Radiographic evaluation of naviculo-cuneiform sag deformity following triplane bunion correction via first tarsometatarsal joint arthrodesis

Abstract

Purpose: To evaluate naviculo-cuneiform joint sag after first tarsometatarsal joint arthrodesis and the possible correlation between the presence of NC sag, loss of anatomic correction, and other radiographic angle measurements such as Calcaneal inclination and Meary's angle. Hypothesis: We propose there is no increase in NC sag following 1st TMTJ arthrodesis and that there is no correlation between NC sag and the calcaneal inclination or Meary's angles. However, we do propose that there is a correlation between post-operative NC sag and loss of triplane bunion correction. Procedures/methods: Retrospective chart review to identify patients with first TMTJ arthrodesis from 2017-first half 2021. Eligible patient's had radiographic analysis and chart reviews performed at 2 weeks, 6 weeks, 12 weeks, and 3-6 months post-operatively. Following that, preoperative and 3-month postoperative weight-bearing radiographs, measuring the following radiographic angles: Meary's angle, Calcaneal inclination angle, Talocalcaneal (Kite's Angle), and NCIA (Naviculo-cuneiform incongruency angle). Loss of correction was measured by either an increase in intermetatarsal angle (IMA) and/or deviation of the sesamoids measured by the tibial sesamoid rotation.Statistical analysis was performed using PRISM version 2. Paired Student's T-test was utilized to compare preoperative and postoperative radiographic angle measurements for NCIA. A Pearson's coefficient correlation was also utilized to assess for any correlation between the preoperative NCIA deformity, post-operative NCIA deformity and the values for pre-operative Calcaneal inclination angle, post-operative Calcaneal inclination angle, pre-operative Meary's angle, and lastly, post-operative Meary's angle. Unpaired Student's t-test was utilized to compare the difference in NCIA post- to preoperative between 96 patients with radiographic union and 15 patients with radiographic non-union. Study design: Retrospective chart review and radiographic evaluation.

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