficacy of enhanced biological approaches, application of these techniques in human rotator cuff repairs is still very limited. Randomized controlled clinical trials and post-marketing surveillance are needed to clearly prove the clinical efficacy and define proper indications for the use of combined biological approaches. The following review article outlines the state of the art of rotator cuff repair and the use of growth factors, scaffolds and stem cells therapy, providing future directions to improve tendon healing after rotator cuff repair.

LEVEL OF EVIDENCE

Expert opinion, Level V.

Considerations on the use of platelet-rich plasma, specifically for burn treatment

Platelet-rich plasma (PRP) is a fraction of blood plasma with a platelet concentration above baseline. After activation of the platelets, growth factors are released, which are involved in wound-healing processes. Application of a multitude of growth factors seems to boost the healing process. In this review the authors provide a comprehensive overview of the many different aspects of PRP; this is followed by a short outline of the evidence for a wide range of applications and finally narrowing down to a more in-depth analysis of the literature on the potential use of PRP in burn treatment. The authors performed an extensive search on PRP and the different biological, as well as practical aspects for the different applications. Furthermore, we performed a systematic search on PRP in the treatment of burn wounds. A high variety exists in PRP products, procedures, and content. This makes interpretation and comparison of the evidence difficult. PRP has been reported to have beneficial effects on wound healing in different fields of surgery and in the treatment of acute, chronic, and diabetic wounds. Literature on the use of PRP in burns is scarce. Separate growth factors have shown beneficial results in the treatment of burns. Furthermore, an animal study and several case reports showed improved burn wound-healing time after the application of PRP. A deep dermal burn could benefit from PRP through its hemostatic antimicrobial abilities and the positive effects seen in wound healing. However, burn patients have an altered physiological state and it is unknown how this may affect platelet function and quality. Furthermore, the effect of PRP on scarring has not been evaluated properly. Future research is needed to elucidate the role of PRP in the treatment of burns.

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.

Platelet-rich plasma in arthroscopic rotator cuff repair: a meta-analysis of randomized controlled trials

PURPOSE

The purpose of this study was to appraise the retear rate and clinical outcomes of platelet-rich plasma use in patients undergoing arthroscopic full-thickness rotator cuff repair.

METHODS

We searched the Cochrane Library, PubMed, and EMBASE databases for randomized controlled trials comparing the outcomes of arthroscopic rotator cuff surgery with or without the use of platelet-rich plasma. Methodological quality was assessed by the Detsky quality scale. When there was no high heterogeneity, we used a fixed-effects model. Dichotomous variables were presented as risk ratios (RRs) with 95% confidence intervals (CIs), and continuous data were measured as mean differences with 95% CIs. The Grading of Recommendations Assessment, Development, and Evaluation (GRADE) system was used to assess the quality of evidence for each individual outcome.

RESULTS

Eight randomized controlled trials were included, with the sample size ranging from 28 to 88. Overall methodological quality was high. Fixed-effects analysis showed that differences were not significant between the 2 groups in retear rate (RR, 0.94; 95% CI, 0.70 to 1.25; P = .66), Constant score (mean difference, 1.12; 95% CI, -1.38 to 3.61; P = .38), and University of California at Los Angeles (UCLA) score (mean difference, -0.68; 95% CI, -2.00 to 0.65; P = .32). The strength of GRADE evidence was categorized respectively as low for retear, moderate for Constant score, and low for UCLA shoulder score.

CONCLUSIONS

Our meta-analysis does not support the use of platelet-rich plasma in the arthroscopic repair of full-thickness rotator cuff tears over repairs without platelet-rich plasma because of similar retear rates and clinical outcomes.

LEVEL OF EVIDENCE

Level II, meta-analysis of Level I and II randomized controlled trials.

New fat-derived products for treating skin-induced lesions of scleroderma in nude mice

INTRODUCTION

Scleroderma is characterized by cutaneous manifestations that mainly affect the hands, arms and face. As of today, there is no treatment for fibrotic skin lesions of scleroderma. Previously we generated and validated a model of scleroderma-like skin sclerosis in nude mice, appropriate to inject human derived products. We showed that the subcutaneous injection of micro-fat (MF), purified and injected using small caliber cannulas, have anti-fibrotic and pro-angiogenic effects and appears more suitable for the treatment of skin lesions of scleroderma compared to the gold standard (Coleman's technique or macro-fat). Here we compared the long-term efficacy of micro-fat "enriched" with other therapeutic products including the stromal vascular fraction (SVF) of fat and platelet-rich plasma (PRP) from blood in our murine model of scleroderma.

METHODS

We used 72 nude mice in this study. We formed six experimental groups: Macro-fat, MF, SVF, PRP, MF + SVF, MF + PRP. This project has three phases: i) Induction of skin sclerosis by daily subcutaneous injections of bleomycin (BLM) for 4 weeks in nude mice; ii) Purification and injection of the different cell therapy products; iii) Histological analyses done 8 weeks post-injections.

RESULTS

MF + SVF and MF + PRP significantly reversed dermal and epidermal sclerosis (P <0.01). Macro-fat, SVF, PRP only corrected the dermal sclerosis (P <0.05). Epidermal sclerosis was reduced in treatments containing MF (P <0.01). MF was more stable. Products containing the SVF were associated with a significant increase of the local vascularization (P <0.01).

