Virtual interactive musculoskeletal system (VIMS) in orthopaedic research, education and clinical patient care

The ability to combine physiology and engineering analyses with computer sciences has opened the door to the possibility of creating the "Virtual Human" reality. This paper presents a broad foundation for a full-featured biomechanical simulator for the human musculoskeletal system physiology. This simulation technology unites the expertise in biomechanical analysis and graphic modeling to investigate joint and connective tissue mechanics at the structural level and to visualize the results in both static and animated forms together with the model. Adaptable anatomical models including prosthetic implants and fracture fixation devices and a robust computational infrastructure for static, kinematic, kinetic, and stress analyses under varying boundary and loading conditions are incorporated on a common platform, the VIMS (Virtual Interactive Musculoskeletal System). Within this software system, a manageable database containing long bone dimensions, connective tissue material properties and a library of skeletal joint system functional activities and loading conditions are also available and they can easily be modified, updated and expanded. Application software is also available to allow end-users to perform biomechanical analyses interactively. Examples using these models and the computational algorithms in a virtual laboratory environment are used to demonstrate the utility of these unique database and simulation technology. This integrated system, model library and database will impact on orthopaedic education, basic research, device development and application, and clinical patient care related to musculoskeletal joint system reconstruction, trauma management, and rehabilitation

Developments in circular external fixators: a review

Circular external fixators (CEFs) are successfully used in orthopedics owing to their highly favorable stiffness characteristics which promote distraction osteogenesis. Although there are different designs of external fixators, how these features produce optimal biomechanics through structural and component designs is not well known. Therefore, the aim of this study was to conduct a review on CEFs following the PRISMA statement. A search for relevant research articles was performed on Scopus and PubMed databases providing the related keywords. Furthermore, a patent search was conducted on the Google Patent database. 126 records were found to be eligible for the review. Different designs of CEFs were summarized and tabulated based on their specific features. A bibliometric analysis was also performed on the eligible research papers. Based on the findings, the developments of CEFs in terms of materials, automation, adjustment methods, component designs, wire-clamping, and performance evaluation have been extensively discussed. The trends of the CEF design and future directions are also discussed in this review. Significant research gaps include a lack of consideration towards ease of assembly, effective wire-clamping methods, and CEFs embedded with online patient-monitoring systems, among others. An apparent lack of research interest from low-middle and low-income countries was also identified

Pre-clinical evaluation of the forces during limb lengthening using manual and automated devices

This thesis was submitted for the degree of Doctor of Philosophy and awarded by Brunel University.Limb lengthening procedures use fixation devices to extend the constantly regenerating bone and surrounding soft tissues. Automated devices have been developed that aim to provide a more gradual tissue extension, resulting in better quality of treatment for the patient. Benefits include pain reduction and probable enhanced tissue outcomes. The development of one such new smart lengthening device is described. An integrated numerical model of tissue mechanics during lengthening is presented. It represents the mechanical environment in which the devices extend. The mechanism of the automated device is also modelled using Matlab software and validation was achieved through experimental testing. Validation of the tissue model includes the design of an experimental hydraulic system with the ability to control the peak loads and relaxation over time. A simplified mechanobiological model for the longer term healing effects is proposed. Calibration of the tissue model to clinical data allows for direct comparison of the load and extension of identical tissues, one being lengthened by a traditional device, the other an automated device. This simulation can be extended to include a range of lengthening rates and frequencies of distraction alongside various patient dependent tissue properties. The models also provide the opportunity to assess the effects of iterative changes to the device parameters (such as stiffness) on its performance as well as analyse the effect that these changes have on tissue extension and loading. Use of these models to optimise the device design alongside optimisation of the extension regime can result in improved device design and consequently improved patient outcomes

A Novel Design to Canine and Feline Bone Healing Using External Fixation

Circular external fixation devices provide stabilization and improved bone healing for cats and dogs through the use of a minimally invasive procedure. This novel circular external fixation device provides an easy to use, radiolucent, safe, and economical design. The new ring design enables veterinarians to have more variability in the placement of the stabilization wires. The new clamp design has fewer parts and can be used with existing standard industry wires and pins. The use of magnets in this innovative design eliminates the complex tooling required for assembly and disassembly of the external fixation device. This design was tested to sustain a load of 584.5N, which exceeds the amount of force produced by a 50 pound canine

