In 1995 I suffered from midportion Achilles tendinosis on the left side. Ultrasound examination showed a thickened Achilles midportion (11 mm) with structural abnormalities located on the ventral side of the tendon. I was a recreational runner and couldn�?´t run because of severe tendon pain. Conservative management with rest and alternative training for 3-4 months was without effect on the painful condition. At that time, on our clinic patients with this condition were treated with open surgery (central longitudinal tenotomy, excision of macroscopically abnormal tendon tissue), followed by immobilization in a cast for 6 weeks and altogether a 4-6 months rehabilitation period. The chief at our clinic, Professor Ronny Lorentzon, refused to operate my Achilles because at that time I was needed in the daily clinical work. Instead I had to look for an alternative non-surgical method, and found the proposal raised by Curwin and Stanish, saying that eccentric training should be included in the treatment of chronic tendon conditions. I tried the eccentric exercises over a step, and found these exercises very painful to perform. The pain actually got worse during the first week of training, but then it subsided and I could add more load before it again was painful to perform the exercises. Interestingly, I found that I gradually could load more and more, and after althogether about 6 weeks I was more or less pain-free and could go back to light jogging. The good results achieved with this painful treatment method on my own Achilles was the start of our research on eccentric training as a treatment model for patients with chronic painful midportion Achilles tendinosis. “If Professor Lorentzon had not refused to operate my Achilles, we would never have started this research”.
Painful Eccentric Calf Muscle Training
Our group designed an eccentric training regimen to be tried on patients suffering from chronic painful midportion Achilles tendinosis, and at the waiting list for surgical treatment. First, a pilot study on 15 patients was done [
1]. The training program included eccentric training over a step-3x15 reps with straight and flexed knee performed 2 times/day, 7 days/week, for 3 months. Very unexpected, all patients were satisfied with the treatment, and didn�?´t want to have surgery. After one year, one patient had regained pain symptoms and this patient was surgically treated. All the other 14 patients were still satisfied and active in Achilles tendon loading activities at 10 year telephone follow-ups. The results of this pilot study were much better than we ever had expected, and because there were no complications like partial or total ruptures, despite this relatively tendon demanding type of treatment, we were not worried to go on and use the method in larger patient groups. After this pilot study we performed more studies on the effects of painful eccentric training for patients with chronic painful midportion Achilles tendinosis [
2,
3]. Overall the results were very good, with around 80% satisfied and pain-free patients. However, it was obvious that high level athletes, especially spike shoe runners and jumpers, had less good results with this treatment. Also, we found it to be of significant importance to establish that the patients had a correct diagnosis before this treatment was instituted. A partial rupture has to be excluded, because eccentric training on a patient with a partial rupture can cause a worsening, possibly a lengthening of the Achilles tendon, a condition that is very difficult to treat. An interesting observation was that in the successfully treated patients the tendon thickness decreased over time, and the structure looked more normal sonographically [
4,
5]. Interestingly, it seems that eccentric calf muscle training has a potential to remodel, and possible also regenerate, the tendinosis tendon. The ultrasound follow-up findings, together with the tolerated high eccentric loads, show that the tendinosis tendon is not a so-called degenerative and weak tendon. It might very well instead be a strong tendon? The new concept of painful eccentric loading of chronic painful tendons created a worldwide high interest, and for physiotherapists this was a new and potentially very helpful tool for treatment of this difficult condition. The good results achieved from our research group were re-produced by several groups in different countries.
New Research
The successful results using painful eccentric training as treatment for the chronic painful midportion Achilles were not expected, and more or less against previous thinking on treatment of chronic painful tendons. To try to better understand the pain mechanisms involved in the chronic painful midportion Achilles extensive research was started.
Using ultrasound+Doppler examinations we found high blood flow inside and outside ventral side in chronic painful midportion Achilles tendinosis tendons, but not in normal tendons [
6]. In a following study ultrasound+Doppler-guided biopsies was taken from the region with high blood flow inside and outside the Achilles midportion, and immunohistochemical analyses of these biopsies showed nerves in close relation to blood vessels outside the tendon, but very few nerves inside the tendon [
7]. Interestingly, there were mainly sympathetic, but also sensory, nerves [
8]. Following ultrasound+Doppler-guided injections of small volumes of the local anaestetic xylocain+Adrenaline, targeting the regions with high blood flow outside the tendon, temporarily cured the tendon pain [
7].
Ultrasound+Doppler-guided Sclerosing Polidocanol Injections
Based on our new research findings, a new treatment method was invented-ultrasound+Doppler-guided injections of the sclerosing substance polidocanol, targeting the regions with high blood flow outside the tendon. This type of treatment showed good clinical results in pilot studies and in a randomized placebo-controlled study [
9,
10]. Following ultrasound+Doppler follow-ups showed decreased tendon thickness and improved structure over time [
11], showing a high potential in the soft tissues outside the ventral side of the Achilles tendon. The limitations with ultrasound+Doppler-guided polidocanol injections are that it is technically demanding, having a relatively long learning curve, and that multiple [
2,
3] injection treatments are needed for a good clinical result.
Ultrasound+Doppler-guided Mini-surgical Scraping
Recently, a mini surgical scraping treatment was invented. Guided by the ultrasound+Doppler findings a minor surgical procedure, done in local anaestesia, were the ventral side of the tendon was scraped in the regions with high blood flow and nerves, was performed [
12]. This is a one stage and more radical approach than the polidocanol injection treatment. Because there is no intra-tendinous trauma, a relatively fast (4-6 weeks) rehabilitation can be used. The clinical results are very good without any side major effects, and the use of this method has been increased to large numbers of patients on different activity levels, also including professional athletes [
13]. Interestingly, the sometimes nearby located plantaris tendon occasionally seems to be involved in the painful condition. These patients have medial side pain, and often respond poor to eccentric training. Therefore, the surgical technique was modified to always use a medial approach for accurate evaluation of a possible interference between the plantaris and Achilles tendons [
14,
15]. Also using this method, ultrasound+Doppler follow-ups have shown a decreased tendon thickness and a more normal structure over time (submitted).
