Physiotherapy - Theses
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ItemFalls prevention after stroke(University of Melbourne, 2010)
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ItemTendon-aponeurosis strain and clinical features of runners with and without achilles tendinopathy(University of Melbourne, 2010)
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ItemThe reliability and validity of the squeeze test for athletic groin pain in Australian Rules Football players(University of Melbourne, 2009)
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ItemHistology of the fascial-periosteal interface in lower limb chronic deep posterior compartment syndrome(University of Melbourne, 2007)
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ItemSensorimotor changes in knee osteoarthritis: from muscle spindle function to brain organisation and activity( 2015)Knee osteoarthritis (OA) is a major cause of disability and it is a growing problem due to the aging population and rising obesity rates. Better understanding of the disease process is required to inform the most efficient and effective methods of treatment for knee OA. Knee OA is associated with changes in motor and sensory function including impaired proprioception and motor output. The underlying causes of these impairments in knee OA remain unclear. Little previous research has investigated whether the proprioceptive impairments associated with knee OA are localised to the knee joint or are generalised across multiple joints in both the upper and lower limb joints. Muscle spindle function and the central processing of muscle spindle related afferent input in the brain are integral to optimal proprioception, however muscle spindle function in people with knee OA has not previously been investigated. Many of the documented motor and sensory function changes associated with knee OA alter input from the periphery. These changes along with the functional or structural reorganisation of the brain associated with other conditions that affect control of movement indicate likely reorganisation of at least the motor cortex and possibly other brain regions. No previous study has investigated reorganisation of the motor cortex or changes in activation across the whole brain associated with knee OA. To investigate whether joint repositioning proprioceptive deficits are localised to the diseased joint or generalised across other joints in people with knee OA, 30 individuals with right knee OA and 30 healthy asymptomatic controls performed active joint repositioning tests of the knee, ankle and elbow. Participants with knee OA had a larger relative error for joint repositioning of the knee than the controls. Relative error did not differ between groups for the ankle or elbow. These results are consistent with a mechanism for proprioceptive change that is localised to the knee joint. Given the important contribution muscle spindles make to proprioception differences, the function of quadriceps, triceps surae and tibialis anterior muscle spindles between people with and without knee OA were investigated. Thirty individuals with knee OA and 30 healthy asymptomatic controls stood comfortably and blindfolded on a force plate, with mechanical vibration applied over the quadriceps, triceps surae or tibialis anterior muscles. Anterior-posterior displacement of centre of pressure was analysed. Although there were no differences between groups for trials with vibration applied to the quadriceps or tibialis anterior, participants with knee OA were initially perturbed more by triceps surae vibration and accommodated less to repeated exposure than controls. This indicates that people with knee OA have less potential to detect or compensate for disturbed input to triceps surae, possibly due to an inability to compensate using muscles spindles in the quadriceps muscle. Differences in the organisation of the motor cortex between people with and without knee OA and possible associations between cortical organisation and accuracy of performance of a motor task were investigated. Functional magnetic resonance imaging (fMRI) data were collected while 11 participants with right knee OA and seven asymptomatic controls performed three force-matching motor tasks involving: 1) quadriceps, 2) tibialis anterior, and 3) finger/thumb flexor muscles. fMRI data were used to map the loci of peak activation in the motor cortex during the three tasks and to assess whether there were differences in the organisation of the motor cortex between the groups for the three motor tasks. Task accuracy was also quantified. A more anterior representation of the knee, and an opposite relative position of the knee and ankle representations in the motor cortex were found in people with knee OA. Poorer performance of the knee task was associated with more anterior placement of motor cortex loci in both groups. To investigate differences in activation of brain regions involved in sensorimotor processing between people with and without knee OA, brain activation during force matching tasks of the knee, ankle, or hand was assessed. fMRI data were collected with the participants, protocol and methods described above for investigations of motor cortex organisation. Areas of activation that differed between groups for each of the three motor tasks across the whole brain were identified. Task accuracy was also quantified. The combination of findings of changes in brain activation largely localised to the knee and of similar levels of performance accuracy across the knee, ankle and hand in the OA group indicate that a combination of factors, including those specific to sensorimotor control, may underlie changes in brain activation during knee, and to a lesser extent, ankle movements in people with knee OA. Brain activation was either not different or minimally different during the hand and ankle tasks, respectively. This indicates differences in sensorimotor processing are largely specific to the knee and not a generalised phenomenon. Overall this thesis provides evidence that in knee OA: 1) proprioceptive impairments are localised to the knee joint and not generalised across the ankle and elbow joints, 2) there are changes to muscle spindle function associated with knee OA, 3) organisation of the motor cortex differs between people with and without knee OA and differing organisation of the motor cortex is related to motor task performance, and 4) there are differences in brain activation between people with and without knee OA across a broad sensorimotor network associated with knee movement and a small number of areas of differing brain activation associated with ankle movement.
