The role of platelets in the treatment of Achilles tendon injuries

Platelet-Rich Plasma in acute Achilles tendon ruptures: A systematic review and meta-analysis

BACKGROUND

Platelet Rich Plasma (PRP) is known to exert multi-directional biological effects favouring tendon healing. However, conclusions drawn by numerous studies on its clinical efficacy for acute Achilles tendon rupture are limited. We performed a systematic review and meta-analysis to investigate this and to compare to those without PRP treatment.

METHODS

The Cochrane Controlled Register of Trials, Pubmed, Medline and Embase were used and assessed according to the PRISMA (Preferred Reporting Items for Systematic Reviews and Meta-Analyses) criteria with the following search terms: ('plasma' OR 'platelet-rich' OR 'platelet-rich plasma' or 'PRP') AND ('Achilles tendon rupture/tear' OR 'calcaneal tendon rupture/tear' OR 'tendo calcaneus rupture/tear'). Data pertaining to biomechanical outcomes (heel endurance test, isokinetic strength, calf-circumference and range of motion), patient-reported outcome measures (PROMs) and incidence of re-ruptures were extracted. Meta-analysis was performed for same outcomes measured in at least three studies. Pooled outcome data were analysed by random- and fixed-effects models.

RESULTS

After abstract and full-text screening, 6 studies were included. In total there were 510 patients of which 256 had local PRP injection and 254 without. The average age was 41.6 years, mean time from injury to treatment 5.9 days and mean follow-up at 61 weeks. Biomechanically, there was similar heel endurance, isokinetic strength, calf circumference and range of motion between both groups. In general, there were no differences in patient reported outcomes from all scoring systems used in the studies. Both groups returned to their pre-injured level at a similar time and there were no differences on the incidence of re-rupture (OR 1.13, 95% CI, 0.46-2.80, p = 0.79).

CONCLUSION

PRP injections for acute Achilles tendon ruptures do not improve medium to long-term biomechanical and clinical outcomes. However, future studies incorporating the ideal application and biological composition of PRP are required to investigate its true clinical efficacy.

Does additional extracorporeal shock wave therapy improve the effect of isolated percutaneous radiofrequency coblation in patients with insertional Achilles tendinopathy? Study protocol for a randomized controlled clinical trial

BACKGROUND

No conclusive evidence recommends a prior treatment for insertional Achilles tendinopathy (IAT). It is theorized that both percutaneous radiofrequency coblation and extracorporeal shockwave therapy (ESWT) relieve pain within the insertion. However, no clinical evidence shows that either treatment promotes the regeneration of the tendon or if the combination of these 2 interventions offers better function and less pain than one therapy.

METHODS

The study is a randomized, controlled trial with patients allocated in a 1:1 ratio to one of two parallel groups. Patients with insertional Achilles tendinopathy who are not satisfied with the effect of conservative treatment will be screened. A minimum of 38 patients will be enrolled after deciding to participate in the trial on an informed basis. Then the intervention group and the control group perform radial ESWT and sham-ESWT respectively at 6 months after percutaneous radiofrequency coblation. The primary outcome will be the Victorian Institute of Sports Assessment Achilles (VISA-A) Score. Secondary outcome measures will be Foot and Ankle Outcome Score (FAOS) scale, visual analog scale (VAS), Tegner Score, and MRI ultra-short echo time (UTE) T2* value. The assessments will occur in 6 months, 1 year, and 2 years, post-operatively. The differences between the 2 groups will be conducted as intention-to-treat basis.

DISCUSSION

We aim to investigate if radiofrequency coblation associated with ESWT can provide more encouraging imaging findings as well as functional and clinical outcomes regarding the treatment of the IAT comparing to the single radiofrequency coblation treatment.

TRIAL REGISTRATION

ChiCTR1800017898; pre-results. Registered on 20 August 2018.

Known data on applied regenerative medicine in tendon healing

Tendons and ligaments are important structures in the musculoskeletal system. Ligaments connect various bones and provide stability in complex movements of joints in the knee. Tendon is made of dense connective tissue and transmits the force of contraction from muscle to bone. They are injured due to direct trauma in sports or roadside accidents. Tendon healing after repair is often poor due to the formation of fibro vascular scar tissues with low mechanical property. Regenerative techniques such as PRP (platelet-rich plasma), stem cells, scaffolds, gene therapy, cell sheets, and scaffolds help augment repair and regenerate tissue in this context. Therefore, it is of interest to document known data (repair process, tissue regeneration, mechanical strength, and clinical outcome) on applied regenerative medicine in tendon healing.

Serial Ultrasonographic and Real-Time Elastosonographic Assessment of the Ovine Common Calcaneal Tendon, after an Experimentally Induced Tendinopathy

