Weight-Bearing CT-Based 3D Presurgical Planning for Hindfoot Realignment in PCFD Reconstruction

Research Type: Level 3 - Retrospective cohort study, Case-control study, Meta-analysis of Level 3 studies Introduction/Purpose: The use of weight-bearing (WB) CT for 3D presurgical planning has increased in foot and ankle reconstruction. In advanced progressive collapsing foot deformity (PCFD), predicting biomechanical effects of each surgical step is challenging. Presurgical planning helps determine the correction needed to reposition foot’s center (centroid) in line with the tibial axis, potentially preventing persistent deformity or tibiotalar valgus tilt after hindfoot fusion. We utilized WB CT-based 3D presurgical planning for PCFD reconstruction in cases requiring hindfoot realignment fusion (subtalar, double, or triple) as part of the procedure. This study aimed to assess whether WB CT-based 3D planning improves surgical accuracy, alignment, and efficiency in PCFD reconstruction. We assessed radiographic and clinical results, operative time, and the surgeon’s adherence to the preoperative plan. Methods: A retrospective comparative analysis was conducted on 23 patients (7 IIB, 9 III,7 IV) who underwent hindfoot realignment fusion (21 subtalar, 1 double, 1 triple) as part of PCFD reconstruction, which also included medializing calcaneal osteotomy (MCO), lateral column lengthening (LCL), and Cotton osteotomy, FDL transfer, and medial ligament reconstruction when indicated. Patients were divided in two groups based on whether WB CT scan based 3D presurgical planning was utilized. In the presurgical planned group, CT images were used for segmentation, identification of the foot centroid, and stepwise simulation in the following order until the foot centroid was aligned with the tibial axis: MCO, subtalar joint fusion with predicted wedge-shaped structural allograft to correct hindfoot valgus alignment, LCL, and Cotton osteotomy. We compared demographics, deformity stage, pre- and postoperative radiographs, PROMIS PI and PF scores, operative time, and the surgeon’s adherence to the presurgical plan. Results: There was no significant difference between the two groups in age (p=0.16), gender (p=0.07), BMI (p=0.77), staging (p=0.35), or pre-operative radiographic measures (TN angle, p=0.98; calcaneal pitch, p=0.82; Meary’s angle, p=0.18; tibiotalar valgus tilt, p=0.85). Post-operative improvements in radiographic measures (TN angle, p=0.68; calcaneal pitch, p=0.96; Meary’s angle, p=0.15; tibiotalar valgus tilt, p=0.61), PROMIS PI (p=0.81)and PF (p=0.81) scores, and operative time (p=0.07) also showed no significant differences. The surgeon consistently performed the MCO and subtalar joint fusion with structural allograft as preoperatively planned. However, LCL and Cotton osteotomy were adjusted intraoperatively in 3 of 6 cases (50%) based on intraoperative assessment. Conclusion: WB CT scan-based 3D presurgical planning provided helpful guidance for complex PCFD reconstruction. However, no significant differences were found in radiographic or clinical outcomes or surgical time between groups. While 3D presurgical planning aids in determining the ideal structural allogenous bone graft for hindfoot correction, such as subtalar joint fusion, surgeons should rely on intraoperative judgement, particularly for LCL and later stages of reconstruction.