Assessment of Inflammation of Infrapatellar Fat Pad and its Contribution to Anterior Knee Pain Severity and Severity of Knee Osteoarthritis

Background: Osteoarthritis is the most common arthritic disease worldwide, characterized by debilitating pain and joint tissue damage. While the exact cause of knee osteoarthritis pain remains unclear, evidence suggests that inflammation plays a role in both disease progression and pain. Early detection and treatment of inflammation may improve outcomes. This study aims to assess infrapatellar fat pad (IPFP) inflammation using Doppler ultrasound in patients with knee osteoarthritis and in those with anterior knee pain without osteoarthritis, and to evaluate its impact on pain severity, and response to treatment (conservative therapy vs. Ultrasound-guided steroid injection). Methodology: This case-control study involved 60 patients with anterior knee pain (30 with knee osteoarthritis and 30 without). Each group was split into two subgroups of 15 patients: one received conservative treatment, and the other received ultrasound-guided injections of methylprednisolone into the infrapatellar fat pad. Clinical and ultrasound assessments were conducted at the start and after 6 months. Pain was evaluated using the Visual Analog Scale (VAS) and the Western Ontario and McMaster universities(WOMAC) index. Results: At baseline, Ultrasound showed IPFP inflammation in both groups, more commonly in osteoarthritis knees. After 6 months, steroid injection groups showed significantly better pain relief and functional improvement than conservatively treated groups (p < 0.05). The best outcomes were seen in non- osteoarthritis patients receiving injections (WOMAC ↓52%, VAS ↓61%). Ultrasound also showed reduced IPFP thickness and vascularity in injected knees, especially non- osteoarthritis ones, with minimal changes in the conservative groups. Conclusion: Infrapatellar fat pad inflammation contributes to anterior knee pain in both osteoarthritis and non- osteoarthritis patients. Doppler ultrasound helps in early detection. Ultrasound guided steroid injections were more effective than conservative treatment, supporting targeted fat pad therapy for better pain control and potential osteoarthritis progression delay.