Cross-Sectional Area Measurement of the Central Tarsometatarsal Articulation: A Review of Computed Tomography Scans

Currently, disagreement exists regarding the superior method for repairing a ligamentous Lisfranc injury regarding whether to use arthrodesis or open reduction internal fixation. The 2 procedures differ in the amount of articular cartilage destroyed. Arthrodesis removes all the articular cartilage, and open reduction internal fixation places transarticular screws, essentially destroying a portion of cartilage. We performed a review of 30 consecutive computed tomography scans that included both foot length and undamaged first, second, and third tarsometatarsal joints to quantify the amount of articular surface area destroyed by placement of standardized 4-mm diameter screws. Measurements were performed using a freeform tool. The calculated surface area of the screws was subtracted from the measured surface area of the joint to yield the amount of surface area occupied by the screws. Our results demonstrated that the average amount of articular surface area destroyed in the first, second, and third tarsometatarsal joints was 4.87%, 4.79%, and 4.86% respectively, with a standard deviation of <1% for each of the joints. Our results have demonstrated that screw placement accounts for only a small percentage of articular surface destroyed. They also showed that the articular surface damage was comparable among the first 3 tarsometatarsal joints. Additionally, our results were similar to the articular surface area calculated from cadaveric specimens in a previous biomechanical study, demonstrating that computed tomography can allow for reliable and accurate assessments of articular surface areas in the foot.