Real-time elastosonography (RTE) is a recently described, non-invasive, ultrasonographic technique developed to assess tissue elasticity. The main aim of this study was to investigate the ultrasonographic and elastosonographic appearance of the common calcaneal tendon (CCT) in an ovine model, and to monitor the progression of tendon healing after an experimentally-induced tendinopathy. Sound tendons were initially evaluated (T₀) with a caliper and by a single operator with ultrasound. Ultrasonographic and elastosonographic images were then acquired. Subsequently, ultrasound-guided tendon lesions were induced by injecting 500 IU of Type IA collagenases proximally to the calcaneal tuberosity. Caliper measurement, ultrasonography and elastosonography were then repeated at 15 (T₁), 30 (T₂) and 60 (T₃) days. Clinically measured width of the tendon, ultrasonographic thickness and width and percentage of hard (Elx-t%hrd) and soft (Elx-t%sft) tissue were recorded. Statistical analysis was performed on the data collected; statistical significance was set at p < 0.05. Intra-class correlation coefficient (ICC) revealed good (0.68) repeatability of elastosonographic evaluation of the CCT. The tendon width was significantly increased when comparing T₀ with T_1–2 and decreased when comparing T_1–2 with T₃. Ultrasound-assessed thickness was significantly increased between T₀–T₁ and decreased between T₁-T_2–3. Elx-t%hrd was significantly decreased at T_1–2–3 and Elx-t%sft was significantly increased at T_1–2–3. In conclusion, the ovine CCT is a highly stiff structure that undergoes a severe loss of stiffness during the healing process. Thickness and width of the tendon increased during the first 30 days and then reduced progressively along the subsequent 30 days. Ultrasonographic appearance of the tendon remained severely abnormal and the tendon showed severely reduced elastic proprieties 60 days after lesion induction.

Comparison on effects of platelet-rich plasma versus autologous conditioned serum on Achilles tendon healing in a rat model

OBJECTIVE

The aim of this study was to compare the effects of local administrations of platelet-rich plasma (PRP) with autologous conditioned serum (ACS) on Achilles tendon healing in a rat model.

METHODS

In this study, 40 male Sprague-Dawley rats, aged 12 months and weighing 350 to 400 g were used. The rats were divided into three groups (n=10 in each group): a control group and two treatment groups (PRP vs ACS). A standardized procedure was applied for the complete rupture and repair of the Achilles tendon in each group. The PRP group received one dose of PRP on the operative area, and ACS group received ACS at 24, 48, and 72 hours after the surgery. The control group received no injection. Animals were sacrificed 30 days after the operation, and tendon healing in each group was assessed histopathologically based on Bonar's semi-quantitative score and Movin's semi-quantitative grading scale. For the biomechanical analyses, unoperated Achilles tendons of all rats in the control and ACS groups were also harvested, and pulling tests were applied to the specimen to measure the longitudinal axis strength. The highest force value among the data obtained was defined as the maximum strength value (Fmax).

RESULTS

The mean Bonar's score was significantly lower in the PRP group (3.8±0.8) than in the ACS (4.8±0.45) and control groups (5.2±0.837) (p=0.0028). The mean Movin's score was significantly lower in the PRP group (7.80±1.49) than in the ACS (9.8±1) and control groups (11.2±2.4) (p=0.029). The ratio of type I collagen was significantly higher in the PRP group (60±6) than in the ACS (52±4.5) and control groups (42±9) (p=0.005). Biomechanical results obtained from operated sites were comparable in terms of Fmax among groups (PRP, 33.93±2.61; ACS, 35.24±3.26; control, 35.69±3.62) (p=0.674). Similarly, the results obtained from unoperated sites were comparable among groups (PRP, 47.71±1.21; ACS, 48.14±2; control, 49.14.69±1.88) (p=0.395).

CONCLUSION

In terms of histopathological results, PRP seems to be more effective than ACS for Achilles tendon healing in rats.

Cytokine and Growth Factor Delivery from Implanted Platelet-Rich Fibrin Enhances Rabbit Achilles Tendon Healing

Tendons are hypocellular and hypovascular tissues, and thus, their natural healing capacity is low. In this study, we sought to evaluate the efficacy of platelet-rich fibrin (PRF) to serve as a bioactive scaffold in promoting the healing of rabbit Achilles tendon injury. For in vitro study, the essence portion of PRF was determined through bioluminescent assay. Furthermore, we analyzed the time-sequential cytokines-release kinetics of PRF and evaluated their effects on tenocytes proliferation and tenogenic gene expressions. In animal study, the rabbit Achilles tendon defect was left untreated or implanted with normal/heat-denatured PRF scaffolds. Six weeks postoperatively, the specimens were evaluated through sonographic imaging and histological analysis. The results revealed significantly more activated platelets on bottom half of the PRF scaffold. Cytokine concentrations released from PRF could be detected from the first hour to six days. For the in vitro study, PRF enhanced cell viability and collagen I, collagen III, tenomodulin, and tenascin gene expression compared to the standard culture medium. For in vivo study, sonographic images revealed significantly better tendon healing in the PRF group in terms of tissue echogenicity and homogeneity. The histological analysis showed that the healing tissues in the PRF group had more organized collagen fiber, less vascularity, and minimal cartilage formation. In conclusion, bioactive PRF promotes in vitro tenocytes viability and tenogenic phenotypic differentiation. Administration of a PRF scaffold at the tendon defect promotes tissue healing as evidenced by imaging and histological outcomes.

Orthobiologics

Use of orthobiologics in sports medicine and musculoskeletal surgery has gained significant interest. However, many of the commercially available and advertised products are lacking in clinical evidence. Widespread use of products before fully understanding their true indications may result in unknown adverse outcomes and may also lead to increased health care costs. As more products become available, it is important to remain judicial in use and to practice evidence-based medicine. Likewise, it is important to continue advances in research in hopes to improve surgical outcomes. This article reviews clinical evidence behind common orthobiologics in the treatment of foot and ankle pathology.

[Differential diagnosis of heel pain]

"Heel pain" describes a very common reason for foot orthopedic consultation and the further differential diagnostic investigation is crucial for the choice of correct treatment. In the treatment of frequent underlying diseases, such as plantar fasciitis or insertional tendinopathy of the Achilles tendon, a variety of modern strategies are available. Rarer diseases, such as tumors or nerve entrapment syndromes must be delineated and correctly classified. This article provides the current state of the diagnostics and treatment of the most common entities of heel pathologies.

