Abstract
Background and aims: People with knee osteoarthritis (OA) frequently exhibit altered gait biomechanics, such as reduced loading time on the affected knee, which can impair function, such as walking. Hence, improving gait could be an essential strategy for treating people with knee OA, given its functional relevance. Exercise and manual therapy are recommended interventions for the management of knee OA. However, the strength and consistency of evidence for their effects on gait biomechanics in people with knee OA remain unclear. Hence, the thesis comprised four studies: to summarise the effects of physiotherapy interventions [exercise, manual therapy, and combined intervention (exercise + manual therapy)] – particularly manual therapy on biomechanical gait outcomes in people with knee OA (Study 1- systematic review & meta-analysis); to obtain preliminary estimates of the effects the manual therapy on knee biomechanics during gait in people with knee OA (Study 2- biomechanical study); to explore the preliminary relationship between biomechanical gait outcomes and clinical outcomes following manual therapy (Study 3- correlation study); and to gain deeper insight into participants' perceptions and experiences with manual therapy for knee OA, and whether the changes in the clinical outcomes following manual therapy were meaningful for them (Study 4- qualitative study).
Methods: Study 1 is a prospective systematic review (PROSPERO registration: CRD42023408884). A literature search was conducted using six databases from inception through December 2024. We included studies of any design that have reported the effect of physiotherapy on at least one biomechanical outcome in level walking in people with knee OA. The risk of bias was assessed. We performed a meta-analysis and applied the Grading of Recommendations Assessment, Development and Evaluation (GRADE) criteria to each outcome. Study 2 is a single-group, pretest-post-test design (registration: ACTRN12624000157572p; HDEC ref no. 2024 EXP 19143). Participants with unilateral knee OA received six sessions of manual therapy, followed by a tailored home exercise program. Gait-related biomechanical outcomes were measured using a three-dimensional gait analysis system at baseline I, 4-week baseline-II, and 8-week follow-up. Clinical outcomes were assessed at all three time points and iii at one additional 6-month follow-up point. We chose a 4-week baseline-II as a prime baseline measure for all outcome measures. Basic descriptive statistics were reported. Nonparametric tests were used to assess changes in biomechanical and clinical outcomes. The level of significance (p-value) reported for median differences. To assess the correlation between biomechanical and clinical outcomes nonparametric test was employed (Study 3). In Study 4, an interpretivist, descriptive approach using one-to-one, semi-structured interviews to collect data, and a reflexive thematic analysis framework with an inductive approach was used to generate codes, sub-themes, and themes.
Summary of conclusion: Findings from Study 1 (systematic review) suggest limited evidence on the effects of manual therapy on biomechanics during gait in people with knee OA. Preliminary evidence from Study 2 (biomechanical study) suggests that manual therapy does not improve gait in people with knee OA. However, our findings showed promising improvements in knee extension range of motion (ROM), pain, and function following manual therapy at 8 weeks, translating to a large effect size and exceeding the minimal clinically important difference (MCID); and sustained at the 6-month follow-up, along with promising improvements in quality of life, fear and avoidance, and physical function. The findings from Study 3 (correlation study) suggest a moderate association between greater pain relief during walking and improved physical function, with increases in peak knee adduction moment (KAM) and knee extension moment (KEM) following manual therapy. The observed correlation could be considered hypothesis-generating rather than a true association, given the high likelihood of a Type I error. The four overarching themes, as expressed by participants, were: osteoarthritis is debilitating; uncertainty about manual therapy; a temporary but meaningful effect; and the value of manual therapy, which emerged from Study 4 (qualitative study).
Considering the overall results, it may be inferred that manual therapy does not improve gait in people with knee OA. Furthermore, it remains unclear whether manual therapy improves clinical outcomes through biomechanical pathways in people with knee OA. However, patients may be loading on the affected knee and experience improved walking following manual therapy. Also, manual therapy may temporarily improve pain and function, with improved patient-related contextual factors, such as confidence in performing daily activities (e.g., walking). This information would further aid understanding of the mechanism of manual iv therapy in knee OA. Future research using adequately powered samples and incorporating measures of neurophysiological and contextual factors is needed to clarify the mechanisms through which manual therapy influences outcomes in knee OA.