The Association of Gait Kinematics, Instability and Patient Reported Outcomes in Patients With Total Knee Replacement

Study Overview
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Brief Summary
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It is unclear why 20% of patients with total knee replacements (TKR) are dissatisfied. Few studies have specifically assessed the way people walk ('gait') with an 'unhappy' or unstable knee or following re-do ('revision') TKR surgery. The investigators conjecture that people having re-do TKR surgery because their knee is unstable will have altered walking patterns (for example, less bending of the knee) before and after surgery, and that these changes are related to how satisfied the patient is with their knee. The investigators will also examine whether there are differences in the way people walk with an unstable knee replacement or with a stable knee replacement, in comparison to people who do not have a knee replacement. This exploratory project will use 3D infrared cameras to analyse differences in walking patterns and whether there is associated change in patient satisfaction. If an association exists, the data from this study may help to develop alternative measures of outcomes, in order to guide treatment decisions.

Detailed Description
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The effect of TKR instability on gait is poorly understood. How does revision TKR surgery for instability alter gait and is there an associated change in patient satisfaction? Are there differences in gait between patients with an unstable TKR and a stable TKR? The objectives of this study are: To investigate the effect of a revision TKR operation on gait kinematics, in patients who have a primary TKR and instability. To investigate the association between changes in gait kinematics and patient satisfaction, before and after revision TKR surgery for patients with instability. To investigate differences in gait kinematics between dissatisfied patients with an unstable primary TKR, satisfied patients with a stable primary TKR and people who do not have a knee replacement. The first part of the investigation will tackle the first two objectives and follow patients who are having a revision TKR due to an unstable knee before and after their operation. The second part will then compare these patients to those with a primary TKR and no instability and to a control group of participants who do not have knee replacements ('native knees') and do not have difficulty walking. This will determine the difference in kinematics between a native knee and a TKR with and without instability. Age, height, weight, leg lengths, measurements of the TKR position on imaging (taken as part of routine clinical practice) and patient reported outcome scores will be documented. The gait assessments will be carried out in the outpatient clinic or physiotherapy department. These patients will have their walking gait assessed using a treadmill-based portable 3D infrared camera system (Vicon Ltd, Oxford, UK). The raw data will be processed by Run3D (Run3D Ltd, Oxford, UK) and Visual3D (C-motion Inc, MD, USA) to calculate knee joint angles. Analysis will focus on within subject (part 1) and between subject differences (part 2). The questions are novel and data will be largely exploratory. Measures, differences and correlations will be presented using descriptive statistics and, where appropriate, correlation and regression coefficients. Where possible, inferential statistics (such as t-tests) will formally test differences in knee kinematic measures and associations with PROMS. Statistical parametric mapping will be applied to analyse continuous quantities over the gait cycle. Published research indicates an effect size of 1.0 may be expected. This suggests sample sizes between 11 and 42 should be sufficient to determine statistically significant two-tailed differences (alpha=0.05, beta=0.2) within subjects or between groups, according to the comparison being assessed. A sample of 42 patients is targeted. In the longer term, this study will enable a better understanding of the functional biomechanics of TKR instability and potentially develop an alternative quantitative measurement of outcome and instability.

Official Title
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The Association of Gait Kinematics, Instability and Patient Reported Outcomes in Patients With Total Knee Replacement

Conditions
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Arthroplasty, Replacement, Knee

Intervention / Treatment
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* Procedure: Revision TKR surgery
* Other: No intervention.


Participation Criteria
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Eligibility Criteria
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Inclusion Criteria: Patients awaiting revision TKR due to instability: Patients who have a primary total knee replacement. Patients who have an unstable knee replacement, as determined by the surgical team. Patients who are being listed for a revision total knee replacement. Primary TKR without instability: Patients with a primary total knee replacement. Patients at least one year after their primary total knee replacement operation. Exclusion Criteria: Patients awaiting revision TKR due to instability: Patients who have suspected infection of the TKR. Patients who are awaiting a two-stage revision procedure. Patients who can walk less than one minute at a time. Patients who can walk for less than five minutes with rests. Patient who are not able to give informed consent. Primary TKR without instability: Patients who have had a previous revision of the total knee replacement. Patients who have an unstable knee replacement, as determined by the surgical team. Patients who have aseptic loosening or wear, as determined by the surgical team. Patients who are not satisfied with their TKR (as determined by the study specific questionnaire). Patients who can walk for less than one minute at a time. Patients who can walk for less than five minutes with rests. Patient who are not able to give informed consent.
Sexes Eligible for Study
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All

Accepts Healthy Volunteers
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Accepts Healthy Volunteers

