Impaired hemodynamics of the patella in patients with patellofemoral pain: A case–control study


Purpose: According to the homeostasis model, patellofemoral pain (PFP) arises as a consequence of disturbed homeostasis of anterior structures of the knee due to vascular insufficiency. Near‐infrared spectroscopy (NIRS) allows to measure changes of concentrations (µmol/cm2) of (de)‐oxygenated hemoglobine (HHb and O2Hb). The aim was to study differences in patellar hemodynamics between patients and healthy controls. Methods: Hemodynamics of patients (n= 30 [female = 20, age = 21.5, BMI = 22.9]) and controls (n = 30 (female = 18, age = 21.4, BMI = 22.4]) were evaluated for two activities (‘Prolonged Sitting’ and ‘Stair Descent’). Blinding for health status was implemented. Results: During ‘Prolonged Sitting’, PFP patients exhibited smaller decreases in mean changes for HHb (PFP [M = −1.5 to −1.9], healthy controls [M = −2.0 to −2.3]) and O2Hb (PFP [M = −2.0 to −3.2], healthy controls [M = −3.4 to −4.1]). However, these differences were statistically non‐significant (p = 0.14–0.82 and p = 0.056–0.18, respectively). Conversely, for ‘Stair Descent’, PFP patients showed statistically significant smaller decreases in mean changes for HHb (PFP [M = −1.9, SD = 1.8], healthy controls [M = −2.5, SD = 1.7], p = 0.043) and O2Hb (PFP [M = −3.2, SD = 3.2], healthy controls [M = −4.9, SD = 2.7], p = 0.004). Conclusions: The differences suggest potential impairment in patellar hemodynamics in PFP patients, providing support for the homeostasis model. Evidence‐based treatment strategies targeting patellar hemodynamics should be further refined and subjected to evaluation in clinical trials.

Journal of Experimental Orthopaedics