CONCLUSIONS

All tested substances were effective in treating skin-induced lesions of scleroderma with different levels of fibrosis and vascular improvement; MF derived products are more stable and SVF demonstrated better pro-angiogenic effects. The observed efficacy of this combination of products in the animal model provides a rationale for potential clinical applications to treat human disease.

Autologous platelet concentrates for bisphosphonate-related osteonecrosis of the jaw treatment and prevention. A systematic review of the literature

PURPOSE

Bisphosphonate related osteonecrosis of the jaw (BRONJ) is an adverse drug reaction consisting of progressive bone destruction in the maxillofacial region of patients under current or previous treatment with a bisphosphonate. Autologous platelet concentrates (APC) demonstrated to enhance bone and soft tissue healing in oral surgery procedures. The present systematic review aimed at evaluating if APC may improve treatment and prevention of BRONJ in patients under bisphosphonate therapy.

METHODS

MEDLINE, Scopus and Cochrane databases were searched using terms like bisphosphonates, osteonecrosis, BRONJ, platelet concentrate, PRP, PRF, PRGF. No language, publication date and study design limitation was set. A hand search of the bibliographies of identified articles was also performed. The primary outcome was recurrence/onset of BRONJ after oral surgery procedures.

RESULTS

Eighteen studies were included, reporting on 362 patients undergoing oral surgery in combination with APC. The adjunct of APC in BRONJ treatment significantly reduced osteonecrosis recurrence with respect to control. APC was associated with a lower BRONJ incidence after tooth extraction, though not significant. Heterogeneity was found regarding bisphosphonate type, clinical indication, treatment duration, triggering factors, study design, follow-up duration, type of APC, outcomes adopted to evaluate treatment success.

CONCLUSION

Though the results of this review must be cautiously interpreted, due to the low evidence level of the studies included, and the limited sample size, they are suggestive of possible benefits of APC when associated with surgical procedures for treatment or prevention of BRONJ. To confirm such indication, prospective comparative studies with a large sample size are urgently needed.

Are platelet concentrates an ideal biomaterial for arthroscopic rotator cuff repair? A meta-analysis of randomized controlled trials

PURPOSE

The present study aims to conduct a meta-analysis of Level I evidence studies to investigate the efficacy of concomitant platelet concentrate (PC) used in arthroscopic rotator cuff repair.

METHODS

We systematically searched electronic databases to identify randomized controlled trials (RCTs) evaluating the role of PC augmentation in arthroscopic rotator cuff repairs for patients with full-thickness tears. The search strategy followed the requirements in the Cochrane Library Handbook. The primary outcome was retearing of the rotator cuff. Functional outcomes were analyzed in terms of Constant score, specific Constant pain score, University of California, Los Angeles (UCLA) shoulder score, Simple Shoulder Test (SST) score, and American Shoulder and Elbow Surgeons (ASES) score.

RESULTS

Seven studies with a total of 417 patients available at the latest follow-up reporting data about retears were analyzed in this meta-analysis. However, 4 studies with Constant scores (n = 237), 3 studies with UCLA scores (n = 168), 2 studies with Constant pain scores (n = 164), 2 studies with ASES scores (n = 101), and 2 studies with SST scores (n = 121) were analyzed. The retear rates and functional scores showed that there was no significant efficacy of PC application in arthroscopic rotator cuff repairs.

CONCLUSIONS

This meta-analysis of high-level evidence suggests that PCs have no benefit regarding retear rate and overall clinical outcomes for the arthroscopic repair of full-thickness rotator cuff tears.

LEVEL OF EVIDENCE

Level II, meta-analysis of randomized controlled trials.

A single platelet-rich plasma injection for chronic midsubstance achilles tendinopathy: a retrospective preliminary analysis

The purpose of this study was to evaluate a series of patients undergoing a single platelet-rich plasma (PRP) injection for the treatment of chronic midsubstance Achilles tendinopathy, in whom conservative treatment had failed. Thirty-two patients underwent a single PRP injection for the treatment of chronic midsubstance Achilles tendinopathy and were evaluated at a 6-month final follow-up using the Foot and Ankle Outcome Score and Short Form 12 general health questionnaire. Magnetic resonance imaging was performed on all patients prior to and 6 months after injection. Twenty-five of 32 patients (78%) reported that they were asymptomatic at the 6-month follow-up visit and were able to participate in their respective sports and daily activities. The remaining 7 patients (22%) who reported symptoms that did not improve after 6 months ultimately required surgery. Four patients went on to have an Achilles tendoscopy, while the other 3 had an open debridement via a tendon splitting approach. A retrospective evaluation of patients receiving a single PRP injection for chronic midsubstance Achilles tendinopathy revealed that 78% had experienced clinical improvement and had avoided surgical intervention at 6-month follow-up.

LEVELS OF EVIDENCE

Therapeutic, Level IV: Retrospective case series.

IMpact of Platelet Rich plasma OVer alternative therapies in patients with lateral Epicondylitis (IMPROVE): protocol for a multicenter randomized controlled study: a multicenter, randomized trial comparing autologous platelet-rich plasma, autologous whole blood, dry needle tendon fenestration, and physical therapy exercises alone on pain and quality of life in patients with lateral epicondylitis

INTRODUCTION

Lateral epicondylitis, commonly known as tennis elbow, is the most common cause of lateral elbow pain and the second most frequently diagnosed musculoskeletal disorder in the neck and upper limb in a primary care setting. Many therapeutic options, including conservative, surgical, and minimally invasive procedures, have been advocated for the treatment of lateral epicondylitis. Although numerous small studies have been performed to assess the efficacy of various treatments, there are conflicting results with no clear consensus on the optimal treatment. In an economic environment with limited health care resources, it is paramount that optimal cost-effective therapies with favorable patient-important outcomes be identified.

