Who most needs to pay attention to this issue?

Lateral epicondylitis (tennis elbow) has an incidence of about 1% to 3% and is most common in adults aged 40 to 55, often linked to repetitive wrist extension and gripping. Although most patients recover on their own within a year, those with persistent pain and dysfunction more often need active evaluation of how to intervene.

What are the common treatments or management options?

Traditional approaches include oral non-steroidal anti-inflammatory drugs, local icing, rehabilitation, or corticosteroid injection, which can ease symptoms in the short term. In recent years, platelet-rich plasma (PRP) injection, rich in growth factors, has become an alternative option; the 2025 randomized controlled trial cited here found that PRP produced more durable functional improvement in the study. The actual choice still depends on your condition and a physician's assessment.

When should you seek medical evaluation?

If pain on the outer side of the elbow persists for more than 3 months and affects everyday grip strength or work function, medical evaluation is advised. The study also cautions that when tracking treatment outcomes, one should not over-rely on ultrasound blood-flow imaging; functional assessment tools such as DASH and PRTEE better reflect actual recovery.

Tennis Elbow After PRP Injection: Tracking Recovery on Ultrasound

Lateral epicondylitis, commonly known as tennis elbow, is a common tendon-attachment disorder with an incidence of about 1% to 3%, most often seen in adults aged 40 to 55. It is linked to repetitive wrist extension and gripping, which cause microtears and inflammation of the forearm extensors at the lateral epicondyle of the humerus. Although most patients recover on their own within a year, for those with persistent pain and dysfunction the medical field continues to look for the best way to intervene.

Traditional treatments such as oral non-steroidal anti-inflammatory drugs, local icing, rehabilitation, or corticosteroid injection can ease symptoms in the short term, but their long-term effectiveness and potential side effects have come under growing scrutiny. As a result, platelet-rich plasma (PRP) injection, rich in growth factors, has gradually become an alternative option and has been widely studied in recent years. However, most clinical evaluations focus on symptom improvement, and whether it is accompanied by improvement in tissue structure remains debated.

A randomized controlled trial published in 2025 by the Istanbul University Faculty of Medicine directly examined the clinical and ultrasound-imaging differences between PRP, corticosteroid, and saline injections in the treatment of lateral epicondylitis. Its results not only highlight the advantage of PRP therapy in functional improvement, but also illustrate the phenomenon of a temporary decoupling between imaging markers and symptom improvement.

Study design

PRP is an autologous blood product in which platelets and growth factors such as PDGF, TGF-beta, and VEGF are concentrated after centrifugation; in theory it can promote repair and remodeling of tendon tissue. Unlike corticosteroid, which works mainly by suppressing the inflammatory response, PRP is thought to activate repair cells and stimulate collagen synthesis, giving it the potential for longer-lasting repair.

In this study, a total of 50 patients (55 elbows) aged 18 and over with symptoms lasting more than 3 months were enrolled; after 14 were lost to follow-up, 36 patients were included in the final analysis, and those with concurrent neuropathy or a surgical history were excluded. Participants were randomly assigned to three groups: PRP injection, corticosteroid injection, and saline (placebo control). All three groups received only a single injection and were followed for 6 months, during which three assessment tools were used to evaluate clinical outcomes:

VAS visual analog pain scale
PRTEE (a tennis-elbow-specific self-report scale)
DASH (Disabilities of the Arm, Shoulder and Hand scale)

In addition, all patients underwent high-resolution ultrasound and Superb Microvascular Imaging (SMI) before and after treatment to assess changes in tendon blood flow and neovascularization index, so as to quantify imaging changes objectively.

PRP’s superior clinical effect

For the clinical assessment, the results showed that the PRP injection group had significantly greater improvement than the other two groups at both 3 and 6 months. Taking the PRTEE score as an example, the PRP group dropped from a baseline mean of 48 to 19, significantly better than the corticosteroid group (34) and the saline group (47). On the DASH functional assessment, the PRP group also fell from 48 to just 13.7, an improvement of over 70% that reached the threshold for a minimal clinically important difference (MCID).

Notably, corticosteroid injection also showed some short-term (3-month) pain relief (VAS dropped to 4.1), but by 6 months it showed a rebound trend (rising to 4.4), reflecting its short-lived effect and tendency to recur. The saline group showed only minimal improvement, and several patients even dropped out midway to switch to other treatments.

These findings support prior literature reporting that PRP is more durable than corticosteroid; for example, the study by Gosens and colleagues also found that PRP continued to outperform corticosteroid in pain relief and functional improvement over 2 years.

Ultrasound and blood-flow imaging cannot predict outcomes for now

Although PRP stood out on the clinical measures, the corresponding ultrasound imaging did not show consistent improvement. In this study, none of the three groups showed a statistically significant difference in ultrasound Doppler blood-flow grade or SMI blood-flow index before and after treatment. Although the PRP group’s SMI value fell from 12.4 to 7.06, the difference did not reach significance (p=0.2). Likewise, the blood-flow changes in the corticosteroid and saline groups showed no clinical relevance.

This pattern of clinical improvement alongside stable imaging echoes observations by earlier researchers. Using contrast-enhanced ultrasound, Chaudhury and colleagues found that PRP can increase neovascularization, but the change takes several months or more to appear and varies greatly between individuals. Furthermore, tendon thickness and blood flow are strongly influenced by age, sex, and daily activity, making them hard to use as a single tracking metric.

Therefore, the study’s conclusion reminds clinicians to interpret imaging follow-up cautiously and not to over-rely on blood-flow markers when judging treatment outcomes. Functional assessment tools such as DASH and PRTEE better reflect a patient’s actual recovery.

Trade-offs between outcome and cost

In this study, PRP showed significant and durable pain relief and functional improvement in patients with moderate to severe lateral epicondylitis; these are trial results and do not predict individual outcomes. Its advantage lies in promoting tendon repair rather than merely suppressing symptoms, which may help lower the risk of recurrence.

However, its cost and technical demands also limit its widespread use. PRP requires a professional preparation and injection process, putting it at a disadvantage compared with corticosteroid in terms of affordability and accessibility. The study’s limitations are also worth noting: a small sample size (36 cases), treatment not performed under ultrasound guidance, and a single-blind design, which may have affected patients’ subjective assessment of the effect. In addition, the lack of long-term follow-up and work-function measures means that judging PRP’s long-term cost-effectiveness still requires further research.

Summary

This study highlights an important medical phenomenon: imaging does not necessarily reveal the true clinical change. As a regenerative therapy, PRP did not show changes on ultrasound imaging at first, yet it had a profound effect on patients’ quality of life, pain control, and functional recovery.

For clinicians, this is a reminder that we cannot rely on imaging numbers alone to make decisions, but should assess treatment outcomes comprehensively from multiple angles (subjective symptoms, functional scales, and psychological state). In the future, as imaging technology and biomarkers advance, we may be able to track PRP’s effect at the tissue level more precisely, further optimizing when and where it is used.

References

Controlled Trial. Medicina. 2025;61(5):894.
J Sports Med. 2011;39(6):1200–1208.