Application of 3D printed guide plate based on anatomic measurement in simple Lisfranc ligament injury

Abstract

Objective To explore the value of the anatomical-based 3D printed guide plate in the treatment of simple Lisfranc ligament injury. Methods A prospective study of 10 cases of residual foot after amputation of lower extremity tumor patients was performed from September 2015 to April 2016 in the First Affiliated Hospital of China Medical University. There were 6 males and 4 females; aged 37-78 years; 5 cases of left foot and 5 cases of right foot. The Lisfranc ligament and its connected bone tissue were isolated from the stump specimen, the appearance and shape of the ligament were observed, and the detailed parameters of the ligament and its surrounding structure were measured. The clinical data of 16 patients with simple Lisfranc ligament injury from the First Hospital of China Medical University from January 2016 to February 2017 were retrospectively analyzed. There were 10 males and 6 females, aged 15 to 57 years old, 7 left foot and 9 right foot. According to Myerson injury classification: 7 patients of type A, 3 patients of type B1, and 6 patients of type B2. According to the different treatment methods, they were divided into two groups. Eight patients that were treated with 3D printed guide plates were the guide plate group, and 8 patients that were treated with positioning guidance devices were the control group. The operation time, number of perspectives and tourniquet time of the 2 groups of patients were recorded and compared. Foot function assessment was performed in the 1st, 3rd and 9th month after surgery using Visual Analogue Score (VAS), Ankle-midfoot Score of American Orthopedic Foot and Ankle Society (AOFAS) and 36 items of MOS item short from health survey(SF-36). Results The Lisfranc ligaments of 10 residual specimens were composed of 2 bundles. The appearance was white, the texture was tough, elastic, surrounded by no fat tissue, starting from the outer side of the medial cuneiform, the direction of travel was slightly inclined to the lateral side, ending at the base of the second metatarsal, tightly connected to the bone tissue. Anatomical measurements: The length of the Lisfranc ligament was (7.74±1.25) mm, the total width was (7.04±1.42) mm, and the thickness was (4.92±0.38) mm. The distance between the attachment point of the ligament and the center of the medial wedge bone was (9.10±0.85) mm. The distance between the ligament stop point attachment point and the distal end of the second humerus wedge joint surface was (4.86±1.32) mm. The inner side of the medial wedge bone was (27.66±1.83) mm and the height was (39.00±2.51) mm. Along the ligament, the Kirschner wire was driven from the medial wedge and passes through it. Two planes A and B were made throught the needle point, which were parallel to the line of the length and height of the medial wedge bone, respectively, and were perpendicular to the inner side of the medial cuneiform. The angle between the ligament and the plane A was 17.5°±1.8°, and the angle with the plane B was 18.5°±2.4°. The distance from the needle insertion point to the needle point of the second metatarsal base was (34.52±3.72)mm. The patients' surgery was successfully pertormed. The operation time, tourniquet use time and fluoroscopy times of the guide plate group were (42.3±5.2) min, (30.1±4.8) min, (2.9±0.8) times, respectively, which were significantly less than the control group (56.7±8.4) min, (45.4±5.3)min、(6.0±1.6)times. The differences were statistically significant (t=-4.122, -4.889, -6.052, all P values 0.05). Conclusions By anatomizing and measuring the Lisfranc ligament and related structures in the specimen, the data support can be provided for the design of the 3D printed guide. In the clinic, with the anatomical data of the Lisfranc ligament and computer-aided design, 3D printing guide plate, it not only can the precise insertion of the screw, but also reduce the operation time and the risk of radiation exposure. The patients recover quickly after surgery and have good results.. Key words: Lisfranc ligament; Anatomy; 3D printing; Guide plate