Reduced EGF receptor signalling aggravates signs of post-traumatic osteoarthritis in the calcified tissues of the knee

Abstract

Purpose: The purpose of this retrospective cross-sectional study was to investigate the association between cartilage lesions assessed with 3T MRI and remodeling of the subchondral bone detected by 99mTc-DPDSPECT/CT. Methods: 99mTc-DPD-SPECT/CT and MRI of 27 knees of 25 patients with chronic knee pain and risk factors for osteoarthritis were evaluated independently by one nuclear physician and one radiologist. Six regions (patella, trochlea, medial/lateral tibia, medial/lateral femur) were visually assessed according to structural joint lesions graded with a modified Whole Organ MR imaging score (WORMS) and according to subchondral 99mTc-DPD-SPECT uptake visually graded with 01⁄4normal uptake, 11⁄4moderately elevated uptake, 21⁄4severely elevated uptake. Relationships between lesion scores and uptake were quantified using two methods: 1. For the global assessment per joint, we used a linear regression and Spearman correlations and 2. For the assessment of each of 162 regions, general estimating equations was used to control for multiple measurements per subject. Results: Elevated subchondral uptake was significantly associated with the grade (p<0.0001) and with the depth of cartilage lesions (p<0.0001). A similar association was observed between bone marrow edema pattern (BMEP) lesions and cartilage lesions. Conclusions: Both, functional and structural changes of the subchondral bone in terms of scintigraphic osseous activity and the presence and degree of BMEP lesions were significantly associated with cartilage lesions in patients with osteoarthritis of the knee. This association was pronounced with full thickness lesions indicating a possible protective effect of the cartilage layer for the subjacent bone.