An in-vitro three-dimensional surgical simulation technique to predict tibial tunnel length in transtibial posterior cruciate ligament reconstruction.

BACKGROUND: During the transtibial posterior cruciate ligament (PCL) reconstruction, drilling depth excessively longer than the tibial tunnel length (TTL) is an important reason to cause popliteal neurovascular bundle injury when preparing the tibial tunnel. This study aims to develop an in-vitro three-dimensional surgical simulation technique to determine the TTL in anteromedial (AM) and anterolateral (AL) approaches. METHODS: A total of 63 knees' 3-dimensional (3D) computed tomography models were included in this study. The SuperImage system was used to reconstruct the 3D knee model and locate the tibial PCL site. The established 3D knee model and the coordinates of the tibial PCL site were imported into Rhinoceros 3D modeling software to simulate AM and AL tibial tunnel approaches with different tibial tunnel angles (TTA). The TTL and the tibial tunnel height (TTH) were measured in this study. RESULTS: In AM and AL tibial tunnel approaches, the TTL showed a strong correlation with the TTA (for AM: r = 0.758, p < 0.001; for AL: r = 0.727, p < 0.001). The best fit equation to calculate the TTL based on the TTA was Y = 1.04X + 14.96 for males in AM approach, Y = 0.93X + 17.76 for males in AL approach, Y = 0.92X + 14.4 for females in AM approach, and Y = 0.94X + 10.5 for females in AL approach. CONCLUSION: Marking the TTL on the guide pin or reamer could help to avoid the drill bit over-penetrated into the popliteal space to damage the neurovascular structure.

Accuracy of detecting burst of the lateral wall in intertrochanteric hip fractures with plain radiographs: Is postoperative CT necessary?

Background: Postoperative burst of the lateral femoral wall is thought to be the main predictor of reoperation for intertrochanteric fractures, which is routinely evaluated using plain radiographs. We retrospectively compared computed tomography (CT) scans and radiographs regarding the ability to detect burst of the lateral wall. We also investigated whether intramedullary nails may cause iatrogenic burst of the lateral wall. Methods: From January 2010 to December 2021, patients aged 65 years and older who undergone intertrochanteric fractures treated with the proximal femoral nail antirotation 2 (PFNA-Ⅱ) were included. The incidence of burst of the lateral wall was evaluated with two different imaging modalities by two observers. Two rounds of evaluation were performed: (1) with plain radiographs alone; and (2) with CT scans combined with radiographs. Interobserver and intraobserver agreement (κ value) for evaluation of the lateral wall burst was assessed. Results: A total of 1507 patients were included (362 males and 1145 females). Compared with radiographs alone (12.0 %, 181/1507 patients), a higher rate of lateral wall burst was found by CT scans combined with radiographs (72.9 %, 1098/1507 patients) for observer 1 at first reading (P < 0.001). Similar results were seen in other evaluations. Interobserver and intraobserver agreement was substantial for radiographs alone (κ, 0.659-0.727) and almost perfect for CT scans combined with radiographs (κ, 0.847-0.926). Conclusions: Computed tomography combined with radiographs is superior to radiographs alone for detecting burst of the lateral wall after intertrochanteric fracture fixation. Additionally, PFNA-Ⅱ could cause iatrogenic burst of the lateral wall for intertrochanteric fractures in the elderly.

Identifying patients at risk of prolonged hospital length of stay after total knee arthroplasty: A real-world study on the creation and validation of a cloud estimator.

