Radiographic Impact on the Clinical Decision Making of Achilles Tenotomy in Clubfoot: In Search of an Objective Cut-Off Value.

BACKGROUND

We tried to determine whether the indication of Achilles tenotomy (AT) in clubfoot patients based on clinical evaluation could be confirmed radiographically, and to find an objective radiographic cut-off value for its indication.

METHODS

Eighty-six clubfeet from 60 patients, (26 bilateral and 34 unilateral) were included. A standard Ponseti treatment regimen was applied. Group 1 comprised patients who underwent AT immediately after serial plaster casting (26 feet). Group 2 comprised patients who underwent AT during the follow-up period (48 feet). Group 3 comprised patients who were assumed to have a corrected foot and did not undergo AT (12 feet). Group 4 comprised the healthy sides of the unilateral cases (34 feet).

RESULTS

Both Group 1 and Group 2 showed significant improvement after tenotomy ( = 0.002). In order to differentiate between the normal and AT groups according to the pre-tenotomy angle, we obtained an optimal cut-off value of >85° according to the Youden index, a sensitivity of 96%, a specificity of 91.2%, a positive predictive value of 95.9%, a negative predictive value of 91.2%, and an accuracy rate of 94.4% (AUC: 0.983; < 0.001).

CONCLUSIONS

Feet with a lateral tibio-calcaneal angle > 85° can be considered pathologic and accepted as candidates for AT.