Study Plan
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How is the study designed?
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Arms and Interventions

| Participant Group/Arm | Intervention/Treatment |
| --- | --- |
| Stable, satisfied primary TKR<br>Participants who have a stable TKR (as assessed by the surgical team) and are satisfied with their knee replacement (as assessed by a questionnaire). | Other: No intervention.<br>* This study will also make a case-control comparison between patients with a stable primary TKR and an unstable primary TKR.<br>|
| Unstable, dissatisfied primary TKR<br>Participants who are dissatisfied with their TKR, with instability (including instability due to aseptic loosening) and consequently awaiting revision TKR. | Procedure: Revision TKR surgery<br>* This study will follow the cohort of patients who have an unstable primary TKR with which they are dissatisfied. They will be assessed before and after their revision TKR surgery.<br>|

What is the study measuring?
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Primary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Change from preoperative maximum knee flexion during swing. | Maximum knee flexion angle during the swing phase of gait. | 8-12 weeks after surgery. | 
| Change from preoperative maximum knee flexion during swing. | Maximum knee flexion angle during the swing phase of gait. | 1 year after surgery. | 

Secondary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Change from preoperative maximum knee flexion during stance. | Maximum knee flexion angle during the stance phase of gait. | 8-12 weeks after surgery. | 
| Change from preoperative maximum knee flexion during stance. | Maximum knee flexion angle during the stance phase of gait. | 1 year after surgery. | 
| Change from preoperative knee sagittal plane range of movement. | Knee sagittal plane range of movement during stance and swing phases of gait. | 8-12 weeks after surgery. | 
| Change from preoperative knee sagittal plane range of movement. | Knee sagittal plane range of movement during stance and swing phases of gait. | 1 year after surgery. | 
| Change from preoperative knee coronal plane range of movement. | Knee coronal plane range of movement during stance and swing phases of gait. | 8-12 weeks after surgery. | 
| Change from preoperative knee coronal plane range of movement. | Knee coronal plane range of movement during stance and swing phases of gait. | 1 year after surgery. | 
| Change from preoperative knee axial plane range of movement. | Knee axial plane range of movement during stance and swing phases of gait. | 8-12 weeks after surgery. | 
| Change from preoperative knee axial plane range of movement. | Knee axial plane range of movement during stance and swing phases of gait. | 1 year after surgery. | 
| Change from preoperative baseline in Oxford Knee Score. | Patient reported outcome measure. Minimum 0, Maximum 48 (48 being best). | 8-12 weeks after surgery. | 
| Change from preoperative baseline in Oxford Knee Score. | Patient reported outcome measure. Minimum 0, Maximum 48 (48 being best). | 1 year after surgery. | 
| Change from preoperative baseline in Knee injury and Osteoarthritis Outcome Score. | Patient reported outcome measure. Minimum 0, Maximum 100 (100 being best). Subscales (pain, symptoms, function, sports and recreation, quality of life) are transformed to the 0-100 overall scale. | 8-12 weeks after surgery. | 
| Change from preoperative baseline in Knee injury and Osteoarthritis Outcome Score. | Patient reported outcome measure. Minimum 0, Maximum 100 (100 being best). Subscales (pain, symptoms, function, sports and recreation, quality of life) are transformed to the 0-100 overall scale. | 1 year after surgery. | 
| Change from preoperative baseline in American Knee Society Score. | Patient reported outcome measure with two subscales. Subscales are the Knee Society Score, Minimum 0, Maximum 100 (100 being best); and Knee Society Function Score Minimum 0, Maximum 100 (100 being best). | 8-12 weeks after surgery. | 
| Change from preoperative baseline in American Knee Society Score. | Patient reported outcome measure with two subscales. Subscales are the Knee Society Score, Minimum 0, Maximum 100 (100 being best); and Knee Society Function Score Minimum 0, Maximum 100 (100 being best). | 1 year after surgery. | 
| Change from preoperative baseline in EQ-5D-5L questionnaire. | Patient reported outcome measure. Subcategories (mobility, self-care, activity, pain, anxiety) scored between 1 and 5 (1 being best) and a visual analog score between 0 and 100 (100 being best). | 8-12 weeks after surgery. | 
| Change from preoperative baseline in EQ-5D-5L questionnaire. | Patient reported outcome measure. Subcategories (mobility, self-care, activity, pain, anxiety) scored between 1 and 5 (1 being best) and a visual analog score between 0 and 100 (100 being best). | 1 year after surgery. | 

 Terms related to the study
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Keywords Provided by Centre Hospitalier Valida
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Total knee replacement, Revision knee surgery, Knee instability, Gait analysis, Patient reported outcome