How To Achieve Improved Results With The Chopart Amputation
- Volume 20 - Issue 7 - July 2007
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When it becomes apparent that the current treatment is not proving effective for a debilitating disease or a trauma induced by accident or warfare, amputation is generally considered the medical intervention of last resort. Indeed, one would exhaustively consider any and all other medical alternatives to save a limb before deeming it necessary to amputate.
However, once the physician has made the decision to amputate, then one has to decide on the level of the amputation. Recent advances such as newer generation antibiotics and endovascular approaches to revascularization have aided in the ability to preserve as much of the affected limb as possible from the effects of disease or trauma.
The effort to preserve the foot, arguably, best illustrates that premise. Beginning from the most distal to the most proximal, amputation levels of the foot include: toe(s), ray and transmetatarsal (TMA) to preserve all or part of the forefoot and structures proximal to it; the Lisfranc procedure to preserve the midfoot and structures proximal to it; the Chopart to preserve the hindfoot; and the Symes amputation level that preserves the lower leg. The benefits of foot preservation include but are not limited to the ability to stand and to walk for short distances without any orthotic or prosthetic device and, for those who have already lost the contralateral lower limb, the ability to transfer with less effort from one place to another.
Let us take a closer look at the Chopart disarticulation at the midtarsal joint between the proximal talus and calcaneus, and the distal navicular and cuboid bones. Historically, research about this level of foot amputation and viable prosthetic devices for the partial foot amputee in general have proved to be indiscriminate and controversial. As in some areas of prosthetics, such as the effective suspension of below-knee prostheses to stay on the amputee’s limb throughout all phases of the gait cycle, overlaps and redundancies exist. At the Chopart amputation level, some fitting and fabrication strategies merged concepts of orthotic and prosthetic disciplines into a hybrid “prosthosis” device.
What Advantages Does The Chopart Amputation Offer?
The Chopart disarticulation was first described by Francois Chopart (1743-1795), a French surgeon. Although the procedure was initially successful, it fell into disrepute because of the equinovarus deformity that developed as a result of unopposed action of the soleus-gastrocnemius muscles and the Achilles tendon on the calcaneus and the anterior tibial tendon medially.
More recently, some have advocated the Chopart disarticulation with appropriate tendon balancing over that of more distal levels such as the Lisfranc or short transmetatarsal. The rationale is that surgeons may obviate the potential equinovarus deformity via the surgical removal of the cuboid bone during the procedure.1 Accordingly, one may entertain this level as a more definitive level of choice over questionable healing or success in comparison to a more distal level. Surgical interventions have included transferring the anterior tibial tendon to the talus, and ankle and subtalar fusion using an intramedullary nail. This method affords rigid control to the rearfoot to prohibit posterior calcaneal extension.2