865 BO33 – Frontal plane knee motion during the downstroke and lower limb functional tests in cyclists with patellofemoral pain compared with non-injured matched controls

Background Patellofemoral pain (PFP) is common in cyclists, but factors associated with PFP in cyclists have not been well studied. Objectives The study aimed to identify factors (lower limb functional and frontal plane knee kinematic variables) associated with PFP in cyclists. Design Matched case-control. Setting SEMLI Biomechanics laboratory, South Africa. Participants 38 recreational cyclists comprising of a PFP group (clinically diagnosed) (n=19) (PFP injured limb vs. PFP uninjured limb), and a matched CON group (n=19) (PFP injured limb vs. CON limb). Assessment of risk factors Selected lower limb functional tests (flexibility, muscle strength and endurance) and frontal plane knee kinematic variables [medio-lateral deviation (◦) during the downstroke of cycling] were explored. Main outcome measurements The association between PFP and the following factors: lower limb functional test variables and knee deviation [degrees of abduction or adduction] in relation to the foot, in the frontal plane. Results There were no significant differences between PFP injured limb vs. CON limb for lower limb functional test variables: sit-and-reach test (p=0.1819), quadriceps flexibility (p=0.5578), one-legged hop test (p=0.0835), standard step-down test (p=1.000), lateral step-down test (p=0.3223), single-leg squat (p=0.6414), step-down test (30sec, max repetitions)(p=0.6373), single-leg squat (30sec, max repetitions)(p=0.4733). Medial deviation (°) during the downstroke was significantly greater in the CON limb vs PFP injured limb at 50° (p=0.0421), 60° (p=0.0402), 100° (p=0.0141), 110° (p=0.0143) and 120° (p=0.0402). The magnitude of significant differences between the CON limb vs. PFP injured limb varied between 0.7°-2.5°. Conclusion There was no association between lower limb functional test variables, nor frontal plane knee kinematic variables, and PFP. This study adds to the limited body of knowledge on the mechanisms and risk factors associated with PFP in cyclists. This area requires substantial more research to aid clinicians in the pursuit of injury prevention strategies for cyclist with PFP.