19 research outputs found
Development of a Solution Method to Promote Proper Bandaging Techniques for Transfemoral Amputees
No full textPost-operative care for lower limb amputees focuses on reducing swelling and promoting healing of the residual limb. Healing and desired residual limb maturation is necessary to achieve a conical shape suitable for prosthesis integration. Elastic bandaging is applied to the residual limb to achieve this conical shape. Bandaging requires skill and frequent reapplication. In many cases, the amputee is unable to bandage the residual limb effectively following surgery and professional assistance may not be readily available, increasing the risk of permanent damage due to improper bandaging. Transfemoral amputees are often confined to a wheelchair and spend the most time without a prosthesis fitted compared to any other lower limb amputee. An effective method in achieving the optimum residual limb shape, while promoting proper bandaging is therefore required. The aim of this study was to develop a solution method to assist transfemoral amputees with proper bandaging to achieve a shorter healing period and promote faster prosthesis integration through residual limb re-shaping. An overall solution method comprising of three sub-systems was designed to instruct bandaging. This included the development of a bandaging template, a mobile application and an elastic bandage dispenser. A printable bandaging template generated by a Python script based on the measurements of the patient's residual limb circumferences was developed to instruct bandaging. Development of a mobile application allowed for the design of an interface to control the dispensing device and instruct bandaging steps. The developed Bandage Utility Dispenser (BUD) transmits unrolled bandage length measurements to the mobile application using Bluetooth, to meet the target bandage lengths. Target bandage lengths are calculated by a second Python script to recommend sufficient bandage lengths. Target bandage lengths are expected to apply adequate pressure, while covering the exposed area of the residual limb for the current bandaging step. Testing occurred on an anatomically correct residual limb model (ACM) and five constructed models (CM) assembled by altering proximal and distal ACM circumferential measurements in increments of 5 cm. Measurement and pressure testing were performed after successfully validating the use of the CMs using a Bland-Altman analysis on the ACM and a CM of equal dimensions. Measurement testing utilised a chi-square goodness of fit test to compare observed and expected bandage length measurements for each model. Results for all models indicated that observed and expected measurements did not differ significantly. Pressure testing was performed by measuring the pressure application along the perimeter of the models with assembled pressure pads. Readings were analysed using a one sample t-test to compare differences between sample means and the recommended pressure application from literature. Testing results indicated that pressure application for five of the six models were in an acceptable range. Future recommendations have been established to potentially improve design, functionality and testing of the current iteration of the BUD solution method
Design and Development Towards a Novel Prosthesis for Total Shoulder Arthroplasty to Reduce Aseptic Glenoid Loosening
No full textTotal shoulder arthroplasty (TSA) is the most common surgical solution, that helps in restoring the structural and functional integrity of a diseased glenohumeral (GH) joint with intact rotator-cuff. A 300% increase in the usage of TSA has been observed since 2007, along with 2.5% increase in revision rate. Aseptic glenoid loosening accounts for 37% of postsurgical failures in TSA. Eccentric loading of the prosthetic glenoid cup, leading to the “rocking horse” effect, is one of the prevalent causes of aseptic glenoid loosening. Current anatomical total shoulder prosthesis (ATSP) geometry does not consider all the GH morphometric features, for example the elliptical shape of the humeral head. Moreover, the morphometric studies leading to the initial ATSP design did not consider the GH morphology of any sub-Saharan population. Hence, there exists a gap in understanding of the implications of certain morphometric features on the functionality of a post-TSA GH joint. This thesis had two primary aims to address this gap in knowledge. Firstly, to study the GH morphometric variations between cohorts representing native European (Swiss) and native sub-Saharan (South African) populations. Secondly, to develop anatomically inspired ATSP design concepts and test them using biomechanical and finite element (FE) models, insilico, under standardised testing protocols. The morphometric analysis suggested that an average Swiss humeral head radius of curvature was larger (P28mm or <19mm. Considering both the populations, the inherent shape of an average humeral head was found to be elliptical. The thickest region of the head was found to lie in the posterior region and not at the geometric center. Hertzian contact