Effectiveness of Reducing Tendon Compression in the Treatment of Insertional Achilles Tendinopathy

Insertional Achilles tendinopathy is a disabling injury that is common in running athletes. Exercise therapy is considered the best treatment option, but there is still no agreement on the modalities. For example, it is thought that compression overload may be a major cause of tendinopathy and should therefore be restricted during rehabilitation. However, this recommendation is based on expert opinion and not on hard scientific evidence. Therefore, this randomised controlled trial (RCT) will investigate whether a therapy that limits the amount of compression of the tendon during a progressive tendon-loading rehabilitation protocol actually has better outcomes in athletes with insertional Achilles tendinopathy.

Athletes with insertional Achilles tendinopathy will be randomised into two treatment groups; (1) an experimental rehabilitation protocol in which the amount of tendon compression is limited and (2) a control rehabilitation protocol in which the amount of tendon compression is not limited and is rather high. Both treatments consist of supervised progressive tendon-loading exercise therapy and patient education. In addition, the experimental group will also receive heel inserts to limit the amount of dorsiflexion during sports or daily activities. At baseline, at 12 weeks (end of intervention) and at 24 weeks (follow-up), pain, functionality, structure and intratendinous pressure will be determined.

Achilles tendinopathy is a debilitating injury that is common among athletes, especially those involved in running sports. Around 30% of all runners exhibit Achilles tendinopathy with an annual incidence of 7-9%. Of these patients, roughly one-third will have insertional Achilles tendinopathy (IAT). Several mechanisms are considered to play a role in the aetiology of Achilles tendinopathy, yet a prominent role seems present for excessive overload. Traditionally, the nature of this overload is thought to be purely tensile. However, the Achilles tendon can also be exposed to compressive loads at the insertion when the tendon wraps around the posterior prominence of the calcaneus during dorsiflexion of the ankle. The formation of fibrocartilage-like tissue, which is typically found in histological examination of tendinopathy, can be considered as an adaptation to this compressive load, driven by the tenocyte's mechanotransduction process. Therefore, it is recommended to reduce the amount of compressive load on the tendon during rehabilitation while exerting sufficient tensile load. However, these recommendations are mainly based on a pilot study and expert opinion. Therefore, this RCT investigates whether a therapy in which the amount of tendon compression is restricted during a progressive tendon-loading rehabilitation protocol actually has better outcomes in terms of pain scores, functionality and structure of the Achilles tendon in athletes with insertional Achilles tendinopathy. Limiting the amount of tendon compression on the Achilles tendon insertion will be achieved by (1) patient education, (2) heel inserts and (3) an adapted exercise regimen.

Eligibility Criteria:
Inclusion Criteria:

* Age 18-60 years old
* Diagnosed with insertional Achilles Tendinopathy by a sports medicine physician
* Have experienced symptoms for more than 3 months but less than 3 years
* A severity level of less than 80 points on the VISA-A score
* Playing running-based sports at least twice a week
* Able to comply with both exercise programs

Exclusion Criteria:

* Have a history of Achilles tendon rupture or surgery
* Have other disorders of the Achilles tendon or ankle (mid-portional Achilles tendinopathy, paratenonitis, osteoarthritis,...)
* Have rheumatological disorder (e.g. Spondylitis Ankylosis)
* Have metabolic or endocrine disorders, such as type I or type II diabetes
* Have had an Achilles injection in the past 3 months
* Have other conditions that prevent following an active exercise programme
* Have already been treated with physiotherapy, shockwave therapy or orthotics in the past 3 months
* Medication use with (fluoro)quinolones antibiotic in the past 2 years
* Currently pregnant