Study notes effects of component location in total ankle replacement on ankle motion

Cenni F, et al. International Orthopaedics (SICOT). 2011. doi: 10.1007/s00264-011-1323-6

Possible residual subluxation and inclination of components used in total ankle replacement are mildly correlated to the motion at the replaced ankle, according to a study from Italian researchers.

The authors noted, however, that they were able to achieve a satisfactory range of motion in patients whose components were unable to be placed in recommended locations due to joint deformity size.

The researchers performed preoperative and postoperative — 7-month and 13-month follow-up — assessments of 14 patients who underwent total ankle replacement. These assessments involved X-rays being taken of the ankle in the static double leg stance, as well as at maximum plantarflexion and dorsiflexion.

A computer program devised specifically for measuring digitized anatomical reference points on the radiograms was used to obtain data, allowing for the position and orientation of the components to be calculated along with joint range of motion.

The authors reported a 34· mean range of motion at first follow-up, which was found to maintain through the second follow-up. Eleven patients demonstrated tibial components more anterior than the mid-tibial shaft, with nine patients demonstrating talar components more anterior than the mid-tibial shaft. Further, the authors found a mean inclination of 4· posterior for the tibial component and 1· anterior for the talar component.

“A significantly larger range of motion was found in ankles both with the talar component located and inclined more anteriorly than the tibial,” they wrote.