Physiotherapy - Theses
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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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ItemGait modification strategies for people with medial knee osteoarthritis( 2012)Knee osteoarthritis, most commonly occurring in the medial compartment, is a leading cause of pain and disability among the elderly. During gait, greater compressive load in the medial compartment is a major risk factor for osteoarthritis. As there is currently no cure, interventions which can reduce compressive loads are needed, because of their potential to slow disease progression. Evaluated during gait, the knee adduction moment is a commonly used surrogate measure of medial knee load and a marker for medial knee osteoarthritis progression. One of the conservative biomechanical approaches which may reduce the knee adduction moment is gait modification, or gait retraining. However, little is known about the strategies and their effects on medial knee load. Firstly, a systematic literature review was conducted to identify gait modifications. Of the 14 gait modifications identified in 24 studies, four strategies demonstrated greatest ability to reduce the knee adduction moment. Several limitations of previous studies were identified, such as poor reporting of methods, inclusion of participants without osteoarthritis, no evaluation of symptoms and limited information regarding the amount of modification required. Because of demonstrated ability to reduce a parameter of the knee adduction moment in cohorts, the following modifications were investigated in separate studies involving participants with symptomatic medial knee osteoarthritis: use of a cane on the contralateral side, increased lateral trunk lean and altered foot progression angle. The effects of contralateral cane use on knee load and pain were investigated in 23 individuals. Participants placed pre-determined magnitudes of support through the cane. Findings showed reductions in all knee load parameters, with a dose-response relationship. Likely due to biomechanical advantages, the technique of cane use influenced the load-reducing efficacy, such as cane positioning and timing of support. Whilst there were no changes in pain with cane use, individuals with greater severity of pain and varus malalignment reduced load more effectively. The effects of ipsilateral trunk lean gait on the knee adduction moment and pain were investigated in 22 individuals. Participants walked with varying magnitudes of trunk lean. Results demonstrated dose-response reductions in all knee load parameters, whilst pain remained unchanged. Timing of the gait modification mediated the efficacy of load reduction. Lastly, effects of altered foot progression angle on pain, the knee adduction and knee flexion moments were investigated in 22 individuals. Participants walked with varying degrees of toe-in and toe-out gait. Whilst pain remained unchanged, toe-in gait reduced the knee adduction moment during early stance but increased the knee flexion moment, knee adduction impulse and late stance adduction moment. Toe-out gait demonstrated opposite effects to toe-in gait. Furthermore, pain and malalignment demonstrated significant mediating effects for some outcomes. This thesis reports new and clinically relevant information on gait modifications for people with medial knee osteoarthritis. It was discovered that participant characteristics, the magnitude of modification and technique of performance altered the efficacy of load reduction achieved by gait modification strategies. Although future longitudinal evaluations are required, gait modifications investigated in this thesis may have potential to slow osteoarthritis progression via load reduction.