Unilateral external fixator and its biomechanical effects in treating different types of femoral fracture: A finite element study with experimental validated model.

Previous works had successfully demonstrated the clinical effectiveness of unilateral external fixator in treating various types of fracture, ranging from the simple type, such as oblique and transverse fractures, to complex fractures. However, literature that investigated its biomechanical analyses to further justify its efficacy is limited. Therefore, this paper aimed to analyse the stability of unilateral external fixator for treating different types of fracture, including the simple oblique, AO32C3 comminuted, and 20 mm gap transverse fracture. These fractures were reconstructed at the distal diaphysis of the femoral bone and computationally analysed through the finite element method under the stance phase condition. Findings showed a decrease in the fixation stiffness in large gap fracture (645.2 Nmm-1 for oblique and comminuted, while 23.4 Nmm-1 for the gap fracture), which resulted in higher displacement, IFM and stress distribution at the pin bone interface. These unfavourable conditions could consequently increase the risk of delayed union, pin loosening and infection, as well as implant failure. Nevertheless, the stress observed on the fracture surfaces was relatively low and in controlled amount, indicating that bone unity is still allowable in all models. Briefly, the unilateral fixation may provide desirable results in smaller fracture gap, but its usage in larger gap fracture might be alarming. These findings could serve as a guide and insight for surgeons and researchers, especially on the biomechanical stability of fixation in different fracture types and how will it affect bone unity.

Office Three-Dimensional Printed Osteotomy Guide for Corrective Osteotomy in Fibrous Dysplasia.

Fibrous dysplasia is a benign condition but can lead to severe long-bone deformities. Three-dimensional (3D) printing technology is a rapidly developing field that has now been popularized to aid surgeons in preoperative planning. We report a case of hip deformity in a 21-year-old woman who suffered from fibrous dysplasia and underwent a corrective osteotomy. We utilized open-source 3D computing software for preoperative planning before producing an osteotomy guide to aid in the operation.

Surgical Management of Cervical Ossification of Posterior Longitudinal Ligament: The Treatment Algorithm and Outcome.

Introduction Managing patients who present with symptoms of cervical myelopathy secondary to cervical ossification of the posterior longitudinal ligament (OPLL) is challenging. Various factors such as the number of levels involved with OPLL, types of OPLL, canal occupying ratio, K-line characteristics, and C2-C7 lordosis angle were found to guide decision-making and surgical approaches in managing this condition. However, no clear treatment algorithm has been published. This study aims to investigate the outcome of the management of cervical OPLL using a treatment algorithm used in a tertiary university hospital. Methods This is a retrospective cross-sectional study. Patients with cervical myelopathy secondary to cervical OPLL who were treated surgically in our center from 2014 to 2020 were included in this study. Demographic data and preoperative parameters that determined the treatment given according to our treatment algorithm were analyzed. Result A total of 24 patients fit the inclusion and exclusion criteria of the study. The mean recovery rate for all groups is 61.8[Formula: see text]21.9% and the mean postoperative neck disability index (NDI) is 17.83[Formula: see text]16.67%. There was a statistically significant difference between preoperative and postoperative Japanese Orthopaedic Association (JOA) scores for both anterior and posterior surgery subgroups. Conclusion We believe that the treatment algorithm used in our center could benefit other surgeons as a guide in managing patients who suffer from cervical myelopathy secondary to cervical OPLL. Further study including newer techniques would increase the surgeon's arsenal in providing the best outcome in managing this condition.

Revision Spinal Surgery for Posterior Migration of Tantalum Cage: Tips and Tricks.

The porous property of tantalum metal coupled with its high frictional surface and biocompatibility has made it an ideal biomaterial to facilitate bony fusion. This biomaterial is not unfamiliar to surgeons as it has been utilized with good clinical outcomes in arthroplasty. The usage of tantalum cages in spine surgery has gained traction. Complications resulting from the use of tantalum cage in lumbar fusion surgery were rarely reported. Here the authors would present a case of revision spinal surgery where the tantalum cage underwent migration from the previous posterior lumbar interbody fusion surgery. We further discuss ways to prevent such complications, precautions, tips, and tricks that could help other surgeons while dealing with this complication.

Biomechanical effects of cross-pin's diameter in reconstruction of anterior cruciate ligament - A specific case study via finite element analysis.

For anterior cruciate ligament reconstruction (ACL-R), one of the crucial aspects of treatment is the fixator selection that could provide initial graft fixation post-operatively. Literature on biomechanical stabilities of different sizes of fixators as femoral graft fixation is limited. Therefore, this study aims to analyse the influence of different diameters of cross-pins on the stability of graft fixations after ACL-R via finite element analysis (FEA). In the methodology, three-dimensional (3D) models of three different diameters of cross-pins were developed, of which anterior tibial loads (ATL) were applied onto the tibia. From the findings, the cross-pin with a smaller diameter (4 mm) provided optimum stability than larger diameter cross-pins, whereby it demonstrated acceptable stresses at the fixators (both cross-pin and interference screw) with a different percentage of 28%, while the stresses at the corresponding bones were favourable for osseointegration to occur. Besides, the strains of the knee joint with 4 mm diameter cross-pin were also superior in providing a good biomechanical environment for bone healing, while the recorded strain values at fixators were comparable with a larger diameter of cross-pins without being inferior in terms of deformation. To conclude, the cross-pin with 4 mm diameter depicted the best biomechanical aspects in graft fixation for ACL-R since it allows better assistance for the osseointegration process and can minimise the possibility of the breakage and migration of fixators. This study is not only useful for medical surgeons to justify their choices of pin diameter to treat patients, but also for researchers to conduct future studies.

Stress Distribution and Stability Evaluation of Difference Number of Screws for Treating Tibia Transverse Fracture: Analysis on Patient-Specific Data

@#Introduction: Screws placement may influence the stress distribution and stability of the plate and bone. Implant failures are normally happened in clinical practise when inappropriate number of screws is implemented. Therefore, intensive investigations are needed to provide additional quantitative data on the use of different number of screws. Therefore, this study was conducted to investigate the biomechanical performance of different number of screws configurations on Locking compression plate (LCP) assembly when treating transverse fractures of the tibia bone. Methods: Finite element method was used to simulate tibia bone fracture treated with LCP in standing phase simulation. To accomplish this, a three-dimensional tibia model was reconstructed using CT dataset images. 11 holes of LCP and 36mm of locking screws were developed using SolidWorks software. From this study, there are three models in total have been developed with different number of screws and screw placements. A diaphysis transverse tibia fracture of 4 mm was constructed. Results: In terms of stress distribution, all configurations provide sufficient stress and do not exceeding the yield strength of that material. Conclusion: In conclusion, eight numbers of screws were the optimum configurations in order to provide ideal stability to the bone with displacement of 0.37 mm and 0.91 mm at plate and bone, respectively.