Talolisthesis in end stage ankle arthrosis.

BACKGROUND: Sagittal displacement in patients with end stage ankle arthritis has been described as the tibiotalar ratio (TTR). Yet the incidence, distribution and predictive factors of talolisthesis are unknown.

METHODS: The radiographs of 470 cases of ankle arthritis were compared with a control group of 49 normal ankles. The TTR was measured for both groups. Additional co-variables included the anterior and lateral distal tibial angles, and talar tilt.

RESULTS: The mean TTR in the arthritis cohort was 34.8+9.12 compared to the normal group of 34.1+2.62. Twenty-eight percent of the ankles had anterior displacement and twenty-eight percent had posterior talolisthesis, while forty-four percent had normal tibiotalar alignment. Multivariate linear regression revealed significant predictors of anterior distal tibial angle (p<0.0001) and talar tilt (p=0.0007) for abnormal TTR.

CONCLUSION: Sagittal displacement is common in end stage ankle arthritis and is affected by ligamentous laxity and joint morphology.