METHODS AND ANALYSIS

This is a protocol paper which outlines a multicenter, multidisciplinary, single-blinded, four-arm randomized controlled trial, comparing platelet-rich plasma (PRP), whole blood injection, dry needle tendon fenestration, and sham injection with physical therapy alone for the treatment of lateral epicondylitis. Patients are screened based on pre-established eligibility criteria and randomized to one of the four study groups using an Internet-based system. The patients are followed at 6-week, 12-week, 24-week, and 52-week time points to assess the primary and secondary outcomes of the study. The primary outcome is pain. Secondary outcomes include health-related quality of life and ultrasound appearance of the common extensor tendon. Two university centers (McMaster University and the University of Michigan) are currently recruiting patients. We have planned a sample size of 100 patients (25 patients per arm) to ensure over 80% power to detect a three-point difference in pain scores at 52 weeks of follow-up.

ETHICS AND DISSEMINATION

This study has ethics approval from the McMaster University Research Ethics Board (REB# 12-146) and the University of Michigan Institutional Review Board (IRB# HUM00067750). Successful completion of this proposed study will significantly impact clinical practice and enhance patients' lives. More broadly, this trial will develop a network of collaboration from which further high-quality trials in ultrasound-guided interventions will follow.

Updates in biological therapies for knee injuries: bone

Bone is a unique tissue because of its mechanical properties, ability for self-repair, and enrollment in different metabolic processes such as calcium homeostasis and hematopoietic cell production. Bone barely tolerates deformation and tends to fail when overloaded. Fracture healing is a complex process that in particular cases is impaired. Osteoprogenitor cells proliferation, growth factors, and a sound tridimensional scaffold at fracture site are key elements for new bone formation and deposition. Mechanical stability and ample vascularity are also of great importance on providing a proper environment for bone healing. From mesenchymal stem cells delivery to custom-made synthetic scaffolds, many are the biological attempts to enhance bone healing. Impaired fracture healing represents a real burden to contemporary society. Sound basic science knowledge has contributed to newer approaches aimed to accelerate and improve the quality of bone healing.

Efficacy and safety of plasma rich in growth factors intra-articular infiltrations in the treatment of knee osteoarthritis

PURPOSE

The goal of this study was to systematically review the efficacy and safety of plasma rich in growth factors (PRGF) as a treatment for reducing symptoms in patients with knee osteoarthritis.

METHODS

A comprehensive and systematic literature search was conducted for PRGF treatment of knee osteoarthritis following the PRISMA (Preferred Reporting Items for Systematic Reviews and Meta-Analyses) guidelines. All the studies had to include a PRGF group and a control group. Pre- and post-treatment measures of joint pain, reduced function, and stiffness were evaluated using the Western Ontario and McMaster Universities Osteoarthritis Index, Knee Injury and Osteoarthritis Outcome Score, International Knee Documentation Committee score, Lequesne index, or number of Outcome Measures for Rheumatology Committee and Osteoarthritis Research Society International Standing Committee for Clinical Trials Response Criteria Initiative (OMERACT-OARSI) responders, with a follow-up period of at least 4 weeks. An assessment of both the quality and risk of bias of the studies was conducted.

RESULTS

The literature search yielded 91 citations, but only 5 were eligible publications that met the inclusion criteria (2 randomized controlled trials, 2 prospective studies, and 1 retrospective analysis). Two studies were rated as having a low risk of bias whereas 3 had a high risk. In both randomized controlled trials, it was observed that after 6 months of treatment, the number of patients with a pain reduction of more than 50% was significantly higher in the PRGF group. In 2 other studies, the patients treated with PRGF showed a significant pain reduction compared with the control group. The remaining variables (Western Ontario and McMaster Universities Osteoarthritis Index scale for pain, function, and stiffness; Lequesne index; Knee Injury and Osteoarthritis Outcome Score scale; and number of OMERACT-OARSI responders) showed a statistically significant superiority of the group treated with PRGF.

CONCLUSIONS

The current clinical evidence suggests that PRGF intra-articular infiltrations in patients with knee osteoarthritis reduce pain and therefore are clinically efficacious in osteoarthritis treatment.

LEVEL OF EVIDENCE

Level III, systematic review of Level I, II, and III studies.

The use of PRP in ligament and meniscal healing

Platelet-rich plasma (PRP) has become a popular treatment for acute and chronic soft tissue injuries. Although the majority of research has focused on its use in tendinopathy, PRP may have potential in meniscus and ligament healing. Some level II studies support a possible benefit for anterior cruciate ligament (ACL) allograft maturation, and preliminary animal studies point to a potential role for PRP in primary ACL repair. However, randomized controlled trials have not demonstrated a benefit of PRP for ACL tendon allograft-tunnel integration. To date, 2 studies document the use of PRP for meniscal applications, but this field is largely unexplored. With respect to ligament and meniscal applications, the current literature suggests PRP may be promising for primary ACL repair in skeletally immature patients, ACL graft maturation, and repair of meniscal tears in the avascular zone.

