Tendinopathy or Posterior Tibial Tendon Dysfunction? A Condition Like No Other (Part 1/2)
Have you ever heard of flat feet developing in adults? This is actually an observed consequence of stage II posterior tibial tendon dysfunction. This will likely be one of the only articles published by The Running Clinic that will state that having a flat foot is problematic! Actually, it is not so much having a flat foot that is problematic, but instead the reason why it appears that is problematic! You absolutely have to read this article for two key reasons:
- It is one of the conditions most frequently misdiagnosed by various health professionals.
- Inadequate management of the early stages of this condition can lead to premature osteoarthritis affecting the foot and ankle.
The posterior tibial tendon is the only tendon in the human body (to my knowledge) that is able to stretch permanently without breaking.
The posterior tibial tendon (posterior tibial muscle) is primarily used to invert and flex the foot . Also, it is key to inverting the ankle and more specifically the hindfoot [2, 3]. It is also important to remember that despite the fact that the posterior tibial tendon is in close proximity to the posterior tibial artery where it passes through the tarsal tunnel, there is very little blood flow in this area. For a reason that remains unknown, the tendon has no direct blood supply over an area of approximately 2.5 cm (Fig. 1) . This peculiar anatomical feature overlaps with the region of the tendon that is most often affected by posterior tibial tendinopathy and is one of the risk factors for developing this pathology [4, 5]. Posterior tibial tendinopathy is the most prevalent condition of the posterior tibial muscle.
This condition affects 3.3% of women over 40 years of age  and is associated with inflammation followed by degeneration (chronic tendinitis) of the posterior tibial tendon. This leads to difficulty and eventually to an inability of the posterior tibial muscle to achieve inversion of the hindfoot. Furthermore, this causes both distal and posterior pain at the medial malleolus, leading to a decrease in the quality of life of sufferers .
In fact, one must keep in mind that all posterior tibial tendon disorders begin with posterior tibial tendon tendinopathy that has not been adequately treated. The biggest problem is when the inflammatory stage becomes truly degenerative and the tendon becomes elongated. The spring ligament and cervical ligament of the talus are damaged by an increase in stress caused by the failure of the posterior tibial tendon to invert the hindfoot and support the medial longitudinal arch. When your patient says that they feel like their foot has collapsed or that their heel is pointing more inward than before, you are probably dealing with a Stage II Posterior Tibial Tendon Dysfunction. Table 1 clearly summarizes the different stages of this condition and the typical signs and symptoms of each.
In short, posterior tibial tendon dysfunction manifests itself first as tendon damage (tendinitis leading to chronic tendinitis), then progresses to ligament damage and eventually, in the more advanced stages, to joint damage. There is a kind of breaking point that occurs between stages II and III, where the previously workable condition becomes unyielding. Once a patient has reached stages III or IV, there is no turning back and surgery (fusion of the cervical and/or talocrural joints) is often the best option to relieve the patient's pain. For this reason, it is essential to optimize treatments during stages I and II and especially during the stage where the condition is still classified as tendinopathy (stage I).
So, is it tendinopathy or dysfunction? It is important to be aware that any tendinopathy of the posterior tibial tendon can evolve into a dysfunction. From this perspective, the term stage I posterior tibial tendon dysfunction is appropriate given the possible adverse progression of an injury to this tendon. Ideal treatments for this condition in stages I and II will be the featured topic of the next blog post.
 K.L. Moore, A.F. Dalley, A.M.R. Agur, Anatomie médicale : aspects fondamentaux et applications cliniques, 3e ed. ed., De Boeck, Bruxelles, 2011.
 J.N. Maharaj, A.G. Cresswell, G.A. Lichtwark, Subtalar Joint Pronation and Energy Absorption Requirements During Walking are Related to Tibialis Posterior Tendinous Tissue Strain, Sci Rep 7(1) (2017) 17958. https://www.ncbi.nlm.nih.gov/pubmed/29263387.
 J.N. Maharaj, A.G. Cresswell, G.A. Lichtwark, The mechanical function of the tibialis posterior muscle and its tendon during locomotion, J Biomech 49(14) (2016) 3238-43. https://www.ncbi.nlm.nih.gov/pubmed/27545079.
 M.C. Manske, K.E. McKeon, J.E. Johnson, J.J. McCormick, S.E. Klein, Arterial anatomy of the tibialis posterior tendon, Foot Ankle Int 36(4) (2015) 436-43. https://www.ncbi.nlm.nih.gov/pubmed/25411117.
 R. Semple, G.S. Murley, J. Woodburn, D.E. Turner, Tibialis posterior in health and disease: a review of structure and function with specific reference to electromyographic studies, J Foot Ankle Res 2 (2009) 24. https://www.ncbi.nlm.nih.gov/pubmed/19691828.
 M.M. Abousayed, J.P. Tartaglione, A.J. Rosenbaum, J.A. Dipreta, Classifications in Brief: Johnson and Strom Classification of Adult-acquired Flatfoot Deformity, Clin Orthop Relat Res 474(2) (2016) 588-93. https://www.ncbi.nlm.nih.gov/pubmed/26472584.
 K.A. Johnson, D.E. Strom, Tibialis posterior tendon dysfunction, Clin Orthop Relat Res (239) (1989) 196-206. https://www.ncbi.nlm.nih.gov/pubmed/2912622.
 J. Kohls-Gatzoulis, B. Woods, J.C. Angel, D. Singh, The prevalence of symptomatic posterior tibialis tendon dysfunction in women over the age of 40 in England, Foot Ankle Surg 15(2) (2009) 75-81. https://www.ncbi.nlm.nih.gov/pubmed/19410173.
 A.M. Horwood, N. Chockalingam, Defining excessive, over, or hyper-pronation: A quandary, Foot (Edinb) 31 (2017) 49-55. https://www.ncbi.nlm.nih.gov/pubmed/28549281.
 H. Uden, R. Scharfbillig, R. Causby, The typically developing paediatric foot: how flat should it be? A systematic review, J Foot Ankle Res 10(1) (2017) 37. https://www.ncbi.nlm.nih.gov/pubmed/28814975.