An animal experimental study on pubourethral ligament restoration with platelet rich plasma for the treatment of stress urinary incontinence

Introduction

Minimally invasive methods for injured ligament and tendon restoration have been developed and gained popularity in recent years. Injury and relaxation of the pubourethral ligament (PUL) can lead to stress urinary incontinence (SUI). The aim of this study was to investigate the impact of injecting platelet rich plasma (PRP) into the PUL following its surgical transection resulting in SUI, confirmed by leak point pressure (LPP) measurements pre- and post-intervention in an experimental animal model.

Material and methods

Twenty female adult Sprague-Dawley rats were assigned in 2 groups: 1) treatment group with transection of the PUL and application of PRP at the time of transection and at one month follow-up and 2) a control group, with transection of the PUL only. Leak point pressures (LPPs) were measured prior to transection, immediately following the transection and at 1 and 2 months in both groups.

Results

The median LPPs for the control group were: LPP – preT: 35.6 (29.8–44.8) cmH₂O, LPP – postT: 14.6 (5.8–19.0) cmH₂O, LPP – 1 month: 27.3 (19.2–33.8) cmH₂O, LPP – 2 months: 29.0 (27.0–34.0) cmH₂O, whereas for the PRP group were: LPP-preT: 40.5 (33.2–46.3) cmH₂O, LPP – postT: 15.7 (3.0–24.0) cmH₂O, LPP – 1month: 31.6 (24.8–37.4) cmH₂O, LPP – 2 months: 36.8 (32.5–45.4) cmH₂O. PRP injections on transected PULs significantly increased LPPs at one month follow-up [31.6 cmH₂O vs. 27.3 cmH₂O, p = .043]. This effect was confirmed at two months [36.8 cmH₂O vs. 29.0 cmH₂O, p <.001].

Conclusions

Injection of PRP into transected PULs significantly improved LPPs at one and two months' follow-up. However, further experimental and clinical research is needed to evaluate the safety and efficacy of this treatment, in clinical practice.

Biologics in the Treatment of Achilles Tendon Pathologies

Regenerative medicine is gaining more and more space for the treatment of Achilles pathologic conditions. Biologics could play a role in the management of midportion Achilles tendinopathy as a step between conservative and surgical treatment or as an augmentation. Higher-level studies are needed before determining a level of treatment recommendation for biologic strategies for insertional Achilles tendinopathy. Combining imaging with patient's functional requests could be the way to reach a protocol for the use of biologics for the treatment of midportion Achilles tendinopathy and, for this perspective, the authors describe the Foot and Ankle Reconstruction Group algorithm of treatment.

Platelet-Rich Plasma

Platelet-rich plasma (PRP) is a promising treatment for musculoskeletal maladies and clinical data to date have shown that PRP is safe. However, evidence of its efficacy has been mixed and highly variable depending on the specific indication. Additional future high-quality large clinical trials will be critical in shaping our perspective of this treatment option. The heterogeneity of PRP preparations, both presently and historically, leads sweeping recommendations about its utility impossible to make. This heterogeneity has also made interpreting existing literature more complicated.

Effects of mesenchymal stromal cells versus serum on tendon healing in a controlled experimental trial in an equine model

BACKGROUND

Mesenchymal stromal cells (MSC) have shown promising results in the treatment of tendinopathy in equine medicine, making this therapeutic approach seem favorable for translation to human medicine. Having demonstrated that MSC engraft within the tendon lesions after local injection in an equine model, we hypothesized that they would improve tendon healing superior to serum injection alone.

METHODS

Quadrilateral tendon lesions were induced in six horses by mechanical tissue disruption combined with collagenase application 3 weeks before treatment. Adipose-derived MSC suspended in serum or serum alone were then injected intralesionally. Clinical examinations, ultrasound and magnetic resonance imaging were performed over 24 weeks. Tendon biopsies for histological assessment were taken from the hindlimbs 3 weeks after treatment. Horses were sacrificed after 24 weeks and forelimb tendons were subjected to macroscopic and histological examination as well as analysis of musculoskeletal marker expression.

RESULTS

Tendons injected with MSC showed a transient increase in inflammation and lesion size, as indicated by clinical and imaging parameters between week 3 and 6 (p < 0.05). Thereafter, symptoms decreased in both groups and, except that in MSC-treated tendons, mean lesion signal intensity as seen in T2w magnetic resonance imaging and cellularity as seen in the histology (p < 0.05) were lower, no major differences could be found at week 24.

CONCLUSIONS

These data suggest that MSC have influenced the inflammatory reaction in a way not described in tendinopathy studies before. However, at the endpoint of the current study, 24 weeks after treatment, no distinct improvement was observed in MSC-treated tendons compared to the serum-injected controls. Future studies are necessary to elucidate whether and under which conditions MSC are beneficial for tendon healing before translation into human medicine.

Achilles Pain, Stiffness, and Muscle Power Deficits: Midportion Achilles Tendinopathy Revision 2018

The Orthopaedic Section of the American Physical Therapy Association (APTA) has an ongoing effort to create evidence-based practice guidelines for orthopaedic physical therapy management of patients with musculoskeletal impairments described in the World Health Organization's International Classification of Functioning, Disability, and Health (ICF). The purpose of these revised clinical practice guidelines is to review recent peer-reviewed literature and make recommendations related to midportion Achilles tendinopathy. J Orthop Sports Phys Ther 2018;48(5):A1-A38. doi:10.2519/jospt.2018.0302.

