Figure 1. Anteroposterior view of left and right feet.
Figure 2. Lateral view of the left foot.
A 45-year-old man with obesity presents with bilateral painful feet. The pain is specifically located on the inside of the ankle and is exacerbated when walking on uneven surfaces and climbing stairs. On physical examination, the patient exhibits planovalgus alignment of both heels, along with bilateral loss of the medial longitudinal arch. Radiographs of the feet are taken (Figures 1 and 2).
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Adult-acquired flatfoot deformity is a relatively common condition seen by clinicians.1 In this case, the patient has started to develop posterior tibial tendon dysfunction (PTTD) as noted by the collapse of his medial arches and planovalgus deformity. Early PTTD is characterized by tendon inflammation without a change in foot shape (stage 1). As the condition progresses, the posterior tibial tendon elongates and the medial arch starts to collapse (stage 2).1 Obesity is one of the risk factors for progressive PTTD.1,2
The main function of the posterior tibial tendon is plantar flexion and inversion of the hindfoot. Single and double heel rises test the functional strength of the posterior tibial tendon. Early in the disease, when the tendon is inflamed, repetitive heel rises can become weak and painful with increasing attempts. As the condition progresses, many patients can’t perform a heel rise at all.1,2
This patient presents with early disease as there is no evidence of forefoot abduction or loss of talar head coverage on AP radiograph (Figure 1). Treatment for early PTTD is conservative with medial arch supports orthotics, stiff-soled shoes, and/or a period of immobilization. Nonoperative management has a success rate ranging from 67% to 90%.2
Dagan Cloutier, MPAS, PA-C, practices in a multispecialty orthopedic group in the southern New Hampshire region and is editor in chief of the Journal of Orthopedics for Physician Assistants.
1. Jackson JB 3rd, Pacana MJ, Gonzalez TA. Adult acquired flatfoot deformity. J Am Acad Orthop Surg. 2022;30(1):e6-e16. doi:10.5435/JAAOS-D-21-00008
2. Abousayed MM, Alley MC, Shakked R, Rosenbaum AJ. Adult acquired flatfoot deformity: etiology, diagnosis, and management. JBJS Rev. 2017;5(8):e7. doi:10.2106/JBJS.RVW.16.00116