Idiopathic clubfoot treated with the Ponseti method: factors associated with patient follow-up.

Background: Follow-up after treatment with the Ponseti method is important because of the known association be- tween lack of brace wear and recurrence. This study was designed to ascertain factors associated with patients who did not return for the recommended follow-up versus those who did.

Methods: Between January 1, 2000, and December 31, 2009, 222 patients were treated for idiopathic clubfoot at the New York Ponseti Clubfoot Center at NYU Hospital for Joint Diseases, of which 93 patients (143 feet) were potentially available for follow-up (i.e., ≤ 7 years of age, had not moved, or transferred care to another institution). Attempts were made to contact all patients' parents or guardians by telephone to respond to a survey, which included questions from the Disease Specific Instrument and the Oxford Ankle Foot Questionnaire. Forty-two of the 93 patients (45%) responded. The responder group, those who answered the survey, was compared to the group of non-responders. The responder group was further divided into a returning group (35 out of 42, 83%) and a lost to follow-up group (17%, not followed-up in over a year). A chart review was performed for demographics, Dimeglio/Bensahel and Catterall/Pirani scores, and treatment.

Results: When comparing the responder and non- responder groups, the responder group had significantly lower (p < 0.05) Catterall/Pirani scores at initial visit than the non-responder group (5.0 versus 5.5), but otherwise these two groups were similar. Among the responders, 91% or more were very satisfied/satisfied with status and appearance of foot in both lost to follow-up and returning groups. The lost to follow-up group was significantly (p < 0.05) older at the time of the survey (5 years versus 3.7 years), required significantly fewer casts (4.4 versus 5.5), had significantly lower Dimeglio/Bensahel scores at time of the start of foot adbuction orthoses (FAO) (0.0 versus 2.0), and trended toward greater footwear limitations (p = 0.051) compared with the returning group.

Conclusions: Number of casts, severity scores at the start of FAO, and footwear limitations are possible factors to differentiate between lost to follow-up and returning patients. This information may help other clubfoot centers provide vigilant outreach and therefore decrease recurrence rate.