A New Anatomical Classification for Tibialis Posterior Tendon Insertion and Its Clinical Implications: A Cadaveric Study.

Jeong-Hyun Park,Kwang-Rak Park,Kwan Hyun Youn,Hyung-Wook Kwon,Mijeong Lee,Jaeho Cho,Yu-Jin Choi,Digud Kim

doi:10.3390/diagnostics11091619

Abstract

The variations in the tibialis posterior tendon (TPT) could not be defined by previous classification; thus, this study used a larger-scale cadaver with the aim to classify the types of TPT insertion based on the combination of the number and location of TPT insertions. A total of 118 feet from adult formalin-fixed cadavers were dissected (68 males, 50 females). The morphological characteristics and measurements of TPT insertion were evaluated. Four types of TPT insertions were classified, wherein the most common type was type 4 (quadruple insertions, 78 feet, 66.1%), which was divided into four new subtypes that were not defined in the previous classification. The second most common type was type 3 (triple insertions, 25 feet, 21.2%) with three subtypes, including the new subtype. Type 2 was found in 13 feet (11%), and the rarest type was type 1 (2 feet, 1.7%), wherein the main tendon was only attached to the navicular bone and the medial cuneiform bone. We suggest high morphological variability of the TPT in relation to the insertion location, along with the possibility of significant differences according to race and gender. Moreover, this classification will help clinicians understand adult flatfoot deformity-related posterior tibial tendon dysfunction (PTTD).

Highlights

Adult acquired flat foot deformity (AAFD) is characterized by the collapse of the medial longitudinal arch, and its causes include posterior tibial tendon dysfunction (PTTD), rheumatoid arthritis, trauma, Charcot’s joint, and neuromuscular deficiency
The main tendon only inserts into the navicular bone and medial cuneiform bone
A clear understanding of the anatomical morphology of the tibialis posterior tendon (TPT) in relation to the insertion location is important for clinicians who encounter flatfoot deformity-related posterior tibial tendon dysfunction (PTTD)

Summary

Introduction

Adult acquired flat foot deformity (AAFD) is characterized by the collapse of the medial longitudinal arch, and its causes include posterior tibial tendon dysfunction (PTTD), rheumatoid arthritis, trauma (sequelae such as calcaneal fracture, tarsometatarsal joint injury, and ankle joint fracture), Charcot’s joint, and neuromuscular deficiency. Rupture of the plantar fascia and the spring ligament complex as a static stabilizer that maintains the medial longitudinal arch has been suggested as the main cause. Among these causes, the most known clinical cause is PTTD, which is synonymous with AAFD in most references and textbooks [1,2,3,4,5,6]. The tibialis posterior tendon (TPT) acts as a primary dynamic stabilizer of the medial longitudinal arch and inverts, adducts, and plantar flexes the midfoot [1,7,8]. Because it is located more medially from the subtalar joint axis than other flexor tendons, the subtalar joint is inverted, and the foot becomes a rigid lever with adduction of the forefoot, locking the hindfoot and maintaining the medial longitudinal arch when the TPT contracts [9].

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Conclusion