There are multiple peer-reviewed randomized trials and meta-analyses of PRP for chronic musculoskeletal injuries, especially tendinopathies and chronic pain, with generally mixed but overall favorable long-term results in selected indications, emphasizing clinical relevance for practitioners.

Key chronic tendinopathy RCTs

Achilles tendinopathy: A double-blind RCT of 54 patients with chronic mid-portion Achilles tendinopathy showed that both PRP and saline groups improved substantially in VISA-A scores at 24 weeks, with no significant difference, indicating limited added benefit from a single PRP injection over eccentric rehab in this protocol, which is essential for clinical decision-making.
Rotator cuff tendinopathy: An RCT with 1-year follow-up in chronic rotator cuff tendinopathy reported that PRP injections produced significant improvements in pain and shoulder scores over time, but in some analyses did not clearly outperform control treatments, underscoring heterogeneity across shoulder trials.

Lateral epicondylitis and patellar tendinopathy

Lateral epicondylitis (tennis elbow):
- Several RCTs and systematic reviews show conflicting results; at least one meta-analysis concludes there is strong evidence that PRP is not superior to placebo for chronic lateral elbow tendinopathy, whereas more recent systematic reviews and network analyses suggest PRP can provide better long-term pain relief and functional improvement than corticosteroid injections, which tend to give only short-term benefit.
Patellar tendinopathy: A 2024 randomized trial in chronic patellar tendinopathy found that PRP injection improved pain over 1 year compared with needle tenotomy and sham, with higher responder rates in the PRP group.

Broader chronic musculoskeletal pain data

A 2025 systematic review of PRP for chronic noncancer pain (including tendinopathies and some spine-related pain) found moderate pain reduction versus active drug treatments in pooled analyses, with acceptable safety and mostly transient post-injection soreness.
A 2022 review on PRP in musculoskeletal medicine concluded that PRP may be effective for certain chronic pain conditions such as discogenic low back pain, radicular pain, facet joint pain, and peripheral tendinopathies. Still, it emphasized the need for standardized preparation, dosing, and high-quality‑RCTs.

Overall takeaways

The evidence is strongest for some chronic tendinopathies (patellar, certain rotator cuff, and elbow cohorts) where PRP can offer better long-term outcomes than corticosteroids and, in some cases, standard care. Still, results for Achilles and lateral epicondylitis are mixed and protocol‑dependent.
Meta-analyses note that platelet concentration, leukocyte content, number of injections, and concurrent rehab significantly influence outcomes, and that PRP should be positioned as a second-line option after structured conservative therapy in chronic musculoskeletal pain.