ReviewThe pathogenesis of Achilles tendinopathy: A systematic review
Introduction
The Achilles tendon is one of the most frequently injured tendons in the human body despite its strength [1]: it not only is the commonest tendon to rupture but also, along with the patellar tendon, it represents one of the two tendons most frequently impaired as a result of overuse [2]. Overuse is by definition a repetitive strain acting on a tendon, so that it can no longer endure stress and tension, but other factors may also play a role: the non-athletic population can be frequently affected [3], 30% of patients referred, do not regularly participate in sport [4]. Patients with Achilles tendinopathy commonly refers to pain in the tendon during initial loading, subsiding with continued activity; as the condition becomes chronic, pain can be persistent, resulting in activity curtailment or cessation [5], [6]. Infact Maffulli et al. [7] recently defined Achilles tendinopathy as a clinical syndrome characterized by three elements, pain, swelling and functional impairment, corresponding to the histological pattern of “tendinosis”, a term that indicates a degenerative non-inflammatory process with a disorganized collagen structure. However, it must be kept in mind that since up to 34% of asymptomatic tendons show histopathological changes [8]: this finding leads to suppose that the intratendinous degenerative changes may not be directly the cause of pain. So overuse is considered to induce the condition but the etiology and pathogenesis have not yet been scientifically clarified; the same is for the source of pain and the background of the pain mechanisms. Many different explanations have been raised and consequently the range of conservative and surgical treatment options is actually very wide [8]: a summary of the current hypotheses is provided, analyzing separately those concerning the pathogenesis of tendinopathy and those concerning the etiology of complaint in patients.
Section snippets
Materials and methods
Prisma guidelines were followed for this systematic review
Multiple databases, as PubMed, Google Scholar, Academic Search Complete, and Health and Wellness Resource Center, were searched for articles published between 1964 and 2013 concerning informations about the etiology of Achilles tendinopathy using the following search filter: “Achilles tendinopathy” and “Achilles pathogenesis” that identified a total of 480 articles dated from 1967 to 2013. The articles were combined into EndNote and
Etiology of intratendinous degenerative changes
It is widely acknowledged that causes of intratendinous changes could be divided into intrinsic and extrinsic factors; extrinsic factors play a major role in the acute lesions of the Achilles tendon, while most commonly will be a combination of both extrinsic and intrinsic factors in chronic tendinopathy [9].
According to the intrinsic risk factors, 68 articles describe the various risk factors involved [8], [10], [11], [12], [13], [14], [15], [16], [17], [18], [19], [20], [21], [22], [23], [24]
Discussion
The pathogenesis pathways of Achilles tendinopathy is heterogeneous (Fig. 1). Various risk factors have been identified: the aim of their identification is to develop and implement prevention strategies, since the extent of Achilles tendon injuries calls for preventive measures [39].
The highest incidence of Achilles tendinopathy is usually reported to occur in middle-age people (30–55 years old) [13]. Age is commonly associated with increased prevalence of degenerative changes, such as
Conclusions
In summary it should be kept in mind that, although loading history and individual factors may influence the onset and amount of tendon pathology, these are not generally considered when developing a treatment plan for painful tendons [138]. The goal of treatment of patients with chronic Achilles tendinopathy is to relieve pain. According to the finding that inflammation plays a role in the early phases of the disease [94] non-steroidal anti-inflammatory drugs and steroids may be beneficial,
Conflict of interest
None
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Imaging of Overuse Injuries of the Ankle and Foot in Sport and Work
2023, Radiologic Clinics of North AmericaScavenging of reactive oxygen species can adjust the differentiation of tendon stem cells and progenitor cells and prevent ectopic calcification in tendinopathy
2022, Acta BiomaterialiaCitation Excerpt :For example, mechanical loading may moderate tendon calcification via mTORC1 pathway [11], and inhibiting mTORC1 pathway can block osteogenic differentiation of tendon cells [12] and suppress calcification in a rat model of tendon heterotopic ossification [13]. The pathological mechanism underlying calcific tendinopathy remains elusive [3,7,14-16]. Interestingly, tendon stem/progenitor cells (TSPCs), tendon-resident mesenchymal cells [17,18], may differentiate into osteoblasts and chondrocytes in an inflammatory environment, resulting in disrupted tendon healing and heterotopic calcification [12,19-21].
Prevalence of Achilles tendinopathy in physical exercise: A systematic review and meta-analysis
2022, Sports Medicine and Health ScienceCitation Excerpt :Achilles tendinopathy (AT) is one of the most common injuries in physical exercise (PE), especially happens to athletes who are always engaged in long-term, continuous and high-intensity competition or training.1 AT is a degenerative disease,2 including tendinitis, accessory tendinitis, insertion tendinitis, retrocalcaneal bursitis and rupture,3 which is caused by the interaction of internal factors (e.g., lateral ankle instability, obesity, lower limb strength) and external factors (e.g., overuse, wrong training method, unsuitable sports equipment).4 The early symptoms of AT are mainly pain at the beginning or end of the exercise, and without movement at an advanced stage, which greatly affects the daily life of patients.5
- 1
Carlo Poma Hospital, Department of Orthopaedic and Traumatology, Strada Lago Paiolo 10, 46100 Mantova, Italy.