Autologous platelet-rich plasma: a revolution in soft tissue sports injury management?

A triple combination of latanoprost, fractional CO2 laser, and platelet-rich plasma in localized vitiligo: A clinical and histopathologic study

BACKGROUND

Several treatment modalities are available for the treatment of vitiligo due to the lack of a uniformly effective therapy. Topical latanoprost 0.005% is an effective topical treatment. Fractional CO2 laser alone or combined with platelet-rich plasma (PRP) has been proposed as effective adjunctive therapies.

OBJECTIVES

We aimed to compare the efficacy of topical latanoprost 0.005% (Ioprost®, Orchidia, Egypt) combined with either add-on fractional CO2 laser or fractional CO2 -PRP versus topical latanoprost monotherapy in the treatment of localized stable vitiligo.

PATIENTS/METHODS

The study included 60 patients randomly assigned into three equal groups. Group A patients received topical latanoprost drops only. Group B patients received topical latanoprost drops and fractional CO2 laser sessions at 2-week interval for 3 months. Group C patients received topical latanoprost drops and fractional CO2 laser sessions combined with PRP at a 2-week interval for 3 months. The mean improvement score by the physician was calculated 4 months after the start of the study. Punch skin biopsies were obtained before treatment and 4 months from the beginning of the study and stained with H&E and HMB-45 antibody for evaluation of pigmentation.

RESULTS

Significant clinical improvement of vitiligo lesions with significant increase of re-pigmentation were reported in the three treated groups. Latanoprost in combination with fractional CO2 and PRP was associated with more significant therapeutic outcomes than either combined latanoprost and fractional CO2 or latanoprost alone.

CONCLUSION

Fractional CO2 laser-PRP enhances the therapeutic efficacy of latanoprost 0.005% in the treatment of localized stable vitiligo.

Transforaminal injection of autologous platelet-rich plasma for lumbar disc herniation: A single-center prospective study in Vietnam

OBJECTIVE

Lumbar radiculopathy is a major health problem, which often treated by neurosurgery or guided lumbar epidural steroids for pain relief. We used autologous Platelet Rich Plasma (PRP) as a novel pharmaceutical agent that has strongly emerged in recent years to treat patients of lumbar disc herniation. From that, we evaluated the efficacy of PRP via transforaminal route in treatment of radicular pain in patients with lumbar disc herniation.

METHODS

Twenty-five patients were enrolled and injected with 4 ml of autologous platelet rich plasma under fluoroscopic guidance via transforaminal epidural injection into area of affected nerve root. They were followed using Visual Analogue Scale (VAS), Modified Oswestry Disability Index (ODI) and Straight Leg Raising Test (SLRT) for clinical assessment.

RESULTS

Patients who received transforaminal injections with autologous PRP showed statistically significant improvements on all three evaluation tools (VAS, ODI, SLRT). The improvements were sustained over twelve-month follow-up and there were no associated complications.

CONCLUSION

Transforaminal injection with autologous PRP helps patients relieve chronic pains and be able return to work. Besides, autologous PRP can be considered as a good alternative to epidural steroids in management of lumbar disc herniation.

Platelet-rich plasma injection vs. operative treatment for lateral elbow tendinosis: a systematic review and meta-analysis

BACKGROUND

Although surgical treatment is considered reliable for lateral elbow tendinosis, local injection therapy may be preferable, as it avoids surgery. Among a number of local injections, platelet-rich plasma has been used successfully to treat lateral elbow tendinosis. The purpose of this study was to compare the outcomes in patients treated with either platelet-rich plasma injections or surgery for lateral elbow tendinosis using a systematic literature review and meta-analysis.

METHODS

MEDLINE, Embase, and Cochrane Library databases were systematically searched for studies published before March 1, 2021, that compared platelet-rich plasma with operative treatment for lateral elbow tendinosis. The pooled analysis was designed to compare the visual analog scale scores and the Patient-Related Tennis Elbow Evaluation scores between the platelet-rich plasma and surgical treatment groups at serial time points.

RESULTS

We included 5 studies involving 340 patients with lateral elbow tendinosis, comprising of 154 patients treated with platelet-rich plasma and 186 patients who underwent surgical treatment. The pooled analysis showed no statistically significant differences in the visual analog scale scores at any of the follow-up time points, namely, 2 months (mean difference [MD] 1.11, 95% confidence interval [CI] -2.51 to 4.74, P = .55, I² = 94%), 6 months (MD 0.80, 95% CI -2.83 to 4.42, P = .67, I² = 92%), and 12 months (MD -0.92, 95% CI -4.63 to 2.80, P = .63, I² = 93%) postintervention and in the Patient-Related Tennis Elbow Evaluation scores at 12 weeks (MD -1.86, 95% CI -22.30 to 18.58, P = .86, I² = 81%), 24 weeks (MD -3.33, 95% CI -21.82 to 15.17, P = .72, I² = 74%), and 52 weeks (MD -3.64, 95% CI -19.65 to 12.37, P = .66, I² = 69%) postintervention.

CONCLUSIONS

Local platelet-rich plasma injections and surgical treatment produced equivalent pain scores and functional outcomes in patients with lateral elbow tendinosis. Thus, platelet-rich plasma injections may represent a reasonable alternative treatment for patients who are apprehensive to proceed with surgery or for poor surgical candidates.

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 Releasate Promotes Early Healing in Tendon After Acute Injury

Background

Acute tendon injury can limit motion and thereby inhibit tendon healing. Positive results have been found after the use of platelet-rich plasma (PRP) to treat tendon injury; however, the early effects of PRP on tendon regeneration are not known.

Purpose/Hypothesis

The purpose of this study was to evaluate the effects of PRP releasate (PRPr) on the early stages of tendon healing in a rat partial tenotomy model. It was hypothesized that PRPr can promote early healing of an Achilles tendon in rats.

Study Design

Controlled laboratory study.

Methods

PRP was prepared by a 2-step method of manual platelet concentration from 10 rats. PRPr was isolated from the clotted preparation after activation by thrombin and was applied to an Achilles tendon on 1 side of 30 rats on the second day after partial tenotomy, with normal saline used as the control on the other side. Achilles tendon samples were harvested 5 and 10 days after tenotomy. At each time point, 15 Achilles tendon samples were obtained, of which 5 samples were evaluated by Masson trichrome staining, apoptosis, and cell proliferation, while the other 10 samples were tested for tensile strength using a material testing machine.

