# Ultrasound-Guided Procedures in Common Tendinopathies at the Elbow: From Image to Needle
## 3 Common Elbow Pathologies
### Tennis Elbow
#### 3.1.2 US scanning and Guided Injection
[41] reported a significant reduction in (visual analogue scale) VAS pain after SS injection, even after one year following administration. The authors also reported a substantial improvement in functional scores. The outcomes in the SS injection group were better than in the noninvasive group. [PERSON] et al. [42] in their meta-analysis reported that 9 out of 10 (randomized controlled trial) RCTs showed no statistically significant difference between SS application and other solution injections such as platelet-rich plasma (PRP), autologous blood (AB), corticosteroids (CS), and botulinum toxin (BT). The most common agents to treat lateral epicondylis are corticosteroids. [PERSON] et al. [43] reported a better effect from shockwave therapy with CS injection regarding VAS and grip strength after 12 weeks follow up. Another option for the treatment of the tennis elbow would be PRP injection. Platelet-rich plasma is an autologous preparation from patients' blood that can enhance the healing process. [PERSON] et al. [44] found no difference in improvement in pain and joint functionality comparing PRP with placebo (SS). Several meta-analyses compared PRP and CS injection effects. Corticosteroids injection provided better outcomes regarding pain and joint function in the short term (4 to 8 weeks after application), while PRP injection improved pain and function in the long-term (6 months to one year) more effectively [45; 46; 47; 48]. As an alternative, AB collected from the patient's peripheral veins can also be administered into the tendon. Application of AB might enhance tissue healing. A meta-analysis by [PERSON] et al. [49] suggested that AB is more effective at decreasing pain than CS injection, but there was no significant difference between AB and  
Figure 4: Ultrasound (US) images of the CET: (**a**) normal image, (**b**) a simple thickening and hypoechogenicity of the CET, (**c**) US image demonstrating a prominent spur (white asterisk) on the tip of the lateral epicondyle (LE) and focal hypoechogenicity in the tendon (white arrow), (**d**) a severe swelling of the CET with increased vascularity on power Doppler, (**e**) a mild swelling of the CET with intrasubstance hyperechogenicity indicating an immature calcification (white arrowhead) without acoustic shadowing, and (**f**) a US-guided peritendinous CET injection showing the needle (white, dotted arrow) being inserted from medial to lateral in a short axis of the CET. PRP. According to [PERSON] et al. 's [50] meta-analysis, AB can improve pain disability scores but has a higher risk of complications than PRP. [PERSON] et al. [51] accessed the use of botulotoxin as a possible method of treating tennis elbow in their meta-analysis. They reported a decrease in pain at 3 months follow up. The authors concluded that BT injection in the forearm might be a suitable treatment method for chronic recalcitrant tennis elbow. One of the technical variants to perform the tennis elbow injection is the same as for the examination in the supine position. The transducer is positioned on the lateral epicondyle perpendicular to the long axis of the forearm. The needle is inserted from lateral to medial (Figure 4f). Depending on the particular procedure plan, the needle tip can reach the peritendinous space or the tendon itself to perform intralesional (e.g., PRP) injection. The approach mentioned above allows the needle course to be parallel to the probe thus providing excellent needle visibility. Alternatively, the needle can be administered from distal to proximal (Supplementary Materials Video S1) or vice versa. When injecting the tennis elbow, potentially vulnerable structures include the anterior branch of the deep brachial artery and the deep branch of the radial nerve. Using US guidance can reduce the risk of iatrogenic injury to the structures mentioned above.