How Many Patients Who Have a Clubfoot Treated Using the Ponseti Method are Likely to Undergo a Tendon Transfer?

BACKGROUND: The Ponseti method has become the standard of care for the treatment of idiopathic clubfoot. A commonly reported problem encountered with this technique is a relapsed deformity that is sometimes treated in patients older than 2.5 years by an anterior tibial tendon transfer (ATTT) to the third cuneiform. Presently, there is insufficient information to properly counsel families whose infants are beginning Ponseti treatment on the probability of needing later tendon transfer surgery.
METHODS: All idiopathic clubfoot patients seen at the authors' institution during the study period who met the inclusion criteria and who were followed for >2.5 years were included (N=137 patients). Kaplan-Meier Survival analysis was used to determine the probability of survival without the need for ATTT surgery. In addition, the influence of patient characteristics, socioeconomic variables, and treatment variables on need for surgery was calculated.
RESULTS: On the basis of the survivorship analysis, the probability of undergoing an ATTT remained below 5% for all patients at 3 years of age, but exceeded 15% by 4 years of age, increasing steadily afterwards such that by 6 years of age, the probability of undergoing an ATTT reached 29% of all patients. Overall, controlling for all other variables in the analysis, parent-reported adherence with bracing reduced the odds of undergoing surgery by 6.88 times, compared with parent-reported nonadherence (P<0.01).
CONCLUSIONS: This is the first study to report the probability of undergoing ATTT surgery as a function of age using survivorship analysis following Ponseti clubfoot treatment. Although the overall probability reached 29% at 6 years, this was significantly reduced by compliance with bracing. This information may be useful to the clinician when counseling families at the start of treatment. LEVEL OF EVIDENCE: Level III-theraputic.