A low-intensity MRI signal in the infrapatellar fat pad was associated with an increased risk of knee cartilage defects, according to study findings.
“The infrapatellar fat pad (IPFP), the local fat around the knee joint, may play an important role in the initiation and progression of knee [osteoarthritis] OA,” Weiyu Han, MD, PhD, at the Menzies Institute for Medical Research of the University of Tanzania, and colleagues wrote. “Biomechanically, it can promote efficient lubrication, reduce impact loading and absorb forces generated through the knee joint, which may be protective against OA. Biochemically, it can produce various proinflammatory cytokines and adipokines, which may be deleterious to the knee joint.”
Han and colleagues performed a cohort study of 874 randomly selected participants followed for up to 2.7 years. They assessed T1- or T2-weighted fat-suppressed MRI for an IPFP low-intensity signal, cartilage volume, cartilage defects and bone marrow lesions. They examined knee pain using the self-administered WOMAC questionnaire. In addition, they examined radiographic OA using the Osteoarthritis Research Society International (OARSI) atlas.
They found — cross-sectionally — low-intensity signals were significantly associated with an increased risk for knee pain, knee cartilage defects and tibiofemoral bone marrow lesions. They found — longitudinally — baseline signal abnormalities were significantly associated with an increased risk for knee pain (odds ratio = 1.36), knee cartilage defects (odds ratio = 2.27) and bone marrow lesions (odds ratio = 1.91). After adjusting for common knee pain factors, the associations with bone marrow lesions and knee pain became non-significant.
“So far, there have been no studies reporting the clinical significance of IPFP hypointense signals observed on T2-weighted fat-saturated MRI images,” the researchers wrote. “Low signal intensity changes with the IPFP may represent fibrosis or postoperative scarring, chronic inflammation progressing from acute inflammation of the synovium due to microtrauma of this tissue, or synovial thickening or fibrosis.” – by Will Offit
Disclosure: The researchers report no relevant financial disclosures.