The basic science of platelet-rich plasma (PRP): what clinicians need to know

Platelet-rich plasma (PRP) has been advocated for the biological augmentation of tissue healing and regeneration through the local introduction of increased levels (above baseline) of platelets and their associated bioactive molecules. In theory, the increased levels of autologous growth factors and secretory proteins provided by the concentrated platelets may enhance the wound healing process, especially in degenerative tissues or biologically compromised individuals. Although PRP has been increasingly utilized in the treatment of a variety of sports-related injuries, improvements in healing and clinical outcomes have not been universally reported. One reason for this may be the fact that all PRP preparations are not the same. Variations in the volume of whole blood taken, the platelet recovery efficacy, the final volume of plasma in which the platelets are suspended, and the presence or absence of white blood cells, and the addition of exogenous thrombin to activate the platelets or calcium chloride to induce fibrin formation, can all affect the character and potential efficacy of the final PRP product. This article will review the basic principles involved in creating PRP and examine the potential basic scientific significance of the individual blood components contained in the various forms of PRP currently used in sports medicine.

Platelet-rich plasma: underlying biology and clinical correlates

Platelet-rich plasma (PRP) has recently become the focus of intensive interest and discussion, in part because of the expanding understanding of platelet function. Anucleate platelets within PRP release a myriad of growth factors and cytokines while contributing to plasma coagulation and fibrin development; the latter acts as vehicle for the local delivery. The biological effects of PRP are largely attributed to the platelet secretome and plasma signaling proteins. Clinical data suggest that PRPs may exploit different regenerative mechanisms under diverse disease conditions, including hemostasis, inflammation, angiogenesis and the synthesis of extracellular matrix. The success of PRP therapies depends on current tissue healing research and the translation of this knowledge into clinical developments.

Platelet-rich plasma for zone II flexor tendon repair

BACKGROUND

Platelet-rich plasma (PRP) has shown promise in the treatment of tendinopathy, including rotator cuff and lateral epicondylitis. Here, we evaluate the effect of PRP on healing in a rabbit zone II flexor tendon model.

METHODS

Thirty New Zealand white rabbits underwent transection and repair of the second and fourth flexor digitorum profundus. Half of the rabbits received autologous PRP intraoperatively, while the other half underwent standard four-strand tendon repair. Tendons were examined at 2, 4, and 8 weeks postoperatively. Range of motion and ultimate tensile strength were assessed on the fourth toes, while second toes underwent histologic analysis with hematoxylin and eosin, Masson Trichrome, and Picrosirius Red, for assessment of cell count, collagen content, and collagen maturity.

RESULTS

There were no significant differences in ultimate tensile strength between treatments at 2, 4, or 8 weeks. There was a trend towards lower tensile strength in the PRP group at 2 weeks. There was no statistically significant difference in excursion or range of motion between PRP and control tendons. Cell counts at 4 weeks were statistically significantly reduced in the PRP tendons as compared to controls. No difference in collagen content or maturity was detected.

CONCLUSIONS

In contrast to previous studies, PRP did not significantly improve ultimate tensile strength. PRP-treated tendons exhibited trends towards reduced healing, including a significant reduction in cell counts as well as a smaller increase in collagen deposition over time as compared to controls. Further study is needed to determine the precise effect of PRP on intrasynovial flexor tendon repairs.

Platelet-rich plasma in the conservative treatment of painful tendinopathy: a systematic review and meta-analysis of controlled studies

BACKGROUND

Platelet-rich plasma (PRP) seeks to meet the multifaceted demand of degenerated tendons providing several molecules capable of boosting healing.

AREAS TIMELY FOR DEVELOPING RESEARCH

PRP is used for managing tendinopathy, but its efficacy is controversial.

SOURCES OF DATA

Electronic databases were searched for clinical studies assessing PRP efficacy. Methodological quality was evaluated using the methods described in the Cochrane Handbook for systematic reviews.

AREAS OF AGREEMENT

Thirteen prospective controlled studies, comprising 886 patients and diverse tendons were included; 53.8% of studies used identical PRP protocol.

AREAS OF CONTROVERSY

Sources of heterogeneity included different comparators, outcome scores, follow-up periods and diverse injection protocols, but not PRP formulation per se.

GROWING POINTS

Pooling pain outcomes over time and across different tendons showed that L-PRP injections ameliorated pain in the intermediate-long term compared with control interventions, weighted mean difference (95% CI): 3 months, -0.61 (-0.97, -0.25); 1 year, -1.56 (-2.27, -0.83). However, these findings cannot be applied to the management of individual patients given low power and precision.

RESEARCH

Further studies circumventing heterogeneity are needed to reach firm conclusions. Available evidence can help to overcome hurdles to future clinical research and bring forward PRP therapies.

Autologous growth factor injections in chronic tendinopathy

REFERENCE

de Vos RJ, van Veldhoven PLJ, Moen MH, Weir A, Tol JL. Autologous growth factor injections in chronic tendinopathy: a systematic review. Br Med Bull. 2010;95:63-77.

CLINICAL QUESTION

The authors of this systematic review evaluated the literature to critically consider the effects of growth factors delivered through autologous whole-blood and platelet-rich-plasma (PRP) injections in managing wrist-flexor and -extensor tendinopathies, plantar fasciopathy, and patellar tendinopathy. The primary question was, according to the published literature, is there sufficient evidence to support the use of growth factors delivered through autologous whole-blood and PRP injections for chronic tendinopathy?

