School of Health and Rehabilitation Science, The University of Queensland
Project:
Patellofemoral osteoarthritis and predictors of progression in young to middle aged adults with chronic patellofemoral pain
Kneecap pain and arthritis are a significant public health problem. Kneecap pain can have a major impact on an individual’s participation in work tasks, caring for children and dependents, and physical activity, each of which contribute more broadly to societal and financial burden.
Kneecap pain affects up to 30% of all adolescents and young adults, and tends to persist and not resolve with time. Importantly, kneecap pain is thought to lead to kneecap arthritis, which is more prevalent, more painful, and occurs earlier in life than general knee arthritis. Young and middle-aged adults with chronic kneecap pain appear to be particularly at risk of kneecap arthritis. Our work has shown that one-quarter of people with kneecap pain aged 26-50 years have signs of arthritis on x-ray, as well as worse function and quality of life compared to those without arthritis.
Because kneecap arthritis has no cure, it’s important that we shift our focus from managing arthritis symptoms to preventing the development and progression of arthritis in at-risk populations. Young and middle-aged adults with chronic kneecap pain may represent an ideal target for arthritis prevention strategies. This research project followed a cohort of people with chronic kneecap pain, who were recruited five years earlier into a study funded by Arthritis Australia. We aimed to determine how kneecap arthritis on x-ray and MRI changes over five years in adults aged 26-50 years with chronic kneecap pain, and how these structural changes relate to changes in symptoms and self-reported disability. Importantly, we also aimed to explore whether factors such as strength, knee alignment and walking patterns – which are potentially modifiable with non-surgical interventions – could predict progression of arthritis on x-ray or MRI over five years.
84 adults with chronic kneecap pain, who were aged 26-50 years, were recruited into the study between 2012 and 2015. They underwent a large battery of tests, including questionnaires, strength and functional tests, alignment measures, x-rays and MRIs of their knee, and detailed assessment of their biomechanics and muscle function during walking, squatting and stair ambulation. At five-year follow-up, 62 (73%) of the original 84 participants completed the online questionnaires, and 45 (54%) underwent x-rays and MRIs of their study knee. The primary reasons that participants did not undergo the x-ray and MRI were a lack of time (e.g. 2due to work or childcare responsibilities), or because they no longer resided in Australia.
Ethical, referral and funding limitations meant that we were not able to conduct imaging in participants who were located overseas. The x-rays and MRIs are currently being graded by our international radiology colleagues, who will provide expert interpretation of the imaging data. This is the same team who graded the baseline x-rays and MRIs, providing important consistency across the five-year study period.
From the questionnaire data, we see some important findings that demonstrate the ongoing burden of kneecap pain and potential impact of kneecap arthritis. Participants who did not have kneecap arthritis at baseline tended to report the same levels of pain, symptoms, functional impairments and reduced quality of life as they did at baseline (5 years earlier), adding further evidence to the persistent nature of kneecap pain. Participants with kneecap pain who had kneecap arthritis on x-ray at baseline also had persistent pain, symptoms, functional impairments and reduced quality of life five years later, with worsening function on higher level sport and recreational activities. Importantly, the severity of their symptoms was worse than those without kneecap arthritis, both at baseline and at five-year follow-up. This highlights the importance of identifying ways that we can prevent the development and progression of arthritis in young and middle-aged adults with kneecap pain.
Once the x-rays and MRIs have been graded, we will be able to answer the primary questions from this project: (i) how kneecap arthritis changes over five years in adults with chronic kneecap pain; (ii) how changes in kneecap arthritis over five years relate to changes in symptoms and disability; and (iii) whether modifiable factors measured at baseline can predict whether someone with chronic kneecap pain develops kneecap arthritis, or progresses in their kneecap arthritis, over five years. The outcomes of this work will directly inform the development of targeted treatments to stop or slow down the development and/or progression of kneecap arthritis in this younger, at-risk group of people with kneecap pain. We plan to investigate these treatments in larger follow up studies. Because there is no cure for kneecap arthritis, this could be a key step to minimise the prevalence and severity of kneecap arthritis, reduce the personal and societal burden of this common and debilitating condition, and keep young and middle-aged people moving well.
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Does kneecap pain when you're young mean arthritis later on?
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Kneecap pain and arthritis are a significant public health problem. Kneecap pain can have a major impact on an individual’s participation in work tasks, caring for children and dependents, and physical activity, each of which contribute more broadly to societal and financial burden.