Accurate prediction of the length of stay for patients undergoing total knee arthroplasty (TKA) is critical for efficient medical resource allocation. This study aimed to create a user-friendly model to assist this estimation process. A secondary analysis was conducted on 2676 patients who underwent elective primary TKA at a tertiary academic medical center in Singapore from January 2013 to June 2014. The eligible patients (n = 2600) were randomly divided into a training cohort (n = 2081) and a validation cohort (n = 519), at a ratio of 4:1. A prolonged hospital stay was defined as exceeding six days. Multivariable logistic regression was used to develop a prediction model, and an online calculator was created to facilitate its application. The model's discrimination power, goodness-of-fit, and clinical applicability were evaluated. Additionally, models using other statistical methods were developed for performance comparison. The model includes predictors such as age, operation duration, history of cerebrovascular accidents, creatinine levels, procedure site, the American Society of Anesthesiologists Physical status, hemoglobin levels, and primary anesthesia type. The model demonstrated robust discrimination power with a C statistic of 0.70 (95% confidence interval, 0.64 to 0.75), satisfactory goodness-of-fit (Hosmer-Lemeshow test, P=0.286), and was applicable when thresholds were between 0.08 and 0.52, based on decision curve analysis. A predictive model was developed that can be used to identify patients who are likely to require an extended stay following TKA. This could assist in planning bed availability and guiding therapeutic decisions.

Design of well-matched end-structure of anatomical proximal femoral locking plate based on computer-assisted imaging combined with 3D printing technology: a quality improvement study.

BACKGROUND: The extramedullary locking plate system was the common internal fixation method for hip fractures. However, common plates were poorly matched to femur, which was because they were designed based on anatomical parameters of the Western populations. Therefore, the aim was to design an end-structure of the anatomical proximal femoral locking plate that closely matched the anatomy of the Chinese population. MATERIALS AND METHODS: From January 2010 to December 2021, consecutive patients aged 18 years and older who underwent a full-length computed tomography scan of the femur were included. The end-structure (male and female model) of the anatomical proximal femoral locking plate was designed based on anatomical parameters of femurs that were measured in three-dimensional space using computer-assisted virtual technology. The match degree between the end-structure and femur were evaluated. Inter-observer and intra-observer agreement for the evaluation of match degree was assessed. The matching evaluation based on a three-dimensional printing model was regarded as the gold standard to assess the reliability. RESULTS: A total of 1672 patients were included, with 701 men and 971 women. Significant differences were seen between male and female for all parameters of the proximal femur (all P <0.001). All match degree of end-structure was over 90%. Inter-observer and intra-observer agreement was almost perfect (all kappa value, >0.81). The sensitivity, specificity, and percentage of correct interpretation of matching evaluation in the computer-assisted virtual model was all greater than 95%. From femur reconstruction to completion of internal fixation matching, the process takes about 3 min. Moreover, reconstruction, measurement, and matching were all completed in one system. CONCLUSIONS: The results showed that based on the larger sample of femoral anatomical parameters, a highly matching end-structure of anatomical proximal femoral locking plate for Chinese population could be designed with use of computer-assisted imaging technology.

Surgically Relevant Morphological Parameters of the L5-S1 Interlaminar Window: A Statistical Analysis Based on 3D Reconstruction of CT Data.

BACKGROUND: The interlaminar window is the most important anatomical corridor during the posterior approach for lumbar and lumbosacral pathologies. Three-dimensional (3D) reconstruction of the L5-S1 interlaminar window including accurate measurements may be beneficial for the surgeon. The aim of this study was to measure relevant surgical parameters of the L5-S1 interlaminar window based on 3D reconstruction of lumbar computed tomography (CT). METHODS: Fifty thin-layer CT data were retrospectively collected, segmented, and reconstructed. Relevant surgical parameters included the width, left height, right height, interpedicular distance (IPD), area, and suitable approach area of the L5-S1 interlaminar window. Morphological measurements were performed independently by two experienced experts. Patients with disk herniation at L5-S1 were regarded as group A (n = 28) and those without L5-S1 disk herniation were regarded as group B (n = 22). RESULTS: The average left height, right height, width, and area of the L5-S1 interlaminar window were 9.14 ± 2.45 mm, 9.55 ± 2.46 mm, 23.55 ± 4.91 mm, and 144.57 ± 57.05 mm2, respectively. The average IPD at the superior, middle, and inferior pedicle levels was 29.29 ± 3.39, 27.96 ± 3.38, and 37.46 ± 4.23 mm, respectively, with significant differences among these three parameters (p < 0.05). The average suitable approach areas of the L5-S1 interlaminar window were the following: left axilla-24.52 ± 15.91 mm2; left shoulder-27.14 ± 15.48 mm2; right axilla-29.95 ± 17.17 mm2; and right shoulder-31.12 ± 16.40 mm2 (p > 0.05). There were no significant differences between groups A and B in these parameters (p > 0.05), except the inferior IPD (36.69 ± 3.73 vs. 39.23 ± 3.01 mm, p = 0.017 < 0.05). CONCLUSION: The morphological measurement of the L5-S1 interlaminar window based on 3D reconstruction provided accurate and reliable reference data for posterior microsurgical and endoscopic approaches as well as percutaneous infiltrations.