DATA SOURCES

The authors performed a comprehensive, systematic literature search in October 2009 using PubMed, MEDLINE, EMBASE, CINAHL, and the Cochrane library without time limits. The following key words were used in different combinations: tendinopathy, tendinosis, tendinitis, tendons, tennis elbow, plantar fasciitis, platelet rich plasma, platelet transfusion, and autologous blood or injection. The search was limited to human studies in English. All bibliographies from the initial literature search were also viewed to identify additional relevant studies.

STUDY SELECTION

Studies were eligible based on the following criteria: (1) Articles were suitable (inclusion criteria) if the participants had been clinically diagnosed as having chronic tendinopathy; (2) the design had to be a prospective clinical study, randomized controlled trial, nonrandomized clinical trial, or prospective case series; (3) a well-described intervention in the form of a growth factor injection with either PRP or autologous whole blood was used; and (4) the outcome was reported in terms of pain or function (or both).

DATA EXTRACTION

All titles and abstracts were assessed by 2 researchers, and all relevant articles were obtained. Two researchers independently read the full text of each article to determine if it met the inclusion criteria. If opinions differed on suitability, a third reviewer was consulted to reach consensus. The data extracted included number of participants, study design, inclusion criteria, intervention, control group, primary outcome measures (pain using a visual analog or ordinal scale or function), time of follow-up, and outcomes for intervention and control group (percentage improvement) using a standardized data-extraction form. Function was evaluated in 9 of the 11 studies using (1) the Nirschl scale (elbow function) or the modified Mayo score for wrist flexors and extensors, (2) the Victorian Institute of Sports Assessment-Patella score, a validated outcome measure for patellar tendinopathy, or the Tegner score for patellar tendinopathy, and (3) the rearfoot score from the American Orthopaedic Foot and Ankle Scale for plantar fasciopathy. The Physiotherapy Evidence Database (PEDro) scale contains 11 items; items 2-11 receive 1 point each for a yes response. Reliability is sufficient (0.68) for the PEDro scale to be used to assess physiotherapy trials. A score of 6 or higher on the PEDro scale is considered a high-quality study; below 6 is considered a low-quality study. The PEDro score results determined the quality of the randomized controlled trial (RCT), nonrandomized clinical trial, or prospective case series (≥6 or <6). A qualitative analysis was used with 5 levels of evidence (strong, moderate, limited, conflicting, or no evidence) to determine recommendations for the use of the intervention. The number of high-quality or low-quality RCT or nonrandomized clinical trial studies with consistent or inconsistent results determined the level of evidence (1-5).

MAIN RESULTS

Using the specific search criteria, the authors identified 418 potential sources. After screening of the title or abstract (or both), they excluded 405 sources, which left 13 studies. After viewing the full text, they excluded 2 additional sources (a case report and a study in which the outcome measure was remission of symptoms and not pain or function), leaving 11 studies for analysis. Six of the 11 studies were characterized by an observational, noncontrolled design; the remaining 5 studies were controlled clinical trials, 2 of which had proper randomization. The mean number of participants included in the studies was 40.5 (range = 20 to 100). Three of the studies were on "tennis elbow," 1 on "golfer's elbow," 1 on wrist extensor or flexor tendinopathy, 3 on plantar fasciopathy, and 3 on chronic patellar tendinopathy. Based on the information reported, there was no standardization of frequency or method of growth factor injection treatment or of preparation of the volume, and an optimal mixture was not described. Autologous whole-blood injections were used in 8 studies; in 5 studies, the autologous whole-blood injection was combined with a local anesthetic. In contrast, a local anesthetic was used in only 1 of the 3 PRP injection studies. The authors of the other 2 studies did not report whether a local anesthetic was used. The number of autologous whole-blood and PRP injections varied, ranging from 1 to 3. The centrifuging process was single or double for the PRP injections. In 2 studies, calcium was added to activate the platelets. A visual analogue or ordinal pain scale was used in 10 of the 11 studies. Function was evaluated in 9 of the 11 studies using (1) the Nirschl scale in 4 elbow studies or the modified Mayo score at baseline in 1 elbow study, (2) the Victorian Institute of Sports Assessment-Patella score for 1 study and the Tegner score for 2 of the patellar tendinopathy studies, and (3) the rearfoot score of the American Orthopaedic Foot and Ankle Scale for 1 plantar fasciopathy study. Only 1 study used an appropriate, disease-specific, validated tendinopathy measure (Victorian Institute of Sports Assessment-Patella). All intervention groups reported a significant improvement in pain or function score (or both), with a mean improvement of 66% over a mean follow-up of 9.4 months. The control groups in these studies also showed a mean improvement of 57%. None of the pain benefits among the intervention groups were greater than those for the control group at final follow-up. In 4 of the studies, the control group and the autologous growth factor injection group had similar results in pain or function or both, whereas in 2 studies, the control group had greater relief in pain than the injection group. Eleven studies were assessed using the PEDro scale. The PEDro scores for these studies ranged from 1 to 7, with an average score of 3.4. Only 3 studies had PEDro scores of ≥6 and were considered high quality. The 3 high-quality plantar fasciopathy studies used autologous growth factor injections but did not show a significant improvement over the control group. One of the studies that showed no beneficial effect for the autologous growth factor injections was compared with corticosteroids. Compared with other treatments, level 1 (strong) evidence demonstrated that autologous growth factor injections did not improve pain or function in plantar fasciopathy. The PRP injection results were based on 3 low-quality studies, 2 for the patellar tendon and 1 for the wrist flexors-extensors; level 3 (limited) evidence suggests that PRP injections improve pain or function.

