Injections of platelet-rich plasma (PRP) or saline yield the same degree of pain reduction in patients with recently developed epicondylitis, suggesting that tendon stimulation may be the actual mechanism behind lesion repair, according to a study presented here at the 2014 Annual Congress of the European League Against Rheumatism (EULAR).
Presentation title: Treatment of Epicondylitis by Ultrasound-Guided Local Injections of Autologous Conditioned Plasma (ACP®): A Double-Blind Placebo-Controlled Randomized Clinical Trial With 1-Year Follow-Up. Abstract OP0013
“The efficacy of each treatment may be linked to a stimulating role of ultrasound-guided intra-tendonous injections, or prolotherapy, on the process of tendon repair,” said lead investigator Patrick Le Goux, MD, Hôpitaux Universitaires Paris Ile-de-France Ouest, Boulogne-Billancourt, France, on June 11.
There are two variants of epicondylitis. Lateral epicondylitis (tennis elbow) occurs where the tendons of the forearm muscles attach to the bone on the outside of the elbow, and medial epicondylitis (golfer’s elbow) occurs where the tendons attach to the bone on the inside of the elbow.
There was good scientific rational for testing PRP, which is known to contain growth factors that stimulate natural repair of cartilage and has been used successfully in cartilage injuries of the knee and ankle, Dr. Le Goux noted.
He and colleagues observed 50 patients (25/group) who had epicondylitis of ≤3 months duration confirmed by magnetic resonance imaging and/or ultrasound to rule out other potential causes of pain.
Each patient received 2 injections that were administered in a blinded and identical manner using a dual-chamber syringe that perforated 3 layers into the tendon to target the lesion without entering it. Patients were evaluated for the variation in pain score from baseline using a visual analogue scale (score range, 0-10).
At 6 months after 2 injections of either PRP or saline administered at 4-week intervals, the researchers observed no difference in pain reduction between treatment groups; pain score reductions were -54.7% with PRP and -63.6% % with saline (P = .24).
Both groups showed significant decreases in pain scores from baseline of 6.8 (±0.8) with PRP and 7.0 (±1.0) with saline at 6 months and of 1.65 (±1.5) and 1.8 (±2.1) with PRP and saline, respectively, at 12 months. No significant difference between the treatment groups was shown, however.
At 6 and 12 months, respectively, 34% and 66% of all patients were asymptomatic. The proportion of patients with persistent pain at 12 months was equivalent, at 23.8% in each group.
Three patients in each arm withdrew from the study within 6 months but not due to treatment-related adverse events. No adverse events were reported.
The mean values of Roles-Maudsley scores were decreased by 1.5 points in both groups at 12 months.
Dr. Le Goux commented that a limitation of the study was the lack of a control group (a no-injection group) with which to compare the pain reduction observed over time with natural healing.
“Local injections of corticosteroid represent a standard of care for epicondylitis, but there are no guidelines, and a recent report indicated that these injections may impair the healing process,” Dr. Le Goux remarked.