Utilizing a relatively high recurrence rate in both surgically and Ponseti treated clubfeet, in cohorts that had been assembled and followed prospectively, we set out to answer several questions regarding clubfoot recurrences. This is the first study of this type to be found in the literature. Other studies discuss recurrences as treatment failures,3,10-16
and in terms of functional results.5,19
In this study we begin to answer four unknown questions.
What percentage of feet showing even slight abnormalities after initial correction required further surgery? In our study population between thirty-five to fifty percent of patients noted to have small early recurrent deformities went on to require further surgical treatment. This was seen for both cohorts and was essentially irrespective of age. Both cohorts had a high percentage (84% in the surgical group and 88% in the Ponseti group) of individuals showing some residual signs of the initial deformity. No statistical difference in the deformities noted could be elicited from our data. These deformities were often noted sooner after initial treatment in the surgical cohort and later in the Ponseti group. Fifty percent of these early recurrent deformities in the Ponseti group and thirty-six percent of the surgical group required further treatment (statistically not significant).
Could we discern between incomplete correction and true recurrence based on time after initial treatment that the first signs of deformity resurfaced? We believe that by using 6 months after initial treatment as a cut-off point, we could identify the recurrences that were most likely an incomplete correction or at least an early failure to maintain correction as opposed to a true recurrence (a foot that was corrected and then over time recurs). Sixteen of 44 patients showed recurrent deformities within the first 6 months after treatment (average 0.2 +/−0.15 years); while 28/44 patients had later recurrences (1.5 +/−1 years). 50% of the early deformities required surgical intervention and 40% of the later deformities required intervention.
Did the surgery required to correct these recurrences differ based on the time the deformities were first noted? From our data, it appears that those early deformities (<6 month from initial treatment) that do not spontaneously resolve or resolve with re-casting; often (7/8 patients) require much more extensive surgery to correct involving repetitive posterior-medial releases or osteotomies. We feel this type of surgery demonstrates the structural nature of the deformities that were not fully corrected or could not be maintained immediately after the initial procedure. Conversely, the deformities that surfaced later (>6months); required less invasive surgery often involved a tibialis tendon transfer, tendo-achilles lengthening, or even a posterior release. These we feel demonstrate a true recurrence and thus are dynamic in nature, i.e., the foot was in a corrected position, cartilaginous bones remodel to there new shape and position, and over time a recurrence occurs due to: anterior tibialis over-pull or gradual tendo-achilles contracture which might also lead to posterior capsular tightness. Thus the surgery to re-correct the foot is more soft tissue and dynamic in nature.
Would there be any differences in these factors between initial treatment options (Ponseti versus Surgical)? Eighty-four percent of the surgically treated clubfeet went on to have early recurrent deformities at a statistically earlier time (0.2 versus 1.7 years) than the Ponseti group. Thirty-six percent of these patients required further surgery as opposed to 50% of the Ponseti group. However, 7/8 patients in the surgical group required structural
surgery to correct these deformities as opposed to the 1/11 in the Ponseti group. We believe these differences to represent a higher incidence of incomplete corrections in surgical group demonstrated by the much earlier noticed deformity (0.2 years after correction) and the type of surgery required to correct the deformity. Whereas the deformities in the Ponseti group were noticed later (average 1.7 years). This makes logical sense as the Ponseti casting has been shown, by Pirani et al through MRI imaging,20
to mold the pliable cartilaginous bones into their correct position and assume a more normal shape; however this casting in no way alters muscular forces affecting the foot. While surgical release abruptly changes the overall relationships between bones, it does not immediately change their shape. Unless the bones re-model while pinned or the healing scar tissue is strong enough to hold the bones in their new position the correction will be incomplete or will quickly return as the misshapen bones assume a more stable configuration. As this is generally done at a later age than the casting (average 6 months in this cohort); the bones of the foot may be less pliable.
Major limitations of this study need to be pointed out. First while starting out with relatively large prospective cohorts, we chose to look primarily at those patients with recurrences, thus limiting our sample size. We also used a two year minimum follow-up (average follow up of roughly 3.5 years) as inclusion criteria. Additional recurrences may continue to be found as time goes on. Despite the records of these children being recorded prospectively, no standardized objective criteria were initially established to designate an early recurrent deformity. Instead the authors relied on subjective references in the patients chart concerning the first recognition of a recurrent deformity while under the care of different clinicians. Despite these weaknesses, we feel that in general the evaluating clinicians put forth honest evaluations and looking at the overall numbers between cohorts in terms of number of overall patients with clinically noticeable deformities and number of deformities requiring surgical correction the evaluation of these groups appears very similar.
This is the first manuscript to evaluate the differences in the recurrences between surgically managed and Ponseti treated clubfeet. We believe this manuscript gives the clinician some knowledge as to what the natural history of an early recurrent deformity will be after the initial treatment of a clubfoot deformity. Furthermore, it may help to further explain the reported long-term functional differences between surgically corrected clubfeet and Ponseti treated clubfeet. Perhaps the majority of recurrences reported in the literature in surgically treated clubfeet are really incomplete corrections resulting in malformed bones and incongruent joints, thus requiring more structural surgery to further correct and resulting in foot stiffness; whereas the Ponseti recurrences, represent true recurrences do to dynamic forces acting on a corrected clubfoot? By following our large prospective cohort in the future, we hope to be able to answer these questions in the future.
From this study, 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. Thus 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.