Clinical risk factors for Achilles tendinopathy – Threshold Physical Therapy and Performance

The British Journal of Sports Medicine (BJSM) recently published an ahead-of-print systematic review on the clinical risk factors for Achilles tendinopathy…

While the Achilles tendon is the largest and strongest tendon in the human body, it is still prone to injury. As the authors noted, Achilles tendinopathy is indicated by the presence of Achilles tendon pain, swelling, and an impaired load-bearing capacity. Interestingly, elite running athletes have a 52% lifetime risk of Achilles tendinopathy but, at the same time, a third of all patients with it have a sedentary lifestyle. Possibly a U-shaped curve?

Worth noting, while previous research indicated a relationship between BMI, body weight, or waist circumference and tendon pathology, the BJSM systematic review was not able to find this association. That being said, there is a lack of high-quality prospective studies investigating factors for Achilles tendinopathy, and the majority of the cohort studies investigating BMI as a risk factor were in adolescent populations.

The review pulled together 10 cohort and 45 cross-sectional studies with 296 total risk factors. While the evidence is limited, there were nine risk factors worth noting:

Prior lower limb tendinopathy or fracture
Training during cold weather
Use of ofloxacin antibiotics
Increased time between heart transplantation and initiation of quinolone treatment for infectious disease
Moderate alcohol use (7-13 units/week for males; 4-6 units/week for females)
Creatinine clearance of <60 mL/min in heart transplant patients
Decreased isokinetic plantar flexor strength
Abnormal gait pattern with decreased forward progression of propulsion
Increased lateral foot-roll over at the forefoot flat phase

Conflicting Evidence?

Mixed evidence on whether age affects the risk
…on how sex (male or female) may affect the risk
…that decreased non-weightbearing ankle dorsiflexion (<11.5 degrees with knee extension) is associated

No Associations? Limited evidence that:

…height does not affect the risk
…BMI or body weight do not affect the risk
…smoking is not associated
…physical activity level, physical activity performance, or hours of sports participation do not affect risk
…the type of shoes is not associated
…the amount of external rotation of the hip is not associated

Provided the studies that were available for review (and per the authors), it is important to keep in mind that most of the studies may have been too underpowered to detect associations.

Are you dealing with foot, ankle, or Achilles pain? Get into your local physical therapist for an evaluation and get those symptoms under control! Thanks for reading!