Movement patterns during a small knee bend test in academy footballers with femoroacetabular impingement (FAI)

Background: Femoracetabular impingement (FAI) is common in footballers and causes hip pain, which may arise from abnormal morphologic features involving the proximal femur and/or acetabulum. Early detection and treatment are important to prevent the development of osteoarthritis (OA). Despite extensive publications on FAI, little is known about hip movement patterns associated with FAI, which may indicate mechanisms of dysfunction to inform development of effective interventions.Design: Observational pilot studyMethods: Nine male academy footballers aged 12–18 years with hip/groin pain, diagnosed with FAI on magnetic resonance imaging, were studied. The hip and pelvis were observed whilst the participant performed a small knee bend test, to see if any abnormal movement patterns were present.Findings: In all nine cases, abnormal movement patterns were observed clinically. Participants were unable to control hip flexion in one or more aspects, mostly seen as the trunk leaning forwards and the hip moving into increased flexion. Participants also demonstrated poorly controlled hip medial rotation.Discussion: These preliminary findings suggest impaired movement control exists in academy footballers with symptomatic FAI. Identifying and classifying these movement faults may prove necessary for effective prevention and management of symptoms by controlling movement adaptations. Further studies are warranted to validate these findings against motion analysis technology and muscle activity using electromyography, and to further understand the mechanisms of movement dysfunction. Since FAI is a strong predictor in the development of hip OA, it is vital that strategies are developed to prevent FAI and its progression to OA