Objective To investigate the application of 3D-printing and digital technology in the preoperative design of internal fixation for intra-articular calcaneal fractures.Methods Thin-layer CT images of bilateral calcanei were collected from 12 patients who had been treated for calcaneal fracture of Sanders type Ⅲ from November 2015 to October 2016.They were 7 men and 5 women,aged from 23 to 53 years (average,38.7 years).The images were uploaded into Mimics software for 3D reconstruction,virtual reduction and digital surgical design.Real-size calcaneal models and navigation modules were produced using 3D printing technology for plate preshaping and surgical simulation.The operations were carried out according to preoperative design.The postoperative calcaneal morphological parameters were evaluated.Comparisons were made between postoperative results and preoperative digital design.Results The operating time for the 12 patients ranged from 60 to 90 minutes,averaging 77.9 minutes.Their follow-ups ranged from 4 to 8 months,averaging 6.2 months.No complications affecting their soft tissues happened.The postoperative B(o)hler angle (32.6° ± 3.6°) and Gissane angle (123.9° ± 9.5°) were significantly improved compared with the preoperative values (12.4° ± 2.1° and 143.9° ± 7.8°) (P ＜ 0.001).The shape of postoperative calcaneus was similar to that of the preoperative reduction model.The internal fixation locations and nail directions were in agreement with the preoperative design.Their average Maryland score was 87.8 and excellent to good rate 91.7％.Conclusion This technique can transform a digital design for intra-articular calcanealfracture into real operation tools to help realize a precise surgical design for such fractures.

Objective:To explore the clinical effect of a modified single-trunk arterialised venous flap in reconstruction of soft tissue defect in hand and foot.Methods:From January 2019 to June 2022, 25 patients with soft tissue defect in hand and foot were treated in the Department of Hand and Foot Plastic Surgery of Lecong Hospital of Shunde in Foshan. The soft tissue defects were reconstructed with a venous flap, of which a single trunk of vein was ligated and then a blood flux of the flap was re-established via a modified single vein trunk. One patient had soft tissue defect in dorsal foot and toes, 3 patients had defects in dorsal hand, 3 patients had defects in 2 digits and 18 patients had defects in single-digit. The sizes of defects were 2.0 cm×1.0 cm-10.0 cm×4.5 cm. The sizes of flaps were 2.0 cm×1.0 cm-12.0 cm×5.5 cm. Donor sites of the 19 cases were directly sutured and 6 were covered by skin grafts. The postoperative follow-ups were conducted at outpatient clinics and via telephone reviews to observe the survival of flaps. Functional recovery of 23 cases whose soft tissue defects in hand were evaluated according to the Evaluation Standard of Upper Limb Partial Functional of Hand Surgery of Chinese Medical Association. The sensory recovery of flaps was evaluated according to the comprehensive flap scale.Results:All 25 single-trunk venous flaps survived successfully. There were small number of blisters on 5 flaps, due to tissue oedema. One patient lost in follow-up. The other 24 patients had 2-18 months of follow-up. The appearance of flaps was soft and thin, with wear-resistant. According to the Evaluation Standard of Upper Limb Partial Functional of Hand Surgery of Chinese Medical Association, the function recovery were excellent in 12 cases, good in 9 cases and poor in 2 cases. Sensations of the flaps were 90-99 point with an average of 97 point according to the comprehensive flap scale, of which 22 flaps were in excellent and 2 in good.Conclusion:The method of ligation of single vein-trunk to make a arterialised venous flap is a simple surgical procedure. There are many selections of donor site with minimum damage. It is an effective method and with satisfactory outcomes.

Objective:To explore the clinical effect of repairing interphalangeal joint defect of hand with free transfer of part of the 2nd metatarsophalangeal joint tissue flap precisely cut with the aid of digital 3D printing technology.Methods:From December 2016 to December 2020, 7 patients with partial joint defects of proximal interphalangeal joints of fingers were treated in Department of Hand and Foot Surgery, Shunde Hospital Affiliated to Guangzhou Medical University(Foshan Shunde Lecong Hospital). Before surgery, three-dimensional data of hand and foot bones were collected, and the 3D printing model was used to simulate the operation in vitro. During the operation, the first dorsal metatarsal artery-the 2nd dorsal metatarsal artery was used as the pedicle, and the 2nd metatarsophalangeal joint composite tissue flap with a required size was harvested with the assistance of the navigation template to tranfer and repair the small joint defects of hand. All 7 cases entered follow-up at outpatient and telephone. Results:All 7 cases survived. Postoperative follow-up was 3-24(mean 9.5) months, Range of motion of the repaired interphalangeal joint was (56 ± 6)°; According to the Evaluation Standard of Thumb and Finger Reconstruction Function of the Society of Hand Surgery of the Chinese Medical Association, 2 cases were excellent, 4 cases were good, and 1 case was poor.Conclusion:Transfer of the free 2nd metatarsophalangeal joint tissue flap assisted by 3D printing technology in repair of the small joint defect of the hand can accurately harvest the tissue flap, which is clinically reliable.