CONCLUSIONS

Strong evidence indicates that autologous growth factor injections do not improve plantar fasciopathy pain or function when combined with anesthetic agents or when compared with corticosteroid injections, dry needling, or exercise therapy treatments. Furthermore, limited evidence suggests that PRP injections are beneficial. Except for 2 high-quality RCT studies, the rest were methodologically flawed. Additional studies should be conducted using proper control groups, randomization, blinding, and validated disability outcome measures for pain and function. Until then, the results remain speculative because autologous whole-blood and PRP injection treatments are not standardized.

Characterization and comparison of 5 platelet-rich plasma preparations in a single-donor model

PURPOSE

The purpose of this study was to compare the biological characteristics of platelet-rich plasma (PRP) obtained from 4 medical devices and a preparation developed in our laboratory using a single-donor model.

METHODS

Ten healthy persons donated blood that was processed to produce PRP by use of 4 commercial preparation systems and a protocol developed in our laboratory. Volumes and platelet, white blood cell (WBC), and red blood cell concentrations were recorded. The platelet activation status was assessed by flow cytometry. Enzyme-linked immunosorbent assay was used to determine the concentrations of vascular endothelial growth factor, platelet-derived growth factor AB, epidermal growth factor, and transforming growth factor β1. We calculated platelet capture efficiency, relative composition, and increase factors from whole blood in platelets and WBC, as well as platelet and growth factor (GF) doses, provided from each preparation.

RESULTS

Leukocyte-rich PRP was obtained with RegenPRP (RegenLab, Le Mont-sur-Lausanne, Switzerland) and the Mini GPS III System (Biomet Biology, Warsaw, IN) and provides PRP with higher proportions of red blood cells, WBCs, and neutrophils than leukocyte-poor PRP obtained with the Selphyl System (Selphyl, Bethlehem, PA), Arthrex ACP (Arthrex, Naples, FL), and the preparation developed in our laboratory. The highest platelet and GF concentrations and doses were obtained with the Mini GPS III System and the preparation developed in our laboratory. Different centrifugation protocols did not show differences in the percentages of activated platelets. Finally, a positive correlation between platelet doses and all the GFs studied was found, whereas a positive correlation between WBC doses and GFs was found only for vascular endothelial growth factor and epidermal growth factor.

CONCLUSIONS

In a single-donor model, significant biological variations in PRP obtained from different preparation systems were highlighted. The observed differences suggest different results for treated tissue and could explain the large variability in the clinical benefit of PRP reported in the literature.

CLINICAL RELEVANCE

Our findings will help clinicians to choose a system that meets their specific needs for a given indication.

Platelet-rich therapies for musculoskeletal soft tissue injuries

BACKGROUND

Platelet-rich therapies are being used increasingly in the treatment of musculoskeletal soft tissue injuries such as ligament, muscle and tendon tears and tendinopathies. These therapies can be used as the principal treatment or as an augmentation procedure (application after surgical repair or reconstruction). Platelet-rich therapies are produced by centrifuging a quantity of the patient's own blood and extracting the active, platelet-rich, fraction. The platelet-rich fraction is applied to the injured tissue; for example, by injection. Platelets have the ability to produce several growth factors, so these therapies should enhance tissue healing. There is a need to assess whether this translates into clinical benefit.

OBJECTIVES

To assess the effects (benefits and harms) of platelet-rich therapies for treating musculoskeletal soft tissue injuries.

SEARCH METHODS

We searched the Cochrane Bone, Joint and Muscle Trauma Group Specialised Register (25 March 2013), the Cochrane Central Register of Controlled Trials (CENTRAL 2013 Issue 2), MEDLINE (1946 to March 2013), EMBASE (1980 to 2013 Week 12) and LILACS (1982 to March 2012). We also searched trial registers (to Week 2 2013) and conference abstracts (2005 to March 2012). No language or publication restrictions were applied.

SELECTION CRITERIA

We included randomised and quasi-randomised controlled trials that compared platelet-rich therapy with either placebo, autologous whole blood, dry needling or no platelet-rich therapy for people with acute or chronic musculoskeletal soft tissue injuries. Primary outcomes were functional status, pain and adverse effects.

DATA COLLECTION AND ANALYSIS

Two review authors independently extracted data and assessed each study's risk of bias. Disagreement was resolved by discussion or by arbitration by a third author. We contacted trial authors for clarification of methods or missing data. Treatment effects were assessed using risk ratios for dichotomous data and mean differences (MD) or standardised mean differences (SMD) for continuous data, together with 95% confidence intervals. Where appropriate, data were pooled using the fixed-effect model for RR and MD, and the random-effects model for SMD. The quality of the evidence for each outcome was assessed using GRADE criteria.

