Platelet-rich plasma (PRP) to treat chronic patellar tendinopathies: comparison of a single versus two closely-timed injections

Management of patellar tendinopathy: a systematic review and network meta-analysis of randomised studies

Objectives

We performed a systematic review and network meta-analysis (NMA) of randomised controlled trials (RCTs) to provide insights into the effectiveness of available treatment modalities in patellar tendinopathy(PT).

Methods

Several databases were searched in May 2021 for RCTs assessing the effectiveness of any intervention compared with any other intervention, placebo or no treatment for pain and/or function in PT. The risk of bias and strength of evidence were assessed with the Cochrane Collaboration and GRADE (Grading of Recommendations, Assessment, Development and Evaluations)/GRADE-NMA tools.

Results

A total of 37 RCTs were eligible that assessed 33 different interventions and their combinations, most represented by single studies. Based on pairwise meta-analyses of two RCTs, extracorporeal shockwave therapy (ESWT) does not appear to be superior to sham ESWT (eccentric exercise in both groups) for short-term pain (mean differences (MD) +0.1, 95% CI (−0.8 to 1), p=0.84) or function (MD −1.8, 95% CI (–8 to 4.4), p=0.57). Based on a pairwise meta-analysis of three RCTs, isometric exercise appears as effective as isotonic exercise for immediate postintervention pain relief (MD −1.03, 95% CI (−2.6 to 0.5), p=0.19). Our NMA showed that topical glyceryl trinitrate (GTN) and hyaluronic acid injection, both combined with eccentric exercise and moderate, slow resistance exercise had the highest probability of being the most effective interventions (low/very low strength of evidence).

Conclusions

Promising interventions with inadequate evidence, such as topical GTN, hyaluronic acid injections and isometric and slow resistance exercise, should be further investigated through high-quality RCTs. Meanwhile, eccentric loading with or without adjuncts should remain the first-line treatment for all individuals with patellar tendinopathy.

Platelet-rich plasma stimulates angiogenesis in mice which may promote hair growth

BACKGROUND

Platelet-rich plasma (PRP) is an autologous concentration of human platelets in plasma. In this paper, we aimed to investigate the effect of PRP on hair growth.

METHODS

Platelet-rich plasma and platelet-poor plasma were prepared by sterile centrifugation and injected into shaved dorsal skin of mice (n = 10). Saline injection was used in the control group. The length of randomly plucked hairs was measured at 8, 13, 18 days after PRP injection. Histological examination was preformed to observe the histologic changes of skins. The immunohistochemistry analysis of CD31 was performed to detect the changes of hair length and formation of new vessels.

RESULTS

At 13 and 18 days after the last injection, the hair length of mice in PRP group (4.24 ± 0.60 and 8.29 ± 0.48 mm, respectively) was significantly longer compared with the control group (3.70 ± 0.52 and 7.21 ± 0.64 mm, p < 0.05). No significant difference in the hair length was found between the PPP group and the control (p > 0.05). In addition, the number of CD31-positive vessel in the PRP group (9.90 ± 0.60) was more than that in the control group (8.60 ± 2.34, p < 0.05).

CONCLUSION

Platelet-rich plasma might promote hair length growth and increase the number of hair follicles by inducing angiogenesis.

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.