Abstract :
[fr] Certaines tendinopathies (l’épicondylite, les tendinopathies d’Achille et rotulienne proximale ou Jumper’s knee) présentent une évolution désespérément rebelle et ce, malgré l’instauration de traitements « classiques » ; différentes thérapeutiques, régulièrement utilisées (repos, orthèse, AINS locaux ou per os, électrothérapie, kinésithérapie, mésothérapie, infiltration de corticoïdes, ondes de choc, intervention chirurgicale…), ne brillent guère par leur efficacité…
Dans le cadre d’épicondylites chroniques, certains travaux (avec ou sans contrôle échographique) rapportent, dans les suites d’une infiltration de sang autologue, une évolution favorable. Ce traitement permettait d’éviter une intervention chirurgicale. Diverses études soulignent les propriétés réparatrices des plaquettes qui, effectivement, pourraient accélérer la cicatrisation de différents tissus: os, muscles et tendons. Le plasma riche en plaquettes (platelet-rich plasma ou PRP) a initialement été utilisé en chirurgie maxillofaciale, en stomatologie et en chirurgie orthopédique. Cette technique pourrait représenter une thérapeutique d’avenir en médecine physique - traumatologie du sport. Mishra et Pavelko, les premiers, ont démontré que le PRP améliore la douleur de patients souffrant d’épicondylite chronique, rebelle aux traitements classiques. Les plaquettes contiennent divers métabolites et facteurs de croissance, libérés lors de leur dégranulation dans les suites de leur activation. Ces facteurs de croissance favoriseraient le remodelage tissulaire, la cicatrisation et l’angiogenèse. Actuellement, les effets du PRP restent toujours discutés voire controversés : les résultats cliniques sont parfois contradictoires même si son efficacité in vitro et sur animal apparait plus franche. Cette variabilité pourrait s’expliquer par l’absence de consensus relatif au mode de préparation du PRP, à la concentration plaquettaire (mais éventuellement aussi érythrocytaire et leucocytaire…), à la technique d’infiltration (activation ou non, avec ou sans contrôle échographique) et au protocole post-infiltration (repos, rééducation classique - excentrique…).
Notre travail appréciera l’efficacité du PRP sur la cicatrisation tendineuse de l’animal et de l’homme souffrant, notamment de jumper’s knee chronique. Nous souhaiterions standardiser le protocole de recueil et de concentration plaquettaire et celui de la rééducation post-infiltration afin d’optimaliser son usage clinique.
[en] Platelet-rich plasma (PRP) may represent a new therapeutic option for chronic tendinopathies. Platelets release various cytokines and growth factors which promote angiogenesis, tissue remodeling, and wound healing. We made an extended literature review of the use of PRP in chronic tendinopathies. Despite the proven efficacy of PRP on tissue regeneration in experimental studies, there is currently scanty tangible clinical evidence with respect to its efficacy in chronic tendon disorders. The few studies that have been performed appear unlikely to be comparable. Randomized controlled studies with appropriate placebo groups are needed to determine the real effectiveness of PRP for treating chronic musculoskeletal injuries.
After, we made a study to compare the platelet concentrations using 5 techniques of preparation of PRP and observed that each provides a very different PRP, with variations in the platelet concentrations and of the amount (if any) of erythrocytes and leucocytes. White blood cells could adversely affect wound healing through the release of proinflammatory factors responsible for extracellular matrix degradation. In addition, erythrocyte lysis releases free radicals that harm tissue structures. We thus think that ideal PRP should not contain any erythrocytes or leucocytes, and that the quality of the PRP could perhaps partially explain the variable results observed in the literature.
The aim of our next 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. We concluded that an injection of PRP in sectioned rat Achilles tendon influences the early phase of tendon healing and results in an ultimately stronger mechanical resistance.
Vascular endothelial growth factor (VEGF) is a platelet growth factor known to regulate angiogenesis. VEGF-111, a biologically active and proteolysis-resistant splice variant of this family, was recently identified. We made a study with the aim of evaluating whether VEGF-111 could have a therapeutic interest in tendon pathologies with the same rat protocol as our previous study. The force necessary to induce tendon rupture was greater for tendons of the VEGF-111 group (but less than the results obtained with the PRP in our previous study), while the section areas of the tendons were similar. The mechanical stress was similar at 5 and 15 days in both groups but was improved for the VEGF-111 group at day 30. No differences were observed in the mRNA expression of collagen III, tenomodulin and MMP-9.
Finally, we made a study, the aim of which was to evaluate the clinical status and the return to sports activities in patients with chronic upper patellar tendinopathies, up to one year after a single infiltration of PRP. Twenty patients with chronic upper patellar tendinopathy were enrolled. Assessments were made before infiltration of PRP, and 6 weeks, 3 months and 1 year after the infiltration, using a 10-point Visual Analogic Scale, clinical examinations with a pressure algometer, algofunctional scores (IKDC and VISA-P), functional assessments (isokinetic and optojump evaluations) and imagery (ultrasounds and MRI). The PRP was obtained with an apheresis system (COM.TEC, Fresenius). Six millilitres of PRP were injected without local anaesthetic. One week after infiltration, patients started a standardised sub-maximal eccentric reeducation. We observed that with time, during the 1-year follow-up, VAS dropped significantly and both IKDC and VISA-P scores improved also significantly. During functional evaluation, it decreased as well, but without significant functional improvement. No improvements in the imagery measurements were observed. Younger patients seemed to be more susceptible to have a relief of pain by the PRP infiltration. Seventy percent of the patients reported a favourable evolution with decrease of pain, 15% reported no improvement and 15% were treated surgically. Seventy percent returned to sports activities, 64,3% without any pain and 50% recovered the same sports level.
Even if 1 infiltration seems to be efficient in the indication of patellar tendinopathies, most studies evaluated the effects of 3 successive infiltrations. However, the multiplication of infiltrations risks increasing complications, and this treatment can be expensive. It seemed relevant to evaluate if 2 infiltrations of PRP would be more effective than only 1.Twenty patients suffering from jumper’s knee for more than 3 months were enrolled and randomized in 2 groups (1 or 2 infiltrations of PRP). The follow-up was made as follows: VAS, IKDC and VISA-P scores, algometer, isokinetic and ultrasounds evaluations. The concentration of the PRP used for each infiltration was similar in both groups, without any red or white blood cells. Results for all the evaluations did not show any difference between the groups. The comparison of 1 or 2 infiltrations of PRP did not show any difference between the 2 groups after a follow-up of 3 months. A second close infiltration of PRP to treat upper patellar tendinopathies is not necessary to improve the efficacy of this treatment in the short term. However, these results must be evaluated at a longer term.
