Traumatic astragalectomy: a case report

Overview

Autori referujú raritný prípad traumatickej astragalectomie u 26ročného motorkára po havárii do poľa. Ťažká otvorená kontaminovaná devastácia členka i nohy si vyžiadala akútnú revíziu, pri ktorej zisťujeme chýbanie, stratu vlastnej členkovej kosti – astragalus (talus). Vzhľadom závažnosť vysokoenergetického otvoreného s ohrozenou vitalitou nohy urobená - po dôkladnej revízii a debridement avitálnych mäkkých štruktúr - crurokalkaneálna osteosyntéza vonkajším fixátorom v I. dobe. Po zhojení mäkkých škruktúr urobená v II. dobe po 10 mesiacoch spongioplastika crurokalkaneálneho priestoru so zámerom artrodézy 3 skrutkami cez kalkaneus do tibiae. Po ďalšom roku v III. dobe odstránený osteosyntetický materiál s pokračovaním cvičení a rehabilitácie. Pacient 5 rokov po úraze chodí bez používania palice s minimálnym krívaním. Autori navrhujú vo všeobecnosti didakticky astragalektómie rozdeliť podľa príčiny: 1. Pre ťažké deformity nohy a členka a postinfekčné (napr. minulosti pre tuberkulózu) - neúrazové. 2. Poúrazové - ktoré sú zmienené v literatúre len raritne po komminutívnych a dislokovaných fraktúrach talu. 3. Traumatické, pri ktorých je úrazovým mechanizmom urobená úplná diskontinuita talu s jeho pôvodných miestom, respektíve jeho úplná strata.

Klíčová slova:
Astragalektómia, otvorená dislokácia tálu.

An astragalectomy (talectomy) is a surgical operation in orthopaedics and traumatology to remove the ankle bone, i.e. the astragalus. It is indicated for persistently recurrent, severe foot deformities in orthopaedics for congenital talipes eqinovarus (clubfoot), arthogryposis and severe infections of the talus bone [6, 12, 13, 15]. An astragalectomy also includes a Pirogova-Boyda amputation at Chopart’s joint, accompanied by an astragalectomy with a necessary subsequent calcaneotibial arthrodesis and another fixation , so this amputation is often not recommended [4, 5].

Another astragalectomy indication mentioned in the literature is post-traumatic avascular necrosis of the talus, which leads to subtalar and talocrural arthritis. A pantalar arthrodesis seriously interferes with the biomechanics of walking, so this operation should only be done as a last resort when there is major trouble. Because arthrodesis heals the necrotic field over a protracted period of time, an astragalectomy and subsequent tibiocalcaneal arthrodesis is recommended in such cases [8, 9, 10].

Case Report:

A 26-year-old and his girlfriend suffered a motorcycle accident when they crashed into a field. He sustained an open contaminated dislocation of his left ankle, Fig. 1.

When he was admitted to the emergency department, an acute surgical revision was indicated due to the nature of the accident and danger to his left foot’s vitality. During the operation, we discovered that the ankle bone (talus bone or astragalus) was missing. Due to the open wound also having been heavily contaminated by soil from the field, debridement was performed after the wound had been thoroughly revised. This was followed by crural-calcaneal osteosynthesis with a unilateral external fixator from the medial side (Fig. 2A, 2B), supplemented with 2 neutralising Kirschner wires drawn through the calcaneus to the distal tibia (Fig. 2C).

No complications occurred during the postoperative period while he was receiving triple-antibiotic therapy.

Even after rehabilitation, the patient still suffered pain in his left ankle and was limping, while his left lower limb had become two centimetres shorter.

In March 2008, he underwent an operation where, after excochleation of a new post-traumatic tibiocalcaneal joint (Fig. 3A), we applied a spongioplasty and performed osteosynthesis with cannulated bone screws (Fig. 3B).

A year later we removed the osteosynthetic material, although osteo tibiocalcaneal fusion never occurred.

After subsequent rehabilitation, however, the patient gradually stopped using a cane while walking and was virtually no longer limping. But he had thoracolumbar compensatory scoliosis when his left lower limb was shortened by 1.5 centimetres. He stands on his right toes while his heel is suspended 2.5 centimetres from the ground (Fig. 4). The patient‘s condition has been evaluated as good. Five years after the accident the patient was walking without a cane and with minimal limping.

Discussion

An astragalectomy seriously intervenes in the biomechanics of the ankle and leg and is generally indicated as a compromise solution to severe foot and ankle deformities in orthopaedics [3, 10, 11, 12, 15, 17, 19]. In traumatology, an astragalectomy is generally not recommended for such severe fractures of the talus bone. The previously recommended Dunn-procedure astragalectomy was rarely successful and had to be supplemented by other operations (shifting the malleolar fork ventrally with a calcaneotibial arthrodesis, likewise rarely successful) in order for the leg to be at least partially able to have supporting functions [16].

Assal and Stern found five cases described in the literature of total talus extrusion where in only three cases was the talus bone re-implanted [1]. They described a further case themselves where the talus bone was completely outside the body because of an open wound. Here they re-implanted the talus bone at its original position. The authors themselves have indicated inconsistencies in the literature where closed luxations of talus bones were also presented by the authors as total dislocations [2, 6, 7, 8, 9, 14, 18].

We believe that open wounds caused by loss of the astragalus, with no connection whatsoever to soft tissue at the original location, need to be clearly designated as traumatic astragalectomy. If we follow up on those cases described in the literature and presented in 2004 by Assal and Stern, then our case report would have described the seventh case therein of a traumatic astragalectomy.

In general, we didactically suggest having an astragalectomy broken down by cause as follows.

MUDr. Jan Cigaňák

jciganak@hotmail.com