Clinical and Radiographic Outcomes of Tibiotalocalcaneal or Pantalar Arthrodesis Using a Novel Lateral Locking Plate

Abstract

Category: Ankle Introduction/Purpose: For patients suffering from severe ankle and hindfoot arthritis or deformity, tibiotalocalcaneal (TTC) or pantalar arthrodesis may be the best option to achieve a plantigrade and painless foot. These fusions are typically fixed with a retrograde intramedullary nail, a lateral side plate, or screws alone. Theoretically, the advantages of a lateral side plate applied via a trans-fibular approach include the use and the multiple points of fixation available in the tibia, talus, and calcaneus. The results of a novel side plate construct with a unique screw hole that extends underneath the calcaneus are presented in this study. A large diameter screw can be inserted retrograde through this inferior hole to engage the medial tibial cortex and provide axial compression across the ankle and subtalar joints. Methods: This study retrospectively evaluated 39 patients that underwent a tibiotalocalcaneal (TTC) or pantalar arthrodesis using this novel lateral plate fixation technique by one of three fellowship trained surgeons at a tertiary referral center. Patients with less than a one year follow up were excluded. Thirty-nine patients were identified between 2012 and 2016. Two patients were deceased from other causes, 2 had a below the knee amputation due to chronic pain, and 9 were lost to follow up. Pre- and postoperative General Health and Wellness (SF-12) and Revised Foot Function Index scores were obtained. Study subjects were seen for a clinical evaluation and final post-operative x-rays. The Shapiro-Wilk test was used to test for normality. The paired student’s t-test was used to compare pre- and post-surgical outcome measures. Results: Twenty-six patients were included in the study group. Mean follow up time was 34.42 ± 12.94 months. The SF-12 score was 32.2 ± 10.22 (physical) and 54.8 ± 10.7 (mental) before surgery, and 41.35 ± 9.21 (p < 0.01) and 56.5 ± 7.47 (p = 0.73) at final follow-up, respectively. The FFI score was 106 ± 32.69 before surgery and 53.94 ± 24.14 after surgery (p = 0.06). Eighteen patients were satisfied or very satisfied with the outcome of the surgery (70%). CT confirmation of joint fusion was obtained in all 26 patients. Twenty out of the 26 patients demonstrated fusion of all joints (77%). There were 2 ankle, 1 subtalar, and 1 talonavicular nonunions. In total, 44 of 48 total joints were fused (91%). Conclusion: Tibiotalocalcanceal and pantalar arthrodesis using a novel lateral plate for the treatment of complex deformity and severe osteoarthritis demonstrated acceptable fusion rates considering the number of patients with high risk factors for nonunion in this study group. Complications included fractures at the proximal end of the plate construct and persistent neurapraxia which was well tolerated. Patients reported significant improvements in SF-12 clinical scores at final 34 month follow-up.