Aetiology

The aetiology of tendinopathy remains unclear and may be related to various factors.

• stresses caused by overuse
  • repetitive overload of the tendon beyond physiological threshold may cause either inflammation of its sheath or degeneration of its body or a combination of the two (1)
  • repetitive micro trauma within the physiological limits (with little time to heal) may lead to tendinopathy
• decreased vascularity and tensile strength with aging
• lack of flexibility
• muscle imbalance or weakness
• genetic predisposition
• endocrine disorders (1)

A variety of intrinsic and extrinsic factors have also been attributed to tendinopathy (2)

• intrinsic factors -
  • biomechanical abnormalities of the lower extremity e.g - leg length discrepancy hyperpronation, varus deformity of the forefoot, pes cavus and limited mobility of the subtalar joint
  • increasing age
  • systemic conditions e.g. - inflammatory arthropathies, diabetes, hypertension, obesity, gout, hyperostotic conditions, lipidaemias
  • drugs e.g. - corticosteroid use,aromatase inhibitors, and quinolone antibiotics
• extrinsic factors -
  • excessive mechanical overload and training errors e.g.- increased interval training, abrupt changes in scheduling, excessive hill training, training on hard or sloping surfaces, increased mileage, increased repetitive loading, poor shock absorption, and wedging from uneven wear (2)

Reference:

• (1) Lopez RG, Jung HG. Achilles tendinosis: treatment options. Clin Orthop Surg. 2015;7(1):1-7.
• (2) Li HY, Hua YH.Achilles Tendinopathy: Current Concepts about the Basic Science and Clinical Treatments. Biomed Res Int. 2016;2016:6492597.