Page 131 - JSOM Spring 2020

An Ongoing Series

Achilles Tendinopathy

Pathophysiology, Epidemiology, Diagnosis,
Treatment, Prevention, and Screening

Joseph J. Knapik, ScD *; Rodney Pope, PhD 2
1

ABSTRACT
Achilles tendinopathy (AT) is a clinical term describing a non- laser therapy. Nonsteroidal anti- inflammatory medication and
rupture injury of the Achilles tendon where the patient presents corticosteroid injections may provide short-term relief but
with pain, swelling, and reduced performance and symptoms do not appear effective in the longer term. Eccentric exercise
exacerbated by physical activity. About 52% of runners ex- and shock wave therapies are treatments with the highest evi-
perience AT in their lifetime and in the United States military dence-based effectiveness. Prevention strategies have not been
the rate of clinically diagnosed AT cases was 5/1000 person-yr well researched, but in specific populations balance training
in 2015. The pathophysiology can be viewed on a continuum (soccer players) and shock- absorbing insoles (military recruits)
proceeding from reactive tendinopathy where tenocytes prolif- may be effective. Ultrasound scans might be useful in predict-
erate, protein production increases, and the tendon thickens; ing future AT occurrences.
to tendon disrepair in which tenocytes and protein production
increase further and there is focal collagen fiber disruption; Keywords: tendinitis; tendinosis; paratenonitis; ultrasound;
to degenerative tendinopathy involving cell death, large areas morning stiffness; palpation pain; nonsteroidal anti-
of collagen disorganization, and areas filled with vessels and inflammatory drugs; eccentric exercise; orthotics; bracing;
nerves. Inflammation may be present, especially in the early shock wave therapy; injection therapies
phases. Some evidence suggests AT pain may be due to neo-
vascularization and the ingrowth of new nerve fibers in asso-
ciation with this process. Prospective studies indicate that risk Introduction
factors include female sex, black race, higher body mass index,
prior tendinopathy or fracture, higher alcohol consumption, AT is a collective term used to describe a spectrum of changes
lower plantar flexion strength, greater weekly volume of run- within the Achilles tendon that gives rise to pain, localized
ning, more years of running, use of spiked or shock absorbing tenderness, swelling, and reduced performance. This disor-
1–3
shoes, training in cold weather, use of oral contraceptives and/ der is one of the most frequent overuse injuries reported in the
or hormone replacement therapy, reduced or excessive ankle literature and is prevalent among both recreational and elite
dorsiflexion range of motion, and consumption of antibiotics athletes and especially among runners and jumpers. A recent
in the fluoroquinolone class. At least 10 simple clinical tests are systematic review of running-related injuries found that AT
available for the diagnosis of AT, but based on accuracy and was the second most common injury (after medial tibial stress
reproducibility, patient self-reports of morning stiffness and/or syndrome) with incidence rates ranging from 9% to 11% of
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pain in the tendon area, pain on palpation of the tendon, and all runners. About 52% of former middle and long distance
detection of Achilles tendon thickening appear to be the most runners experience AT in their lifetime (i.e., lifetime preva-
useful. Both ultrasound and magnetic resonance imaging (MRI) lence) and 24% from a wide variety of sports will experience
are useful in assisting in diagnosis with MRI providing slightly it. Although individuals not involved in running and other
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better sensitivity and specificity. Conservative treatments that sport activities can experience AT, the age and occupation
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have been researched include: (1) nonsteroidal anti-inflam- adjusted risk among former athletes in one study was 5 to 7
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matory medication, (2) eccentric exercise, (3) stretching, (4) times higher than among healthy controls. In Belge military
orthotics, (5) bracing, (6) glyceryl trinitrate patches, (7) injec- officers in 6 weeks of basic training, 15% developed a clini-
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tion therapies (corticosteroids, hyaluronic acid, platelet-rich cally diagnosed Achilles tendon overuse injury and 11% of
plasma injections), (8) shock wave therapy, and (9) low-level conscripts developed AT during Norwegian basic training. 8
*Correspondence to joseph.knapik@JSOMonline.org
1 MAJ (Ret) Knapik ScD, served in the US military as a wheel vehicle mechanic, medic, Medical Service Corps officer, and Department of De-
fense civilian. He is currently a senior epidemiologist/research physiologist with the Henry M. Jackson Foundation and an adjunct professor at
Uniformed Services University (Bethesda, MD) and Bond University (Robina, Australia). Dr Pope is Professor of Physiotherapy at Charles Sturt
2
University and honorary adjunct professor with the Tactical Research Unit headquartered at Bond University, in Australia. Rod has spent much
of his 30-year career researching, practicing, and advising on injury risk management in military and other tactical populations.
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