Association of the lateral wall integrity with clinical outcomes in older patients with intertrochanteric hip fractures treated with the proximal femoral nail anti-rotation-Asia.

PURPOSE: The purpose of this study is to assess the role of the lateral wall in post-operative clinical outcomes in patients with intertrochanteric fractures treated with the proximal femoral nail anti-rotation-Asia (PFNA-II). METHODS: A cohort of 466 patients (OTA type 31A1 or A2) was divided into two groups: one was intact lateral wall group, and the other was fractured lateral wall group. Radiographic outcomes were measured by using the loss of neck-shaft angle (NSA), femoral neck shortening (FNS), and offset shortening (OS). Functional outcomes were assessed by using the Harris score and SF-36 Physical Component Summary (SF-36 PCS). Post-operative complications were recorded. RESULTS: The fractured lateral wall group had a greater loss of NSA (mean [SD], fractured group (8.7°) [2.7°] vs intact group (4.8°) [2.8°]; mean difference, 3.3° [95% CI 2.9 to 3.8]; P < 0.001) compared with the intact lateral wall group. Similar results were found for FNS and OS. The fractured lateral wall group had a worse Harris scores at the three month follow-up (mean [SD] score, fractured group (66.6) [5.2] points vs intact group (71.3) [5.8] points; mean difference, - 3.3 points [95% CI - 3.9 to - 2.7]; P < 0.001) compared with the intact lateral wall group. Similar results were observed for Harris scores at the three and 12-month follow-ups and SF-36 PCS at the three, six and 12-month follow-ups. The fractured lateral wall group had a higher risk of post-operative complications compared with the intact lateral wall group. CONCLUSION: Among older patients with intertrochanteric fractures, the fractured lateral wall was associated with worse clinical outcomes compared with the intact lateral wall. Clinicians should pay attention to the lateral wall integrity in patients with intertrochanteric fractures treated with the PFNA-II.

Influence of Timing of Postoperative Weight-Bearing on Implant Failure Rate Among Older Patients With Intertrochanteric Hip Fractures: A Propensity Score Matching Cohort Study.

Introduction: The purpose of this study was to determine whether immediate weight-bearing as tolerated increased the risk of implant failure and decreased functional outcomes compared with restricted weight-bearing. Methods: From January 2010 to December 2018, 1,125 consecutive patients (≥65 years) with intertrochanteric fractures were identified. Of them, 130 patients were excluded, resulting in 995 patients in final cohort (563 receiving immediate weight-bearing and 432 receiving restricted weight-bearing). Propensity score (PS) matching yielded 403 patient pairs. Primary outcome was implant failure at 12 months. Secondary outcomes were implant failure at 3 months, functional outcomes at 12 months, and time to full weight-bearing. Results: Among 806 patients who were matched by PS, the mean age was 77.8 years (SD, 7.6), and 603 patients (74.8%) were women. After matching, there was no significant difference between immediate (10.0% [39/389]) and restricted (9.1%, [35/385]) weight-bearing for implant failure at 12 months (absolute risk difference, 0.93% [95% CI, -3.26 to 5.13%]; RR, 1.11 [95% CI, 0.69 to 1.80]; p = 0.66). Additionally, no significant difference was seen for implant failure at 3 months and functional outcomes at 12 months. Patients with immediate weight-bearing had shorter time to full weight-bearing (mean [SD], 87.6 days [7.5] vs. 121.3 days [11.0]; mean difference, -33.7 [95% CI, -35.0 to -32.3]; p < 0.001). Conclusions: Among older patients with intertrochanteric fractures, receipt of immediate weight-bearing as tolerated did not increase risks of implant failure or worsen functional outcomes compared with receipt of restricted weight-bearing. However, patients receiving immediate weight-bearing had a shorter time to full weight-bearing.