[Pharmacological treatment of osteoarthritis-related pain]

Joint pain due to osteoarthritis (OA) is often severe and disabling and affects a large proportion of the aging population impairing daily living and quality of life. Numerous pharmacological treatment approaches are available. Including major OA guidelines this review presents the current evidence of pharmacological therapies in OA-related pain and covers topical, oral and intraarticular treatment approaches. In patients with mild OA topical nonsteroidal antiinflammatory drugs (NSAIDs) can be recommended. Topical capsaicin can be used when other treatments are ineffective or contraindicated. In patients with moderate to severe OA oral NSAIDs are suggested at the lowest effective dose for the shortest possible duration to control symptoms. Importantly, drug-related side effects and gastrointestinal, cardiovascular and renal comorbidities need to be taken into account. In patients with multiple-joint OA and high risk of NSAID-induced adverse events duloxetine can be considered. The evidence of metamizole, symptomatic slow-acting drugs in osteoarthritis and other nutritional supplements in the treatment of OA pain is uncertain and the use of opioids is not routinely recommended. In patients suffering from severe OA-related pain intraarticular injections with glucocorticoids can be suggested to achieve short-term pain relief. Evidence for interventional approaches using hyaluronic acid or platelet-rich plasma is uncertain. Yet, the efficacy of pharmacological therapies in OA-related pain is often inconsistent and severe adverse events might occur. Thus, critical use of the different treatment options considering patient-related comorbidities and nonpharmacological therapies is of major importance.

Noninsertional Tendinopathy of the Achilles

Noninsertional Achilles tendinosis is differentiated from insertional Achilles tendinosis based on anatomic location. Tendinosis, as opposed to tendonitis, is primarily a degenerative process and the role of inflammation is believed limited. The etiology of Achilles tendinopathy may include overuse leading to repetitive microtrauma, poor vascularity of the tissue, mechanical imbalances of the extremity, or combination of these elements. There is evidence to support eccentric exercise nonoperative management for patients with noninsertional Achilles tendinopathy. Operative treatment options include percutaneous longitudinal tenotomies, minimally invasive tendon scraping, open débridement and tubularization, and tendon augmentation with flexor hallucis longus.

Platelet rich Plasma in Achilles Tendon Healing 2 (PATH-2) trial: protocol for a multicentre, participant and assessor-blinded, parallel-group randomised clinical trial comparing platelet-rich plasma (PRP) injection versus placebo injection for Achilles tendon rupture

BACKGROUND

Achilles tendon injuries give rise to substantial long-lasting morbidity and pose considerable challenges for clinicians and patients during the lengthy healing period. Current treatment strategies struggle to curb the burden of this injury on health systems and society due to lengthy rehabilitation, work absence and reinjury risk. Platelet-rich plasma (PRP) is an autologous preparation that has been shown to improve the mechanobiological properties of tendons in laboratory and animal studies. The use of PRP in musculoskeletal injuries is on the increase despite the lack of adequately powered clinical studies.

METHODS AND DESIGN

This is a multicentre randomised controlled trial to evaluate the efficacy and mechanism of PRP in patients with acute Achilles tendon rupture (ATR). All adults with acute ATR presenting within 12 days of the injury who are to be treated non-operatively are eligible. A total of 230 consenting patients will be randomly allocated via a remote web-based service to receive PRP injection or placebo injection to the site of the injury. All participants will be blinded to the intervention and will receive standardised rehabilitation to reduce efficacy interference.Participants will be followed up with blinded assessments of muscle-tendon function, quality of life, pain and overall patient's functional goals at 4, 7, 13, 24 weeks and 24 months post-treatment. The primary outcome is the heel-rise endurance test (HRET), which will be supervised by a blinded assessor at 24 weeks. A subgroup of 16 participants in one centre will have needle biopsy under ultrasound guidance at 6 weeks. Blood and PRP will be analysed for cell count, platelet activation and growth factor concentrations.

ETHICS AND DISSEMINATION

The protocol has been approved by the Oxfordshire Research Ethics Committee (Oxfordshire Research Ethics Committee A, reference no 14/SC/1333). The trial will be reported in accordance with the CONSORT statement and published in peer-reviewed scientific journals.

TRIAL REGISTRATION NUMBER

ISRCTN: 54992179, assigned 12 January 2015. ClinicalTrials.gov: NCT02302664, received 18 November 2014. UK Clinical Research Network Study Portfolio Database: ID 17850.

Conservative treatment for Insertional Achilles Tendinopathy: platelet-rich plasma and focused shock waves. A retrospective study

BACKGROUND

Insertional Achilles tendinopathy (IAT) represents a serious challenge for both physiatrists and surgeons. Here we analyse the results obtained by two conservative treatments [platelet-rich plasma (PRP) injections and focused extracorporeal shock-wave therapy (ESWT)] in physically active patients with IAT.

METHODS

During two consecutive periods, 45 consecutive patients with IAT were treated with 3 sessions of ESWT (2400 impulses at 0.17-0.25 mJ/mm² per session) (24 cases between September 2011 and July 2013) or with 2 autologous PRP injections over two weeks (21 cases between September 2013 and July 2015). All patients were evaluated at 0, 2-, 4-, 6-month follow-up after therapy. The outcome measures were VISA-A, VAS, Patient Satisfaction.

RESULTS

Intra-group analysis showed a significant improvement of VISA-A and VAS scores in both groups at all time-points. No differences between groups were observed for VAS and VISA-A scores at all time-points, excepted for VISA-A at 4-months in favour of ESWT group (P=0.049). Patient satisfaction increased progressively (>70% at 6 months) and with no differences between two groups.

