Exercise and footwear in medial knee osteoarthritis: a randomized controlled trial comparing flat flexible footwear to stable supportive shoes

Objective This randomized controlled trial (RCT) investigated whether adding daily use of flat flexible footwear (FFF) to a strengthening and aerobic exercise program improved short- and longer-term outcomes compared with adding stable supportive shoes (SSS) in people with medial tibiofemoral OA.Methods Participants (n = 97) with medial tibiofemoral OA were randomly assigned (1:1) to the FFF (n = 50) or SSS (n = 47) group. Participants in both groups received a 9-month intervention (3 months supervised followed by 6 months unsupervised exercise). The primary outcome was the change in knee pain on walking at 3 months measured using an 11-point numeric rating scale (NRS). Secondary outcomes included the change from baseline to 3 and 9 months in the severity of knee pain overall (NRS), physical function (WOMAC subscale), habitual physical activity level (Physical Activity Scale for the Elderly), quality of life (QoL) (European Quality of Life 5-Dimensions 5-Levels questionnaire) and markers of inflammation (effusion and Hoffa synovitis) and structural disease progression (bone marrow lesions).Results There were no significant differences between the groups in the change in pain on walking [between-group difference -0.67 (95% CI -1.62, 0.29)] at 3 months. Knee pain on walking and overall knee pain significantly decreased in both groups at 3 and 9 months. Physical function and QoL improved in both groups at 3 and 9 months. We found no between-group differences in any secondary outcome at any time.Conclusions FFF added to exercise therapy did not provide additional better symptom nor structure-modification benefit compared with conventional SSS and exercise in people with medial tibiofemoral OA.Trial registration ClinicalTrials.gov (http://clinicaltrials.gov), NCT03796832. What does this mean for patients?This study aimed to see if wearing flexible flat footwear (FFF) alongside a 9-month exercise program could provide more pain relief and functional improvement for people with knee osteoarthritis (OA) than wearing stable supportive shoes (SSS) with the same exercise program. We randomly assigned 97 participants with (medial tibiofemoral) knee OA into two groups: one wore FFF and the other wore SSS, with both groups doing exercises (strength and endurance) for 3 months supervised by physiotherapists followed by exercising 6 months at home. After 3 months, the main outcome was knee pain during walking, rated on a scale of 0 to 10. Both groups showed similar improvements in pain and overall knee function, and these improvements continued after 9 months. There was no significant difference between the FFF and SSS groups for knee pain, physical functioning, quality of life and physical activity. In summary, exercise benefits knee pain during walking in people with knee OA. Adding FFF to this program did not provide extra benefits over wearing SSS.