BACKGROUND: The combination of dorsal dislocation of the navicular from the talus and an associated comminuted fracture of the calcaneus (transcalcaneal talonavicular dislocation) is an unusual and severe injury. Six cases have been described previously. The purposes of this study were to report the prevalence of this injury and the variations in injury pattern and to characterize methods of treatment and patient outcomes. METHODS: Eight patients with nine cases of transcalcaneal talonavicular dislocation were treated by the senior author between January 1, 1990, and February 28, 1998. The comminuted fracture of the calcaneus was apparently caused by plantar flexion of the talus through the anterior portion of the calcaneus. There were five open Grade-III injuries and three associated lacerations of the posterior tibial artery. After initial provisional stabilization of the hindfoot and management of the soft tissues, all injuries were treated with delayed open reduction and internal fixation of the calcaneus and fusion of the subtalar joint. At the last follow-up examination, the outcomes were rated with the Maryland foot score, the American Orthopaedic Foot and Ankle Society (AOFAS) ankle-hindfoot rating score, and the Creighton-Nebraska score for all patients who had not had an amputation. RESULTS: The duration of follow-up ranged from 1.1 to eight years. Chronic osteomyelitis developed in four patients, and three of them ultimately had an amputation. The Creighton-Nebraska scores for the remaining six feet ranged from 33 to 92 points, with only one having a good or excellent result. Five of the six patients had a limp, difficulty with shoe wear, limitation with regard to walking, and moderate pain. CONCLUSIONS: Transcalcaneal talonavicular dislocation is a severe injury that often leads to osteomyelitis and amputation. Patients who do not lose the leg as a result of uncontrolled infection should be counseled to expect severe functional limitations and/or chronic pain.
