J Exp Orthop. 2023 Nov 29;10(1):124. doi: 10.1186/s40634-023-00709-6.
ABSTRACT
PURPOSE: According to the homeostasis model, patellofemoral pain (PFP) results from disturbed homeostasis due to vascular insufficiency in the anterior knee. Near-Infrared Spectroscopy (NIRS) measures relative changes in concentrations (in µmol/cm2) of (de-)oxygenated hemoglobine (HHb and O2Hb). The aims were to: 1) investigate the characteristics of the NIRS signal derived from the patella during experiments affecting hemodynamics in healthy controls, and 2) determine the test-retest reliability of NIRS in positions clinically relevant for PFP patients.
METHODS: Two experiments were conducted on 10 healthy controls and analysed using Student’s t-test. Reliability (ICC2,1) was evaluated for two activities (‘Prolonged Sitting’ and ‘Stair Descent’) in five PFP patients and 15 healthy controls, performed twice within five days.
RESULTS: The NIRS signal (HHb and O2Hb) showed a statistically significant increase (p < .001 – .002) on all optodes (30, 35, 40 mm) during ‘Venous Occlusion’ (M = 1.0 – 2.0), while it showed no statistically significant change (p = .075 – .61) during ‘Skin Compression’ (M = -0.9 – 0.9) on the 30 and 35 mm optode. Reliability of NIRS (HHb and O2Hb) ranged from moderate to almost perfect (ICC2,1 = .47 – .95) on the 30 mm optode for ‘Prolonged Sitting’, and from moderate to substantial (ICC2,1 = .50 – .68) on the 35 mm optode for ‘Stair Descent’.
CONCLUSIONS: Patella NIRS measurements are affected by venous occlusion, but not by skin compression, and are sufficiently reliable as research application to compare real-time patellar bone hemodynamics. These insights may assist to improve effectiveness of evidence-based treatment strategies for PFP.
TRIAL REGISTRATION: ISRCTN Trial Registration under number: 90377123.
PMID:38017345 | DOI:10.1186/s40634-023-00709-6
