The Battleship Technique: A Reliable Method to Quantify Intraarticular Distance Maps Patterns and Correlate Hindfoot Alignment

Research Type: Level 3 - Retrospective cohort study, Case-control study, Meta-analysis of Level 3 studies Introduction/Purpose: WBCT creates color-coded distance maps (DM) to analyze intraarticular contact areas, offering detailed joint surface interactions assessment. This study introduces the "Battleship Technique (BST)" to evaluate contact area patterns in patients with talar dome osteoarthritis, producing a distance map weighted sum (DMWS). The DMWS serves as a potential reference for assessing hindfoot deformities and guiding clinical decisions, including surgical planning. We hypothesize that the BST is reliable for calculating the DMWS and that the DMWS correlates with hindfoot alignment, providing a tool to improve deformity evaluation. The primary aim was to evaluate the reliability of the BST, and the secondary aim was to determine if the DMWS is influenced by hindfoot alignment. Methods: Two raters independently calculated DMWS using BST for forty ankle OA patients. Patients were categorized into coronal (varus/valgus) and sagittal (anterior/posterior) groups based on DMWS location relative to the joint center. Hindfoot alignment was statistically compared between groups Results: Excellent interobserver and intraobserver agreement was observed. Significant differences were found in α angle, talar surface angle (TSA), hindfoot alignment angle (HFA), and talar tilt (TT) (p=0.047, p< 0.001, p=0.003, p=0.04) between coronal groups, and in β angle and tibiotalar ratio (TTR) (p < 0.001) between sagittal groups. Correlations were identified between DMWS and TSA (r=0.6, p< 0.001), TT (r=-0.6, p< 0.001), β angle (r=0.2, p< 0.001), and TTR (r=-0.4, p< 0.001). Conclusion: The BST reliably calculates the DMWS, correlating with foot and ankle alignment. BST provides a standardized, noninvasive method to evaluate intraarticular contact patterns, offering valuable insights for preoperative planning and postoperative assessment. Its integration into practice may enhance surgical precision in complex realignment procedures.