Taylor Spatial Frame: Kinematics, Mechanical Properties and Automation

The Taylor Spatial Frame (TSF) is a recently introduced form of a circular external orthopaedic fixator for long bone fracture reduction and deformity correction. The TSF is constructed from two circular rings interconnected with six variable-length struts. Its kinematics are based on the Stewart-Gough platform. The TSF is attached to the patient's anatomy using fine wires and half-pins. In this thesis, three aspects of the TSF are analysed. First, the solution to non-trivial forward and inverse kinematics has been addressed. Second, the mechanical properties of the TSF fixator are investigated. Individual component stiffness is assessed separately and then the complete fixator is modelled. Simple stiffuess models of fine wires and half-pins are derived. Considerations for the use of the TSF for the peri-articular fractures are investigated and potential modifications are proposed. The effect of backlash in the frame components on the accuracy of the fixator has been analysed. Finally, in rder to validate the kinematics solution, to provide a training aid for surgeons and to demonstrate the concept of accurately controlled interfragmentary motion, a prototype of an active TSF was designed and built. Computationally efficient algorithms for solving the forward and inverse kinematics have been developed that require little numerical processing overhead and can be implemented on a mobile computing device. It was found that the TSF fixator has similar axial stiffuess to the circular Ilizarov ring fixator, since wires and half-pins are significantly less stiff than the frames. Furthermore, the TSF exhibits more uniform stiffuess for a range of off-axis loads and is significantly stiffer for torsional loads than the Ilizarov fixator. Slack, in the form of a backlash, can lead to severe strains in the unloaded frames and therefore fractures, and hence precautions are recommended. Finally, considerations and prototype for the automated TSF are presented that can be utilised for demonstration purposes and surgeon training. Keywords: Taylor Spatial Frame, fine wire, half-pin, peri-articular fracture, active fixator, kinematics, orthopaedics, Stewart-Gough platform.EThOS - Electronic Theses Online ServiceGBUnited Kingdo

Reconstruction of Temporomandibular Joint using Distraction Osteogenesis

CONCLUSION: Reconstruction of the TMJ has proved to be a challenging & complicated endeaver. Distraction osteogenesis has revolutionized surgical reconstruction with regards to head & neck region. Distraction osteogenesis allows for attainment of many of the goals needed for sucessful TMJ reconstruction. Distraction osteogenesis has proved to be safe & effective due to its unique advantages like low risk, decreased morbidity, simple manipulation, high curative rate , less relapse with stable results. Skeletal distractrion proceeds parallel to expansion of soft tissues, thereby accheiving better aesthetic results. This proves it to be superior to other reconstructive procedures. Distraction osteogenesis is being a sensitive procedure, requires careful planning & execution following the vector principle. Patient compliance during the entire treatment period is essential & thus careful patient selection & adequate motivation is of utmost importance. Although number of cases & period of followup is minimal in our study, this technique of using Indigeniously designed Internal distraction device for reconstruction of TMJ has shown good results among the study group. We conclude by saying that Distraction osteogenesis can be considered as an effective treatment of choice for reconstruction of TMJ. However to know the long term effects of distraction, periodic followup is essential

Evaluation of the clinical outcome of curvilinear transport distraction osteogenesis and revascularised fibula free flaps in the reconstruction of large post-maxillectomy defects

Background: Maxillary defects caused by trauma or tumour resection in the head and neck region can be devastating to the patient from a cosmetic and functional perspective. Patients who undergo maxillectomy procedures experience a substantial deterioration in their primary oral functions such as breathing, mastication, salivation, deglutition and phonation, which has a collective adverse influence on their quality of life (QOL). The revascularised free fibula flap (RFFF) has been demonstrated to be most reliable for the reconstruction of maxillary defects, and has been regarded as the 'gold standard.' A novel method of regenerating bone and soft tissue through the process of curvilinear transport distraction oseteogenesis (CTDO) has been developed and compared with the RFFF technique. Method: A prospective cohort study of 6 post-maxillectomy patients was compared regarding the clinical outcome of function and aesthetics with a group of 6 patients who had undergone RFFF reconstruction. The new bone (regenerate) was compared with the parent bone from which it had been generated. Objective measuring tools were employed to assess pre and post quality of life (QOL) aspects. The RFFF patients were not subjected to any invasive procedures save to undergo a clinical evaluation and undergo a CT scan of their maxillae. A cohort of 6 participants was treated prospectively using CTDO and the results were analysed within that cohort. These results were compared with a retrospective group of 6 participants of similar age and gender distribution who had undergone RFFF reconstruction as an external control. The patented Hendricks-Vicatos (H-V) maxillary transport distractor was applied to all selected participants by the primary investigator under general anaesthesia at Groote Schuur Hospital or a private clinic. The H-V maxillary transport distractor (5 prototypes) was pre-shaped and pre-fitted onto a 3-D model of the participant's maxilla, in a laboratory. This method reduced clinical installation time. If teeth were present in the area to be distracted, then at least 2 teeth were removed from the maxilla, preferably three months before the date of distraction. In the first few cases, this was the protocol for developing bone stock. This protocol was revised in the last 2 patients of the study, where no teeth were extracted at all. A linear fracture (bi-cortical) was created in the maxilla in a vertical direction (segmentally) to develop a mobile, well-vascularised transport disc. This carrier disc was attached to the metal plate of the 'crawler' via small titanium screws. The crawler was then moved on the reconstruction plate (BiometTM Zimmer Biomet