Rajshree Mootanah

Foot type biomechanics part 1: Structure and function of the asymptomatic foot

BACKGROUND Differences in foot structure are thought to be associated with differences in foot function during movement. Many foot pathologies are of a biomechanical nature and often associated with foot type. Fundamental to the understanding of foot pathomechanics is the question: do different foot types have distinctly different structure and function? AIM To determine if objective measures of foot structure and function differ between planus, rectus and cavus foot types in asymptomatic individuals. METHODS Sixty-one asymptomatic healthy adults between 18 and 77 years old, that had the same foot type bilaterally (44 planus feet, 54 rectus feet, and 24 cavus feet), were recruited. Structural and functional measurements were taken using custom equipment, an emed-x plantar pressure measuring device, a GaitMat II gait pattern measurement system, and a goniometer. Generalized Estimation Equation modeling was employed to determine if each dependent variable of foot structure and function was significantly different across foot type while accounting for potential dependencies between sides. Post hoc testing was performed to assess pair wise comparisons. RESULTS Several measures of foot structure (malleolar valgus index and arch height index) were significantly different between foot types. Gait pattern parameters were invariant across foot types. Peak pressure, maximum force, pressure-time-integral, force-time-integral and contact area were significantly different in several medial forefoot and arch locations between foot types. Planus feet exhibited significantly different center of pressure excursion indices compared to rectus and cavus feet. CONCLUSIONS Planus, rectus and cavus feet exhibited significantly different measures of foot structure and function.

Video-assisted swallowing therapy for patients with Parkinson's disease

BACKGROUND Conventional swallowing therapy for patients with Parkinsons disease (PD) and swallowing difficulties has poor carryover to everyday life. Herein, we test the effectiveness of visual information while treating swallowing disturbances in patients with PD. METHODS Forty two non-demented PD patients with swallowing disturbances were randomly divided into two groups. An experimental group received video-assisted swallowing therapy (VAST) and a control group (n = 21) was given conventional therapy. Both groups were given 6 interventional sessions by the same speech and swallowing therapist. Patients in the VAST group were exposed to video of the swallowing process in general as well as of their own, as part of all therapy sessions. Swallowing function was assessed before and post-intervention by fiberoptic endoscopic evaluation of swallowing (FEES). Quality of life, quality of care and the degree of pleasure from eating were also assessed by questioners pre and post-intervention. RESULTS There was a significant improvement in swallowing functions following both interventions. The FEESs demonstrated a significantly greater reduction in food residues in the pharynx in the VAST group compared to the conventional treatment group. There were significant group improvement in some parameters of the quality of life, quality of care and pleasure of eating scales. CONCLUSION In cognitively intact patients with PD with swallowing disturbances VAST was associated with improved swallowing related QOL and less food residues in the pharynx.

Anxiety, depression and swallowing disorders in patients with Parkinson's disease

Swallowing disturbances (SDs), anxiety and depression are commonly present in Parkinsons disease (PD) patients. We hypothesized that there is an association between the presence of SDs and the PD affective state. Sixty-nine PD patients were assessed for the presence of SDs by undergoing cognitive screening with the Mini Mental State Examination (MMSE), completing three inventories: a swallowing disturbance questionnaire (SDQ), the Spielberger manual for the trait anxiety and Beck depression inventories. All patients underwent clinical swallowing evaluations by a speech and language pathologist (SLP). Patients diagnosed with SDs were also assessed by fiberoptic endoscopic evaluation of swallowing (FEES) performed by an ENT and SLP. Thirty-eight patients experienced SDs, the other 31 did not. The clinical characteristics of the two groups were matched. Patients with SDs experienced increased anxiety and depression compared to patients without SDs. Comparisons between patients who scored in the two opposite ends of the anxiety and depression ranges demonstrated that the most anxious and depressed patients reported more swallowing difficulties (SDQ scores) compared with the least anxious and depressed ones. In addition, the most anxious patients had significantly increased disease severity and decreased MMSE scores compared with the least anxious patients. Disease severity was also increased in the most depressed patients compared with the least depressed ones. Advanced disease emerged as being associated with high anxiety levels and greater numbers of SDs. The contribution of anxiety or depression to the development or worsening of SDs and their role in treatment strategy warrant further investigation.

Development and validation of a computational model of the knee joint for the evaluation of surgical treatments for osteoarthritis

A three-dimensional (3D) knee joint computational model was developed and validated to predict knee joint contact forces and pressures for different degrees of malalignment. A 3D computational knee model was created from high-resolution radiological images to emulate passive sagittal rotation (full-extension to 65°-flexion) and weight acceptance. A cadaveric knee mounted on a six-degree-of-freedom robot was subjected to matching boundary and loading conditions. A ligament-tuning process minimised kinematic differences between the robotically loaded cadaver specimen and the finite element (FE) model. The model was validated by measured intra-articular force and pressure measurements. Percent full scale error between FE-predicted and in vitro-measured values in the medial and lateral compartments were 6.67% and 5.94%, respectively, for normalised peak pressure values, and 7.56% and 4.48%, respectively, for normalised force values. The knee model can accurately predict normalised intra-articular pressure and forces for different loading conditions and could be further developed for subject-specific surgical planning.

