The influence of lower limb biomechanics on the development, persistence and management of patellofemoral pain in recreational runners

Abstract

Background Patellofemoral pain (PFP) is a common complaint characterised by diffuse retropatellar or peripatellar pain during activities such as running, stair descent or squatting. We aimed to determine the influence of lower limb biomechanics on the development, persistence and management of PFP in recreational runners. Methods Two systematic reviews with meta-analysis explored risk factors for, and the associations between, PFP and lower limb biomechanics respectively. A case-control study investigated lower limb kinematics during treadmill running and a feasibility study explored recruitment, retention and delivery of a step rate intervention in mixed-sex runners. Finally, a validity study investigated the potential for two-dimensional (2D) video to predict three-dimensional (3D) running kinematics. Results Understanding of which variables contribute to PFP development is inadequate, requiring further exploration. Multiple retrospective associations between and potential treatment mechanisms for lower limb biomechanics and PFP were identified, but prospective data is lacking. A mixed-sex cohort of runners demonstrated higher peak hip adduction compared to controls. Higher peak hip adduction was also observed when comparing females with PFP to controls, but data for males were non-significant. Recruitment and retention of a mixed-sex cohort of runners with PFP to a step rate intervention was feasible. Clinically relevant changes in pain and potential kinematic treatment mechanisms were identified post-retraining, though these mechanisms were not detectable with 2D video. Conclusion Potential influences of lower limb biomechanics once a recreational runner has PFP are well established. Further work is required to determine what biomechanical variables may contribute to PFP development, with novel approaches required. Sex influences lower limb kinematics and as such, males and females may have different symptom drivers requiring individual treatment strategies. Step rate retraining demonstrated potential efficacy and treatment mechanisms that warrant further appraisal in an adequately powered randomised controlled trial to long-term follow up.