Results

Compared with saline-treated control tendons, the PRPr-treated tendons showed increased collagen synthesis near the cut edge and fewer apoptotic cells (P = .01). An immunohistochemical analysis revealed more Ki-67-positive cells but fewer cluster of differentiation (CD) 68⁺ (ED1⁺) macrophages in PRPr tendons compared with saline-treated tendons (P < .01). Tendons treated with PRPr also showed higher ultimate tensile strength than those treated with saline (P = .03).

Conclusion

PRPr treatment promotes tissue recovery in the early phase of tendon healing by stimulating tendon cell proliferation and collagen production while inhibiting cell apoptosis and CD68⁺ (ED1⁺) macrophage infiltration.

Clinical Relevance

These findings suggest that with PRPr treatment, higher loads can be applied to the healing tendon at an earlier time, which can help the patient resume activity earlier.

Platelet-rich plasma-hyaluronic acid/chondrotin sulfate/carboxymethyl chitosan hydrogel for cartilage regeneration

In this study, the chondrogenic potential of hyaluronic acid/chondrotin sulfate/carboxymethyl chitosan hydrogels with adipose-derived mesenchymal stem cells (ADMSCs) was evaluated. Here, hyaluronic acid, chondrotin sulfate, and carboxymethyl chitosan were used as the substrate for cartilage tissue engineering in which the hydrogel is formed due to electrostatic and hydrogen bonds through mixing the polymers. Because of the instability of this hydrogel in the biological environment, 1-ethyl-3-(3-dimethylaminopropyl-carbodiimide hydrochloride/N-hydroxy-succinimide was used as a crosslinker to increase the hydrogel stability. The hydrogels showed reasonable stability due to the combined effect of self-crosslinking and chemical crosslinking. The cells were treated with the prepared hydrogel samples for 14 and 21 days in nondifferentiation medium for evaluation of the cellular behavior of ADMSCs. Gene expression evaluation was performed, and expression of specific genes involved in differentiation was shown in the crosslinked hydrogel with platelet-rich plasma (PRP) (H-EN-P) had increased the gene expression levels. Quantification of immunofluorescence intensity indicated the high level of expression of SOX9 in H-EN-P hydrogel. Based on the results, we confirmed that the presence of PRP and the similarity of the hydrogel constituents to the cartilage extracellular matrix could have positive effects on the differentiation of the cells, which is favorable for cartilage tissue engineering approaches.

The effect of lyophilized platelet rich-plasma on skin aging: a non-randomized, controlled, pilot trial

Platelet-rich plasma (PRP) showed positive results in the improvement of skin aging. Lyophilized PRP can be interesting in clinical practice due to the facility to obtain many samples in a single blood collection and can be used in multiple injections. To evaluate the effect of lyophilized PRP in the treatment of skin aging, through a Phase II pilot study. Nineteen women (54 years ± 7 years) with Glogau photoaging II and III types were select for this non-randomized, split-face controlled study. They received monthly intradermal injections of lyophilized PRP and saline solution (as control) into the facial skin, during a period of 2 months. The evaluation was performed by imaging method, histological techniques, and multiphoton microscopy. Although lyophilized PRP presented 10 times the platelet baseline value (P < .0001) and growth factors in adequate levels, only saline solution showed an increase of dermis thickness (p = .0009). Collagen pre and post-application remained the same for both types of treatments. The use of lyophilized PRP by mesotherapy showed no improvement on skin aging. TRIAL REGISTRATION APPROVAL: RBR-3n9wxw, UTN U1111-1226-6093-retrospectively registered.

Optimal double-spin method for maximizing the concentration of platelets in equine platelet-rich plasma

This study optimized the double-spin conditions for preparing equine platelet-rich plasma (PRP): leukocyte-rich PRP (L-PRP) and leukocyte-poor PRP (P-PRP). Whole blood samples were centrifuged at various double-spin conditions. Both L-PRP and P-PRP were prepared at each stage, and complete blood counts and growth factor concentrations were compared. Samples centrifuged at 160 × 900 g, 160 × 2,000 g, and 400 × 2,000 g exhibited the highest platelet counts. P-PRP had significantly lower leukocyte and erythrocyte contents than L-PRP, especially at 400 × 2,000 g. No significant differences were observed in growth factor concentrations. Our data suggest that optimum L-PRP preparation should include centrifugation under the aforementioned conditions, whereas centrifugation at 400 × 2,000 g is optimal for P-PRP.

Comparison of ultrasound-guided platelet-rich plasma, prolotherapy, and corticosteroid injections in rotator cuff lesions

BACKGROUND

Injections are a good alternative to conventional treatment-resistant cases with rotator cuff (RC) lesions before operation. Currently, different injection methods are used in RC lesions.

OBJECTIVE

To evaluate the efficacy of different injection methods (platelet-rich plasma [PRP], corticosteroid [COR] and prolotherapy [PRO]) in RC tendon lesions.

METHODS

One hundred and twenty-nine patients were divided into 4 groups as PRP, COR, PRO and the lidocaine group. Subacromial injection was applied to all groups. They were evaluated using the Visual Analogue Scale (VAS), American Shoulder and Elbow Surgeons Standardized Shoulder Assessment Form (ASES), and Western Ontario Rotator Cuff Index (WORC) at 3, 12 and 24 weeks post-injection.

RESULTS

In the COR group in the 3rd week, VAS and WORC scores were significantly lower than the other groups (p< 0.01 and p< 0.05 respectively). In the PRP group in the 24th week, VAS and WORC scores were found to be significantly lower than the COR group (p< 0.01 and p< 0.05 respectively). In the COR group in the 3rd week the ASES score was found to be significantly higher than the PRP and PRO group (p< 0.01).

CONCLUSION

In patients with RC lesions, corticosteroid injection provides short-term relief for pain, function, and quality of life, while PRP injection works for long-term wellbeing. For all types of applied injections, improvement in pain, function and quality of life were observed.

