ABSTRACT
BACKGROUND: Treatment of displaced intra-articular calcaneal fractures (DIACFs) with percutaneous screw fixation remains defective in some aspects. A novel three-dimensional (3D) printed cast was devised to assist screw placement. This study assessed the radiological and functional outcomes of 3D-printed cast assisted screw fixation for patients with DIACFs. METHODS: Patients with unilateral Sanders type II or III DIACFs admitted to a single-centre hospital underwent either 3D-printed cast assisted screw fixation (3D group) or minimally invasive plate fixation (control group) from September 2020 to November 2022. All patients were assessed at one, two, three, and six months of follow-up. Comparison between groups was conducted in operative duration, fluoroscopic times, radiographic measurements of the calcaneus, and the American Orthopaedic Foot and Ankle Society (AOFAS) Ankle-Hindfoot Score. RESULTS: A total of 32 patients were enrolled (19 in the 3D group versus 13 in the control group). Significant differences were detected between the 3D group and control group in operative duration (53.63±8.95 min, 95.08±8.31 min, P <0.001), fluoroscopic times (7.37±1.21, 16.85±1.57, P <0.001). At a follow-up of six months, the 3D group showed better restoration than the control group in calcaneal width, height, Bohler angle, and AOFAS Ankle-Hindfoot scores (all P <0.001). No significant differences were shown in calcaneal length and Gissane angle (P >0.05). No wound-related complications occurred in either group. CONCLUSION: The 3D-printed cast assisted screw fixation has shown superiority over minimally invasive plate fixation in the operative duration, fluoroscopic exposure, morphological restoration of the calcaneus, and functional outcomes in the treatment of DIACFs.
Subject(s)
Ankle Injuries , Calcaneus , Foot Injuries , Fractures, Bone , Intra-Articular Fractures , Knee Injuries , Humans , Prospective Studies , Fracture Fixation, Internal/methods , Treatment Outcome , Fractures, Bone/diagnostic imaging , Fractures, Bone/surgery , Calcaneus/diagnostic imaging , Calcaneus/surgery , Bone Screws , Intra-Articular Fractures/surgery , Retrospective StudiesABSTRACT
The light pen is one of the most useful spatial coordinate measurement methods. However, due to the principle of vision measurement, the traditional light pen has the disadvantages such as limited measurement range, large structure size and complex calibration process. In order to revolutionize the design of light pen, this paper proposes a full space coordinate measurement method with a portable light pen by using hybrid light field imaging. Firstly, a light field imaging system with depth estimation ability has been introduced to simplify the light pen structure to three target points by using P3P method. In order to improve the accuracy of the depth estimation, a hybrid imaging method and EPI method have been used. Secondly, a full spatial measurement method with a rotation platform has been presented in detail. Finally, the experiments have been designed to verify the effectiveness and accuracy of the proposed method.
