Arthroscopic Management of an Unusual Fibrofatty Loose Body Presumed to Arise From Hoffa's Fat Pad: A Case Report.

We report the case of a 31-year-old man with persistent anterior knee pain and mechanical locking and catching despite conservative management. Preoperative magnetic resonance imaging (MRI) demonstrated an intra-articular loose body in the patellofemoral compartment with associated lateral meniscal and synovial abnormalities. Arthroscopy identified a greater than 5-mm fibrofatty loose body whose gross appearance was considered suggestive of a detached remnant of Hoffa's fat pad. Histopathologic analysis was not obtained, and direct continuity with the infrapatellar fat pad was not documented; therefore, the tissue of origin remains presumed. The loose body was removed with suction and arthroscopic forceps, and associated plica, synovial, and lateral meniscal pathology was treated concurrently. At six weeks, the patient demonstrated marked short-term improvement after combined arthroscopic treatment, with a visual analog scale pain score decreasing from 7/10 to 1/10, resolution of locking, and improvement in range of motion from 10°-110° to 0°-130°. This case illustrates the diagnostic uncertainty that may accompany unusual intra-articular fibrofatty lesions and highlights the complementary roles of MRI and arthroscopy when persistent mechanical symptoms warrant operative evaluation.