Background: This study aimed to determine the difference between computer-assisted virtual surgical technology and 3-dimensional (3D) printing technology in preoperative planning for proximal humeral fractures. Methods: Between February 2009 and October 2015, 131 patients with 3 and 4-part proximal humeral fractures were divided into 3 groups on the basis of the preoperative planning method: conventional (n = 53), virtual surgical (n = 46), and 3D printing (n = 32). Fracture characteristics and intraoperative realization of preoperative planning (reduction shape and implant choices) were evaluated. Postoperative functional outcomes were assessed using the American Shoulder and Elbow Surgeons, Constant-Murley, and Short Form-36 (SF-36) scoring systems and shoulder range of motion; postoperative radiographic outcomes were assessed with respect to the loss of the neck-shaft angle (NSA) and loss of humeral head height (HHH). Results: Excellent sensitivity, specificity, and accuracy for fracture characteristics were seen in all 3 groups. The correlations for NSA (p = 0.033) and HHH (p = 0.035) were higher in the virtual surgical group than in the 3D printing group. The lengths of the medial support screws in the actual choices were shorter than those in the preoperative plan for the 3D printing group, but a similar pattern was not seen in the virtual surgical group. Compared with the conventional method, the virtual surgical and 3D printing methods of preoperative planning resulted in shorter operative time, less blood loss, and fewer fluoroscopic images. The functional outcomes in both the 3D printing and virtual surgical groups were better than those in the conventional group. The virtual surgical method was faster than the 3D printing method, as suggested by a shorter time to surgery (2.5 compared with 4.6 days; p < 0.001), a shorter time for preoperative planning (30.4 compared with 262.4 minutes; p < 0.001), and a decreased duration of hospital stay (10.9 compared with 14.6 days; p < 0.001). Conclusions: The clinical outcomes in both the virtual surgical and 3D printing groups were better than those in the conventional group. However, computer-assisted virtual surgical technology is more convenient and efficient, considering the shorter time for preoperative planning. In addition, it has improved correlation with preoperative planning. Level of Evidence: Therapeutic Level III. See Instructions for Authors for a complete description of levels of evidence.

Background: Syndesmotic injury may be difficult to diagnose, and radiological evaluation is very important. The purpose of this study was to offer a series of reliable and repeatable normal tibiofibular syndesmosis parameters in diagnosing injuries of the syndesmosis.Methods: Multi‐detector computed tomography (MDCT) and radiographs of the distal tibiofibular syndesmosis in 484 cases were retrospectively reviewed. Relevant parameters included the tibiofibular clear space (TCS), the tibiofibular overlap (TFO), the depth of the incisura fibularis (IFD), and the height of the incisura fibularis (IFH), which were measured by novel three‐dimensional (3‐D) and two‐dimensional (2‐D) techniques. The distance between the measuring plane of the distal tibiofibular syndesmosis and the tibial plafond was measured. Intra‐ and inter‐rater reliability was assessed by intraclass correlation coefficient (ICC) and the root mean square standard deviation (RMS‐SD), to determine measurement precision. Sex differences of parameters were analyzed using analysis of covariance (ANCOVA) with body height as the covariate. Paired sample t‐testing was used to compare parameters in different image modalities, including radiography, and 2‐D and 3‐D CT.Results: The reliability of the 3‐D images measurement (ICC range, 0.907 to 0.972) was greater than that for the 2‐D axial images (ICC range, 0.895 to 0.927), and the AP view radiographs (ICC range, 0.742 to 0.838). The intra‐rater RMS‐SD of the 3‐D CT, 2‐D CT and radiographic measurements were less than 0.94 mm, 0.26 mm, and 2.87 mm, respectively. The measuring plane of the distal tibiofibular syndesmosis showed the sex difference, which was 12.1 mm proximal to the tibial plafond in the male group and 7.8 mm in the female group. In this plane, the parameters for tibiofibular syndesmosis were measured in different image modalities. All variables were significantly different between females and males (p < 0.05).Conclusions: 3‐D measurement technique could be helpful to identify the precise measurement planes for syndesmosis, which were not at the fixed level above the tibial plafond because of the sex difference. In this plane, reliable measurement results could be provided, in either 2‐D or 3‐D MDCT images.

