The role of core endurance and proprioception on knee functionality in patients with patellofemoral pain

Background/Aim: Patellofemoral pain (PFP) is one of the most common musculoskeletal diagnoses which is considered to be a complex and multifactorial problem. We aimed to determine how the deficiencies in body/core muscle strength and proprioception may affect PFP development. 
Methods: Fifty patients with diffuse anterior knee pain and/or diagnosed with chondromalacia patella in the study group and 50 healthy adults in the control group were included in this prospective cross-sectional study. The patients with knee disorders except for chondromalacia patella, those who had lower extremity and spinal surgery, and/or had physical therapy in the last 3-months were excluded from the study. Active proprioceptive repositioning test and the prone-bridge test and side-bridge tests was used for primarily assessment of core muscles capacity. The knee functionality was evaluated with Kujala's knee score, and physical activity levels were evaluated with the short form of the International Physical Activity Questionnaire. 
Results: The mean age, weight, and median of body mass index were higher in the patient group while active working patients were significantly higher in control group. (p=0.041) The mean of Kujala, Prone-bridge, Side-bridge (right and left) tests were significantly higher in the control group than the patient group. (p=0.012) The mean Flex-30 test was significantly higher in the patient group than control group. (p=0.037) In the study group, there were very strong correlation between hyperextension of body and Kujala tests and between hyperextension of body and prone-bridge tests (p<0.05) while, there was a very strong correlation between hyperextension of body and flex-30 tests in the control group. (p<0.05) 
Conclusion: As our body has a closed kinetic chain system, it is obvious that core musculature has great importance on the knee joint. In the current study, we demonstrated the importance of core musculature both in the sense of motor and sensory on the functionality of knee joint in PFP.