Evaluation of risk factors associated with patellofemoral pain syndrome

Abstract

Objective: Patellofemoral Pain Syndrome (PFPS) is the most common diagnosis in patients presenting knee pain (~25%), and one of the most common diagnosis in sports medicine centers. Here we examine believed risk factors in Patellofemoral Pain Syndrome (PFPS) and assess their relationship to PFPS. Methods: The study was a retrospective study completed at Johns Hopkins Department of Orthopaedic Surgery. All patients, who were referred to physical therapy at Johns Hopkins Rehabilitation Therapy Services Clinic, were diagnosed with PFPS for the first time and were mostly recreational runners. Body mass indexes (BMI) were calculated from weight and height. Pain scores were taken using the visual analog scale. Strength measurements were taken from the left and right leg for the following measurements: hip abduction external rotation, hip abduction, knee extension, and hip extension. Balance measurements were also taken on the left and right sides measuring the postural sway with eyes open and eyes closed. Statistical analysis were accomplished using excel. Results: A total of 23 patients were included in the present study, 9 females and 14 males. BMI's (lb/in^2) for the population was 25.1 (±4.2), males were 26.4 (±3.6) and females were 23.2 (±4.2). Pain scores were 6 (±1.9) out of 10 for the total population, males, and females. The total population had composite hip scores 35.0% and 22.9% for the right and left sides, while the knee extension was 50.7% and 51.7%. All hip scores were below 40 except for right hip ABD/ER in females and lower than knee extension scores in males, females, and total population. The ratio for right eyes closed to open was 34.2 (±62.7) and left eye closed to open was 24.7 (±44.3) for the total population Conclusion: This study demonstrated that age and BMI may have an effect on the development of PFPS but no statistical significance was confirmed. Results suggest that hip strength is a better indicator than knee strength in risk associated with PFPS. Balance appears to be more of an indicator of poor hip strength than as a measurement or potential risk factor for PFPS.