Optimal activation methods for maximizing the concentrations of platelet-derived growth factor-BB and transforming growth factor-β1 in equine platelet-rich plasma

Platelet-rich plasma (PRP) therapy has been widely applied in various medical fields including humans and horses. This study aimed to establish an optimal activation method to stably and reproducibly maximize the concentrations of platelet-derived growth factor-BB (PDGF-BB) and transforming growth factor-β1 (TGF-β1) contained in equine PRP. Autologous PRP was prepared from 11 Thoroughbreds. For the activation test, PRP was activated by either a single freeze-thaw cycle (Fr) or adding calcium and autologous serum containing thrombin (Ca). PDGF-BB and TGF-β1 concentrations in Fr, Ca, nonactivated (No), and platelet-poor plasma (PPP) samples were determined using ELISA and compared. For repetitive freeze-thaw test, PRP was subjected to single (Fr1), double (Fr2), triple (Fr3), or quadruple (Fr4) freeze-thaw cycles and the concentrations of both growth factors in samples were compared similarly. The PDGF-BB concentration in Ca was significantly higher than that in other preparations. The TGF-β1 concentrations in Fr and Ca were significantly higher than those in PPP and No, with no significant differences between Fr and Ca. The concentrations of both factors were significantly increased in PRP treated with multiple cycles of freeze-thaw compared with that in PRP treated with a single cycle. No significant differences were noted among Fr2, Fr3, and Fr4. Our findings suggest that activation by adding calcium and autologous serum is optimal for instant use of PRP and that double freeze-thawing is an easier and optimal activation method for cryopreserved PRP.

Plasma-Alginate Composite Material Provides Improved Mechanical Support for Stem Cell Growth and Delivery

Blood plasma-based products have been recently utilized in different tissue engineering applications, ranging from soft tissue repair to bone regeneration. Plasma contains fibrinogen which can be converted to an insoluble fibrin-laden gel in the presence of activated thrombin. In tissue engineering, these plasma-based materials can serve either as a three-dimensional scaffold to deliver therapeutic cells in vivo or as a growth factor-rich supply for tissue regeneration. Unfortunately, plasma-based materials are often mechanically weak and easily deformed, thus limiting their usability in harsh clinical settings. Simpler methods to create sturdier plasma-based materials are therefore needed. To this end, we hypothesized that combining alginate with plasma can create a composite plasma material with improved mechanical properties. Incorporating alginate into plasma produced composite gels with increasing bulk stiffness, as measured by rheology. Specifically, the plasma-alginate composite (PAC) gels with an alginate concentration of 2.86 mg/mL were 10-fold stiffer than pure plasma gels (11 vs 112 Pa). Interestingly, gel lysis rates were unchanged despite increasing alginate concentration (lysis time approximately 50 min). Adipose-derived stem cells cultured in the stiffer PAC gels expressed stemness markers (THY1, ENG, NT5E) at levels comparable to those in the pure plasma gels. Similarly, proangiogenic factor secretion was also constant across all gel conditions. In sum, we envision this PAC gel system will extend the use of plasma gel-based therapies into more rigorous clinical applications.

Efficacy of Intra-articular Injection of a Newly Developed Plasma Rich in Growth Factor (PRGF) Versus Hyaluronic Acid on Pain and Function of Patients with Knee Osteoarthritis: A Single-Blinded Randomized Clinical Trial

Background and objectives:

Knee osteoarthritis is the most common joint disease. We aimed to compare the efficacy and safety of intra-articular injection of a newly developed plasma rich in growth factor (PRGF) versus hyaluronic acid (HA) on pain and function of patients with knee osteoarthritis.

Methods:

In this single-blinded randomized clinical trial, patients with symptomatic osteoarthritis of knee were assigned to receive 2 intra-articular injections of our newly developed PRGF in 3 weeks or 3 weekly injections of HA. Our primary outcome was the mean change from baseline until 2 and 6 months post intervention in scores of visual analog scale, Western Ontario and McMaster Universities Osteoarthritis Index (WOMAC), and Lequesne index. We used analysis of variance for repeated-measures statistical test.

Results:

A total of 69 patients entered final analysis. The mean age of patients was 58.2 ± 7.41 years and 81.2% were women. In particular, total WOMAC index decreased from 42.9 ± 13.51 to 26.8 ± 13.45 and 24.4 ± 16.54 at 2 and 6 months in the newly developed PRGF group (within subjects P = .001), and from 38.8 ± 12.62 to 27.8 ± 11.01 and 27.4 ± 11.38 at 2 and 6 months in the HA group (within subjects P = .001), respectively (between subjects P = .631). There was no significant difference between PRGF and HA groups in patients’ satisfaction and minor complications of injection, whereas patients in HA group reported significantly lower injection-induced pain.

Conclusions:

In 6 months follow up, our newly developed PRGF and HA, both are effective options to decrease pain and improvement of function in patients with symptomatic mild to moderate knee osteoarthritis.

Treatment of Early Hip Osteoarthritis: Ultrasound-Guided Platelet Rich Plasma versus Hyaluronic Acid Injections in a Randomized Clinical Trial

Purpose  The aim of this study was to compare the clinical efficacy of ultrasound-guided intra-articular injections of autologous platelet rich plasma (PRP) versus hyaluronic acid (HA) for symptomatic early osteoarthritis (OA) of the hip.

Methods  A prospective controlled double-blinded randomized trial on 80 patients with hip OA was conducted. The patients were divided in two groups of 40 patients each: group 1 underwent three PRP intra-articular ultrasound-guided injections, whereas group 2 underwent three HA injections. WOMAC, VAS, and Harris Hip Score were evaluated for both groups before and at 6 and 12 months after treatment.

Results  The two groups were comparable in age, sex, body mass index, and severity of hip OA. Both groups showed a significant improvement from baseline at 6-month and 12-month follow-ups for all the outcome measures. No major complications were observed during the treatment and at follow-ups in both the groups.

Conclusion  PRP did not offer significantly better results compared with HA in patients with moderate signs of OA, and thus it should not be considered as first-line treatment.

Level of Evidence  Level II, randomized controlled trial.

Does the injection of platelet-rich plasma induce changes in the gene expression and morphology of intact Thoroughbred skeletal muscle?

Platelet-rich plasma (PRP) therapy is promising for treating skeletal muscle injuries in human athletes by promoting muscle regeneration. It might also be useful for treating muscle injuries in equine athletes. In the present study, muscle regeneration induced by injection of PRP into intact muscle of Thoroughbred was investigated. Autologous PRP and saline were injected twice into intact left and right gluteus medius muscles of seven clinically healthy Thoroughbreds. Muscle samples were collected from the injection sites by needle biopsy at 2 and 7 days after PRP injection. Immunohistochemical staining to identify the types of myosin heavy chains (MHCs) and satellite cells was performed to compare morphological changes among intact (pre-injection), saline-, and PRP-injected muscles. The expression of marker genes related to muscle regeneration (MHC-I, MHC-II, and embryonic MHC [MHC-e]), satellite cell activity (CK, Pax7, MyoD, and myogenin), and proinflammatory and promyogenic cytokines (IL-6, IGF-1, and HGF) was analyzed and compared between saline- and PRP-injected muscles. There were no obvious morphological differences among the three treatments. There were no significant differences in gene expression associated with satellite cell activity between saline and PRP injection at 7 days after injection. MHC genes showed significantly higher expression levels with PRP than with saline, including MHC-e at 2 days and MHC-I at 7 days after injection. It is suggested that injection of PRP into intact skeletal muscle does not induce specific morphological changes, but upregulate the expression of genes related to muscle regeneration.

