Length of the casting phase in the treatment of clubfoot

INTRODUCTION Clubfoot is generally treated by the Ponseti method [1]. The deformity is reduced step-wise. Each interval starts with the manual manipulation of the deformed foot according to a strict protocol, after which a plaster cast is applied to the foot in (partially) corrected position. After on average five to six steps the corrective treatment is finalized, usually requiring an Achilles tenotomy upon completion, followed by a bracing period of several years. The rationale behind the length of the time interval (seven days) in clubfoot treatment is unclear. There seems to be no scientific reason for this specific duration, nor have we found studies seeking to establish an optimum interval length. In contrast, in treatment of hand contractures the optimum interval is suggested to be 2 days [2], and for treating joint contractures in cerebral spasticity patients, 1 to 3 days [3]. Thus, the question arises whether the casting treatment duration can be potentially be shortened by reducing the interval length. METHODS We performed a systematic review of the literature regarding the influence of the cast change interval on the effectivity of the method. Search terms included “clubfoot”, “Ponseti”, and “duration”. The result is as follows:  346 studies were retrieved through Scopus, PubMed, COCHRANE, WebOfKnowledge and Google Scholar  38 more studies were retrieved through other sources (e.g. reference lists)  359 studies remained after duplicates removed  265 studies were excluded by title and abstract (inappropriate objectives e.g. bracing, review, metaanalysis, case-study, conference abstracts, conversations, no Ponseti treatment  94 full-text remained for further investigation  87 studies excluded for reasons of: o No control group o Modifications to the Ponseti method o Non-idiopathic clubfeet  7 studies included for review The resulting 7 studies were further screened for possible bias (e.g. selection bias, reporting bias). Among the factors that were extracted are cast change interval, number of casts, treatment duration and failure rate (failure defined as post-casting Pirani score > 1 [4]). Findings were assessed and ranked according to levels of evidence (strong/ moderate/ limiting/ conflicting/ no). RESULTS AND DISCUSSION The results are summarized in Table 1 Table 1: Relationship with cast interval Nr of studies Range Best evidence synthesis Casting interval 7 7 (N) 2.3 - 5 (S) Average #of casts 7 4 - 5.25 (N) 4.15 - 7.4 (S) Strong evidence no relationship Duration (days) 6 24 - 57.4 (N) 16 - 23.8 (S) Strong evidence positive relationship Failure 5 0 - 16% (N) 0 - 15% (S) Strong evidence no relationship N = Normal interval; S = Shortened interval A shorter casting interval results in a shorter treatment duration, but a lower limit is to be expected. It should be noted that no long term results are presented. Further biomechanical analysis is needed to interpret the results and to give a theoretical basis for an optimal interval. CONCLUSIONS We have found strong evidence that, while maintaining the Ponseti-method, the casting interval can be reduced by at least several days. Since this will not have an effect on the required number of casts the treatment duration will be decreased, without deterioration of the short-term clinical outcome. ACKNOWLEDGEMENTS This study has been partly supported by the Dutch Technology Foundation. REFERENCES 1. Ponseti IV, et al. The Journal of Bone & Joint Surgery. 45(2):261-344, 1963. 2. Bell-Krotoski JA, et al. Journal of Hand Therapy. 8(2):131-137, 1995. 3. Pohl M, et al. Archives of Physical Medicine and Rehabilitation. 83(6):784-790, 2002. 4. Dyer, P. et al. Journal of Bone & Joint Surgery-British Volume 88: 1082-1084, 2006.