Feasibility of Computer‐Aided Design in Limb Lengthening Surgery: Surgical Simulation and Guide Plates

Abstract

Objective: To evaluate the feasibility and utility of computer-aided design (CAD) in surgical treatment of leg length discrepancy (LLD) using monorail external fixators. Methods:In the present case series, we retrospectively analyzed seven patients diagnosed with LLD who were surgically treated using a monorail external fixator between June 2018 and August 2020. A personalized surgical emulation of each patient was designed using CAD based on preoperative CT scans to measure limb parameters. Through reverse engineering, a surgical guide plate was then designed to assist with correcting the limb deformity. Patient general information and clinical history, leg length, mechanical lateral distal femoral angle (mLDFA), anatomical anterior distal tibial angle (aADTA), and surgical parameters were recorded during the perioperative period. Three months after external fixator removal, distraction-consolidation time (DCT), healing index (HI), and lower extremity function score (LEFS) were calculated, and statistically analyzed by paired T-test. Results:The mean limb lengthening achieved was 6.41 AE 2.54 (range, 3.30-10.54) cm with either varus or valgus correction. The mean operative duration was 151 AE 41.87 (84-217) minutes and mean blood loss was 53.58 AE 22.51(25-87) ml. The mean distraction-consolidation time was 3.67 AE 1.13 (range, 2.5-6.0) months and mean external fixator duration was 11 AE 2.45 (range, 8-14) months. The mean healing index (HI) was 18.11

Accuracy of correction of a hexapod frame, patient-specific osteotomy and reduction guides, and hinged circular external fixation in a 3D-printed canine antebrachial deformity model

“…Computer-aided design (CAD)-based surgical planning and 3D-printing of both patient-specific guides and patient-specific implants are established in veterinary orthopedics ( 19 ), and multiple reports document the accuracy of both deformity correction and implant placement using this technology ( 10 , 20 , 21 ). In human orthopedics, CAD-based planning and 3D-patient-specific guides (3D-PSGs) have also been used for deformity correction ( 22 ) and have recently been used to aid in the orientation of external fixation pin placement, which then sets the position of the subsequent external skeletal fixator construct on the bone ( 23 ).…”