Ultrasonography-Guided Injection for Quadriceps Fat Pad Edema: Preliminary Report of a Six-Month Clinical and Radiological Follow-Up

Purpose: To investigate efficacy and safety of ultrasonography-guided local corticosteroid and anesthetic injection followed by physical therapy for the management of quadriceps fat pad (QFP) edema. Materials and Methods: We prospectively evaluated 1671 knee MRI examinations in 1542 patients for QFP edema with mass effect, which was present in 109 (6.5%) knees. Participants were assigned into injection and therapy groups (both received the same physical therapy program). Injection group was first treated with ultrasonography-guided QFP injection of 1 mL corticosteroid and 1 mL local anesthetic agent. Patients were evaluated at baseline and 1-, 2-, 6-month follow-up for pain using static and dynamic visual analogue scale (VAS), suprapatellar tenderness, and QFP edema on MRI. Results: Final sample size consisted of 19 knees (injection group, 10; therapy group, 9) in 17 patients. An overall improvement was detected in both groups between baseline and final assessments. The injection group fared better than the therapy group in static VAS scores (3.33 +/- 1.70 versus 0.56 +/- 1.33), while there was no such difference for dynamic VAS. Incidence of suprapatellar tenderness decreased in both groups, statistically significantly in the injection group (from 100% to 0%). Pain reduction was greater in the injection group at the first month (88.9%-90% good response versus 50%-66.7% good response, static-dynamic VAS scoring, respectively), whereas there was no such superiority at the sixth month. No severe adverse events were identified. Conclusion: Ultrasonography-guided local injection followed by physical therapy is safe in the management of QFP edema; however, it is not superior to stand-alone physical therapy program in the long term.