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ItemPost-traumatic knee osteoarthritis after anterior cruciate ligament reconstruction: Psychological, functional and biomechanical factors and the effect of a targeted brace( 2015)Post-traumatic knee osteoarthritis (OA) after anterior cruciate ligament reconstruction (ACLR) is prevalent in younger adults and has the potential to cause substantial knee-related symptoms and limit physical function. Physical and psychological impairments are likely to adversely affect quality of life and work participation. Knowledge of modifiable risk factors associated with knee OA post-ACLR has the greatest capacity to lead to new interventions that could change the natural history of knee OA. What are the modifiable factors associated with knee OA post-ACLR? Section A of this thesis describes the results of two cross-sectional studies which revealed that individuals with knee OA five to 12 years post-ACLR have worse knee confidence and greater kinesiophobia compared with individuals who have no OA five to 12 years post-ACLR. In individuals with knee OA five to 20 years post-ACLR, those with worse knee confidence have worse knee-related symptoms, poorer function, greater kinesiophobia, and poorer perceived self-efficacy and health-related quality of life. Section B of this thesis investigated knee biomechanics during walking in individuals post-ACLR. Pooled data from a systematic review revealed that, compared to healthy controls and uninjured contralateral knees, ACLR knees have abnormal knee biomechanics, particularly in the sagittal plane. Systematic review findings also revealed that the type of graft (hamstring or patellar) and time post-surgery could also influence knee biomechanics. A cross-sectional study also evaluated biomechanics in people with lateral knee OA post-ACLR. Compared to healthy controls, individuals with lateral knee OA five to 20 years post-ACLR had greater knee flexion and lower knee internal rotation angles, as well as greater pelvic anterior tilt, and hip flexion angles. Is there a potential intervention for modifiable risk factors associated with knee OA post-ACLR? A targeted knee brace was investigated for individuals with knee OA post-ACLR. First, a within-subject randomized study investigated the immediate and four-week effects of a targeted knee brace on knee-related symptoms and function in individuals with knee OA post-ACLR. The brace produced improvements in knee-related symptoms immediately and following four weeks of intervention. Second, a within-subject randomized study evaluated the immediate effects of varus bracing on gait characteristics in individuals with lateral knee OA post-ACLR. Results revealed that the unloader brace significantly altered gait characteristics associated with lateral knee OA post-ACLR. Overall, this thesis sheds light on some of the modifiable risk factors associated with knee OA post-ACLR, and investigated one targeted intervention with the potential to improve quality of life of individuals with knee OA post-ACLR. Targeting psychological, functional and biomechanical risk factors in individuals post-ACLR may aid in optimal recovery, and slowing disease progression in individuals with knee OA post-ACLR.
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ItemSternal management following cardiac surgery( 2015)Patients who have undergone cardiac surgery involving a median sternotomy are routinely asked to follow sternal precautions post-operatively that are not standardised, with significant variation in the type and duration for which they are recommended. These precautions usually include the restricted use of the upper limbs and trunk, with the broad aim of preventing the development of sternal complications such as sternal instability. However, there is limited research investigating the basis of these precautions and as such it is not known how tasks involving the upper limbs and trunk affect the healing sternum. If sternal precautions are overly restrictive, they may delay functional recovery, which is significant in a patient population that is presenting with a greater number of co-morbidities pre-operatively. This poses the question of whether sternal precautions are warranted in all patients following cardiac surgery involving a median sternotomy. This thesis aims to: (1) explore the physiotherapy management of patients following cardiac surgery involving a median sternotomy, (2) investigate the risk factors for sternal complications in this patient population, (3) determine the clinical utility of ultrasound as a tool to assess sternal healing and (4) examine how tasks involving the upper limbs and trunk affect the sternum in this patient population.
