Review Question - QID 217421

This patient has posterior tibial insufficiency (PTTI) and the resulting valgus hindfoot deformity often leads to contracture of the gastrocnemius muscle, noted with a positive Silfverskiöld test.

PTTI is a foot condition that presents commonly in women in their 50s and 60s. It is caused by attenuation and tenosynovitis of the posterior tibial tendon which leads to collapse of the medial foot arch. Examination may differ based on varying degrees of severity. Most patients are unable to perform a single leg heel raise and usually have tenderness to palpation posteromedially about the foot and ankle. Pes planus and hindfoot valgus are also extremely common. Hindfoot valgus may be flexible or rigid. The forefoot may also be abducted with talonavicular uncoverage in more advanced stages and the forefoot can be positioned in compensatory varus in order to maintain a plantigrade foot. Gastrocnemius contracture may be under appreciated but is common, because when the hindfoot is positioned in valgus the gastrocnemius is shortened.

Kaiser et al. reviewed management of gastrocnemius contracture in flatfoot deformities. They highlight the primary dynamic muscular and deforming forces in the foot. They note that equinus contracture is often seen with PTTI and consideration should be given to gastrocnemius or achilles lengthening based on the results of the Silfverskiöld test.

Meszaros et al. reviewed the surgical management of equinus in PTTI. They noted the topic is controversial, with gastrocnemius recession offering less weakness and better cosmesis, but with less powerful correction. They note that the ultimate choice in management of equinus in PTTI depends on patient-specific goals and their physical examination.

Incorrect Answers:
Answer 1: Posterior tibial tendon insufficiency is the most common cause of acquired flatfoot deformity, not involvement of the flexor hallucis longus (FHL), which controls flexion of the hallux
Answer 2: Plantarflexion of the first ray is a compensatory deformity seen with cases of cavovarus feet in order to maintain a plantigrade foot.
Answer 4: Correction of deformity with Coleman block testing indicates a flexible hindfoot with a forefoot driven cavovarus foot.
Answer 5: Patients with PTTI usually have a compensatory forefoot varus which can be observed by placing the heel in a neutral position.