Abstract

Background: Treatment of chronic painful tennis elbow is known to be difficult, and the source of pain has not been clarified. A recent study has shown that the fibrous layer on the superficial side of the extensor origin is rich in sensory nerves. This study aimed to evaluate the effects on grip pain and strength after targeted injections of a local anesthetic, in patients with chronic painful Tennis elbow.
Material: Fourteen patients (6 men, mean age 60 years and 8 women, mean age 43 years) with clinical and US-verified changes corresponding to the diagnosis Tennis Elbow in 15 elbows, were included. All had had a long duration (average 19 months, range 6-48 months) of pain symptoms and undergone multiple different treatments without effect.
Methods: A US-guided injection of 1-1.5ml Polidocanol (10mg/ml) was placed targeting the region with high blood flow in the fibrous tissue layer on the superficial side of the extensor origin. Grip pain and strength during a standardized dynamometer test was evaluated on a 10cm VAS scale, before and 15 minutes after injection.
Result: In 12/14 patients (13/15 elbows) there was decreased pain during gripping (VAS from mean 7 (SD 1.3) to mean 2.5 (SD 1.6), p<0.05), and increased strength during straight arm test (from mean 30kg (SD 10.7) to mean 39kg (SD 13.5), p<0.05).
Conclusion: In patients with Tennis elbow, there were significant effects on pain and grip strength after US-guided injections of a local anesthetic targeting the nerve rich fibrous layer on the superficial side of the extensor origin. These findings might have implications for treatment.

Keywords:Tennis elbow; Anesthetic injections; Straight arm test; Sensory nerves; Achilles; Patellar tendinopathy