MAIN RESULTS

We included data from 19 small single centre trials (17 randomised and two quasi-randomised; 1088 participants) that compared platelet-rich therapy with placebo, autologous whole blood, dry needling or no platelet-rich therapy. These trials covered eight clinical conditions: rotator cuff tears (arthroscopic repair) (six trials); shoulder impingement syndrome surgery (one trial); elbow epicondylitis (three trials); anterior cruciate ligament (ACL) reconstruction (four trials), ACL reconstruction (donor graft site application) (two trials), patellar tendinopathy (one trial), Achilles tendinopathy (one trial) and acute Achilles rupture surgical repair (one trial). We also grouped trials into 'tendinopathies' where platelet-rich therapy (PRT) injections were the main treatment (five trials), and surgical augmentation procedures where PRT was applied during surgery (14 trials). Trial participants were mainly male, except in trials including rotator cuff tears, and elbow and Achilles tendinopathies.Three trials were judged as being at low risk of bias; the other 16 were at high or unclear risk of bias relating to selection, detection, attrition or selective reporting, or combinations of these. The methods of preparing platelet-rich plasma (PRP) varied and lacked standardisation and quantification of the PRP applied to the patient.We were able to pool data for our primary outcomes (function, pain, adverse events) for a maximum of 11 trials and 45% of participants. The evidence for all primary outcomes was judged as being of very low quality.Data assessing function in the short term (up to three months) were pooled from four trials that assessed PRT in three clinical conditions and used four different measures. These showed no significant difference between PRT and control (SMD 0.26; 95% confidence interval (CI) -0.19 to 0.71; P value 0.26; I² = 51%; 162 participants; positive values favour PRT). Medium-term function data (at six months) were pooled from five trials that assessed PRT in five clinical conditions and used five different measures. These also showed no difference between groups (SMD -0.09, 95% CI -0.56 to 0.39; P value 0.72; I² = 50%; 151 participants). Long-term function data (at one year) were pooled from 10 trials that assessed PRT in five clinical conditions and used six different measures. These also showed no difference between groups (SMD 0.25, 95% CI -0.07 to 0.57; P value 0.12; I² = 66%; 484 participants). Although the 95% confidence intervals indicate the possibility of a poorer outcome in the PRT group up to a moderate difference in favour of PRT at short- and long-term follow-up, these do not translate into clinically relevant differences.Data pooled from four trials that assessed PRT in three clinical conditions showed a small reduction in short-term pain in favour of PRT on a 10-point scale (MD -0.95, 95% CI -1.41 to -0.48; I² = 0%; 175 participants). The clinical significance of this result is marginal.Four trials reported adverse events; another seven trials reported an absence of adverse events. There was no difference between treatment groups in the numbers of participants with adverse effects (7/241 versus 5/245; RR 1.31, 95% CI 0.48 to 3.59; I² = 0%; 486 participants).In terms of individual conditions, we pooled heterogeneous data for long-term function from six trials of PRT application during rotator cuff tear surgery. This showed no statistically or clinically significant differences between the two groups (324 participants).The available evidence is insufficient to indicate whether the effects of PRT will differ importantly in individual clinical conditions.

AUTHORS' CONCLUSIONS

Overall, and for the individual clinical conditions, there is currently insufficient evidence to support the use of PRT for treating musculoskeletal soft tissue injuries. Researchers contemplating RCTs should consider the coverage of currently ongoing trials when assessing the need for future RCTs on specific conditions. There is need for standardisation of PRP preparation methods.

Variance of matrix metalloproteinase (MMP) and tissue inhibitor of metalloproteinase (TIMP) concentrations in activated, concentrated platelets from healthy male donors

BACKGROUND

The use of autologous blood concentrates, such as activated, concentrated platelets, in orthopaedic clinical applications has had mixed results. Research on this topic has focused on growth factors and cytokines, with little directed towards matrix metalloproteinases (MMPs) which are involved in post-wound tissue remodeling.

METHODS

In this study, the authors measured the levels of MMP-2, MMP-9 and a disintegrin and metalloproteinase with a thrombospondin type 1 motif, member 13 (ADAMTS13), in activated platelets derived from blood of healthy, male volunteers (n = 92), 19 to 60 years old. The levels of the natural inhibitors of these proteases, tissue inhibitor of metalloproteinase 1 (TIMP-1), TIMP-2 and TIMP-4 were also assessed.

RESULTS

Notably, there was no significant change in concentration with age in four of six targets tested. However, TIMP-2 and TIMP-4 demonstrated a statistically significant increase in concentration for subjects older than 30 years of age compared to those 30 years and younger (P = 0.04 and P = 0.04, respectively).

CONCLUSION

TIMP-2 and TIMP-4 are global inhibitors of MMPs, including MMP-2 (Gelatinase A). MMP-2 targets native collagens, gelatin and elastin to remodel the extracellular matrix during wound healing. A decreased availability of pharmacologically active MMP-2 may diminish the effectiveness of the use of activated, concentrated platelets from older patients, and may also contribute to longer healing times in this population.

Bone marrow concentrate with allograft equivalent to autograft in lumbar fusions

STUDY DESIGN

Prospective randomized study.

OBJECTIVE

To compare autologous bone marrow concentrate mixed with allograft cancellous bone to iliac crest autograft in lumbar fusions.

SUMMARY OF BACKGROUND DATA

Bone marrow has been shown to be a rich source of osteoprogenitor cells. Osteoprogenitor cells have been shown in animals, and some human studies, to have potential in use as a bone graft substitute.

METHODS

Twenty-five patients underwent from 1- to 3-level lumbar fusions. One patient was lost to follow-up. On one half of the spine, allograft plus autologous bone marrow concentrate was used, whereas on the other half, autologous iliac crest bone was used. Cellular analysis, consisting of nucleated cell count, mononuclear cell count, CD34+ count, and colony-forming-units-fibroblast count, was done on marrow aspirates and concentrates. At 1 year postoperation, computed tomographic scans of the fusions were evaluated on a blinded basis by 2 neuroradiologists independent of each other. Radiographical fusion was the primary outcome measure.