Association of Computer-Assisted Virtual Preoperative Planning With Postoperative Mortality and Complications in Older Patients With Intertrochanteric Hip Fracture.

Importance: The outcomes of surgical treatment in patients with intertrochanteric hip fractures are unsatisfactory. Computer-assisted virtual preoperative planning may provide an opportunity to solve this treatment dilemma. Virtual preoperative planning is a technique based on dynamic 3-dimensional computed tomographic imaging, which allows precise evaluation of fracture details and simulation of reduction of fracture and internal fixation procedures before surgery is performed. Objective: To evaluate the association of computer-assisted virtual preoperative planning with the risk of 90-day all-cause mortality and postoperative complications. Design, Setting, and Participants: This retrospective cohort study was conducted from using patient data from a level 1 trauma center database. A total of 1445 patients 65 years and older with intertrochanteric hip fractures between January 1, 2009, and March 31, 2018, were identified and divided into 2 cohorts: 558 patients received computer-assisted virtual preoperative planning (virtual planning group), and 887 patients received conventional preoperative planning (conventional planning group). Of the initial 1445 patients, 224 patients (93 patients in the virtual planning group and 131 patients in the conventional planning group) were excluded, resulting in 1221 patients in the final cohort. Data were analyzed from April 5 to October 5, 2019. Exposures: Computer-assisted virtual vs conventional surgical preoperative planning. Main Outcomes and Measures: Primary outcomes were 90-day all-cause mortality and postoperative complications (including myocardial infarction, heart failure, stroke, kidney failure, and sepsis). Secondary outcomes were 90-day outpatient visits, hospital readmissions, and reoperations. Results: Among 1221 patients who underwent hip surgery, the mean (SD) age was 73.2 (12.3) years, and 927 patients (75.9%) were women. A total of 465 patients (38.1%) were in the virtual planning group and 756 patients (61.9%) were in the conventional planning group. Among the 814 patients (407 patients in each group) who were matched by propensity score, the virtual planning group had a lower incidence of mortality (37 patients [9.1%] vs 55 patients [13.5%]; hazard ratio [HR], 0.64; 95% CI, 0.41-0.99; P = .04) and postoperative complications (25 patients [6.1%] vs 44 patients [10.8%]; HR, 0.54; 95% CI, 0.32-0.90; P = .02) compared with the conventional planning group. The incidence of outpatient visits was not substantially different in the virtual planning group (1.51 incidents per 30 person-days) compared with the conventional planning group (1.48 incidents per 30 person-days; incidence rate ratio [IRR], 0.90; 95% CI, 0.49-1.68; P = .75). Similar results were observed for the rate of hospital readmissions (0.99 incidents per 30 person-days in the virtual planning group and 1.01 incidents per 30 person-days in the conventional planning group; IRR, 0.91; 95% CI, 0.49-1.67; P = .76). However, the rate of reoperations was lower in the virtual planning group (0.76 incidents per 30 person-days) than in the conventional planning group (0.97 incidents per 30 person-days; IRR, 0.41; 95% CI, 0.22-0.76; P = .01). Conclusions and Relevance: Among older patients with intertrochanteric hip fractures, computer-assisted virtual preoperative planning was associated with decreases in the risks of all-cause 90-day mortality, postoperative complications, and reoperations compared with conventional preoperative planning.

