Evaluation of hindfoot dimensions: a radiological study.
BACKGROUND: Realignment of the foot and good ligament balancing are mandatory for successful reconstruction of complex hindfoot disorders. This is why references for restoration of the normal anatomy and function are necessary when considering surgical reconstruction, such as osteotomies, arthrodeses, and total ankle replacement. However, no data are available regarding the normal anatomical dimensions on standard radiographs of the hindfoot. The purpose of this radiographic study was to define relevant and reproducible measures on lateral hindfoot radiographs and to assess their reliability. METHODS: Lateral radigraphic views were taken of 100 consecutive patients (37 women, 63 men) who consulted the emergency room for foot trauma. Dimensions assessed were the talar coverage by the tibia, the angle of the distal tibial joint plane to the tibial axis (tilt), the width of the tibia, the height of the talus, the joint radius of the ankle joint, and the offset of the center of rotation from the tibial axis. RESULTS: The tibial coverage of the talus was 88.1 (SD = 6.7) degrees, the tibial tilt was 83 (SD = 3.6) degrees, the width of the distal tibia was 33.6 mm (SD = 3.6 mm), the radius of the ankle joint was 18.6 mm (SD = 2.3 mm) with an anterior offset of the center of rotation of 1.7 mm (SD = 2.1 mm), and the height of the talus was 28.2 mm (SD = 4.0 mm). CONCLUSIONS: Several easily accessible measures on radiographs were found to be reliable in describing normal hindfoot anatomy and therefore may be used to evaluate hindfoot disorders. Additionally, because any reconstruction of the hindfoot should aim to correct the feet in a physiological way, these references may be helpful in the preoperative planning for treatment of complex deformities and posttraumatic disorders.