Jean-François Kaux

Effects of platelet-rich plasma (PRP) on the healing of Achilles tendons of rats

Platelet‐rich plasma (PRP) contains growth factors involved in the tissular healing process. The aim of the study was to determine if an injection of PRP could improve the healing of sectioned Achilles tendons of rats. After surgery, rats received an injection of PRP (n = 60) or a physiological solution (n = 60) in situ. After 5, 15, and 30 days, 20 rats of both groups were euthanized and 15 collected tendons were submitted to a biomechanical test using cryo‐jaws before performing transcriptomic analyses. Histological and biochemical analyses were performed on the five remaining tendons in each group. Tendons in the PRP group were more resistant to rupture at 15 and 30 days. The mechanical stress was significantly increased in tendons of the PRP group at day 30. Histological analysis showed a precocious deposition of fibrillar collagen at day 5 confirmed by a biochemical measurement. The expression of tenomodulin was significantly higher at day 5. The messenger RNA levels of type III collagen, matrix metalloproteinases 2, 3, and 9, were similar in the two groups at all time points, whereas type I collagen was significantly increased at day 30 in the PRP group. In conclusion, an injection of PRP in sectioned rat Achilles tendon influences the early phase of tendon healing and results in an ultimately stronger mechanical resistance.

Étude comparative de cinq techniques de préparation plaquettaire (platelet-rich plasma)

AIM OF THE STUDY Injections of platelet-rich plasma (PRP) constitute a new therapeutic for treating chronic tendinopathies. The injection being carried out in the tendon, the volume of PRP should thus be minimal (to decrease the intratendinous pressure and to minimize pain). This PRP should also have a raised platelet count. The quantity of released growth factors could be related to the system of preparation employed. We thus carried out a comparative study of five techniques of preparation of PRP described in the literature. MATERIALS AND METHODS Samples of venous blood were taken among five patients in order to compare five techniques of preparation of PRP: University Hospital of Liège technique, Curasan(®) PRP Kit, Plateltex(®), GPS(®)II and RegenLab(®). RESULTS The various techniques make it possible to obtain more important platelet concentration than in blood, with variable volumes (0,3 to 6ml). The number of platelets per microlitre appears higher with Plateltex(®) and obtains smallest volume of PRP. The other techniques also give small volumes except for the GPS(®)II. The number of collected platelets with this technique appears thus higher. The best collect efficiency is obtained with RegenLab(®). CONCLUSION The technique Plateltex(®) makes it possible to collect the highest concentration of platelets in the smallest volume available.

Eccentric training improves tendon biomechanical properties: A rat model

The treatment of choice for tendinopathies is eccentric reeducation. Although the clinical results appear favorable, the biomechanical changes to the tissue are not yet clear. Even if the mechanotransduction theory is commonly accepted, the physiology of tendons is not clearly understood. We aimed to better define the biomechanical and histological changes that affect healthy tendon after eccentric and concentric training. This study compared the effects of two methods of training (eccentric [E] training and concentric [C] training) with untrained (U) rats. The animals were trained over a period of 5 weeks. The tricipital, patellar, and Achilles tendons were removed, measured and a tensile test until failure was performed. A histological analysis (hematoxylin and eosin and Massons trichrome stains) was also realized. There was a significant increase in the rupture force of the patellar and tricipital tendons between the U and E groups. The tricipital tendons in the control group presented a significantly smaller cross‐sectional area than the E‐ and C‐trained groups, but none was constated between E and C groups. No significant difference was observed for the mechanical stress between the three groups for all three tendons. Histological studies demonstrated the development of a greater number of blood vessels and a larger quantity of collagen in the E group. The mechanical properties of tendons in rats improve after specific training, especially following eccentric training. Our results partly explained how mechanical loading, especially in eccentric mode, could improve the healing of tendon.

Exuberant inflammatory reaction as a side effect of platelet-rich plasma injection in treating one case of tendinopathy.

Platelet-rich plasma (PRP) contains a large number of growth factors, which may enhance tendon healing processes. Local injection of PRP represents a relatively new treatment for tendinopathies. To date, no side effects have been reported after injection of PRP to treat tendinopathy. We report a case of exuberant inflammatory reaction after 1 injection of PRP to treat jumpers knee in a 35-year-old male type 1 diabetic patient. Injections of PRP should be proposed only after careful consideration in cases of patients with morbidity risks linked to insulin-dependent diabetes.

Using platelet-rich plasma to treat jumper's knees: Exploring the effect of a second closely-timed infiltration

OBJECTIVES Some clinical series have evaluated the effect of platelet-rich plasma (PRP) in the treatment of proximal patellar tendinopathy. Although it is possible that a single infiltrative administration may prove to be an effective treatment for this indication, most of the existing studies evaluated the effects of two or three successive infiltrations. The aim of this study was to evaluate whether two infiltrations of PRP proves more effective than a single treatment. DESIGN Prospective, randomized and comparative study of level 2. METHODS Twenty patients suffering from chronic proximal patellar tendinopathy were enrolled into the study and split into two randomized groups (one or two infiltrations of PRP, respectively). The 3-month follow-up evaluation consisted of VAS, IKDC and VISA-P scores, along with algometer, isokinetic and ultrasounds evaluations. After 1 year, subjects were contacted to define their functional evolution. RESULTS The concentration of the PRP used for each infiltration was similar in both groups, and contained no red or white cells. Results revealed no difference in treatment efficacy between the groups. CONCLUSIONS The comparison between one or two infiltrations of PRP did not reveal any difference between the two groups at short to mid term. A second closely-timed infiltration of PRP to treat proximal patellar tendinopathies is not necessary to improve the efficacy of this treatment in the short term.

