Patellofemoral joint stress and its relation to patellofemoral pain, cartilage morphology, and cartilage composition

UnrestrictedAlthough patellofemoral pain (PFP) is commonly believed to be the result of excessive patellofemoral stress and subsequent cartilage wear, little evidence exists to support this premise. The primary objective of this dissertation was to define the relationship between PFP, patellofemoral stress, and cartilage morphology/composition in young females. To accomplish this objective, 3 studies were undertaken.; The purpose of study #1 was to test the hypothesis that individuals with PFP exhibit greater patellofemoral stress compared to persons who are pain-free. Using a finite element modeling approach, patella and femur stress profiles were quantified during a squat task. On average, individuals with PFP exhibited greater peak and mean hydrostatic and octahedral shear stresses compared to controls. This finding supports the premise that elevated stress may be a predisposing factor with respect to PFP.; The purpose of study #2 was to compare patella cartilage morphology and composition between a group of females with PFP and a group of pain-free controls. Quantitative imaging of the patella cartilage was performed. Compared to the control group, individuals with PFP demonstrated reductions in patella cartilage volume and thickness but no change in T2 relaxation time. The finding of reduced cartilage morphology in the PFP group supports the assertion that the presence of symptoms may be indicative of cartilage changes consistent with early stage osteoarthritis.; The purpose of study #3 was to evaluate whether the cartilage of individuals with PFP demonstrates a less adaptive response to loading. Quantitative imaging of the patella cartilage was performed before and after subjects performed 50 deep knee bends. On average, individuals with PFP exhibited less cartilage deformation following exercise compared to the control group. This suggests that the mechanical behavior of the patella cartilage was impaired in the PFP group.; The findings from this dissertation support the premise that PFP is associated with excessive patellofemoral stress and cartilage characteristics consistent with early stage osteoarthritis. Taken together, knowledge gained from this dissertation is an important step to improve patient related outcomes and for the development of strategies to prevent or delay long-term patellofemoral joint disease