Hoffa's Fat Pad Impingement (HFPI)

Hoffa's Fat Pad Impingement (HFPI): Saline Injection Verus Ultrasound Guided Cortisone Injection: A Randomized Trial in Adolescent Female Athletes

The aim of the study is to investigate treatment outcomes for refractory anterior knee pain due to Hoffa's Fat Pad Impingement (HFPI) in young female athletes. Specifically, the study team will study pediatric female athletes with HFPI, and treatment outcomes of US-guided Hoffa's Fat Pad (HFP) corticosteroid injection compared to standard care (physical therapy, bracing, no injection) and saline injection. There will be two arms in this study, 1, a corticosteroid injection and physical therapy and 2, physical therapy and a saline injection. The intent of this study is to measure treatment outcomes, and the research team is not looking at the safety and effectiveness of the lidocaine-methylprednisolone mixture.

Inclusion Criteria:

• Clinical diagnosis of HFPI (defined as pain to palpation over the medial or lateral aspect of the infrapatellar fat pad, and/or positive hoffa test which is performed by exerting direct pressure over the infrapatellar fat pad as the knee is passively moved from flexion to extension; pain is positive hoffa test)
• Age 12-18 years
• Patients who identify as female
• Organized sports participation is defined as any adult-led game or sport in which three or more people play and/or practice together regularly in a league or association or an adult-led individual athletic activity. Non-organized sport is excluded such as free play.
• Xray and non-contrast MRI of the knee must have been completed for the symptomatic knee
• Must have completed physician-prescribed course of physical therapy for 6-8 weeks

Exclusion Criteria:

• History of patellar dislocation or subluxation, Ehlers-Danlos syndrome, patellar tendinitis/tendinosis, quadriceps tendinitis/tendinosis, medial plica syndrome, osteochondritis dessicans (OCD) of the knee, knee osteoarthritis, prior knee surgery
• Other concurrent knee derangement such as meniscus or ligament tears
• Radiographic evidence of bony abnormalities other than lateral patellar tilt, patella alta/baja, trochlear dysplasia
• MR positive for internal knee joint derangement, synovitis/inflammatory changes/effusion, OCD
• Patients receiving other knee injections during the study time period (i.e., viscosupplementation injection, Toradol injection)