CONCLUSION

Both ESWT and PRP therapy are effective and safe. Our study confirms the success of these conservative treatments in Achilles tendinopathy, even in the insertional one.

LEVEL OF EVIDENCE

IIIa.

Midsubstance Tendinopathy, Surgical Management

Noninsertional Achilles tendinopathy often responds to nonoperative treatment. When nonoperative treatment fails, the clinician must distinguish between paratendinopathy and noninsertional tendinopathy. In paratendinopathy, myofibroblasts synthesize collagen, causing adhesions, and the paratenon may be released or excised. If a core area of tendinopathy is identified on MRI, the area is excised longitudinally and repaired with a side-to-side suture. If greater than 50% of the tendon diameter is excised, the authors recommend a short flexor hallucis longus tendon transfer with an interference screw. A turndown flap of the gastrocnemius aponeurosis is also described with good results.

Impact of cyclic mechanical stimulation on the expression of extracellular matrix proteins in human primary rotator cuff fibroblasts

PURPOSE

Mechanical stimulation plays an important role in the development and remodelling of tendons. The aim of the study was to evaluate the effects of mechanical stimulation on the expression of extracellular matrix proteins in human primary rotator cuff (RC) fibroblasts.

METHODS

RC fibroblasts were isolated from patients with degenerative RC tears and characterized using flow cytometry and immunohistochemistry. Cells were stimulated using the Flexcell FX5K™ Tension System. The stimulation regime was a uniaxial sinusoidal waveform with 10 % elongation and a frequency of 0.5 Hz, whereby each cycle consists of 10-s strain and 30-s relaxation. Data were normalized to mechanically unstimulated control groups for every experimental condition. RT-qPCR was performed to determine relative mRNA levels, and collagen production was measured by a colorimetric assay.

RESULTS

The positive expression of CD91 and CD10, and negativity for CD45 and CD4 confirmed the fibroblast phenotype of RC primary cells. RT-qPCR revealed that 10 % continuous cyclic strain for 7 and 14 days induced a significant increase in the mRNA expression both on the matrix metalloproteinases MMP1, MMP3, MMP13, and MMP14 and on the extracellular matrix proteins decorin, tenascin-C, and scleraxis. Furthermore, mechanically stimulated groups produced significantly higher amounts of total collagen.

CONCLUSION

These results may contribute to a better understanding of strain-induced tendon remodelling and will form the basis for the correct choice of applied force in rehabilitation after orthopaedic surgery. These findings underline the fact that early passive motion of the joint in order to induce remodelling of the tendon should be included within a rehabilitation protocol for rotator cuff repair.

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.

Can platelet-rich plasma have a role in Achilles tendon surgical repair?

PURPOSE

Our hypothesis was that the Achilles tendon healing process after surgical treatment would be promoted by PRP with a faster return to sports activities.

METHODS

Thirty patients with Achilles tendon rupture and surgically treated with a combined mini-open and percutaneous technique were prospectively enroled in the study. Patients were alternately case-by-case assigned to Group A (control group; 15 patients) or Group B (study group; 15 patients). In Group B, PRP was locally infiltrated both during surgery and 14 days after surgery. Patients in both groups were followed up at 1, 3, 6 and 24 months post-operatively via physical examination, VAS, FAOS and VISA-A scales; ultrasonography (US) and MRI were also conducted at one and 6 months; at the 6-month follow-up, isokinetic and jumping capacity tests were also performed.

RESULTS

The VAS, FAOS and VISA-A scale showed no difference between the two groups at 1, 3, 6 and 24 months post-operatively. Isokinetic evaluation showed no differences at both angular speeds. Jumping evaluation showed no difference at 6 months. Also US evaluation showed no differences. MRI data analysis before administration of gadolinium did not reveal significant differences between the two groups. Moreover, after intravenous injection of gadolinium, patients in Group B showed signal enhancement in 30 % of patients compared to 80 % in Group A at 6 months, as indirect evidence of better tendon remodelling (P < 0.05).

CONCLUSIONS

A substantial equivalence in structural and functional results in Achilles tendon ruptures surgically treated with and without addition of PRP is shown by present study. Clinical results, morphological features and jumping capability were similar in both groups. The addition of PRP to the surgical treatment of Achilles tendon rupture does not appear to offer superior clinical and functional results.

LEVEL OF EVIDENCE

IV.

Efficacy of Intra-articular Platelet-Rich Plasma Injections in Knee Osteoarthritis: A Systematic Review

PURPOSE

To determine (1) whether platelet-rich plasma (PRP) injection significantly improves validated patient-reported outcomes in patients with symptomatic knee osteoarthritis (OA) at 6 and 12 months postinjection, (2) differences in outcomes between PRP and corticosteroid injections or viscosupplementation or placebo injections at 6 and 12 months postinjection, and (3) similarities and differences in outcomes based on the PRP formulations used in the analyzed studies.

METHODS

PubMed, Cochrane Central Register of Controlled Trials, SCOPUS, and Sport Discus were searched for English-language, level I evidence, human in vivo studies on the treatment of symptomatic knee OA with intra-articular PRP compared with other options, with a minimum of 6 months of follow-up. A quality assessment of all articles was performed using the Modified Coleman Methodology Score (average, 83.3/100), and outcomes were analyzed using 2-proportion z-tests.