theory was applied to calculate the GH stresses produced by symmetric and asymmetric elliptical heads. Higher concentric stresses (P<0.001), within the acceptable limit for polyethylene, were observed to be imparted by the asymmetric heads. Population-specific musculoskeletal models were developed to study the post-TSA kinematic variation. When an identical range of motion (RoM) was performed by these models, population-specific variation in muscle moment arms was observed. The novel glenoid designs were not found to alter the post-surgical kinematics. FE models of the biradial, compartmental and pear-shaped glenoid implant designs were subjected to compressive and shear loading according to the American Society for Testing and Materials (ASTM). Using the bi-radial the glenoid cup, with thickened posterior-superior surface, anatomically relevant force distribution patterns could be replicated. Compartmentalising the glenoid prosthesis into concentric and eccentric regions with the gaps, proved to be highly beneficial. When compared to a commercially available glenoid prosthesis, the compartmental prosthesis was able to contain the GH forces to the concentric region for longer, delaying the eccentric loading and therefore potentially reducing the “rocking horse” effect. In the light of the above observations, two conclusions can be drawn from this thesis. Firstly, it would be beneficial if population-specific ATSP were made available for natives of certain geographic locations. Secondly, glenoid prosthesis designs could be compartmentalised to contain the GH joint forces within the concentric regions of the cup which might aid in the reduction of post-TSA complications
Novel Device to Accurately Locate Femoral Insertion Landmark in Medial Patellofemoral Ligament (MPFL) Reconstruction
No full textMedial Patello Femoral Ligament (MPFL) is the main stabilizer of the patellar bone in the knee complex. This fan shaped ligament prevents lateral dislocations of patella, especially during the initial 30° of knee flexion as there is minimal bony support from femur on the lateral aspect of the patella [1–2]. Patella dislocations are one of the common knee joint pathologies and it has been reported that each dislocation of the patella induces micro-tears in the MPFL [3]. It has been also observed in previous studies that there exists a very high chance of patellar re-dislocations for those individuals who have experienced the dislocation once. Complete MPFL rupture occurs in 94% of the patients suffering from repeated patellar dislocations [3–4].
Out of the 130 various methods of MPFL reconstruction, the Double Bundle Procedure is the most commonly used as it provides a larger degree of pain-free range of motion [5–8]. Locating the exact drilling location on the medial aspect of the patella and the medial femur is a challenge for the surgeon and literature suggests that the current procedure leads to non-anatomical placement of the ligament [9]. A novel device has been developed (Pat-Rig) to address the issue of locating the exact drill locations of the ligament graft tunnels into the patella [10–12]. This paper addresses the second problem of locating the femoral landmark accurately.</jats:p
Effect of Al doping on thermoelectric power of Mg1−xAlxB2 phonon drag and carrier diffusion contribution
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Residual limb modelling for optimal shape and bandaging in transfemoral amputees
No full textEffective compression bandaging of transfemoral residual limbs is essential for managing postoperative swelling and achieving a conical limb shape appropriate for prosthetic fitting. However, conventional bandaging techniques often lack personalised adjustment based on the residual limb’s changing dimensions, potentially compromising pressure consistency and therapeutic outcomes. This study aimed to demonstrate the modelling and validation of residual limbs for optimal shape and bandaging in transfemoral amputees, by integrating patient‑specific circumferential measurements into custom-printed A4 templates and mobile-driven guidance. Six residual limb models (ACM, CM1–CM5) were developed with incrementally increasing circumferential dimensions. Predicted bandage lengths were calculated for each model using Python scripts, and pressure readings were obtained using a Force Sensitive Resistor circuit, with outputs converted to mmHg based on calibration values. Statistical analyses were conducted, including chi-square goodness of fit tests and one-sample t-tests, to assess the differences between observed and expected values. Results demonstrated that differences between observed and expected bandage lengths were not statistically significant across all models, with mean differences increasing proportionally with model size. Pressure readings for most models remained within 0.5 mmHg of the approximated ideal target of 20 mmHg, with only CM5 showing a statistically significant deviation (mean pressure: 18.2 mmHg, p = 0.01), suggesting potential limitations at higher limb volumes. In addition, a consistent trend of increased pressure during diagonal wrapping steps (steps 2 and 3) and lower pressure during lateral and final steps (steps 1 and 4) was observed. These findings confirm the validity of the prediction model for bandage length and support the technique's effectiveness in applying therapeutic compression for optimal shape. This study establishes a foundation for optimising residual limb bandaging practices and suggests that further testing with larger models and clinical trials could enhance personalised compression therapy for amputees