The use of platelet-rich plasma to augment conservative and surgical treatment of hip and pelvic disorders

BACKGROUND

In recent years, platelet-rich plasma (PRP) has gained popularity within the orthopaedic community as a treatment modality to enhance tissue healing.

PURPOSE

This review aims to concisely present the current indications for PRP injections in the treatment of hip and pelvic pathologies and to describe some novel applications for PRP which have not yet been reported in the literature.

METHODS

We reviewed the literature on the non-operative and operative indications for PRP in the treatment of hip and pelvic pathologies.

CONCLUSIONS

With regard to hip and pelvic pathologies, PRP injections are used most commonly as a non-operative intervention, and have been described in the literature to treat osteoarthritis of the hip joint as well as tendinopathy of the hamstrings, adductor longus, and gluteus medius. In contrast, most of the surgical applications of PRP for the hip are novel, with few reported studies in the literature. Because of the increasing awareness of PRP's beneficial effects on musculoskeletal healing and thus the growing number of indications for its use, this review also describes some novel applications for PRP, including osteitis pubis, post-microfracture of the hip, tears of the rectus femoris, and avulsion of the sartorius muscle.

LEVEL OF EVIDENCE

V.

Treatment of muscle injuries in football

Muscle injuries are frequent and represent one of the most substantial medical problems in professional football. They can have both traumatic and overuse causes with direct practical consequence due to differences in terms of the post-primary care regimen and prognosis. An accurate diagnosis is the first step towards a specific treatment and usually allows to predict return to play (RTP). Current treatment principles have no firm scientific basis; they are practiced largely as empirical medicine due to a lack of prospective randomised studies. Immediate treatment usually follows the PRICE-principle (protection, rest, ice, compression, elevation). Depending on the type of the muscle injury, specific physical and physiotherapeutical procedures as well as rehabilitative exercises and gradual training therapy are used to recondition the injured structure, to restore coordination and proprioception, and to normalise movement patterns. Injection therapy with various substances is frequently used, with positive results empirically, but evidence in form of prospective randomised studies is lacking. A precise rehabilitation plan should be developed for every muscle injury, including recommendations for sport-specific training with increasing intensity. Since there are no guidelines regarding safe RTP, regular follow-up examinations on the current muscle status are crucial to evaluate the progress made in terms of healing and to determine when the injured muscle can be exposed to the next step of load. This narrative review describes the various factors that a medical team should consider during assessment, treatment and rehabilitation of a muscle injury with particular focus on professional football.

Effect of platelet mediator concentrate (PMC) on Achilles tenocytes: an in vitro study

Background

Although there are many studies discussing the etiological and pathological factors leading to both, acute and chronic tendon injuries, the pathophysiology of tendon injuries is still not clearly understood. Although most lesions are uncomplicated, treatment is long and unsatisfactory due to the poor vascularity of tendon tissue. Platelet mediator concentrate (PMC) contains many growth factors derived from platelets, which can promote wound healing. In this study we investigate the effects of PMC on tenocyte proliferation and differentiation in order to provide an experimental basis for tissue regeneration strategies and to develop new treatment concepts.

Methods

Using enzyme linked immunosorbent assay (ELISA) we were able to quantify the several growth factors and cytokines found in PMC. Tenocytes were isolated both from human and from mouse Achilles tendons and stimulated with PMC. CyQuant® and Cell Titer Blue® assays were carried out to analyze tendon growth and viability at different concentrations of PMC. Real time RT-PCR was used to analyze tenocyte gene expression with or without PMC treatment. Immunohistochemistry was carried out to detect the tenocyte-specific antibody tenomodulin (TNMD) and scleraxis (SCX).

Results

We were able to detect numerous mediators such as platelet derived growth factor BB (PDGF-BB), interleukin 6 (IL-6), vascular endothelial growth factor (VEGF), tumor necrosis factor (TNF-α), transforming growth factor beta 1 (TGF-ß1), and bone morphogenetic proteins 2, 4 and 7 (BMP-4, BMP-2, BMP-7) in PMC. It was possible to show a positive effect of PMC on human tendon cell growth and viability in a dose-dependent manner. Furthermore, PMC treatment led to induction of gene expression of scleraxis (SCX), type I collagen A 1 (Col1A1) and TNMD by tenocytes.

Conclusions

We suggest that the use of autologous PMC may be a suitable addition to conventional tendon therapy that is capable of increasing and optimizing tendon healing and reducing the risk of recurrence.

Is there a treatment protocol in which platelet-rich plasma is effective?

AIM

We aimed to reveal whether there are prospective suggestions for effective and standard platelet-rich plasma applications.

METHODS

We searched for clinical trials and traced all the references of incorporated documents.

RESULTS

In literature, there was no study indicating which disease is treated by which mechanism of action, how much dose and content are prepared and applied, when the treatment is applied and how many cures are applied.

CONCLUSION

Guides introducing which concentrations of PRP are used for which diseases are to be prepared immediately by a committee which is comprised of primarily orthopedists, clinical pharmacologists and toxicologists.

Efficacy of platelet-rich plasma in arthroscopic repair of full-thickness rotator cuff tears: a meta-analysis

BACKGROUND

The use of platelet-rich plasma (PRP) is an innovative clinical therapy, especially in arthroscopic rotator cuff repair. The purpose of this study was to compare the clinical improvement and tendon-to-bone healing with and without PRP therapy in arthroscopic rotator cuff repair.

METHODS

A systematic search was done in the major medical databases to evaluate the studies using PRP therapy (PRP+) or with no PRP (PRP-) for the treatment of patients with rotator cuff tears. We reviewed clinical scores such as the Constant score, the American Shoulder and Elbow Surgeons score, the University of California at Los Angeles (UCLA) Shoulder Rating Scale, the Simple Shoulder Test, and the failure-to-heal rate by magnetic resonance imaging between PRP+ and PRP- groups.