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ItemFalls and postural balance in chronic obstructive pulmonary disease( 2014)Chronic obstructive pulmonary disease (COPD) is a major cause of breathlessness and disability associated with functional impairment and reduced quality of life. The presence of chronic conditions has been related to a higher fall risk in the elderly, and individuals with COPD may be at an increased fall risk due to the respiratory and systemic manifestations of the disease. Balance deficits are one of the most important risk factor for falls in older adults and preliminary evidence suggests that people with COPD may present with impaired postural balance compared to healthy older adults. However, limited information is available regarding falls and postural balance in the COPD population, particularly during an acute exacerbation. In addition, an increased fear of falling is prevalent among individuals with advanced age and is not exclusive to those who have experienced a prior fall. Although an increased fear of falling has been related to impaired physical function, decline in activities of daily living, and increased fall risk in older adults, the physical determinants and consequences of this fear have not been examined in those with COPD. An increased fall frequency has been reported among people with COPD, this is an important research outcome. However, the lack of a standardised reporting in COPD could influence the interpretation of falls data in this population. The integrative review described in Chapter 2 demonstrated a variety of study designs and falls definition used to investigate falls outcomes and associated risk factors in the COPD literature. Based on the current literature, risk factors associated with higher odds of having a fall in those with COPD are: fall history in the prior 6 months, coronary heart disease, use of supplemental oxygen, female gender and age. However, the lack of standardised falls outcome reporting and the use retrospective study design or limited follow-up make it difficult to draw definite conclusions. In Chapter 6, a prospective 12-month cohort study with falls monitoring was conducted using international recommendations for falls outcome reporting. Individuals with COPD presented a high fall incidence rate. Smoking history, number of medications, history of falls, fear of falling, and higher score on fall risk assessment questionnaire were identified as fall predictors. In addition, smoking history, number of hospitalised days due to acute exacerbation and advanced age contributes to an earlier time to first fall following initial assessment. The second area of work in this thesis systematically reviewed the assessment instruments used to evaluate postural balance and fear of falling in people with COPD. Different instruments with heterogeneous content have been used to assess these two outcomes in COPD. This systematic review described in Chapter 4 identified the need of use of standardised assessment methods and best evidence on their measurement properties reported in the COPD population. Recommendation is given about suitable instruments to assess balance and fear of falling in clinical practice. Further evaluation of balance performance in COPD included a controlled, cross-sectional study outlined in Chapter 7. This study investigated balance performance in hospitalised patients with COPD during an acute exacerbation compared to community-dwelling stable COPD and healthy controls. Falls incidence following hospital discharge was also recorded. Impairment on anteroposterior control of balance was found in the majority of balance tasks studied compared with healthy controls. Increased dyspnoea and reduced muscle strength were associated with balance deficits during an acute exacerbation of COPD. In addition, increased fall incidence rate and a high number of injurious falls were observed during 12-months following hospital discharge. Fear of falling assessment in COPD was the third area of investigation in this thesis. The proportion of fearful individuals and the level of fear in a sample of people with stable COPD were investigated and compared to age- and gender-matched healthy controls. A higher proportion of individuals and higher fear of falling scores were found among those with COPD compared to controls. Increased fear of falling was associated with impaired postural balance, lower quadriceps strength, reduced physical activity and higher fall risk.
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ItemNeuromuscular and biomechanical factors in people following partial meniscectomy( 2014)Arthroscopic partial meniscectomy (APM) is a common surgical procedure for meniscal tears and knee osteoarthritis (OA) is often reported in people who have undergone an APM. Knee OA is a major public health problem worldwide causing pain and disability, for which there is currently no cure. Cross-sectional data suggest that people following APM have a higher knee adduction moment (KAM, an indicator of medial to lateral knee load distribution) during gait, as well as reduced knee extensor muscle strength compared to healthy controls. These factors are potential contributors to knee OA and are potentially modifiable with appropriately targeted treatments. However, prospective studies are needed to identify if these modifiable risk factors contribute to the development of structural changes to knee joint cartilage in this group. Moreover, interventions that target identified modifiable risk factors for knee OA in people following APM are urgently required to combat the individual and societal burden of the disease. Part I of this thesis describes analyses from a prospective longitudinal study that included 82 people assessed 3 months following medial APM and re-assessed 2 years later (n=66). A comparison control group of 38 healthy participants was also assessed at baseline and 2 years (n=23). Exploratory analyses revealed that the APM cohort had a higher KAM during gait and weaker knee extensor and flexor muscle strength compared to controls at 3 months following surgery. However, knee muscle strength improved in the APM cohort over time, such that no differences in strength were found 2 years later compared to controls. Peak KAM increased in the APM leg over 2 years, although this change in KAM over time was not significantly different to that seen in controls. An investigation into the mechanisms that might explain the increase in peak KAM following APM was performed. Results indicated that an increased varus position of the tibia during gait partially explained the 2-year increase in peak KAM in people following APM. Further analyses found no evidence to suggest that knee muscle weakness at 3 months predicted 2-year change in KAM. Part I also evaluated whether alterations in the KAM and knee extensor strength were associated with measures of knee joint structural change (cartilage defects and cartilage volume). These analyses demonstrated that in people 3 months following APM, a higher peak KAM during fast pace walking, but not knee muscle strength, was associated with medial tibiofemoral cartilage defect onset or deterioriation over the subsequent 2 years. Part II of this thesis describes a single-blind randomised controlled trial conducted to evaluate the effects of a specific neuromuscular exercise program (‘ALIGN’) on the peak KAM during gait and a one-leg sit-to-stand task in 62 people who had undergone APM 3-12 months earlier. Secondary outcome measures included peak KAM during fast pace gait, one-leg hop for distance, peak KAM impulse during one-leg sit-to-stand task, knee and hip muscle strength, objective measures of physical function and self-reported measures of physical function and symptoms. Findings showed that the neuromuscular exercise program did not significantly change the peak KAM during gait or a one-leg sit-to-stand task. No between-group differences were found for any of the secondary outcomes. Overall, this thesis provides some evidence to suggest that a higher peak KAM during gait may be related to knee cartilage degradation over time following APM. Interventions that aim to improve varus malalignment of the tibia could potentially delay or prevent structural changes to knee joint cartilage following APM. However, the neuromuscular exercises included in this research did not reduce the KAM during gait or a one-leg sit-to-stand task. Nevertheless, we did not quantify structural change in this study; we therefore cannot conclude that neuromuscular exercise fails to delay or prevent osteoarthritic structural change in APM patients.
