SLR - August 2023 - Ryan J. Larsen, DPM
Title: Incidence and predictors of valgus tibiotalar tilt after progressive collapsing foot deformity reconstruction using subtalar fusion with concomitant proceduresReference: Kim J, Rajan L, Henry J, Mizher R, Johnson AH, Demetracopoulos C, Ellis S, Deland J. Incidence and predictors of valgus tibiotalar tilt after progressive collapsing foot deformity reconstruction using subtalar fusion with concomitant procedures. Archives of Orthopaedic and Trauma Surgery. 2023 May; doi: 10.1007/s00402-023-04906-x. Epub ahead of print. PMID: 37160446.
Scientific Literature Review
Reviewed By: Ryan J. Larsen, DPM Residency Program: Ascension St. Vincent
Podiatric Relevance: Valgus tibiotalar tilt is a relatively common complication that can occur following subtalar joint (STJ) fusion for progressive collapsing foot deformity (PCFD) reconstruction. This tilt can be detrimental to patients as it can lead to cartilage wear and subsequent ankle arthritis over time. The factors associated with the development of valgus tibiotalar tilt after STJ fusion in PCFD correction are not well understood. Under-correction of heel alignment and excessive foot stiffness resulting from multiple foot fusion surgeries have been suggested as contributing factors. However, there are currently no studies in the literature evaluating predictors of valgus tibiotalar tilt following STJ fusion in PCFD correction. The purpose of this study was to define the incidence and determine predictors of valgus tibiotalar tilt after PCFD reconstruction with STJ fusion.
Methods: This retrospective cohort examined patients who underwent PCFD reconstruction utilizing a STJ fusion between 2016 and 2020. The study included 59 patients who met the inclusion criteria being older than 18 years of age and achieving a radiographic post-surgical follow up of 6 months or greater (mean follow up was 15 months). Exclusion criteria included preoperative tibiotalar malalignment, preoperative valgus tibiotalar tilt exceeding 2 degrees, and a lack of postoperative ankle radiographs. Primary outcomes were determined through pre-operative and post-operative radiographic analysis (valgus talar tilt of > 2 degrees). Univariate regression analysis was used to identify factors associated with postoperative valgus tibiotalar tilt.
Results: Among the 59 ankles analyzed, 17 patients (28.8%) developed valgus tibiotalar tilt after surgery, with a mean tilt of 5.4 degrees. The development of tilt occurred at a mean time of 7.7 months after surgery, with 47.1% of patients showing tilt within the first 3 months. No significant differences were found in the proportion of additional procedures between patients with and without tilt. However, logistic regression analysis indicated that a higher preoperative hindfoot moment arm (HMA) was associated with an increased risk of postoperative valgus tibiotalar tilt. An increase in preoperative HMA by 1 mm was associated with a 6% increase in risk for developing postoperative valgus tibiotalar tilt. Other demographic and radiographic parameters did not differ significantly between the groups.
Conclusions: Valgus tibiotalar tilt was found to be a relatively common complication after STJ fusion for PCFD reconstruction, with an incidence of 28.8%. The authors recommend including both postoperative and preoperative ankle radiographs in the follow-up of these patients, as the degree of valgus hindfoot was identified as a significant predictor for the development of tibiotalar tilt. They suggest that ensuring neutral heel alignment and establishing a stable foot tripod during subtalar fusion may be important in preventing this complication. This study emphasizes the importance and challenge of identifying and treating the deforming force(s) acting on a PCFD in the presence of fusing the STJ. Increasing the power of this study by increasing the sample size and mean follow up may help to uncover other significant correlations, particularly as it pertains to the addition of adjunctive procedures. I would be curious to know if clinical findings such as resting calcaneal stance position and forefoot varus have any significant correlation.