RESULTS

Five studies included in this review were used for a meta-analysis based on data availability. There were no statistically significant differences between PRP+ and PRP- groups for overall outcome scores (P > .05). However, the PRP+ group exhibited better healing rates postoperatively than the PRP- group (P = .03) in small/moderate full-thickness tears.

CONCLUSION

The use of PRP therapy in full-thickness rotator cuff repairs showed no statistically significant difference compared with no PRP therapy in clinical outcome scores, but the failure-to-heal rate was significantly decreased when PRP was used for treatment of small-to-moderately sized tears. PRP therapy may improve tendon-to-bone healing in patients with small or moderate rotator cuff tears.

Plasma rich in growth factors (PRGF) as a treatment for high ankle sprain in elite athletes: a randomized control trial

PURPOSE

Syndesmotic sprains are uncommon injuries that require prolonged recovery. The influence of ultrasound-guided injections of platelet-rich plasma (PRP) into the injured antero-inferior tibio-fibular ligaments (AITFL) in athletes on return to play (RTP) and dynamic stability was studied.

METHODS

Sixteen elite athletes with AITFL tears were randomized to a treatment group receiving injections of PRP or to a control group. All patients followed an identical rehabilitation protocol and RTP criteria. Patients were prospectively evaluated for clinical ability to return to full activity and residual pain. Dynamic ultrasound examinations were performed at initial examination and at 6 weeks post-injury to demonstrate re-stabilization of the syndesmosis joint and correlation with subjective outcome.

RESULTS

All patients presented with a tear to the AITFL with dynamic syndesmosis instability in dorsiflexion-external rotation, and larger neutral tibia-fibula distance on ultrasound. Early diagnosis and treatment lead to shorter RTP, with 40.8 (±8.9) and 59.6 (±12.0) days for the PRP and control groups, respectively (p = 0.006). Significantly less residual pain upon return to activity was found in the PRP group; five patients (62.5 %) in the control group returned to play with minor discomfort versus one patient in the treatment group (12.5 %). One patient in the control group had continuous pain and disability and subsequently underwent syndesmosis reconstruction.

CONCLUSIONS

Athletes suffering from high ankle sprains benefit from ultrasound-guided PRP injections with a shorter RTP, re-stabilization of the syndesmosis joint and less long-term residual pain.

LEVEL OF EVIDENCE

II.

Immunohistochemical Expression of Collagens in the Skin of Horses Treated with Leukocyte-Poor Platelet-Rich Plasma

This study evaluated the immunohistochemical expression of type I (COL I) and III (COL III) collagens during the healing process of skin treated with leukocyte-poor platelet-rich plasma (LP-PRP). Seven healthy gelding crossbred horses aged 16 to 17 years were used. Two rectangle-shaped wounds were created surgically in the right and left gluteal regions. Twelve hours after wound induction, 0.5 mL of the LP-PRP was administered in each edge of the wounds of one of the gluteal regions. The contralateral region was used as control (CG). Three samples were obtained: after wound induction (T0), 14 days (T1) of healing process, and after complete closure of the skin (T2). The normal skin (T0) showed strong staining for type III and I collagen in papillary and reticular dermis, respectively. In the scar of the treated group, COL III showed important (p < 0.05) increase in immunoreaction in T2 compared with T1. The administration of a single dose of LP-PRP 12 h after induction of wound in horses does not influence formation of collagens I and III. However, the intense labeling for COL III suggests that the tissue was still weak during the macroscopic closure of the wound, demonstrating that healing was not completely finished.

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 increases proliferation of tendon cells by modulating Stat3 and p27 to up-regulate expression of cyclins and cyclin-dependent kinases

OBJECTIVES

To investigate effects of platelet-rich plasma on tendon cell proliferation and the underlying molecular mechanisms.

MATERIALS AND METHODS

Platelet-rich plasma was prepared manually by two-step centrifugation. Proliferation was evaluated in cultured rat tendon cells by the 3-[4,5-dimethylthiazol-2-yl]-2,5-diphenyltetrazolium bromide assay. Cell cycle progression was assessed by flow cytometry. Messenger RNA expression of proliferating cell nuclear antigen (PCNA), cyclin E1, A2 and B1, and cyclin-dependent kinases (Cdks) 1 and 2 was assessed by real-time polymerase chain reaction. Protein expression of the above cyclins and Cdks and of signal transducer and activator of transcription (Stat) 3 and p27 was evaluated by western blotting.

RESULTS

Platelet-rich plasma used in the present study had concentrations of platelets, TGF-β1 and PDGF over 3-fold higher than normal whole blood. Platelet-rich plasma enhanced tendon cell proliferation (P = 0.008) by promoting G1 /S phase transition in the cell cycle, and increased expression of PCNA, cyclin E1, A2 and B1, Cdks1 and 2, and phosphorylated Stat3, while inhibiting p27 expression.

CONCLUSIONS

Platelet-rich plasma contains high concentrations of TGF-β1 and PDGF that increase tendon cell proliferation by modulating Stat3/p27(Kip1), which enhances expression of cyclin-Cdk complexes that promote cell cycle progression. These results provide molecular evidence for positive effects of platelet-rich plasma on tendon cell proliferation, which can be useful in clinical applications of tendon injury.

The role of platelet gel in osteoarticular injuries of young and old patients

BACKGROUND

The use of autologous platelet gel in orthopedics is effective in accelerating the healing process of osteochondral, muscle, tendon and ligament lesions. The aim of our study was to verify whether the variability in response to infiltration with platelet gel was dependent on the underlying disease treated, sex and age of the patients. During four years, 140 patients have been treated for musculoskeletal injuries by infiltration of gel platelet and lysate platelet obtained from autologous thrombin, with echo-ultrasound guided. The response to treatment was assessed at different time points T0, T1, T2 with respect to pain estimation (VAS), joint mobility (ROM scale) and echo-ultrasound evaluation. This data collection has allowed classifying the response to treated lesions in three categories: NR (no response), PR (partial response), CR (complete response).

RESULTS

The data here reported showed that the ability to physical recovery response is evident in tendon injuries, while the large joints injuries gave a poor response. Almost all patients showed a significant pain relief after the first infiltration, but in terms of echo-ultrasound evaluation and tissue repair, only the muscle and tendon injuries showed hyperechoic areas, signs or evidences of repair. Concerning the correlation between response to infiltration with platelet gel and gender/age of the patients, the clinical results appear not influenced by the age and the gender of the patient.

