Tennis elbow – impingement at the common extensor origin? Case report
We thank Dr Knobloch and colleagues for raising questions of the influence of elbow position on the area with high blood flow seen in the common extensor origin and outcome measurement in patients with painful tennis elbow. The first question raised is if the grip strength with 900 elbow flexion might change as well as the grip strength with extended elbow changes in response to the intratendinous injection treatment. This question will be answered in an original article in the future.
The other question raised is if the area with high blood flow inside the area of structural changes seen on ultrasound examination is influenced by elbow position. One of the findings on ultrasound examinations of the common extensor origin is “tendon thickening”. We believe that this thickening in some cases is exposed to internal compressive forces. This belief is based on the findings we have made when we have performed ultrasound and colour Doppler examinations during elbow movement. When the elbow is flexed 70-800 there is plenty of space between the head of the radial bone and the lateral epicondyle but during extension of the elbow, the radius makes a movement towards the lateral epicondyle and there will be impingement of the area with structural changes and high blood flow (Figure 1a and 1c). The raised pressure in the thickened tendon due to impingement at the extensor origin will diminish the high blood flow (not detectable), and like on palpation (applying external compressive force), the patient will experience pain. To perform an intratendinous injection targeting the area with high blood flow, the blood flow must be visible on colour Doppler examination which is the case when the elbow is flexed 70- 800, not when the elbow is extended (Figure 1b and 1d). This theory of impingement at the common extensor origin in tennis elbow might be the explanation behind good results in arthroscopic debridement of the area. Other authors have also noted impingement during elbow arthroscopy, Mullet and colleagues classified their findings as degenerative capsular fold. We hope this case rapport is an acceptable answer to the question at the time being. Further studies of the biomechanical prosperities of the elbow and the effect on the soft tissue are highly indicated. Are some individuals more prone to develop recalcitrance painful tennis elbow?
 Zeisig E, Fahlstrom M, Ohberg L, et al. Pain relief after intratendinous injections in patients with tennis elbow: results of a randomised study. British journal of sports medicine. 2008 Apr;42(4):267- 71.
 Levin D, Nazarian LN, Miller TT, et al. Lateral epicondylitis of the
elbow: US findings. Radiology. 2005 Oct;237(1):230-4.
 Cummins CA. Lateral epicondylitis: in vivo assessment of arthroscopic debridement and correlation with patient outcomes. The American journal of sports medicine. 2006 Sep;34(9):1486-91.
 Mullett H, Sprague M, Brown G, et al. Arthroscopic treatment of lateral epicondylitis: clinical and cadaveric studies. Clinical orthopaedics and related research. 2005 Oct;439:123-8.