RESULTS

Six articles (739 patients, 817 knees, 39% males, mean age of 59.9 years, with 38 weeks average follow-up) were analyzed. All studies met minimal clinical important difference criteria and showed significant improvements in statistical and clinical outcomes, including pain, physical function, and stiffness, with PRP. All but one study showed significant differences in clinical outcomes between PRP and hyaluronic acid (HA) or PRP and placebo in pain and function. Average pretreatment Western Ontario and McMaster Universities Osteoarthritis Index (WOMAC) scores were 52.36 and 52.05 for the PRP and HA groups, respectively (P = .420). Mean post-treatment WOMAC scores for PRP were significantly better than for HA at 3 to 6 months (28.5 and 43.4, respectively; P = .0008) and at 6 to 12 months (22.8 and 38.1, respectively; P = .0062). None of the included studies used corticosteroids.

CONCLUSIONS

In patients with symptomatic knee OA, PRP injection results in significant clinical improvements up to 12 months postinjection. Clinical outcomes and WOMAC scores are significantly better after PRP versus HA at 3 to 12 months postinjection. There is limited evidence for comparing leukocyte-rich versus leukocyte-poor PRP or PRP versus steroids in this study.

LEVEL OF EVIDENCE

Level I, systematic review of Level I studies.

Retrospective Analysis of the Effectiveness of Platelet-Rich Plasma in the Treatment of Achilles Tendinopathy: Pretreatment and Posttreatment Correlation of Magnetic Resonance Imaging and Clinical Assessment

Platelet-rich plasma (PRP) has been presented as a means of treating Achilles tendinopathy. Over the past dozen years, a plethora of medical articles have advocated this treatment, yet little evidentiary-based research exists in support of this approach. Treatment protocols with PRP have been performed in 2 ways during this time: administered adjunctively during tendon surgery and as a stand-alone injection. The senior author has utilized PRP by both methods to treat Achilles tendinopathy over the past 7 years; 26 patients so treated were able to be recalled, half having undergone Achilles tendon surgery in combination with PRP administration and the other half PRP alone. In this retrospective study, qualified patients had pretreatment and posttreatment magnetic imaging studies and completed a Victorian Institute of Sports Assessment-Achilles questionnaire. In this limited study, PRP showed promise in the treatment of Achilles tendinopathy. Both the stand-alone injection group and surgical/injection groups had statistically significant degrees of improvement in pre-MRI and post-MRI imaging studies. There was no statistically significant difference between the 2 treatment groups. Of interest, it appears that the difference between the MRI scoring correlates with the survey score.

LEVEL OF EVIDENCE

Therapeutic, Level, IV: Case series.

Ultrasound-guided intervention in the ankle and foot

In this comprehensive review, we discuss the main interventions performed in the foot and ankle for Achilles tendinopathy, Morton's neuromas and Plantar fasciitis as well as techniques for intra-articular and peritendinous injections. We present the different imaging techniques and injectable agents that can be used in clinical practice, trying to help the reader decide the most appropriate way of managing the patient with a problem in the ankle and foot.

Role of embedded pure xenogenous bovine platelet gel on experimental tendon healing, modelling and remodelling

BACKGROUND AND OBJECTIVES

Surgical reconstruction of large tendon defects is technically demanding. In addition, tendon healing has poor quality and is associated with development of peritendinous adhesions. Tissue engineering and regenerative medicine is an option. A combination of scaffolds and factors that promote healing, such as a bioactive graft, could be a valuable strategy for treatment of the injured tendons. Different forms of platelets have been used for tendon healing. Since the availability and cost effectiveness of biomaterials are important in tissue engineering, bovine platelets could be a valuable alternative option for the autograft platelets. We investigated whether bovine platelet gel embedded within an artificial tendon could be effective in tendon healing and regeneration, in vivo.

METHODS

After in vitro evaluations, a large tendon defect model was produced in rabbits and the defect maintained align using Kessler suture. The animals were divided into four groups of control (no implant), treatment with collagen implant, collagen implant-polydioxanone sheath, and collagen implant-polydioxanone sheet-bovine platelet gel. The healing and regeneration were assessed by gross- micro- and nano-morphologic analyses, biomechanical testing, biochemistry, bioelectricity, and clinical evaluations at 60 and 120 days after injury.

RESULTS

Bovine platelet gel induced cellular proliferation and enhanced cell viability in vitro. In vivo, it significantly increased inflammation in the short term, enhanced cellular distribution, proliferation, migration, differentiation and matrix production at mid-term and finally it facilitated graft degradation, incorporation and acceptance in the newly regenerated tendon. Compared with the control groups, the platelet-treated neotendon had significantly higher mechanical strength which was due to the collagen fibril's better density, diameter, number, differentiation and distribution, collagen fibril to fiber and fiber bundle differentiation and lower peritendinous adhesion, muscle fibrosis and atrophy.

CONCLUSION

Bovine platelet gel-embedded artificial tendon could be considered as a new option in reconstruction and healing of large tendon defects.

