Abstract :
[en] Introduction: The treatment of patellar tendinopathies could be difficult. This is the reason why new treatments have been developed, among which platelet rich plasma (PRP) injections. Some clinical series have previously evaluated the effect of PRP in the treatment of proximal patellar tendinopathies. Recent systematic review concluded that PRP could be recommend as a treatment in such indication (1). Recently, the viscoelastic properties of hyaluronic acid (HA) on liquid connective tissue have been proposed for the treatment of tendinopathies (2). Some fundamental studies show encouraging results on HA’s 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.
Purpose: We aimed to compare the effect of PRP injection versus two injections of HA after three months on patients who have a proximal patellar tendinopathy.
Methods: Eleven leisure football players with proximal patellar tendinopathies being not relieved after minimum three months of physiotherapy treatments where included. Six of them (group 1: 29.5±9.9 y.o.; 78.9±12.8kg; 177.4±6;9cm) have received a leukocyte poor PRP injection (obtained using an aphaeresis machine) under US guidance. This technique of PRP collection enable to obtain reproducible pure PRP with the same chosen concentration of 850 000 platelets/microliter. The other five subjects (group 2: 29.3±8.1 y.o.; 77.1±10.6kg; 178.1±5.8cm) received two HA 2% (40mg/2mL) injections (2mL) at one week apart. All of them have benefited of standardized rehabilitation, 3 times a week. Concerning the evaluation of the pathology, algo-functional tests (visual analogic scale (VAS), pressure algometer, IKDC score, VISA-P score), isokinetics (Cybex Norm; concentric 60°/s (C60), concentric 240°/s (C240) and eccentric 30°/s(E30)) associated to VAS, along with the patellar tendon ultrasonography (US) have been realized over three times (pre-injection, after 6 weeks, after 3 months post-injections).
Results: The results of VAS (p<0,01), algometric scores (p<0,01), IKDC scores (p<0,01) and VISA-P (p<0,01) show a considerable improvement in the two groups, but not for the US findings. For the group 1 (Table 1), isokinetic tests show significant results for the hamstrings in C60°/s with an improvement of maximum peak torque (p=0,01) for the pathological limb, a diminution (p>0,05) for the healthy limb and during the analysis of the bilateral difference (p=0,0002). For the group 2, the improvement of quadriceps maximum peak torque in C240°/s is significant (p>0,01) for the pathological knee after 6 weeks post-injections only. The VAS associated with isokinetic tests decreases significantly for all contraction modes after three months of study.
Conclusions: Both PRP and HA can improve the symptoms of proximal patellar tendinopathy, even if the results are slightly better in the PRP group.
