Evaluation of function in individuals with knee osteoarthritis

Introduction: Osteoarthritis, the most common joint disease, results in joint pain and limited function. In clinical practice, the array of measurements used to evaluate function are generally restricted to patient-reported outcome measures and performance-based tests, as they do not require special equipment. What these measures are unable to answer is how a given activity is performed. Thus, there may be additional important aspects of function, including examination of movement patterns, which could provide complementary information in the evaluation of function. This thesis evaluates methods used to objectively assess function – e.g., gait patterns, movement strategies, and performance-based function – in individuals with knee osteoarthritis. Methods: The studies include 40 individuals with primary knee osteoarthritis scheduled for total knee arthroplasty and a convenience sample of 25 healthy controls matched by age strata to individuals with osteoarthritis. All study participants completed a three-dimensional motion analysis session that rendered measurements of gait patterns and movement patterns used to perform a Sit-to-Stand test. Participants performed three performance-based tests including the Five Times Sit-to-Stand test, the Timed Up and Go test, and the Single Limb Mini Squat test. Participants completed one knee-specific questionnaire and one generic health-related quality of life questionnaire. Perceived pain was evaluated using a visual analogue scale. Individuals with osteoarthritis were evaluated within one month prior to total knee arthroplasty and one year after surgery. Controls were evaluated once. Results: In Study I, the overall gait pattern, as represented by the Gait Deviation Index for kinematics and kinetics, was found to be affected on both the painful osteoarthritis limb and the contralateral limb compared to controls. In Study II, one year after surgery, measures of overall gait patterns and performance-based function were found to be improved although not restored to the level of healthy controls. In Study III, individuals reporting improvement in Knee-related Quality of Life displayed improved knee biomechanics during gait, whereas patients reporting small or no improvement in Knee-related Quality of Life remained unchanged one year after surgery despite similar reductions in pain. In Study IV, the body’s Center of Mass was shown to be shifted anteriorly and towards the contralateral limb in individuals with osteoarthritis performing the Five Times Sit-to-Stand test. After surgery, when pain was substantially reduced, Center of Mass trajectories were comparable to those of healthy controls. Conclusions: Alterations in joint loading were associated with both performance-based function and patient-reported outcomes whereas kinematic gait alterations were not associated to either, indicating that clinical outcome measures of function are not aligned with kinematic gait deviations. Based on post-operative changes in Five Times Sit-to-Stand test performance, individuals with considerable gait pattern improvements were identified. However, patientreported measures of function could not detect differences between individuals improving in performance-based function and those who did not. Nevertheless, improvements in knee flexion-extension range during gait were related to large improvements in Knee-related Quality of Life. The body’s Center of Mass trajectory during the Five Times Sit-to-Stand test was found to be a sensitive and responsive measure of functional compensations typical of knee osteoarthritis pathology. POPULAR SCIENCE SUMMARY Introduction: Osteoarthritis is the most common joint disease. Knee osteoarthritis causes joint pain and limits function. To establish which treatments have the best effect on improving function, appropriate evaluation measurements must be used. Today, function is typically evaluated using questionnaires, where individuals report their perceived function, or by having individuals perform specific tests, such as rising from a chair, or walking tests, and measuring the time taken to execute the test. However, questionnaires and performance tests are unable to answer how these movements are performed – i.e., the movement pattern. Greater knowledge of how persons with knee osteoarthritis move will help to identify how best to treat patients to improve function. This thesis evaluates methods used to assess function, including movement patterns and performance tests, in individuals with knee osteoarthritis. Methods: The studies include 40 individuals with knee osteoarthritis scheduled for total knee replacement and 25 healthy controls. All study participants completed a three-dimensional motion analysis session, rendering biomechanical measures of walking (gait) patterns, and movement patterns used to perform a timed chair rising test (Sit-to-Stand test). Participants also completed questionnaires to report their knee function and general health and rated their perceived pain using a visual analogue scale. Results: In Study I, knee osteoarthritis affected the way people walked by changing the movement of the painful leg with osteoarthritis as well as the other (contralateral) leg. In Study II, one year after surgery, function was found to improve, as measured by evaluation of gait pattern and performance on a Sit-to-Stand test. These improvements did however not reach the level of persons who were healthy and of the same age and gender. Results from the questionnaires could not differentiate between persons who improved on the Sit-to-Stand test and those who did not. In Study III, knee biomechanics during gait were evaluated among persons reporting a small or large improvement in Knee-related Quality of Life. Those reporting a large improvement in Knee-related Quality of Life displayed improved knee biomechanics, whereas patients reporting a small improvement remained unchanged one year after surgery despite similar reductions in pain. In Study IV, movement patterns used to perform a Sit-to-Stand test were found to be different among persons with osteoarthritis compared to controls. Conclusions: In persons with knee osteoarthritis who were scheduled for knee replacement surgery, the disease affected the way they walked with both legs. One year after knee replacement surgery, function improved as measured by questionnaires, performance-based tests, and evaluation of how they walk and rise from a chair. However, the improvements found with surgery did not help these individuals reach the same level of performance as their ageand gender-matched healthy peers. Questionnaires have limited use in detecting the degree of changes in the way a person walks or how well they execute a timed chair rising test. Methods to examine movement patterns and the way a person walks may be used as complementary methods to objectively evaluate function. LIST OF SCIENTIFIC PAPERS This thesis is based on the following original papers and manuscript. They will be referred to in the text by their Roman numerals as indicated below: I. Naili, J.E, Esbjörnsson, AC, Iversen, M.D, Schwartz, M.H, Hedström, M, Häger, C.K, Broström, E.W. The impact of symptomatic knee osteoarthritis on overall gait pattern deviations and its association with performance-based measures and patient-reported outcomes. Knee (2017) 24:536-546. II. Naili, J.E, Iversen, M.D, Esbjörnsson, AC, Hedström, M, Schwartz, M.H, Häger, C.K, Broström, E.W. Deficits in functional performance and gait one year after total knee arthroplasty despite improved self-reported function. Knee Surg Sports Traumatol Arthrosc (2016). DOI:10.1007/s00167-0164234-7. III. Naili, J.E, Wretenberg, P, Lindgren, V, Iversen, M.D, Hedström, M, Broström, E.W. Improved knee biomechanics among patients reporting a good outcome in knee-related quality of life one year after total knee arthroplasty. BMC Musculoskelet Disord (2017) 18:122. IV. Naili, J.E, Broström, E.W, Gutierrez-Farewik, E, Schwartz, M.H. The centre of mass trajectory is a sensitive and responsive measure of functional compensations in individuals with knee osteoarthritis performing the Five Times Sit-to-Stand test. Submitted manuscript.