DISCUSSION

Our data indicate that, pain relief and ability to physical recovery of muscles, tendons and ligaments depend on tissue repair clearly visible by echo ultrasound evaluation. On the other hand tissue repair seems not occur in the large joints (hip and knee) where arthritis and /or corrosion of articular cartilage cannot be repaired and the only relief is exclusively linked to the reduction of periarticular inflammation (reduction of the inflammatory leakage and signs).

Mean platelet volume (MPV) predicts middle distance running performance

BACKGROUND

Running economy and performance in middle distance running depend on several physiological factors, which include anthropometric variables, functional characteristics, training volume and intensity. Since little information is available about hematological predictors of middle distance running time, we investigated whether some hematological parameters may be associated with middle distance running performance in a large sample of recreational runners.

METHODS

The study population consisted in 43 amateur runners (15 females, 28 males; median age 47 years), who successfully concluded a 21.1 km half-marathon at 75-85% of their maximal aerobic power (VO2max). Whole blood was collected 10 min before the run started and immediately thereafter, and hematological testing was completed within 2 hours after sample collection.

RESULTS

The values of lymphocytes and eosinophils exhibited a significant decrease compared to pre-run values, whereas those of mean corpuscular volume (MCV), platelets, mean platelet volume (MPV), white blood cells (WBCs), neutrophils and monocytes were significantly increased after the run. In univariate analysis, significant associations with running time were found for pre-run values of hematocrit, hemoglobin, mean corpuscular hemoglobin (MCH), red blood cell distribution width (RDW), MPV, reticulocyte hemoglobin concentration (RetCHR), and post-run values of MCH, RDW, MPV, monocytes and RetCHR. In multivariate analysis, in which running time was entered as dependent variable whereas age, sex, blood lactate, body mass index, VO2max, mean training regimen and the hematological parameters significantly associated with running performance in univariate analysis were entered as independent variables, only MPV values before and after the trial remained significantly associated with running time. After adjustment for platelet count, the MPV value before the run (p = 0.042), but not thereafter (p = 0.247), remained significantly associated with running performance.

CONCLUSION

The significant association between baseline MPV and running time suggest that hyperactive platelets may exert some pleiotropic effects on endurance performance.

Evaluation of pain regression in patients with temporomandibular dysfunction treated by intra-articular platelet-rich plasma injections: a preliminary report

OBJECTIVE

The objective of this study was to evaluate the regression of temporomandibular pain as a result of intra-articular injections of platelet-rich plasma (PRP) to patients with temporomandibular joint dysfunction previously subjected to prosthetic treatment.

MATERIALS AND METHODS

The baseline study material consisted of 10 patients, both males and females, aged 28 to 53 years, previously treated due to painful temporomandibular joint dysfunction using occlusal splints. All patients were carried out to a specialist functional assessment of the dysfunction using the Polish version of the RDC/TMD questionnaire axis I and II. Intra-articular injections were preceded by a preparation of PRP. The injection sites were determined by the method used during arthroscopic surgical procedures. Following aspiration, 0.5 mL of plasma was injected into each temporomandibular joint.

RESULTS

The comparison of the intensity of pain during all examinations suggests a beneficial effect of the procedure being performed as the mean VAS score was 6.5 at examination I, 2.8 at examination II, and 0.6 at examination III.

CONCLUSION

Application of the intra-articular injections of platelet-rich plasma into the temporomandibular joints has a positive impact on the reduction of the intensity of pain experienced by patients treated for temporomandibular joint dysfunction.

Quantificação de fatores de crescimento na pele de equinos tratada com plasma rico em plaquetas

O plasma rico em plaquetas (PRP) é um produto derivado da centrifugação do sangue total, sendo rico em fatores bioativos, como os de crescimento. Apesar da ampla utilização em processos cicatriciais, há controvérsia sobre a eficácia da terapia na cicatrização cutânea. O objetivo desse estudo foi quantificar e comparar a concentração dos fatores TGF-β1 e PDGF-BB no PRP, plasma sanguíneo e pele, durante diferentes fases do processo de cicatrização da pele tratada ou não com PRP. Foram utilizados sete equinos machos castrados, mestiços, hígidos, com idade entre 16 e 17 (16,14±0,63) anos. Três lesões em formato quadrangular (6,25cm²) foram produzidas cirurgicamente nas regiões glúteas direita e esquerda de todos os animais. Doze horas após indução das feridas, 0,5mL do PRP foi administrado em cada uma das quatro extremidades das feridas de uma das regiões glúteas (Grupo tratado = GT), escolhida aleatoriamente. A região contralateral foi utilizada como controle (GC). As feridas foram submetidas à limpeza diária com água Milli Q, e amostras foram obtidas mediante biópsias realizadas com Punch de 6mm. Foram obtidas seis biópsias de pele, sendo a primeira realizada logo após a produção da ferida (T0), e as demais com 1 (T1) 2 (T2) 7 (T3) e 14 (T4) dias após a indução da lesão. A sexta biópsia (T5) foi obtida após completo fechamento da pele, que ocorreu aproximadamente aos 37 dias (36,85±7,45, GC; 38,85±6,46, GT). Também foram obtidas amostras de sangue com EDTA em todos os tempos mencionados. A quantificação dos fatores de crescimento TGF-β1 e PDGF-BB na pele, PRP e plasma sanguíneo foi realizada pela técnica ELISA. Os dados foram analisados estatisticamente pelo teste t, correlação de Pearson e regressão, utilizando nível de significância de 5%. Não houve diferença entre os grupos, nos valores dos dois fatores de crescimento mensurados na pele, nos diferentes tempos. Também não houve correlação entre a quantidade dos fatores de crescimento presentes na pele e no plasma. Por outro lado, correlação positiva foi observada entre PRP e pele no grupo tratado, para os fatores de crescimento TGF-β1 (r=0,31) e PDGF-BB (r=0,38), bem como entre ambos os fatores de crescimento presentes no PRP (r=0,81). Considerando as concentrações dos fatores de crescimento no T0, os maiores valores cutâneos (p<0,05) do TGF-β1, em ambos os grupos, ocorreram nos tempos T3 e T5. Valores mais elevados (p<0,05) do PDGF-BB ocorreram no T4 (GT) e T5 (GC). No plasma não houve alteração nas concentrações desses fatores em relação ao T0, o que sugere que o PRP não acarreta efeito sistêmico, quando os procedimentos adotados na presente pesquisa são utilizados. A administração local de PRP no volume estudado, 12 h após indução cirúrgica de ferida cutânea na região glútea de equinos não ocasiona maiores concentrações dos fatores de crescimento TGF-β1 e PDGF-BB no plasma sanguíneo e pele, durante o processo de cicatrização.

