SLR - November 2015 - Alexander R. Pérez
Lateral Tibiocalcaneal Angle As a Determinant for Percutaneous Achilles Tenotomy for Idiopathic Clubfeet
Reference: Kang S, Park SS. Lateral Tibiocalcaneal Angle As a Determinant for Percutaneous Achilles Tenotomy for Idiopathic Clubfeet. J Bone Joint Surg Am. 2015 Aug 5;97(15):1246-54.
Scientific Literature Review
Reviewed By: Alexander R. Pérez, DPM
Residency Program: Englewood Hospital and Medical Center, Englewood, NJ.
Podiatric Relevance: When evaluating patients with idiopathic talipes equinovalgus deformity, physical examination may be subjective when determining need for percutaneous Achilles tenotomy following Ponsetti casting. Evaluation of ankle dorsiflexion via the ankle dorsiflexion angle (ADF) may mask any pseudo-correction arising from breakage of the midfoot. This can, however, be avoided by evaluation of the lateral tibiocalcaneal angle (LTiC) on plain films, with the patient placed in maximal dorsiflexion. This article sought to evaluate groups of patients according to their LTiC and ADF angles and correlate each with clinical outcomes for each group.
Methods: This Level III retrospective study evaluated 82 patients with 125 idiopathic clubfeet treated at one single institution over the course of six years. Mean follow-up time was 48.5 months. Patients were casted via Ponsetti method by one experienced pediatric orthopedic surgeon. Once initial correction was achieved (except ankle equinus deformity), the LTiC and ADF angles were evaluated. If LTiC was found to be >80° then percutaneous Achilles tenotomy was recommended. After tenotomy, all patients were placed in a long leg cast with the ankle in maximum dorsiflexion, 70° of abduction, and the foot rotated outwardly with respect to the thigh. The cast then remained in place for three weeks. Subsequently, the patients were placed in a Denis-Browne abduction orthosis at all times for three months. The orthosis was then applied only at night until the patient reached age 3. If tenotomy was not performed, the patient was immediately placed in a Denis-Browne abduction orthosis.
Results: Patients with a favorable LTiC ankle experienced no sagittal relapse or surgery; in contrast, 13.7 percent and 9.8 percent of patients in two groups with a favorable ADF angle underwent sagittal relapse and surgery, respectively. For patients with conflicting LTiC/ADF angle values who underwent percutaneous Achilles tenotomy, the results were as follows: none of the seven patients with favorable LTiC angle and unfavorable ADF angle experienced sagittal relapse. In contrast, three of the five patients with an unfavorable LTiC angle and favorable ADF angle experienced sagittal relapse with subsequent surgical intervention. Multivariate analytic results of prognostic effects of both angles revealed that the LTiC angle was a more determinative value for percutaneous Achilles tenotomy as compared to the ADF angle.
Conclusions: Given the findings that the LTiC angle is objectively a better prognosticator of both sagittal relapse and subsequent surgical intervention following percutaneous Achilles tenotomy, the author recommends the use of the LTiC angle over the ADF angle as a determining indicator for performance of percutaneous Achilles tenotomy. In particular, the clinical nature of the ADF angle does not take into account the pseudocorrection that may occur at the midfoot due to breakage at the midfoot level. The LTiC angle radiographically presents pure ankle joint motion, in contrast, which demonstrates the relationship of the tibia with respect to the calcaneus.