To our knowledge, this is the first case report of a pilon fracture with PTT interposition in the fracture site lateral to the tibial shaft which prevented reduction. The negative consequences of this were threefold. First, the ankle dislocation and fracture of the distal part of the tibia could not be reduced, contributing to additional damage to the chondral surfaces of the talus and tibial plafond. Second, as a result of the laterally translated ankle, pressure necrosis of the skin developed caused by tenting of the skin over the medial malleolar region. Third, the prolonged abrasion of the tendon within the fracture site might have had detrimental effects on the long-term function of the tendon. All of these features were directly caused by the interposition of the tendon into the fracture site and not by the fracture itself.
Closed reduction attempts at the referring institution, and sixteen days later at our institution, were unsuccessful. Intraoperatively, the diagnosis of an interposed PTT was made, effectively preventing reduction. Once the tendon was reduced, the fracture and talus reduced immediately.
This injury bears some anatomic similarities to a particular type of irreducible ankle fracture-dislocation complicated by PTT interposition. There are four case reports of this particular injury in the literature7-10, in which the PTT displaces posterolaterally behind the tibia, then anteriorly through the widened syndesmosis during an ankle fracture-dislocation, ultimately becoming lodged between the talus and the tibial plafond. As in our case, the tendon prevented reduction of the talus in the mortise.
In conclusion, soft-tissue interposition may act as a barrier to the reduction of any type of fracture. We present this case to illustrate yet another potential challenge in the management of pilon fractures, and we hope it will alert orthopaedic surgeons to the possibility that PTT entrapment within the fracture site may be the reason that reduction attempts are not successful. This report also serves as a reminder to adhere to basic principles. If closed reduction of a pilon fracture cannot be obtained (and maintained) with an external fixator, the next step is to perform open reduction. Furthermore, our case highlights the dangers of failing to recognize the severity of injury, to anticipate the resultant complications, and to communicate this effectively when planning on transferring a patient’s care to another institution. If PTT entrapment is not recognized promptly, delays in appropriate management can ensue and perhaps contribute to subsequent bone and soft-tissue complications, as demonstrated in our patient.