Abstract

It is frequently observed that midportion Achilles tendinopathy/tendinosis occurs bilaterally. With this as a background, the outcome of unilateral operations was evaluated in 13 patients (seven males and six females) with chronic painful bilateral midportion Achilles tendinopathy (tendinosis) (symptom duration: 6–12 months). Prolonged periods of rest did not have an effect. As surgical treatment, an ultrasound and Doppler-guided scraping procedure outside the ventral part of the tendon was performed in local anaesthesia, a method that recently has been found to be successful for patients with Achilles tendinosis. Surgical treatment was performed only on one side, the other side being left untreated. The patients started walking on the first day after surgery, and were followed over time. In an additional part of the study, specimens from Achilles and plantaris tendons in 3 patients with bilateral Achilles tendinosis were examined. Follow-ups showed postoperative improvement also on the non-operated side in 11/13 patients, and a final follow up after 37 (mean) months showed significant pain relief and patient satisfaction on both sides for these 11 patients. In 2/13 patients, operation on the other, initially non-operated side, was needed. Morphologically, it was found that there were similar morphological characteristics and similar immunohistochemical patterns concerning enzymes involved in signal substance production bilaterally, the microscopic findings being in line with previous information from tendinosis tendons. It can be concluded that the structural affections are similar on both sides in bilateral Achilles tendinosis. The study showed that unilateral operative treatment can also have benefits contra-laterally. A hypothesis is that unilateral influences on the sensory innervation in the peritendinous tissue in response to the scraping operation have secondary effects contralaterally, that is, influences on the pattern of primary-afferent activation on one side can have effects contra-laterally. The interpretation concerning a presumable cross-talk between right and left sides are in line with the results of recent experimental studies in animals showing that tendinosis-like features occur bilaterally in the Achilles tendons in response to unilateral overuse, suggesting that there is an involvement of central neuronal mechanisms. The observations of bilateral effects in response to unilateral treatment have clinical implications.