The accuracy of intra-operative fluoroscopy in evaluating the reduction quality of intertrochanteric hip fractures.

PURPOSE: To investigate the capability of intra-operative fluoroscopy to determine the reduction quality of intertrochanteric fractures and to determine which view (anteroposterior [AP] or lateral) can better predict the reduction quality. METHODS: A retrospective analysis of 128 patients with intertrochanteric fractures. Two observers were asked to independently evaluate the quality of reduction (positive or non-positive support) based on intra-operative fluoroscopy (AP and lateral view). Results based on CT scans were considered as the gold standard. Sensitivity, specificity, percentage of correct interpretations, and agreement were calculated. RESULTS: At the first reading, sensitivity, false-negative rate, specificity, false-positive rate, and percentage of correct interpretations were 86.1%, 13.9%, 69.4%, 30.6%, and 79.7% for junior resident and 81.0%, 19.0%, 67.3%, 32.7%, and 75.8% for senior resident (all p > 0.05). It was highly predictive of a reliable cortical support when cortical position in AP view was consistent with that in lateral view (85/85, 100% for junior, and 86/86, 100% for senior). Lateral view was generally predictive of a final cortical support when the position between AP and lateral view was inconsistent (90.7% [39/43] vs 9.3% [4/43] for junior, p < 0.001; 92.9% [39/42] vs 7.1% [3/42] for senior). Comparable results were reported at the second reading. The average inter-observer and intra-observer agreement was 0.670 and 0.654, respectively. CONCLUSIONS: We should ensure the cortical support for both AP and lateral view are positive intra-operatively as far as possible. Even if this is not possible, we need to make sure the lateral position is positive support.

Computational Biomechanical Analysis of Postoperative Calcaneal Fractures with Different Placement of the Sustentaculum Screw.

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.

Quantitative Evaluation of Articular Involvement of Posterior Malleolus Associated with Operative Indication: A Comparative Study of Six Methods Based on Radiography and CT.

The aim of this study was to compare the values of six methods in measuring the involvement of posterior malleolus and to demonstrate the reliability and reproducibility of each method. Three independent orthopaedic surgeons, retrospectively, measured 106 cases. The difference between the six methods was analyzed using Bonferroni-corrected paired t-tests after one-way ANOVA. The agreement between the six methods was analyzed using Bland-Altman analysis. The intraclass correlation coefficient (ICC) was used to assess intraobserver reproducibility and interobserver reliability. Significant differences were observed between values of any two of the six measurement methods (P < 0.0033), except between any two of the plane radiograph linear, axial CT linear, sagittal CT linear, and 3D CT linear. The Bland-Altman plots demonstrated poor agreement between values of any two of the six methods. The lowest intraobserver reproducibility was 0.46 (moderate) for resident surgeon using plain radiographs. The intraobserver reproducibility for three surgeons using two-dimensional (2D) and 3D images was almost perfect (ICC, 0.82-0.96). The lowest interobserver reliability was 0.41 (moderate) between chief and attending surgeon using plain radiographs, and it improved to almost perfect (ICC, 0.81-0.95) with the use of 3D CT images. The standard error of measurement showed almost the same results as ICC values. The existing operative indications which were determined based on plain radiography are neither reliable nor suitable for other measurement methods. Both 3D linear and 3D surface measurement methods are reliable and reproducible in measuring posterior fragment involvement, and experience is not so crucial. Operative indications for posterior malleolar fractures need to be redefined based on the 3D measurement method.

Computer-assisted preoperative planning improves the learning curve of PFNA-II in the treatment of intertrochanteric femoral fractures.

