Association of tibialis posterior tendon pathology with other radiographic findings in the foot: a case-control study.

The purpose of this study was to analyze the prevalence of spring ligament pathology and other radiographic changes related to flatfoot deformity in the presence of different degrees of tibialis posterior tendon pathology. A total of 72 patients (24 with tibialis posterior tendon abnormality and 48 sex- and age-matched controls) were evaluated for tibialis posterior tendon pathology, spring ligament pathology, and plain pedal radiographic angles, including cuboid abduction, talar declination, calcaneal inclination, and Meary's angles. The patients with tibialis posterior tendon pathology were subdivided into either minor (Type I) or severe (Type II/III), according to the Conti classification of tibialis posterior tendon pathology on MRI. All the continuous data of radiographic angles were dichotomized into either a flatfoot group or normal/cavus foot group. Associations between these nominal variables were analyzed. There was no association between Type I tibialis posterior tendon pathology and spring ligament pathologies (OR = 0.8, 95% CI = 0.15-4.65). Conversely, every patient with Type II/III tibialis posterior tendon pathology had spring ligament abnormality. Type II/III group also showed statistically significant associations with both increased talar declination angle (OR = 10.4, 95% CI = 1.62-109.22) and Meary's angle (OR = 7.5, 95% CI = 1.35-51.12), while no such associations were found with Type I tibialis posterior tendon pathology (OR = 1.0, 95% CI = 0.18-6.18 with talar declination angle; OR = 3.9, 95% CI = 0.65-27.71 with Meary's angle). In this investigation, only advanced tibialis posterior tendon pathology was statistically significantly associated with adult-acquired flatfoot deformity and spring ligament pathology.