Ultrasound-guided platelet-rich plasma injections for the treatment of common peroneal nerve palsy associated with multiple ligament injuries of the knee

PURPOSE

Peroneal nerve palsy in traumatic knee dislocations associated with multiple ligament injuries is common. Several surgical approaches are described for this lesion with less-than-optimal outcomes. The present case represents the application of plasma rich in growth factors (PRGF) technology for the treatment of peroneal nerve palsy with drop foot. This technology has already been proven its therapeutic potential for various musculoskeletal disorders. Based on these results, we hypothesized that PRGF could stimulate the healing process of traumatic peroneal nerve palsy with drop foot.

METHODS

The patient was a healthy 28-year-old man. He suffered peroneal nerve palsy with drop foot after multiple ligament injuries of the knee. PRGF was prepared according to the manufactured instruction. Eleven months after the trauma with severe axonotmesis, serial intraneural infiltrations of PRGF were started using ultrasound guidance. The therapeutic effect was assessed by electromyography (EMG), echogenicity of the peroneal nerve under ultrasound (US) and manual muscle testing.

RESULTS

Twenty-one months after the first injection, not complete but partial useful recovery is obtained. He is satisfied with walking and running without orthosis. Sensitivity demonstrates almost full recovery in the peroneal nerve distribution area. EMG controls show complete reinnervation for the peroneus longus and a better reinnervation for the tibialis anterior muscle, compared with previous examinations.

CONCLUSION

Plasma rich in growth factors (PRGF) infiltrations could enhance healing process of peroneal nerve palsy with drop foot. This case report demonstrates the therapeutic potential of this technology for traumatic peripheral nerve palsy and the usefulness of US-guided PRGF.

LEVEL OF EVIDENCE

V.

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.

Efficacy of second intra-tendinous platelet-rich-plasma injection in case of incomplete response of the first injection: three-year follow up experience

PURPOSE

Tendinopathy is a frequent and ubiquitous disease developing early disorganized collagen fibers with neo-angiogenesis on histology. Peritendinous injection of corticosteroid is the commonly accepted strategy despite the absence of inflammation in tendinopathy. Platelet-rich plasma (PRP) might be a useful strategy to rapidly accelerate healing of the tendinopathy but there is a lack ok knowledge about the amount of PRP to be injected and the opportunity of a second injection in case of partial pain relief. The aim of our study was to assess the potential therapeutic effect of early second PRP intra-tendinous to treat persistent painful tendon tear and tendinosis in a long-term follow-up by ultrasonography (US) and clinical data in case of incomplete efficiency of first PRP treatment injection.

MATERIALS AND METHODS

Twenty-four consecutive patients referred for US treatment of tendon tear or tendinosis (T+) were included retrospectively. All had previously received a single intra-tendinous injection of PRP under US guidance (PRPT+) and benefited of a second PRP injection (PRPT2+) under US guidance in order to treat persistent painful. US and clinical data were collected for each anatomic compartment for upper and lower limbs before treatment (D0), 6 weeks (W6) after first treatment, 6 weeks (W12) after second treatment and until 32-month follow-up. We used Mac Nemar test and regression model to compare US and clinical data.

RESULTS

The residual US size of lesions was not significantly lower at W12 after PRPT2+ as compared to W6 (P=0.86 in upper and P=NS in lower member) independently of age (P=0.22), gender (P=0.97) and kind of tendinopathy (P=NS). Quick dash test values and WOMAC values were not significantly lower in PRPT+ at W12 (average: 21.5 months) as compared to W6 (P>0.66) and long-term follow-up (P>0.75) independently of age (P=0.39), gender (P=0.63) and kind of tendinopathy (P=NS). Nevertheless, comparison between D0 and long-term follow-up (LTF) functionnal score was statistically significant (p<0.001 in upper and lower member).

CONCLUSION

Our study suggests that second early intra-tendinous PRP injection under US guidance does not permit rapid decrease of tendinopathy area in US, nor does it quickly improve clinical pain and functional data in case of incomplete efficiency of first PRP injection. However, in long-term follow-up, patients improved their ability to mobilize pathologic tendons.

Use of platelet-rich plasma in the care of sports injuries: our experience with ultrasound-guided injection

BACKGROUND

Platelet-rich plasma is being used more frequently to promote healing of muscle injuries. The growth factors contained in platelet-rich plasma accelerate physiological healing processes and the use of these factors is simple and minimally invasive. The aim of this study was to demonstrate the efficacy of ultrasound-guided injection of platelet-rich plasma in muscle strains and the absence of side effects.

MATERIALS AND METHODS

Fifty-three recreational athletes were enrolled in the study. The patients were recruited from the Emergency Room in the University Hospital at Parma according to a pre-defined protocol. Every patient was assessed by ultrasound imaging to evaluate the extent and degree of muscle injuries. Only grade II lesions were treated with three ultrasound-guided injections of autologous platelet-rich plasma every 7 days. Platelet concentrate was produced according to standard methods, with a 10% variability in platelet count. The platelet gel for clinical use was obtained by adding thrombin to the concentrates under standardised conditions. Outcomes assessed were: pain reduction, muscle function recovery and return to sports activity, ultrasound-imaging tissue healing, relapses, local infections, and any side effect during the treatment.

RESULTS

In all cases muscle lesions healed fully on ultrasound-imaging, the pain disappeared, and muscle function recovery was documented with a return to sports activity. A single patient had a relapse 1 year after treatment.

DISCUSSION

Platelet-rich plasma injected into the injury site is one of the most important factors rendering the treatment effective. To maximise its efficacy the preliminary ultrasound must be done accurately to localise the lesion and guide the needle into the corresponding lesion. According to the current results, which document full muscle recovery and no relapse except for one case, platelet-rich plasma ultrasound-guided injection represents a valid mini-invasive treatment for muscle injuries.