BACKGROUND: Intertrochanteric femoral fractures are prevalent among the elderly, and usually demands surgical treatments. Proximal femoral nail antirotation Asian version (PFNA-II) is widely used for intertrochanteric fracture treatment. The computer-assisted preoperative planning (CAPP) system has the potential to reduce the difficulty of PFNA-II in the treatment of intertrochanteric fractures. The aim of the study was to investigate and compare the learning curves of PFNA-II treatment with CAPP and conventional preoperational planning methods for intertrochanteric femoral fractures. METHODS: A total of 125 patients with intertrochanteric fracture who were treated with PFNA-II between March 2012 and June 2015 were retrospectively analyzed. Patients who underwent surgery with CAPP procedure by a junior surgeon were regarded as group A (n = 53); patients who underwent the conventional surgery by another junior surgeon were regarded as group B (n = 72). Each group was divided into three subgroups (case 1-20, case 21-40, case 41-53 or case 41-72). RESULTS: The average operation time of group A was 45.00(42.00, 50.00) minutes, and in group B was 55.00 (50.00, 60.00) minutes (P < 0.01). Average radiation frequency and blood loss were 13.02 ± 2.32, 160.00 (140.00, 170.00) ml and 20.92 ± 3.27, 250.00 (195.00, 279.50) ml, respectively, with significant differences (P < 0.01). The learning curve of the surgical procedure in group A was steeper than that in group B. There were no significant differences in patient reported outcomes, hospital stay and complication rate between the two groups. Significant differences were observed between group A and B in Harris score at last follow-up in the AO/OTA type 31-A2 intertrochanteric fracture (P < 0.05). CONCLUSION: Compared with conventional preoperative planning methods, CAPP system significantly reduced operation time, radiation frequency and blood loss, thus reshaped the learning curve of PFNA-II treatment with lower learning difficulty. TRIAL REGISTRATION: researchregistry4770. Registered 25 March 2019.

Evaluation of the computer-assisted virtual surgical technology in preoperative planning for distal femoral fracture.

BACKGROUND: The application of computer-assisted virtual surgical technology in preoperative planning for distal femoral fractures has been rarely presented. This study aimed to evaluate the intra-operative realization of this technology and the clinical outcomes based on it for distal femoral fractures. METHODS: Between February 2014 and May 2017, 32 patients with distal femoral fractures treated by open reduction and internal fixation were included and divided into 2 groups on the basis of preoperative planning methods: conventional (N = 17) and virtual surgical (N = 15). The time required for virtual segmentation, reduction, and fixation of the fracture fragments in virtual surgical group were analyzed. Operation time, intra-operative blood loss, times of fluoroscopy during operation and days of hospital stay in two groups were compared. Postoperative functional outcomes were assessed using the Knee Society Score (KSS), Short Form-36 (SF-36) scoring systems, and visual analogue scale (VAS) for pain. RESULTS: Mean total planning time for 33-A, 33-B, and 33-C fractures in virtual surgical group were 43.0 ±â€¯1.7, 23.0 ±â€¯1.3, and 51.4 ±â€¯3.7 min, respectively. Compared with the conventional group, Patients in virtual surgical group had lower blood loss, fewer fluoroscopic images, less operative time, and shorter days of hospital stay (P < 0.05). No significant difference could detected in the KSS, SF-36, or VAS scores between the two groups at the final follow-up (P > 0.05). CONCLUSIONS: Computer-assisted virtual surgical technology could rapidly complete surgical treatment protocol, improve operative efficiency, and provide satisfying clinical and radiographic outcomes for distal femoral fractures.

The influence of selective arthrodesis on three-dimensional range of motion of hindfoot joint: A cadaveric study.

