Exploring the effect of a second closely-timed PRP infiltration for tendinopathy

Introduction: Some clinical series have previously evaluated the effect of PRP in the treatment of proximal patellar tendinopathies. 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 successive infiltrations which is arguably likely to increase the risks of complications.
Methods: Our study is a single blinded, randomized controlled clinical trial on 20 leisure sportsmen (2 groups, respectively 1 or 2 infiltrations of pure PRP) with chronic proximal patellar tendinopathies, rebel to classical management. PRP was obtained using an aphaeresis machine. The one-year follow-up evaluation consisted of VAS, IKDC and VISA-P scores, while algometer, isokinetic and ultrasounds evaluations were carried out up to 3 months.
Results: The concentration of the PRP used was similar in both groups. The VAS significantly decreased with time over the 3-month follow-up period (p=0.002), with no difference observed between the two groups (p=0.2). Values obtained with the pressure algometer increased with time across both groups over the 3-month follow-up period (p<0.0001), and values were significantly higher for Group 1 (p=0.001). The IKDC score increased with time in both groups over the follow-up period (p=0.034), with values again significantly higher for Group 1 (p=0.0026). The VISA-P score increased with time in both groups over the follow-up period (p=0.0023), with no difference observed between the groups (p=0.41). No improvements in isokinetic physical performance were observed in either group. However, pain during E30 significantly decreased over the 3-month follow-up period (p=0.027) for patients in both groups. No improvement in either jumping performances or in pain was observed in either group during opto-jump evaluation. No improvements in US findings were observed. After one year, 90% patients of group 1 did not report anymore pain during daily activities, in comparison with only 20% in group 2.
Conclusions: A second closely-timed infiltration of PRP to treat proximal patellar tendinopathies is not necessary to improve the efficacy of this treatment.