Separating the chicken from the egg: an attempt to discern between clubfoot recurrences and incomplete corrections.

Purpose: To better delineate between incomplete clubfoot correction and true clubfoot recurrence based on the time at which the deformity reappears and the treatment necessary to correct the foot.

Methods: A chart review of all idiopathic clubfoot at a single institution treated by either the Ponseti method or short leg casting and surgery were reviewed for recurrent deformity involving the tibia, ankle, or foot. Comparisons of treatment required to correct deformities were made between those noticed within six months of initial treatment and those noticed after six months. Similar comparisons were made based on the initial treatment of the deformity.

Results: Forty-four of 51 patients showed some clinical deformities after their initial treatment. Over half of these deformities either resolved or did not require operative intervention at a minimum of two years follow-up, while 43% (19/44) were felt to require surgery. Eight patients had deformities re-appear within six months of initial treatment and eleven patients after six months. Six of the eight patients requiring surgery with deformities noticed less than six months after initial treatment required correction of structural deformities (osteotomies and posterior-medial releases), whereas 10/11 patients requiring surgery for deformities noticed after six months required correction for dynamic deformities. These differences were significant (p=0.01). No difference in terms of the number of deformities noticed (22/25 and 22/26) and number requiring surgery (11/22 in the Ponseti group and 8/22 in the surgical group) were found. However, deformities requiring further surgery in the surgical group re-appeared earlier 0.23±0.2 years than those in the Ponstei group 1.7±1 years (p=0.001). These earlier re-appearing deformities required more structural surgery (6/8) than those in the later appearing Ponseti group (1/11; p=0.01).

Conclusions: Nearly half of all re-appearing deformities required surgery. The deformities noticed within six months of initial correction required more structural surgery to correct than those noticed after six months. We propose that the recurrent deformities noticed before six months of age represent incomplete corrections and those after six months true recurrences. Feet initially treated with surgery may be more prone to incomplete correction whereas those treated by the Ponseti method may be more prone to recurrence.

Significance: Not all re-appearing clubfoot deformities are the same. The initial treatment and time at which they first appear may have implications as to the surgery required to correct.