RESULTS

There was no statistical difference in fusion scores between allograft and autograft in the lateral gutters, interbody cages, or facet joints. There was a positive trend between CD34+ counts and radiographical fusion.

CONCLUSION

The study shows equivalence between cancellous allograft mixed with bone marrow concentrate and autologous iliac crest bone for lumbar fusions.

LEVEL OF EVIDENCE

2.

Is Platelet-rich plasma superior to whole blood in the management of chronic tennis elbow: one year randomized clinical trial

BACKGROUND

Lateral humeral epicondylitis, or 'tennis elbow', is a common condition with a variety of treatment options. Platelet-rich plasma (PRP) and Autologous Whole Blood (AWB) represent new therapeutic options for chronic tendinopathies including tennis elbow. The aim of the present study was to compare the long term effects of PRP versus autologous whole blood local injection in patients with chronic tennis elbow.

METHODS

Seventy six patients with chronic lateral humeral epicondylitis with duration of symptoms more than 3 months were included in this study and randomized into 2 groups. Group 1 was treated with a single injection of 2 mL of autologous leukocyte rich PRP (4.8 times of plasma) and group 2 with 2 mL of AWB. Tennis elbow strap, stretching and strengthening exercises were administered for both groups. Pain and functional improvements were assessed using visual analogue scale (VAS), Mayo score (modified Mayo Clinic performance index for the elbow) and pressure pain threshold (PPT) at 0, 4, 8 weeks and 6 and 12 months.

RESULTS

All pain variables including VAS, PPT and Mayo scores improved significantly in both groups at each follow up intervals compared to baseline. No statistically significant difference was noted between groups regarding pain, functional scores and treatment success rates in all follow up examinations (P >0/05).

CONCLUSION

PRP and autologous whole blood injections are both effective methods to treat chronic lateral epicondylitis and their efficacy persisted during long term follow up. PRP was not superior to AWB in long term follow up.

The effect of platelet-rich plasma on osteochondral defects treated with mosaicplasty

PURPOSE

This study investigated the efficacy of platelet-rich plasma (PRP) on articular surfaces on which the mosaicplasty technique was performed. Our hypothesis was that PRP can accelerate the osseointegration process and enhance the quality of articular integrity after the mosaicplasty procedure.

METHODS

Standard defects were created in the femoral groove of both patellofemoral joints of 12 New Zealand rabbits. PRP solution was placed inside the defect before fixation of the osteochondral autografts and injected inside the involved joint after capsular closure of the tested knees. The contralateral knees served as the control sides. The animals were euthanized three or six weeks after mosaicplasty, and both limbs were assessed according to Pineda's histological grading scale. Significance level was set at p ≤ 0.05 a priori, and the Mann-Whitney U test was used for statistical analysis.

RESULTS

Histologic findings at the interface between the transferred autograft and the original cartilage revealed better integration of the adjacent surfaces in the mosaicplasty with PRP group three weeks after the procedure; the difference was significant (p < 0.05). However, no significant difference in the transition zone was observed between the groups six weeks after the experiment (p = 0.59).

CONCLUSIONS

Our animal model showed that adjunctive use of PRP produced a better healing response and resulted in superior histological scores after three weeks compared with the mosaicplasty-only procedure. Interpretation of our results is important in terms of rapid return to previous activity levels. Thus, application of PRP can represent a valid therapeutic option for improving the efficacy of mosaicplasty by stimulating the local healing response.

Bio-modulators in platelet-rich plasma: a comparison of the amounts in products from healthy donors and patients produced with three different techniques

BACKGROUND

Platelet-rich plasma consists of platelets concentrated in a small volume of plasma and constitutes a reservoir of bio-modulators potentially useful in tissue repair. The amounts of bio-modulators detectable in platelet-rich plasma prepared with various commercial or "in house" methods have been reported, but virtually all the analyses described have been performed on platelet-rich plasma derived from healthy donors. Since leucocyte contamination is technically unavoidable, we investigated whether platelet-rich plasma prepared from patients could contain different amounts of bio-modulators because of a possible activated status of the leucocytes.

MATERIALS AND METHODS

We evaluated platelet-rich plasma prepared with three different techniques (the commercial Vivostat and Biomet recover GPS II systems and an "in house" method) starting from whole blood from healthy donors and patients. Specifically, we compared the levels of sHLA-I, sFasL, platelet-derived growth factor, transforming growth factors-beta and vascular endothelial growth factor in the platelet-rich plasma releasates according to the method of preparation and to the immune system activation status of the subjects.

RESULTS

With the exception of sHLA-I levels, no differences were found in the surrogate indices of lymphocyte activation between healthy donors and patients. No significant differences were found in sHLA-I, sFasL, platelet-derived growth factor, transforming growth factors-beta and vascular endothelial growth factor levels detectable in platelet-rich plasma produced with the three different methods in either healthy donors or patients.

DISCUSSION

On the whole our findings indicate that the overall content of bio-modulators in autologous platelet-rich plasma is not influenced by T-lymphocyte activation status, at least in patients with uncomplicated femoral fractures. The amounts of sFasL and sHLA-I detected in all the platelet-rich plasma releasates studied were very small, far below the amounts detectable in all clinically available blood derivatives and absolutely insufficient to induce sHLA-I and/or sFasL mediated immunomodulation.