BACKGROUND: The purpose of this study was to measure the three-dimensional range of motion of adjacent, unfused joint or joints after different arthrodesis of hindfoot. METHODS: Sixteen fresh frozen cadaver feet were immobilized in the non-weight bearing position. The three-dimensional coordinates of markers in tarsal were measured in six directions (involving dorsiflexion-plantarflexion, eversion-inversion, and adduction-abduction) before and after single (involving subtalar joint, talonavicular joint, and calcaneocuboid joint) and double (talonavicular and calcaneocuboid joints) arthrodesis with a three-dimensional coordinate instrument. The range of motion of the joint was calculated with the least square method and matrix transformation. FINDINGS: We found that the range of motion of joints in all direction was reduced significantly after any combination of selective arthrodesis (all p < 0.001). After arthrodesis of the subtalar joint, the motion of talonavicular joint was reduced by 72%, and that of calcaneocuboid joint by 36%. After arthrodesis of talonavicular joint, the motion of subtalar joint was diminished by 36%, and that of calcaneocuboid joint by 51%. After arthrodesis of calcaneocuboid joint, the motion of subtalar joint was decreased by 21%, and that of talonavicular joint by 42%. After double arthrodesis, the motion of subtalar joint was reduced by 62%. INTERPRETATION: In single arthrodesis, subtalar arthrodesis had the greatest effect on the motion of unfused joints, and the least was the calcaneocuboid arthrodesis. The motion of the subtalar joint was eliminated more than half after double arthrodesis. The data provide a biomechanical rationale to ascertain the clinical implication of the arthrodesis.

Computer-assisted virtual surgical technology in pre-operative design for the reconstruction of calcaneal fracture malunion.

PURPOSE: No computer-assisted pre-operative design for calcaneal fracture malunions has been presented. The aim of the study is to evaluate the intra-operative realization of computer-assisted pre-operative planning (CAPP) and the clinical outcomes based on computer-assisted virtual surgical technology for calcaneal malunions. METHODS: Between 2010 and 2016, 20 patients with 21 calcaneal fracture malunions were retrospectively reviewed with the average follow-up time of 22.3 months (range, 12 to 43 months), which were operatively treated with the help of CAPP. The CAPP steps included the image segmentation, exostectomy of lateral wall, simulated reconstruction of calcaneal thalamus, morphological evaluation, and the implantation of internal fixation devices. Post-operative outcomes were assessed with the American Orthopaedic Foot and Ankle Society (AOFAS) score, SF-36 physical component summary (PCS), VAS for pain, range of motion of ankle, and the morphological parameters of the calcaneus including the axial length of the calcaneus, the height of the posterior facet, the talocalcaneal angle, Böhler's angle, and Gissane's angle. RESULTS: The mean time required for CAPP was 41.8 minutes. All the surgical processes were carried out according to CAPP. Six patients (6 feet) were treated with the joint-preserving osteotomy. Fourteen patients (15 feet) underwent the subtalar distraction bone block arthrodesis, among which the medial displacement calcaneal osteotomy was additionally performed in six patients (6 feet). At the final follow-up, the average AOFAS, SF-36 PCS, and VAS scores were significantly improved to 77.4, 64.3, and 1.4, respectively (P < 0.001). The postoperative calcaneal morphological parameters and the range of motion of ankle were significantly restored (P < 0.05). CONCLUSION: CAPP can assist surgeons in understanding calcaneal malunions, thereby improving intraoperative correction and reconstruction. The satisfying clinical and radiographic outcomes could be provided after treating calcaneal malunions aided by the computer-assisted virtual surgical technology.

Detection of Intra-Articular Screw Penetration of Proximal Humerus Fractures: Is Postoperative Computed Tomography the Necessary Imaging Modality?

RATIONALE AND OBJECTIVE: Screw penetration is the common complication of proximal humerus fractures treated with locking plates. This study compared postoperative plain radiography to computed tomography (CT) for their abilities in determining screw penetration, and was to evaluate whether advanced imaging modalities (two-dimensional [2D] CT; three-dimensional [3D] CT) could increase surgeons' level of confidence regarding their diagnoses. MATERIALS AND METHODS: Two observers reviewed radiological images of 134 patients who sustained proximal humerus fractures treated with locking plates. The observers were asked to answer two questions: (1) Is there screw penetrating into glenohumeral joint for this patient (Yes/No)? and (2) On a scale from 0 to 10, how confident are you about this diagnosis: (0-10) (0 = not at all confident; 10 = very confident)? Three evaluations were performed: (1) plain radiography alone, (2) radiography and 2D CT 4 weeks later, and (3) radiography in combination with 2D and 3D CT after that. This process was then repeated for intraobserver analysis. RESULTS: CT obtained almost perfect interobserver and intraobserver agreement (0.818-0.961), which was higher than radiography (0.377-0.655). For incidence of screw penetration, the significant difference was found between radiographs and CT images (P< .0125), but not between 2D and 3D CT images (P > .05). For confidence of diagnosis, the differences between imaging modalities were significant (all P< .001). CONCLUSIONS: We suggest that postoperative CT scans (especially 3D CT images) should be used to evaluate the intra-articular screw penetration of proximal humerus fractures, especially when surgeons have not enough confidence in determining screw penetration using radiography alone.