Intense physical exercise related to the emergent generation of cardiovascular risk markers: a review

Objective: The present review was performed in order to bring together the current knowledge about the impact of intense physical exercise on cardiovascular function, especially on plasma levels of cardiovascular risk markers such as cardiac troponin T (cTnT), myeloperoxidase (MPO), amino-terminal pro-brain natriuretic peptide (NT-proBNP), C-reactive protein (CRP) and oxidized low-density lipoprotein (oxLDL). Methods: Data were collected using the PubMed database. The articles were chosen for their relevance and importance in the area of interest. Results: The literature describes numerous examples where physical exercise induces plasma variation for the markers studied. Intense physical effort increases the levels of cTnT, MPO and NT proBNP, whereas CRP and oxLDL levels tend to be decreased with regular sport activities. Conclusions: The present literature investigation confirms the fact that intense physical exercise has an impact on the plasma variations of the five cardiovascular risk markers studied. However, practising regular exercise remains one of the first strategies for the prevention of cardiovascular disorders.

Responders to Platelet-Rich Plasma in Osteoarthritis: A Technical Analysis

Purpose To evaluate the similarities and differences between the variety of platelet-rich plasma (PRP) formulations, preparation, and uses to try to determine the best responses for the treatment of knee osteoarthritis. Materials and Methods A comparison of the outcomes of randomized controlled trials (RCTs) included in the 3 most recent and high-quality meta-analyses to classify the different studies in 2 groups (bad responders group (BRG) and very good responders group (VGRG)). Results and Discussion From the 19 RCTs analyzed, 7 trials were included in the VGRG and 4 in the BRG. In VGRG, 1 or 2 injections were performed in 4/7 trials, time between injections was 2 to 3 weeks in 4/5 studies with many injections, volume injected varied from 2.5 to 8 mL, and single spinning technique was used in 5/7 studies. PRP classification was Mishra 4B and PAWP2Bβ in 5/7 studies. The use of PRP with leukocytes is only found in the BRG. Conclusion There is a lack of standardization in PRP preparation technique for knee osteoarthritis. However it appears that the use of a single spinning technique, a platelet concentration lower than 5 times the baseline, and avoidance of leukocytes should be preferred.

Tumor-induced osteomalacia: The tumor may stay hidden!

We report the case of a patient with severe muscular and articular tenderness that caused almost complete immobility. This subject had severe hypophosphatemia due to hyperphosphaturia. Fibroblast growth factor 23 (FGF-23) was abnormally high and the diagnostic of tumor-induced osteomalacia was made. Despite multiple tests, the tumor was not localized. In this report, we discuss different possible investigations to localize the tumor. Lastly, we review the potential therapy available when tumor is not found and can thus not be excised.

Identification of cardiac repercussions after intense and prolonged concentric isokinetic exercise in young sedentary people

Cardiopathies are the worlds leading cause of mortality and morbidity. Although rare, cardiovascular accidents can occur during intense and infrequent sporting activity, particularly among those who are unaware of their heart condition. The development of cardiospecific biochemical markers has led to a reconsideration of the role of biology in the diagnosis of cardiovascular illnesses. The aim of this study therefore was, through the use of cardiac biomarker assays, to highlight the impact of sustained physical effort in the form of intense and prolonged concentric isokinetic exercise and to research potential cardiovascular risks.

Hyaluronic acid and tendon lesions.

INTRODUCTION recently, the viscoelastic properties of hyaluronic acid (HA) on liquid connective tissue have been proposed for the treatment of tendinopathies. Some fundamental studies show encouraging results on hyaluronic acids ability to promote tendon gliding and reduce adhesion as well as to improve tendon architectural organisation. Some observations also support its use in a clinical setting to improve pain and function. This literature review analyses studies relating to the use of hyaluronic acid in the treatment of tendinopathies. METHODS this review was constructed using the Medline database via Pubmed, Scopus and Google Scholar. The key words hyaluronic acid, tendon and tendinopathy were used for the research. RESULTS in total, 28 articles (in English and French) on the application of hyaluronic acid to tendons were selected for their relevance and scientific quality, including 13 for the in vitro part, 7 for the in vivo animal part and 8 for the human section. CONCLUSIONS preclinical studies demonstrate encouraging results: HA permits tendon gliding, reduces adhesions, creates better tendon architectural organisation and limits inflammation. These laboratory observations appear to be supported by limited but encouraging short-term clinical results on pain and function. However, controlled randomised studies are still needed.