Stress analysis in single molar tooth.

The human tooth faces different stresses under environments of different loading conditions, these loading produces major factors in weakness of the tooth and bone structure. The need to save natural teeth has prompted the development of novel and complex techniques in endodontology, prosthodontics and periodontology. Despite a poor long-term prognosis and some prejudice to local bone, considerable efforts have been exerted for the realization of these techniques. Nowadays, the 3D finite element analysis (FEA) is one of the more recently used techniques for stress analysis in single human tooth under different loading cases. The von Mises stress distribution indicated that the greatest effort area of tooth lies at the base of crown up to the gingival line with varying intensities in the different loading cases. The highest stress in the cortical bone was predominantly found around the cervical region of the tooth and lowest in the cancellous bone and periodontal ligament (PDL). The PDL is a soft tissue, and it could function as an intermediate cushion element which absorbs the impact force and uniformly transfers the occlusal forces into the surrounding bone.

Stresses in cement mantles of hip replacements: effect of femoral implant sizes, body mass index and bone quality

The effects of femoral prosthetic heads of diameters 22 and 28 mm were investigated on the stability of reconstructed hemi-pelves with cement mantles of thicknesses 1–4 mm and different bone qualities. Materialise medical imaging package and I-Deas finite element (FE) software were used to create accurate geometry of a hemi-pelvis from CT-scan images. Our FE results show an increase in cement mantle stresses associated with the larger femoral head. When a 22 mm femoral head is used on acetabulae of diameters 56 mm and above, the probability of survivorship can be increased by creating a cement mantle of at least 1 mm thick. However, when a 28 mm femoral head is used, a cement mantle thickness of at least 4 mm is needed. Poor bone quality resulted in an average 45% increase in the tensile stresses of the cement mantles, indicating resulting poor survivorship rate.

Tribological investigation of ultra-high molecular weight polyethylene against advanced ceramic surfaces in total hip joint replacement

The aim of the study was to investigate whether a modified ceramic head surface could reduce the friction and wear rate of simulated ceramic-on-polyethylene hip joints. To address this aim, ultra-high molecular weight polyethylene (UHMWPE) was made to slide on aluminium oxide (Al2O3), dimpled Al2O3, diamond-like carbon (DLC) coated and DLC-coated dimpled substrates. The experiment condition was replicated to simulate artificial hip joints in terms of contact pressure, speed and temperature. UHMWPE on non-dimpled Al2O3 showed lower friction coefficient and wear rate compared to other advanced surfaces. Lower wettability, and higher hardness and surface adhesion of DLC resulted in increased friction and wear. The high difference in modulus of elasticity and hardness between UHMWPE and both, Al2O3 and DLC, reduced the effectiveness of textured surface techniques in friction and wear reduction. Therefore, no tribological benefit was found by fabricating either DLC coating or surface texturing on hard surface when rubbed against softer UHMWPE.

Principles of assessment for project and research based learning

Purpose – The purpose of this paper is to provide assessment guidelines which help to implement research‐based education in science and technology areas, which would benefit from the quality of this type of education within this subject area.Design/methodology/approach – This paper is a reflection on, and analysis of, different aspects of assessment. From one side, it looks at assessment in general, in society at large.Findings – Assessment could be improved within this field in order to contribute to the learning process, rather than merely measure and categorise a students performance after the fact. To do this the paper not only looks at different forms of assessment and different ways of conducting the assessment, but also argues that certain ways of teaching and of structuring a class and an assignment are more conducive to creating an atmosphere in which students will be wanting to receive feedback to improve their learning and performance rather than a mark as a prize or reward.Originality/value –...

Configuration of anchorage holes affects fixation of the acetabular component in cemented total hip replacement—a finite element study

Our survey of current practice among UK orthopaedic surgeons shows wide variations in fixation techniques. The aim of this study, is to investigate the effect of drilling different configurations of anchorage holes in the acetabulum on implant stability. To avoid variables that could incur during in vitro testing, we used commercially available COSMOS finite element analysis package to investigate the stress distributions, deformations, and strains on the cement mantle when drilling three large anchorage holes and six smaller ones, with straight and rounded cement pegs. The results, which are in line with our in vitro studies on simulated reconstructed acetabulae, indicate better stability of the acetabular component when three larger holes than six smaller holes are drilled and when the necks of the anchorage holes are rounded. The longevity of total hip replacements could be improved by drilling three large anchorage holes, rather than many smaller ones, as initially proposed by Charnley.

ACHIEVING UNIFORM CEMENT MANTLE OF OPTIMUM THICKNESS DURING ORTHOPAEDIC SURGERY

The stability of cemented hip replacements can be improved by achieving a uniform and optimum cement mantle thickness. However, in surgery, it is difficult to achieve this even thickness of cement mantle due the bottoming out of the cup. Some acetabular cups with 3 mm cement spacers exist on the market. However, the optimum cement thickness is not always 3mm [Lamvohee et. al., 2006]. We investigated the use of cement spacers to produce uniform cement mantles of pre-defined thicknesses. Although bone cement is reasonably strong in compression, it is a relatively brittle material, making it susceptible to fracture as a result of tensile loads [Harper et al., 2000].