Background: Although computed tomography (CT) with three‐dimensional (3D) rendering of the calcaneus is used for diagnostic evaluation of disorders, morphological measurements for the calcaneus are mostly based on a two‐dimensional plane. The purposes of this study were to design a method for 3D morphological measurements of the normal calcaneus based on CT post‐processing techniques, to measure morphological parameters in the male and female groups and describe gender differences of the parameters, and to investigate the reliability of such measurements.Methods: One hundred and seventy‐nine patients (83 men and 96 women) with a mean age of 40.6 (range, 21 to 59) years who underwent CT scans for their feet were reviewed retrospectively. The 3D structure of a normal calcaneus after shaded surface display reconstruction was extracted by interactive and automatic segmentation. Morphological measurements were achieved by means of a 3D measurement method based on CT image post‐processing. Lengths and heights of the main parts of the calcaneus, Gissane's angle, Böhler's angle and the area of articular facet were worked out in 3D space. Gender‐related size differences of parameters were compared using analysis of covariance (ANCOVA), adjusting for body height. Intra‐observer and inter‐observer reliabilities were assessed using intraclass correlation coefficients (ICCs) and the root mean square standard deviation (RMS‐SD) for precision study.Results: A large range of measurement values was found. Only the length of the anterior process was without gender difference (p > 0.05). The other parameters in the male group were greater than those in the female group (p < 0.01 for each, ANCOVA). All parameters had excellent reliability and reproducibility (ICC > 0.8). Precision was acceptable for intra‐observer RMS‐SD (linear, angular and areal measurements no more than 0.6 mm, 1.2° and 0.25 mm², respectively). Inter‐observer RMS‐SD ranged from 0.4 to 1.6 mm for linear measurements, 1.2 to 2.5° for angles and 0.24 to 0.40 mm² for areas.Conclusions: Three‐dimensional morphological measurement based on a CT post‐processing technique was highly reliable and repeatable for calcaneal anatomic morphological measurement. The current data will be helpful for anatomic reduction of calcaneal fractures and calcaneal malunion.

Single, double, and triple hindfoot arthrodeses are used to correct hindfoot deformities and relieve chronic pain. However, joint fusion may lead to dysfunction in adjacent articular surfaces. We compared range of motion in adjacent joints before and after arthrodesis to determine the effects of each procedure on joint motion. The theory of moment of couple, bending moment and balanced loading was applied to each of 16 fresh cadaver feet to induce dorsiflexion, plantarflexion, internal rotation, external rotation, inversion, and eversion. Range of motion was measured with a 3-axis coordinate measuring machine in a control foot and in feet after subtalar, talonavicular, calcaneocuboid, double, or triple arthrodesis. All arthrodeses restricted mainly internal-external rotation and inversion-eversion. The restriction in a double arthrodesis was more than that in a single arthrodesis, but that in a calcaneocuboid arthrodesis was relatively low. After triple arthrodeses, the restriction on dorsiflexion and plantarflexion movements was substantial, and internal-external rotation and inversion-eversion were almost lost. Considering that different arthrodesis procedures cause complex, three-dimensional hindfoot motion reductions, we recommend talonavicular or calcaneocuboid arthrodesis for patients with well-preserved functions of plantarflexion/dorsiflexion before operation, subtalar or calcaneocuboid arthrodesis for patients with well-preserved abduction/adduction, and talonavicular arthrodesis for patients with well-preserved eversion/inversion.

Objective: To evaluate the computational biomechanical analysis of intra‐articular calcaneal fractures with different fixation status of the sustentaculum plate screw, when the finite element modeling of calcaneal fractures were fixed by the lateral locking plate.Methods: The normal right foot of a male (age: 36 years; height: 174 cm; body weight: 65 kg) was scanned by the CT scanner. As the computational biomechanical study, the three‐dimensional finite element model of the simplified Sanders type‐II calcaneal fracture was built. Fixation with the lateral calcaneal locking plate and screws was simulated using a finite element software package according to clinical operation. According to the different placement of the sustentaculum plate screw, the models were categorized as the accurate fixation group, marginal fixation group, and non‐fixation group. The loading of 650 N with the vertical axial compression was applied to simulate the standing phase with single foot. The Von Mises stress distribution, maximal displacement, and contact area of the subtalar joint were analyzed among three groups.Results: The pressure distribution of the subtalar joint facet was inhomogeneous. The stress concentration of the calcaneus was located at the medial zone of the posterior subtalar joint facet. The peak Von Mises stress distribution in three groups was similar at the subtalar joint facet of 4.9 MPa, 5.1 MPa, and 5.4 MPa. In the accurate fixation group, the contact area on the posterior articular facet was 277.1 mm²; the maximal displacement was 0.18 mm. The contact area of the marginal fixation group was 265.3 mm² on the posterior facet, where the maximal displacement was 0.23 mm. In the non‐fixation group, the contact area was 253.8 mm²; the maximal displacement was 0.25 mm. There was a slight change in the contact area of the subtalar joint and no prominent displacement of the calcaneus could be detected among the three groups.Conclusions: The biomechanical results, including the peak stress distribution, contact area, and maximal displacement of subtalar joint, were similar whether the screw is placed exactly within the sustentaculum tali or not, when the calcaneal fractures were fixed by the lateral locking plate. The sustentaculum plate screw had less effect on the biomechanical performance of the calcaneus.