Computer-Assisted Virtual Surgical Technology Versus Three-Dimensional Printing Technology in Preoperative Planning for Displaced Three and Four-Part Fractures of the Proximal End of the Humerus.

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.

Comparison between three-dimensional CT and conventional radiography in proximal tibia morphology.

To provide morphological parameters of the normal tibial plateau by using three-dimensional (3D) CT and conventional radiography.We performed morphological measurements of tibial plateau on 157 consecutive adults using radiographic and 3D computed tomography (CT). Gender differences as well as differences in measurement techniques were statistically compared. Intraclass correlation coefficient (ICC) was used to evaluate intra- and interobserver reproducibility.The mediolateral dimensions, anteroposterior dimensions of tibial plateau showed significant differences according to gender, but no statistical differences were observed in coronal tibial slope as well as in posterior slope. There were significant differences in all parameters between 2 measurement techniques. 3D-CT measurements had a higher ICC in all parameters than that in the radiographs.This study confirmed that 3D morphological measurements of tibial plateau have more reproducibility than radiographs. Our data will be helpful for tibial component design and placement.

Computational biomechanical analysis of postoperative inferior tibiofibular syndesmosis: a modified modeling method.

To analyze the biomechanical effect of syndesmotic screw through three and four cortices, a total of 12 finite element models simulating healthy ankles, tibiofibular syndesmosis injured ankles, and post-operative ankles by screw fixations through three or four cortices were built. A set of biomechanical data were obtained to find that screw fixation methods for inferior tibiofibular syndesmosis can help recover most of the biomechanical relations of the ankle especially the tricortical fixation, while the screw of quadricortical fixation bear more stress than the tricortical fixation. The modeling method for finite element models was also modified for saving more time and realizing personalized modeling for clinical application.

Assessment of Screw Length of Proximal Humerus Internal Locking System (PHILOS) Plate for Proximal Humeral Fractures Using Three-Dimensional Computed Tomography Scan.

BACKGROUND Screw perforation and varus collapse are common complications of treatment with a PHILOS (proximal humerus internal locking system) plate for proximal humerus fractures, which are associated with improper screw length selection and lack of medial column support. The purposes of this study were: (1) to measure the proper length of periarticular screws of the PHILOS plate in the humeral head, and (2) to determine what factors influence the screw length and implantation of the inferomedial support screw. MATERIAL AND METHODS Computed tomography (CT) images of the normal proximal humerus in 134 cases were retrospectively reviewed. The length of periarticular screws was measured using three-dimensional (3D) techniques. Intraobserver and interobserver reliability of measurement were evaluated using intraclass correlation coefficients (ICCs). Sex and body height influences on screw length and implantation of the inferomedial screw were analyzed. RESULTS All measurements had excellent agreement (ICC>0.75). The screw length and implantation rate of the inferomedial screw were greater in males than in females. Positive correlations were observed between body height and screw length and implantation of the inferomedial screw (all P<0.001). CONCLUSIONS The screws were longer and the implantation rate was higher for inferomedial screws in males than in females, and were positively correlated with body height. Our data can be used as a reference for surgeons to reduce the number of times screws are changed intraoperatively and to reduce operation duration and minimize use of intraoperative fluoroscopy for proximal humerus fractures treated with the PHILOS plate.