The infrapatellar fat pad produces interleukin-6-secreting T cells in response to a proteoglycan aggrecan peptide and provides dominant soluble mediators different from that present in synovial fluid

Analogies Between Platelet-Rich Plasma Versus Hyaluronic Acid Intra-articular Injections in the Treatment of Advanced Knee Arthritis: A Single-Center Study

Background Knee osteoarthritis (KOA), a degenerative joint disease, is a common cause of chronic knee pain and disability in adults. Conservative management options are the first-line approach, but intra-articular injections, such as platelet-rich plasma (PRP) and hyaluronic acid (HA), are considered for advanced cases. This study aims to compare the efficacy of PRP versus HA injections in patients with advanced KOA. Methods A retrospective study was conducted on 145 patients with advanced KOA. Seventy patients received PRP injections, while 75 patients received HA injections. The Visual Analog Scale (VAS), Western Ontario and McMaster Universities Osteoarthritis Index (WOMAC) score, and International Knee Documentation Committee (IKDC) score were employed to evaluate the treatment's efficacy. Adverse events associated with these injections were also recorded. Results Both PRP and HA injections significantly reduced pain and improved joint function in patients with advanced KOA. PRP injections were slightly more effective than HA injections in reducing pain scores. Both treatments showed similar improvements in functional outcomes. Adverse events were minimal and self-limiting for both treatments. Conclusions Both PRP and HA injections effectively ameliorate advanced KOA by reducing pain and improving function. PRP injections showed a slightly greater improvement in pain scores and functional outcomes. The choice between PRP and HA injections may depend on factors like cost, availability, and patient preference. Further research is needed to validate these findings and understand treatment suitability for different patient populations.

Quantitative evaluation of the infrapatellar fat pad in knee osteoarthritis: MRI-based radiomic signature

BACKGROUND

The infrapatellar fat pad (IFP) may have bilateral influence on knee osteoarthritis (KOA). IFP evaluation may be a key contributor to the diagnostic and clinical management of KOA. Few studies have evaluated KOA-related IFP alteration with radiomics. We investigated radiomic signature for the assessment of IFP for KOA progression in older adults.

METHODS

A total of 164 knees were enrolled and grouped based on Kellgren-Lawrence (KL) scoring. MRI-based radiomic features were calculated from IFP segmentation. The radiomic signature was developed using the most predictive subset of features and the machine-learning algorithm with minimum relative standard deviation. KOA severity and structure abnormality were assessed using a modified whole-organ magnetic resonance imaging score (WORMS). The performance of the radiomic signature was evaluated and the correlation with WORMS assessments was analyzed.

RESULTS

The area under the curve of the radiomic signature for diagnosing KOA was 0.83 and 0.78 in the training and test datasets, respectively. Rad-scores were 0.41 and 2.01 for the training dataset in the groups with and without KOA (P < 0.001) and 0.63 and 2.31 for the test dataset (P = 0.005), respectively. WORMS significantly and positively correlated with rad-scores.

CONCLUSIONS

The radiomic signature may be a reliable biomarker to detect IFP abnormality of KOA. Radiomic alterations in IFP were associated with severity and knee structural abnormalities of KOA in older adults.

Osteoarthritis Pathophysiology: Therapeutic Target Discovery may Require a Multifaceted Approach

Molecular understanding of osteoarthritis (OA) has greatly increased through careful analysis of tissue samples, preclinical models, and large-scale agnostic "-omic" studies. There is broad acceptance that systemic and biomechanical signals affect multiple tissues of the joint, each of which could potentially be targeted to improve patient outcomes. In this review six experts in different aspects of OA pathogenesis provide their independent view on what they believe to be good tractable approaches to OA target discovery. We conclude that molecular discovery has been high but future transformative studies require a multidisciplinary holistic approach to develop therapeutic strategies with high clinical efficacy.

Quantitative MR evaluation of the infrapatellar fat pad for knee osteoarthritis: using proton density fat fraction and T2* relaxation based on DIXON

OBJECTIVES

To investigate the efficacy of fat fraction (FF) and T2* relaxation based on DIXON in the assessment of infrapatellar fat pad (IFP) for knee osteoarthritis (KOA) progression in older adults.

METHODS

Ninety volunteers (age range 51-70 years, 65 females) were enrolled in this study. Participants were grouped based on the Kellgren-Lawrence grading (KLG). The FF and T2* values were measured based on the 3D-modified DXION technique. Cartilage defects, bone marrow lesions, and synovitis were assessed based on a modified version of whole-organ magnetic resonance imaging score (WORMS). Knee pain was assessed by self-administered Western Ontario and McMaster Osteoarthritis Index (WOMAC) questionnaire. The differences of FF and T2* measurement and the correlation with WORMS and WOMAC assessments were analyzed. Diagnostic efficiency was analyzed by using receiver operating characteristic (ROC) curves.

RESULTS

A total of 60 knees were finally included (n = 20 in each group). The values were 82.6 ± 3.7%, 74.7 ± 5.4%, and 60.5 ± 14.1% for FF is the no OA, mild OA, and advanced OA groups, and were 50.7 ± 6.6 ms, 44.1 ± 6.6 ms, and 39.1 ± 4.2 ms for T2*, respectively (all p values < 0.001). The WORMS assessment and WOMAC pain assessment showed negative correlation with FF and T2* values. The ROC showed the area under the curve (AUC), sensitivity, and specificity for diagnosing OA were 0.93, 77.5%, and 100% using FF, and were 0.86, 75.0%, and 90.0% using T2*, respectively.

CONCLUSIONS

FF and T2* alternations in IFP are associated with knee structural abnormalities and clinical symptoms cross-sectionally and may have the potential to predict the severity of KOA.

KEY POINTS

• Fat fraction (FF) and T2* relaxation based on DIXON imaging are novel methods to quantitatively assess the infrapatellar fat pad for knee osteoarthritis (KOA) progression in older adults. • The alterations of FF and T2* using mDIXON technique in IFP were associated with knee structural abnormalities and clinical symptoms. • FF and T2* alternations in IFP can serve as the new imaging biomarkers for fast, simple, and noninvasive assessment in KOA.