Changes in infrapatellar fat pad echo intensity and stiffness following a 6-week exercise intervention in older people with knee pain: an exploratory study

Background/Aims The infrapatellar fat pad is implicated in knee osteoarthritis pain; however, the effects of exercise on the infrapatellar fat pad remain unclear. The aim of this study was to explore changes in infrapatellar fat pad echo intensity and stiffness following an exercise intervention in older adults with knee pain. Methods A total of 31 community-dwelling older people with knee pain took part in the study. Participants underwent a 6-week exercise programme, consisting of strength training, stretching and aerobic exercise. Ultrasound elastography and greyscale imaging assessed infrapatellar fat pad stiffness and echo intensity. Knee pain and function were evaluated using the Knee injury and Osteoarthritis Outcome Score, Intermittent and Constant Osteoarthritis Pain questionnaire, Numeric Rating Scale and Timed Up and Go test. Pre and post intervention differences and correlations between changes were analysed. Results Infrapatellar fat pad echo intensity significantly increased (pre: 52.9 ± 16.6; post: 60.3 ± 17.5, P =0.03), while stiffness significantly decreased during the intervention (pre: 6.55 ± 4.12 kPa; post: 4.18 ± 2.75 kPa, P <0.01). Additionally, total Knee injury and Osteoarthritis Outcome Score scores and intermittent and constant osteoarthritis pain intensity significantly improved. A significant negative correlation was observed between infrapatellar fat pad echo intensity and intermittent and constant osteoarthritis pain constant scores (r=-0.46, P =0.01), whereas infrapatellar fat pad stiffness showed a significant positive correlation with intermittent and constant osteoarthritis pain constant scores (r=0.39, P =0.03). Conclusions Changes in infrapatellar fat pad and pain reduction following the exercise programme appeared favourable, suggesting potential benefits associated with the intervention. Implications for practice Exercise interventions can change the condition of the infrapatellar fat pad, suggesting a potential therapeutic role in managing knee pain.