Biologics in Achilles tendon healing and repair: a review

Injuries of the Achilles tendon are relatively common with potentially devastating outcomes. Healing Achilles tendons form a fibrovascular scar resulting in a tendon which may be mechanically weaker than the native tendon. The resulting strength deficit causes a high risk for reinjury and other complications. Treatments using biologics aim to restore the normal properties of the native tendon and reduce the risk of rerupture and maximize tendon function. The purpose of this review was to summarize the current findings of various therapies using biologics in an attempt to improve the prognosis of Achilles tendon ruptures and tendinopathies. A PubMed search was performed using specific search terms. The search was open for original manuscripts and review papers limited to publication within the last 10 years. From these searches, papers were included in the review if they investigated the effects of biological augmentation on Achilles tendon repair or healing. Platelet-rich plasma may assist in the healing process of Achilles tendon ruptures, while the evidence to support its use in the treatment of chronic Achilles tendinopathies remains insufficient. The use of growth factors such as hepatocyte growth factor, recombinant human platelet-derived growth factor-BB, interleukin-6, and transforming growth factor beta as well as several bone morphogenetic proteins have shown promising results for Achilles tendon repair. In vitro and preclinical studies have indicated the potential effectiveness of bone marrow aspirate as well. Stem cells also have positive effects on Achilles tendon healing, particularly during the early phases. Polyhydroxyalkanoates (PHA), decellularized tendon tissue, and porcine small intestinal submucosa (SIS) are biomaterials which have shown promising results as scaffolds used in Achilles tendon repair. The application of biological augmentation techniques in Achilles tendon repair appears promising; however, several techniques require further investigation to evaluate their clinical application.

Synthesis, development, characterization and effectiveness of bovine pure platelet gel-collagen-polydioxanone bioactive graft on tendon healing

Bovine platelet gel (BPG) is an accessible and cost-effective source of growth factors which may have a value in tendon regenerative medicine. We produced a collagen implant (CI) as a tendon proper, covered it with polydioxanone (PDS) sheath to simulate paratenon and finally embedded the BPG as an active source of growth factor within the bioimplant to test whether BPG would be able to accelerate and enhance tendon regeneration and repair. After in vitro characterization of the bioactive grafts, the grafts were implanted in rabbit large tendon defect model. Untreated tendons and tendons treated with either CI or CI-PDS were served as controls for the CI-PDS-BPG. The animals were investigated clinically, ultrasonographically and haematologically for 120 days. After euthanasia, dry matter content, water uptake and delivery characteristics and also gross morphological, histopathological and scanning electron microscopic features of the healing tendons were assessed. In vitro, the activated platelets in the scaffold, released their growth factors significantly more than the controls. BPG also increased cell viability, and enhanced cellular differentiation, maturation and proliferation inside the CI-PDS compared with the controls. In vivo, the BPG modulated inflammation, increased quality and rate of fibroplasia and produced a remodelled tendon that had significantly higher collagen content and superior collagen fibril and fibre differentiation than controls. Treatment also significantly improved tendon water uptake and delivery characteristics, animals' serum PDGF level, CI-PDS biocompatibility and biodegradability and reduced peritendinous adhesions, muscle fibrosis and atrophy. BPG was effective on tendon healing and CI-PDS-BPG may be a valuable bioscaffold in tendon reconstructive surgery.

Effect of platelet-rich plasma with self-assembled peptide on the rotator cuff tear model in rat

Several trials have been carried out to improve the healing of rotator cuff tear, but their effects remain controversial. In this study, we examined the therapeutic effect of platelet-rich plasma (PRP) in combination with self-assembled peptide (SAP) on the healing of rotator cuff tear in the rat. Twenty-seven Sprague-Dawley rats, aged 15 weeks, were used for the rotator cuff tear model. The supraspinatus muscle at the insertion site was dissected and truncated, leaving the cut edge free. A week after the surgery, the rats were randomly divided into SAP, PRP, SAP-PRP and control groups and 0.2 ml SAP, PRP, SAP-PRP and saline were injected, respectively. Bonar scores and synovial inflammation grade were checked 5 weeks after the injection. Immunofluorescence staining for heat shock protein (HSP)-70 and caspase-3 was conducted. Furthermore, maximum stride length was measured before and at 2 and 4 weeks after the injection. The Bonar scores were 6.4 ± 1.8 in the SAP group, 5.9 ± 2.0 in the PRP group, 4.7 ± 1.1 in the SAP-PRP group and 8.3 ± 2.3 in the control group. There was significant difference between the SAP-PRP and control groups in post hoc multiple comparison analysis. Among four categories of Bonar scores, collagen arrangement and vascular infiltration showed improvement after SAP-PRP injection. Immunofluorescence images showed that HSP-70 and caspase-3 were much less expressed in the SAP-PRP group than in the other groups. In conclusion, SAP-PRP can be effective in healing a rotator cuff tear by enhancing the collagen arrangement and inhibiting inflammatory changes and apoptosis. Copyright © 2015 John Wiley & Sons, Ltd.

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.

Treatment of tendinopathies with platelet-rich plasma

Pain and dysfunction related to tendinopathy are often refractory to traditional treatments and offer a unique challenge to physicians, because no gold standard treatment exists. Injectable biologics may represent a new modality in conjunction with a multifaceted treatment approach. Platelet-rich plasma (PRP) injections are not associated with the systemic or tendon degradation risks of corticosteroids or the inherent risks of surgery. Studies are promising but have not been replicated with high-powered evidence at the clinical level. Further evidence to expand understanding of the role of PRP in the treatment of tendinopathy is needed.