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ItemNeuromuscular control and knee function after anterior cruciate ligament reconstruction( 2014)Knee functional outcomes after anterior cruciate ligament reconstruction (ACLR) are variable, particularly amongst recreational athletes. Functional performance tests and self-reported measures of knee function are used clinically to quantify knee function after ACLR. Although these tests provide some indication of gross-motor function, they do not accurately quantify neuromuscular control. Sub-optimal neuromuscular control may be associated with poor knee function and, in turn, to altered knee joint loading and knee osteoarthritis. Despite years of ACLR research, knowledge of the relationship between neuromuscular control and knee function is limited mostly to bivariate analyses. These analyses do not account for participant characteristics such as age, sex, body mass index, the presence of chondral and meniscal injuries, greater anterior knee joint laxity or the participation limitations experienced by individuals. Knowledge of these associations is necessary to help explain the variability in knee functional outcomes following ACLR. Therefore, the aim of the research reported in this thesis was to investigate the cross-sectional associations between clinical tests of knee joint function and i) sports participation, ii) participant characteristics and iii) neuromuscular control following ACLR. To address this broad aim, four studies were conducted using a cross-sectional, observational study design. Sixty-six participants (23 women, median age 28.4, range 19-39) at an average of 18 months (SD 3 months) following ACLR with an ipsilateral hamstring graft, and 41 matched control participants (16 women, median age 25.8, range 18-39) were recruited. The inter-session reliability and standard error of measurement of variables were determined with 26 control participants (8 women, median age 24.7, range 19-37). In Study 1, the knee function of ACLR and control participants was assessed using a battery of self-reported and functional performance (hop) tests. Compared to control participants, ACLR participants demonstrated significant limitations in self-reported knee function and functional performance and significantly more ACLR participants failed the battery of functional tests. In a multivariate logistic regression model, older age, higher BMI and greater anterior knee joint laxity were significant predictors of failing the battery of knee functional tests. In Study 2, the quadriceps force control and thigh muscle activation strategies of ACLR and control participants were assessed using a novel, sub-maximal intensity, open kinetic chain force-matching task. Participants used quadriceps force to match a moving target torque that was displayed on a screen. ACLR participants demonstrated significantly greater target matching error, indicative of less-accurate quadriceps force production and higher levels of quadriceps activation and hamstring coactivation. In a multivariate linear regression model, less-accurate quadriceps force production was associated with greater vastus lateralis activation, lower lateral hamstring coactivation, female sex, older age at the time of testing, greater anterior knee joint laxity and meniscal surgery at the time of ACLR. Together these variables explained 42% of the variance in quadriceps force control in the ACLR group. In Study 3, the trunk and lower limb biomechanics of ACLR and control participants were compared in the landing phase of a novel forward hopping task which involved a dynamic take-off. Hop distance and take-off velocity were standardised to minimise variability in task performance between individuals. Significantly smaller knee flexion excursion, peak knee extensor moments and peak trunk flexion angles were observed in the ACLR group. In a multivariate linear regression model, greater anterior knee joint laxity, higher vastus medialis activation, lower medial hamstring coactivation and lower quadriceps strength relative to body mass accounted for 54% of the variance in knee flexion excursion in the ACLR group. Study 4 addressed the main aim of the thesis by investigating the multivariate associations between knee joint function, participant characteristics and neuromuscular control. Less-accurate quadriceps force production, greater lateral hamstring coactivation during the force matching task and female sex were significant predictors of failing the functional test battery. In the closed kinetic chain, smaller knee flexion excursion, smaller peak knee extensor moment and greater anterior knee joint laxity were significant predictors of failing the test battery. Prospective studies are now needed to determine whether the biomechanical and neuromuscular variables identified by this research are predictive of long-term knee function and knee osteoarthritis.
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