Comparative analysis of clinical outcomes of talocalcaneal coalition resection: subtalar joint middle and posterior facet involvement versus isolated posterior facet involvement - a retrospective cohort study.

Background: Despite coalition resection being the preferred treatment for talocalcaneal coalition (TCC), postoperative complications, suboptimal functional recovery, and recurrence risks remain challenges. Although current TCC classification systems guide personalized surgical plans, the impact of middle and posterior facet coalitions on TCC resection surgery's effectiveness is still poorly understood. Therefore, this study aims to compare the clinical outcomes of TCC patients with and without involvement of the subtalar joint's (STJ) middle and posterior facets undergoing coalition resection to explore the potential impact of these coalitions on surgical outcomes.

Methods: We conducted a retrospective study on 115 patients who underwent coalition resection surgery due to symptomatic TCC between November 2009 and February 2023. According to preoperative CT scan results, patients were divided into an isolated posterior facet coalition (P-type) group and a middle-posterior facet coalition (MP-type) group. Demographic characteristics (including age, sex, body mass index (BMI), follow-up time, and medical history duration), pre-and postoperative assessments (including Visual Analog Scale (VAS), American Orthopaedic Foot & Ankle Society (AOFAS) score, Pain Interference (PI) and Physical Function (PF) scores from the Patient-Reported Outcomes Measurement Information System (PROMIS)), as well as postoperative self-assessment of efficacy (excellent, good, fair, poor) and hindfoot stiffness, were compared between the two groups. Postoperatively, TCC recurrence was evaluated through imaging follow-up examinations.

Results: 69 patients meeting the inclusion criteria were included, with 30 patients in the P-type group and 39 in the MP-type group. There were no statistically significant differences between the two groups in demographic characteristics (P<0.05). There were also no statistically significant differences between the two groups in preoperative VAS score, AOFAS score, PI score, and PF score. However, postoperatively, there were statistically significant differences between the two groups in VAS score (1(1,1.5) vs. 2(1,2), P<0.01), AOFAS score (92.5(87,96.5) vs. 82(69.5,87), P<0.01), PI score (39(39,43) vs. 39(39,51), P = 0.014), PF score (73(61,73) vs. 55(51,73), P = 0.001), fair or poor outcome (4(13%) vs. 14(35.9%), P = 0.034), and hindfoot stiffness (3(10.3%) vs. 16(37.2%), P = 0.011). There was no statistically significant differences in the recurrence rate between the two groups postoperatively (0(0%) vs. 3(7.69%), P = 0.252).

Conclusion: Even with complete coalition resection during surgery and rehabilitation following standardized protocols, the surgical outcomes in MP-type TCC patients are still inferior to those in P-type patients.