Fat Pad Entrapment in Suprapatellar Pouch Following Previous Arthroscopic Resection of Infrapatellar Fat Pad and Medial Plica: A Rare Complication

Abstract

Background: A 27-year-old woman who failed conservative management was operated on for anterior knee pain due to fat pad syndrome in the Hoffa zone. The patient underwent arthroscopy with resection of the Hoffa and possible medial plica and did well postoperatively in the initial three to four weeks. After that, she developed a sense of a loose body in the superior medial aspects of the knee. This occurred with knee flexion and extension and was aggravated by hyperflexion of the knee.

Findings: The loose body was palpable in the superomedial aspect near the superomedial portal. Ultrasound demonstrated a mobile mass of 2.5 centimeters in the suprapatellar pouch. A second arthroscopy was performed which noted that the mass was tethered to the superomedial portal and the suprapatellar pouch. Histology of the loose body revealed fibroadipose tissue.

Conclusions: During arthroscopic resection of the fat pad and removal through the superior medial portal, a portion of fat must have remained in this portal and became tethered and hypertrophied, causing this postoperative complication.

KEYWORDS:

• Knee arthroscopy
• fat pad
• pedicle mass
• complication