LAUSR

CONTEXT Rehabilitative exercises alleviate pain for patients with Patellofemoral pain (PFP); however, no research has analyzed cartilage response after a bout of those athletic activities in patients with PFP. OBJECTIVE To determine if a single session of rehabilitative exercises alters femoral cartilage morphology. DESIGN Crossover study. SETTING Research laboratory. PATIENTS OR OTHER PARTICIPANTS Twelve participants with PFP (age=21.0±2.0years, height=1.72±0.1, mass=68.7±12.6) and 12 matched healthy participants (age=21.3±2.8, height=1.71±0.1, mass=65.9±12.2) were enrolled. INTERVENTION(S) Participants completed treadmill running, lower extremity strengthening exercises and plyometric exercises each for 30 minutes. MAIN OUTCOME MEASURE(S) Patient-reported outcomes (PROs) of Visual Analog Scale (VAS), Anterior Knee Pain Scale (AKPS), Knee Injury and Osteoarthritis Outcome Score (KOOS), and Knee Injury and Osteoarthritis Outcome Score for Patellofemoral Pain and Osteoarthritis (KOOSPF) were collected. Femoral cartilage ultrasonographic images were obtained at 140° knee flexion. Ultrasound images were segmented into medial and lateral by the intercondylar notch. Medial and lateral cartilage cross sectional area (CSA; mm2) and echo intensity (EI), defined as the average grayscale from 0 to 255, were analyzed by ImageJ software. The difference between loading conditions were calculated using repeated-measures ANOVA. Spearman's correlation was calculated to find association between cartilage percent change (Δ%) and PROs. RESULTS Pain increased in the PFP group following all loading conditions (p<0.007). There were no statistically significant differences in cartilage CSA or EI alteration between or within groups (p>0.06). KOOS was negatively associated with Δ% of the lateral femoral cartilage EI following plyometric loading (ρ =-0.87, p=0.001), and AKPS was positively correlated to the Δ% of lateral femoral cartilage EI (ρ =0.57, p=0.05). CONCLUSIONS Ultrasound imaging did not identify the cartilaginous deformation following all loading conditions. However, as lateral cartilaginous EI changes were associated with AKPS and KOOS, those questionnaires may be useful to monitor changes of femoral cartilage health.