Jeffrey C Christensen1, John M Schuberth2, Eric G Powell3. 1. Attending Surgeon, Department of Orthopedics Swedish Medical Center, Seattle, WA. 3131 Nassau Street, Suite 101, Everett WA 98201. Electronic address: jccdpm@gmail.com. 2. Chief of Foot & Ankle Service, Kaiser Permanente, San Francisco, CA. Department of Orthopedic Surgery, 450 6(th) Avenue, San Francisco, CA 94118. Electronic address: jmfoot@aol.com. 3. Attending Staff, Minor and James Medical Clinic 515 Minor Avenue, Suite 24 Seattle, WA 98122. Electronic address: eric.egp@gmail.com.
Abstract
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.
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.