Tendon and ligament regeneration and repair: clinical relevance and developmental paradigm

As dense connective tissues connecting bone to muscle and bone to bone, respectively, tendon and ligament (T/L) arise from the somitic mesoderm, originating in a recently discovered somitic compartment, the syndetome. Inductive signals from the adjacent sclerotome and myotome upregulate expression of Scleraxis, a key transcription factor for tenogenic and ligamentogenic differentiation. Understanding T/L development is critical to establishing a knowledge base for improving the healing and repair of T/L injuries, a high-burden disease due to the intrinsically poor natural healing response. Current treatment of the three most common tendon injuries-tearing of the rotator cuff of the shoulder, flexor tendon of the hand, and Achilles tendon-include mostly surgical repair and/or conservative approaches, including biophysical modalities such as rehabilitation and cryotherapy. Unfortunately, the fibrovascular scar formed during healing possesses inferior mechanical and biochemical properties, resulting in compromised tissue functionality. Regenerative approaches have sought to augment the injured tissue with cells, scaffolds, bioactive agents, and mechanical stimulation to improve the natural healing response. The key challenges in restoring full T/L function following injury include optimal combination of these biological agents as well as their delivery to the injury site. A greater understanding of the molecular mechanisms involved in T/L development and natural healing, coupled with the capability of producing complex biomaterials to deliver multiple biofactors with high spatiotemporal resolution and specificity, should lead to regenerative procedures that more closely recapitulate T/L morphogenesis, thereby offering future patients the prospect of T/L regeneration, as opposed to simple tissue repair.

Freeze-thaw cycles enhance decellularization of large tendons

The use of decellularized tendon tissue as a scaffold for tendon tissue engineering provides great opportunities for future clinical and current research applications. The aim of this study was to assess the effect of repetitive freeze-thaw cycles and two different detergents, t-octyl-phenoxypolyethoxyethanol (Triton X-100) and sodium dodecyl sulfate (SDS), on decellularization effectiveness and cytocompatibility in large tendons. Freshly collected equine superficial and deep digital flexor tendons were subjected to decellularization according to four different protocols (1 and 2: freeze-thaw cycles combined with either Triton X-100 or SDS; 3 and 4: Triton X-100 or SDS). Decellularization effectiveness was assessed based on the reduction of vital cell counts, histologically visible nuclei, and DNA content. Transmission electron microscopy was performed to evaluate cellular and extracellular matrix integrity. Further, cytocompatibility of scaffolds that had been decellularized according to the protocols including freeze-thaw cycles (protocols 1 and 2) was assessed by seeding the scaffolds with superparamagnetic iron oxide labeled mesenchymal stromal cells and monitoring the cells histologically and by magnetic resonance imaging for two weeks. Decellularization was significantly more effective when using the protocols including freeze-thaw cycles, leaving only roughly 1% residual nuclei and 20% residual DNA, whereas samples that had not undergone additional freeze-thaw cycles contained roughly 20% residual nuclei and 40% residual DNA. No morphological extracellular matrix alterations due to decellularization could be observed. Scaffolds prepared by both protocols including freeze-thaw cycles were cytocompatible, but the cell distribution into the scaffold tended to be better in scaffolds that had been decellularized using freeze-thaw cycles combined with Triton X-100 instead of SDS.

Effect of platelet-rich plasma on the biologic activity of the human rotator-cuff fibroblasts: A controlled in vitro study

To assess the in vitro effect of platelet-rich plasma (PRP) on biological activity of the human rotator cuff fibroblasts and to describe the optimal dose-response to maximize cellular stimulation while reducing potential risk. Rotator cuff (RC) fibroblasts of n = 6 patients (mean age of 65.2 years) undergoing arthroscopic cuff tear reconstruction were cultured in vitro for 21 days and stimulated with PRP in three different concentrations (1-, 5-, and 10-fold). Samples were obtained for DNA and GAG measurement at 1, 7, 14, and 21 days. The biological outcomes were regressed on the PRP concentration. The application of PRP significantly influenced the fibroblast proliferation and activity of the human rotator cuff with elevated glycosaminoglycan (GAG) and DNA levels. The dosage of PRP had the significantly highest impact on this proliferation using a onefold or fivefold application. PRP has a significant effect on fibroblast proliferation of the human rotator cuff in vitro with an optimal benefit using a onefold or fivefold PRP concentration. This study justifies further in vivo investigations using PRP at the human rotator cuff.

Long-term outcomes of muscle volume and Achilles tendon length after Achilles tendon ruptures

PURPOSE

The best treatment for Achilles tendon (AT) ruptures remains controversial. Long-term follow-up with radiological and clinical measurements is needed.

METHODS

In this retrospective multicentre cohort study, patients (n = 52) were assessed at a mean of 91 months follow-up after unilateral AT rupture treated by open, percutaneous or conservative (non-surgical) treatment. Demographic parameters, time off work, maximum calf circumference and clinical scores (ATRS, Hannover, AOFAS) were evaluated. Muscle volume and cross-sectional area of the calf and AT length were measured on MR images and were compared between groups and to each patient's healthy contralateral leg.

RESULTS

Reduced muscle volume was found across all groups with a higher muscle volume in the conservative (729.9 ± 130.3 cm(3)) compared to the percutaneous group (675.9 ± 207.4 cm(3), p = 0.04). AT length was longer in the affected leg (198.4 ± 24.1 vs. 180.6 ± 25.0 mm, p < 0.0001) without difference in subgroup analysis. Clinically measured ankle dorsiflexion showed poor correlation with AT length (R (2) = 0.07, p = 0.008). Muscle volume strongly correlated with the cross-sectional area (R (2) = 0.6, p < 0.0001) but showed a weak correlation with the Hannover score (R (2) = 0.08, p = 0.048). Maximum calf circumference correlated with muscle volume (R (2) = 0.42, p < 0.0001).

CONCLUSIONS

No significant difference between the treatment groups was found in muscle volume, AT length, clinical measures or days off work. Cross-sectional area and maximum calf circumference are cost-effective measurements and a good approximation of muscle volume and can thus be used in a clinical setting while clinical dorsiflexion should not be used.