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 ( = 97) with medial tibiofemoral OA were randomly assigned (1:1) to the FFF ( = 50) or SSS ( = 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.