Pre-operative planning for reverse shoulder arthroplasty in low-resource centres : a modified Delphi study in South Africa
No full textDATA AVAILABILITY STATEMENT :
The datasets used and analyzed during the current study are avail-
able from the corresponding author on reasonable request.BACKGROUND : Pre-operative planning for reverse shoulder arthroplasty (RSA) poses challenges, particularly when dealing with glenoid bone loss. This modified Delphi study aimed to assess expert consensus on RSA planning processes and rationale, specifically targeting low-resourced institutions. Our objective was to offer pre-operative decision-making algorithms tailored for surgeons practising in resource-constrained hospitals with limited access to computed tomography (CT) scans. METHODS : A working group generated statements on pre-operative imaging and glenoid of glenoid morphology and intra-operative decision-making. The study was conducted in three stages, with virtual consensus meetings in between. Stages 2 and 3 consisted only of closed questions/statements. The statements with over 70% were considered consensus achieved and those with less than 10% were considered disagreement consensus achieved. RESULTS : Twelve shoulder surgeons participated, with 67% having over five years of experience in shoulder arthroplasty. In the absence of glenoid bone loss, the sole use of plain radiographs for pre-operative planning reached consensus and is recommended by these groups, while 100% advise using CT scans when bone loss is present. Most surgeons (70%) recommend using patient-specific instrumentation (PSI) in cases of structural bone loss. Most of the statements on intra-operative decision-making related to component placement and enhancing stability failed to reach consensus. CONCLUSION : While consensus was achieved on most aspects of pre-operative imaging and planning, technical aspects of surgery lacked consensus. Planning for patients with structural glenoid bone loss necessitates CT scans and planning tools.http://www.sicot-j.orghj2024Orthopaedic SurgerySDG-03:Good heatlh and well-bein
Quantitative fit analysis of acromion fracture plating systems using three-dimensional reconstructed scapula fractures – A multi-observer study
No full textIntroduction: Surgical treatment of displaced acromial and scapula spine fractures may be challenging due to the bony anatomy and variable fracture patterns. This difficulty is accentuated by the limitations of the available scapular plates for fracture fixation. This study compares the quantitative fitting of anatomic scapular plates and clavicle plates, using three-dimensional (3D) printed fractured scapulae. Methods: Fourteen scapulae with acromion and spine fractures were used for this study. Computerized tomographic (CT) scans of the fractured scapulae were obtained from the Philips picture archiving and communication system (PACS) database of patients admitted to a tertiary teaching hospital in Cape Town, South Africa between 2012 and 2016. The reconstructed scapulae were 3D printed and the anatomical acromion and clavicle plates were templated about the fracture regions. The fit assessment was performed by five observers who classified the plates as no-fit, intermediate fit, and anatomical fit according to the surgical guidelines. Results: The 6-hole anterior clavicle plate performed better than any of the scapular plates as they were able to fit 45.7% of the fractured acromion, including the spine. Among the pre-contoured anatomical scapula plates, both the short and the long acromion plates could fit only 27.3% of the fractured acromion. The intraclass correlation coefficient was 0.965 suggesting excellent consensus among the five observers. Conclusion: Clavicle plates were found to be better suited to fit around a scapula fracture in its acromion and spine region
A narrative review of treatment strategies for major glenoid defects during primary reverse shoulder arthroplasty, with a focus on the use of structural bone graft
No full textStructural glenoid defects are common during primary reverse shoulder arthroplasty (RSA) and are often associated with poor outcomes.
The lack of pre-operative imaging protocols for determining the depth and degree of glenoid wear hinders our ability to accurately plan and correct these defects.
Although bone grafting has been reported to be effective in reducing glenoid wear during RSA, there is limited information on when to utilise it and how to prepare the graft.
We conducted this review to assess the evidence for the management of glenoid defects, with an emphasis on bone grafts to treat structural glenoid bone loss in primary RSA patients