The impact of platelet-rich plasma on the prevention of tunnel widening in anterior cruciate ligament reconstruction using quadrupled autologous hamstring tendon: a randomised clinical trial

The use of platelet-rich plasma (PRP) as an adjuvant to tissue repair is gaining favour in orthopaedic surgery. Tunnel widening after anterior cruciate ligament (ACL) reconstruction is a recognised phenomenon that could compromise revision surgery. The purpose of this study was to determine whether PRP might prevent tunnel widening in ACL reconstruction.Patients undergoing ACL reconstruction using a hamstring graft were randomly allocated either to have PRP introduced into the tunnels peri-operatively or not. CT scanning of the knees was carried out on the day after surgery and at three months post-operatively and the width of the tunnels was measured. Patients were also evaluated clinically at three months, when laxity was also measured.Each group comprised 25 patients, and at three months post-operatively all were pain-free with stable knees, a negative Lachman test and a good range of movement. Arthrometric results had improved significantly in both groups (p < 0.001). Despite slightly less tunnel widening in the PRP group, there was no significant difference between the groups at the femoral opening or the mid-tunnel (p = 0.370 and p = 0.363, respectively) nor at the tibial opening or mid-tunnel (p = 0.333 and p = 0.177, respectively).We conclude that PRP has no significant effect in preventing tunnel widening after ACL reconstruction.

Platelet-rich plasma intra-articular injections for cartilage degeneration and osteoarthritis: single- versus double-spinning approach

PURPOSE

To compare the safety and efficacy of two different approaches of platelet-rich plasma (PRP) production methods as intra-articular injection treatment for knee cartilage degenerative lesions and osteoarthritis (OA).

METHODS

The study involved 144 symptomatic patients affected by cartilage degenerative lesions and OA. Seventy-two patients were treated with 3 injections of platelet concentrate prepared with a single-spinning procedure (PRGF), the other 72 with 3 injections of PRP obtained with a double-spinning approach. The patients were evaluated prospectively at the enrollment and at 2, 6, and 12 months' follow-up with IKDC, EQ-VAS and Tegner scores; adverse events and patient satisfaction were also recorded.

RESULTS

Both treatment groups presented a statistically significant improvement in all the scores evaluated at all the follow-up times. Better results were achieved in both groups in younger patients with a lower degree of cartilage degeneration. The comparative analysis showed similar improvements with the two procedures: in particular, IKDC subjective evaluation increased from 45.0 ± 10.1 to 59.0 ± 16.2, 61.3 ± 16.3, and 61.6 ± 16.2 at 2, 6, and 12 months in the PRGF group, and from 42.1 ± 13.5 to 60.8 ± 16.6, 62.5 ± 19.9, and 59.9 ± 20.0 at 2, 6, and 12 months in the PRP group, respectively. Concerning adverse events, more swelling (P = 0.03) and pain reaction (P = 0.0005), were found after PRP injections.

CONCLUSIONS

Although PRP injections produced more pain and swelling reaction with respect to that produced by PRGF, similar results were found at the follow-up times, with a significant clinical improvement with respect to the basal level. Better results were achieved in younger patients with a low degree of cartilage degeneration.

LEVEL OF EVIDENCE

II.

Engaging stem cells for customized tendon regeneration

The need for a consistent therapeutic approach to tendon injury repair is long overdue. Patients with tendon microtears or full ruptures are eligible for a wide range of invasive and non invasive interventions, often subjectively decided by the physician. Surgery produces the best outcomes, and while studies have been conducted to optimize graft constructs and to track outcomes, the data from these studies have been inconclusive on the whole. What has been established is a clear understanding of healthy tendon architecture and the inherent process of healing. With this knowledge, tissue regeneration efforts have achieved immense progress in scaffold design, cell line selection, and, more recently, the appropriate use of cytokines and growth factors. This paper evaluates the plasticity of bone-marrow-derived stem cells and the elasticity of recently developed biomaterials towards tendon regeneration efforts. Mesenchymal stem cells (MSCs), hematopoietic progenitor cells, and poly(1,8-octanediol co-citrate) scaffolds (POC) are discussed in the context of established grafting strategies. With POC scaffolds to cradle the growth of MSCs and hematopoietic progenitor cells, developing a fibroelastic network guided by cytokines and growth factors may contribute towards consistent graft constructs, enhanced functionality, and better patient outcomes.

Platelet-rich plasma in sports medicine: hot favourite or non-starter?

In the field of sports injury, musculoskeletal injuries require prompt treatment to allow a quick return to the pre-injury level of function. Ideally, any given treatment should, among other factors, be minimally invasive and highly effective, with minimal side effects. One emerging strategy to accelerate tissue healing is the use of platelet rich plasma. Platelet-rich plasma has been used in clinical practice since the 1980s, in dentistry, maxillofacial surgery and dermatology (Margolis et al, 2001). The treatment developed because platelet-rich plasma is seen as a preparation of growth factors which facilitate rapid healing of damaged tissue. There have been wide variations in agreeing a definition of platelet-rich plasma.

Regenerative tendon and ligament healing: opportunities with recombinant human platelet-derived growth factor BB-homodimer

Intrinsic tendon healing in response to injury is a reparative process that often results in formation of scar tissue with functional and mechanical properties inferior to those of the native tendon. Development of therapies that can promote regenerative, rather than reparative, healing hold the promise of improving patient recovery from tendon and ligament injuries by producing tissue that is morphologically and functionally equivalent to the native tissue. One therapeutic approach that has been a frequent topic of investigation in the preclinical literature is the use of recombinant human platelet-derived growth factor-BB (rhPDGF-BB) to augment tendon and ligament repair. The chemotactic, mitogenic, and pro-angiogenic properties of rhPDGF-BB have been shown to result in recruitment and proliferation of tenogenic cells and a commensurate boost in extracellular matrix deposition and organization, improving the morphological and biomechanical properties of healing tendons and ligaments. The outcomes of the preclinical studies reviewed here strongly suggest that rhPDGF-BB will provide a new therapeutic opportunity to improve the treatment of injured tendons and ligaments.

Role of growth factors in rotator cuff healing

The histologic lesion underlying overuse rotator cuff tendinopathy is a failed healing response, with haphazard proliferation of tenocytes, disruption of tendon cells and collagen fibers, and increased noncollagenous extracellular matrix. Recent attention has focused on the biological pathways by which tendons heal, leading to the identification of several growth factors (GFs) involved in this process. No studies have been published on the time course of the various GFs during rotator cuff healing process in vivo, in humans. We review what is known about these GFs and their role in rotator cuff healing.