How To Address Subtalar Joint Instability

By Lowell Weil Jr., DPM, MBA

Emphasizing careful assessment of the etiology and underlying contributing factor to subtalar joint instability, this author reviews pertinent conservative and surgical options for treating this conditin in children and adults.

There are two forms of subtalar joint instability. It has been recognized as a cause of ankle symptoms secondary to ligamentous injury or laxity of the subtalar joint. This contributes to instability of the ankle as well. Studies show that sectioning of the calcaneal fibular ligament and cervical ligament of the subtalar joint can lead to as much as a 7 mm increase in talar tilt. Surgical repairs to correct lateral ankle instability should include repair or substitution of the calcaneofibular ligament if subtalar instability is a consideration.

   The other form of subtalar instability is associated with an excessive range of motion with or without pathology. It can be a process of increased motion that leads to minor pathology and muscular fatigue. Alternatively, it may cause a more complex situation of excessive pronatory motion, leading to collapse of the midtarsal joint and global mechanical problems for the foot and lower extremity.

   For the purposes of this article, I will consider subtalar joint instability as excessive subtalar joint motion or a position that leads to pain and subjective or objective complaints for a patient.

Treating Excessive Subtalar Joint Motion In Children

One may appreciate excessive subtalar joint motion early in a child’s life. Often young children will come in with their parents and present with markedly flatfeet and the majority of the collapse originates from the subtalar joint. More often than not, these patients do not have pain but there is a fear of the future ramifications of this position.

   A full evaluation of the possible pathological etiologies of this condition is necessary. The majority of the children will present these findings as their normal musculoskeletal position. It is debatable whether one should treat a painless/ unstable foot in this situation. Certainly, there are situations in which there is accompanying pain or when findings are so clear that one must institute treatment.

   However, in the majority of cases involving excessive subtalar joint motion in children, it has been our experience that it is usually best to leave these patients untreated if they are asymptomatic. Over the years of treating professional athletes, it has been our observation that many of the fastest runners and highest jumpers have significant flatfeet that were likely present since childhood. It is hard for us to justify treatment in a child without pain considering the level of achievement of unstable subtalar joints in the professional athletic population.

   In children who have pain associated with instability of the subtalar joint, utilizing a functional orthotic device or UCBL device can have profound effects on the foot. Children who suffer from pain associated with subtalar joint instability will frequently complain of vague foot/ankle pain, leg pain, “growing pain” and fatiguing quickly when walking or running. By stabilizing the subtalar joint with an external supportive device, clinicians can facilitate more efficient function of the lower extremity and allow for a return to normal activities with reduced pain.

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