[Clinical application research of three-dimensional printed patient-specific cutting guides in Cole midfoot...

To evaluate effectiveness of three-dimensional (3D) printed patient-specific cutting guides (PSCGs) in Cole midfoot osteotomy for treatment of rigid pes cavus deformity associated with Charcot-Marie-Tooth (CMT) disease, and to analyze learning curve for PSCGs-assisted surgery.

A retrospective analysis was conducted of 20 patients (40 feet) with rigid pes cavus deformity associated with CMT who were admitted between March 2021 and July 2023 and met the inclusion criteria. The cohort comprised 13 men and 7 women, with ages ranging from 17 to 62 years (mean, 37.3 years). All patients underwent whole-genome sequencing, which identified 17 patients with CMT type 1 and 3 patients with CMT type 2. Preoperatively, 3D models of bilateral feet were reconstructed based on CT data, and PSCGs were designed and fabricated accordingly. All patients underwent a Cole midfoot osteotomy assisted by the guides. Operation time, number of intraoperative fluoroscopic exposures, and intraoperative complications were recorded. Pre- and post-operative outcomes were compared using the visual analogue scale (VAS) score for pain, the American Orthopaedic Foot & Ankle Society (AOFAS) ankle-hindfoot score, and domain scores of the 36-Item Short Form Health Survey (SF-36), as well as radiographic parameters including the Meary's angle, Pitch angle, talo-first metatarsal angle (T1MT), talocalcaneal angle (TCA), and Djian-Annonier angle, to assess the corrective effect of the osteotomy. A modified cumulative sum analysis was performed to evaluate the learning curve for PSCGs-assisted surgery.

All procedures in the 20 patients (40 feet) were completed successfully, with no cases of massive hemorrhage or injury to critical neurovascular or tendinous structures. The operation time ranged from 63 to 129 minutes (mean, 82.9 minutes), and fluoroscopy was performed 2-11 times (mean, 4.7 times). Postoperatively, 1 patient (1 foot) developed a mild superficial surgical-site infection, which resolved with symptomatic treatment; no deep infections occurred. All patients were followed up 8-43 months (mean, 17 months). At last follow-up, the AOFAS ankle-hindfoot score and all domain scores of the SF-36 were significantly higher than preoperative values, and the VAS score, the Meary's angle, T1MT, TCA, and Djian-Annonier angle significantly decreased, Pitch angle significantly increased ( P<0.05). The imaging confirmed osteotomy union in all feet, and no fixation-related complications was observed. Learning-curve analysis indicated that both operation time and fluoroscopy usage plateaued after the 13th case, suggesting stabilization of surgical performance from that point onward.

The use of PSCGs during Cole midfoot osteotomy enables precise and efficient correction of complex midfoot deformities while significantly reducing intraoperative fluoroscopic exposure. Moreover, this technique appears to have a short learning-curve and good reproducibility, which may facilitate its broader adoption in clinical practice.