Because of the low cost and easy access, surgical video has become a popular method of acquiring surgical skills outside operating rooms without disrupting normal surgical flow. However, currently existing video systems all use a single point of view (POV). Some complex orthopedic procedures, such as joint replacement, require a level of accuracy in several dimensions. So single and fixed POV video may not be enough to provide all the necessary information for educational and training purposes. The aim of our project was to develop a novel multiple POV video system and evaluate its efficacy as an aid for learning joint replacement procedure compared with traditional method. Based on the videos of a hip resurfacing procedure performed by an expert orthopedic surgeon captured by 8 cameras fixed all around the operating table, we developed a novel multiple POV video system which enables users to autonomously switch between optimal viewpoints (Figure 1). 30 student doctors (undergraduate years 3–5 and naive to hip resurfacing procedure) were recruited and randomly allocated to 2 groups: experiment group and control group, and were assigned to learn the procedure using multiple or single POV video systems respectively. Before learning they were first asked to complete a multiple choicetest designed using a modified Delphi technique with the advice and feedback sought from 4 experienced orthopedic surgeons to test the participants' baseline knowledge of hip resurfacing procedure. After video learning, they were asked to answer the test again to verify their gained information and comprehension of the procedure, followed by a 5-point Likert-scale questionnaire to demonstrate their self-perception of confidence and satisfaction with the learning experience. The scores in the 2 tests and in the Likert-scale questionnaire were compared between 2 groups using Independent-Samples t-test (for normally distributed data) or Mann-Whitney U test (for non-normally distributed data). Statistical significance was set as p<0.05.Introduction
Materials and Methods
Patient Specific Instrumentation (PSI) has the potential to allow surgeons to perform procedures more accurately, at lower cost and faster than conventional instrumentation. However, studies using PSI have failed to convincingly demonstrate any of these benefits clinically. The influence of guide design on the accuracy of placement of PSI has received no attention within the literature. Our experience has suggested that surgeons gain greater benefit from PSI when undertaking procedures they are less familiar with. Lateral unicompartmental knee replacement (UKR) is relatively infrequently performed and may be an example of an operation for which PSI would be of benefit. We aimed to investigate the impact on accuracy of PSI with respect to the area of contact, the nature of the contact (smooth or studded guide surfaces) and the effect of increasing the number of contact points in different planes. A standard anatomy tibial Sawbone was selected for use in the study and a computed tomography scan obtained to facilitate the production of PSI. Nylon PSI guides were printed on the basis of a lateral UKR plan devised by an orthopaedic surgeon. A control PSI guide with similar dimensions to the cutting block of the Oxford Phase 3 UKR tibial guide was produced, contoured to the anterior tibial surface with multiple studs on the tibial contact surface. Variants of this guide were designed to assess the impact of design features on accuracy. These were: a studded guide with a 40% reduction in tibial contact area, a non-studded version of the control guide, the control guide with a shim to provide articular contact, a guide with an extension to allow distal referencing at the ankle and a guide with a distal extension and an articular shim. All guides were designed with an appendage that facilitated direct attachment to a navigation machine (figure 1). 36 volunteers were asked to place each guide on the tibia with reference to a 3D model of the operative plan. The order of placement was varied using a counterbalanced latin square design to limit the impact of the learning effect. The navigation machine recorded deviations from the plan in respect of proximal-distal and medial-lateral translations as well as rotation around all three axes. Statistical analysis was performed on the compound translational and rotational errors for each guide using ANOVA with Bonferroni correction with statistical significance at p<0.05.Introduction
Method
We aimed to measure cerebral microemboli load during total hip [THA] and knee arthroplasty (TKA) using transcranial Doppler ultrasound (TCD) and to investigate whether cerebral embolic load influences neuropsychiatric outcome. The timing of the microemboli was also related to certain surgical activities to determine if a specific relationship exists and the presence of a patent foramen ovale was investigated. Patients undergoing primary THA and TKA underwent a battery of ten neuropsychiatric tests pre-operatively and at 6 weeks and 6 months post-operatively. Microembolic load was recorded using TCD onto VHS tape for subsequent analysis. Patent foramen ovale detection was performed using bolus intravenous injection of agitated saline followed by valsalva manoeuvre. The timing of specific surgical steps was recorded for each operation and embolic load calculated for that period. All patients were assessed for quality of life and orthopaedic outcome measures. 45 THA patients and 50 TKA patients were studied. Cerebral microembolisation occurred in 35% of all patients (10 THA patients and 19 TKA patients). Mean microembolic load was 2.8 per patient for THA and 3.76 per patient for TKA patients. PFO was detected in 29 patients overall. Insertion of the femoral component and deflation of the tourniquet were associated with a larger microembolic loads. Neuropsychiatric outcome was not affected by the low embolic loads. Quality of life and Orthopaedic outcome at 6 months was good. Cerebral microembolisation occurs in a significant proportion of patients during total hip and knee arthroplasty. The presence of a patent foramen ovale does not appear to influence the incidence of microembolisation or load. Specific surgical activities are associated with generating greater embolic loads and methods of avoiding these emboli such as venting the femur may minimise complications and optimise outcomes. Neuropsychiatric outcomes do not seem to be affected by microembolisation of the brain during total joint arthroplasty.Results
Conclusion
