Findings: The Hoffa's fat pad shows moderate pathological alterations with partial preservation of adipose tissue architecture. Approximately 50-60% of the fat pad volume maintains recognizable adipose echostructure (hyperechoic), while the remaining 40-50% demonstrates fibrotic transformation. The overall thickness measures 9.5mm, representing moderate enlargement compared to age-matched controls (expected 6-7mm in elderly patients). Multiple hypoechoic areas are distributed throughout the fat pad, with the largest measuring 12x7mm in the superior central portion, representing zones of fibrotic tissue replacement and hemosiderin deposition from recurrent hemorrhagic episodes. Several discrete hyperechoic foci without posterior shadowing are scattered within the fat pad, consistent with hemosiderin deposits rather than calcifications, appearing as 1-2mm punctate echogenic spots. Approximately 5-6 fibrous bands (thickness 1.5-2mm each) traverse the fat pad in various orientations, most prominently in the superior and lateral aspects, creating a reticular pattern that disrupts the normal homogeneous adipose appearance. These bands likely represent organized fibrous septa from previous hemorrhagic organization. The anterior border adjacent to the patellar ligament shows irregular interface with loss of the normal smooth plane, suggesting adhesion formation. The posterior border demonstrates moderate thickening and irregularity where it interfaces with the synovium. A small loculated fluid collection (5x3mm) is present in the lateral recess of the fat pad, possibly representing a small hemorrhagic cyst or loculated effusion. Color Doppler examination reveals moderate increase in vascularity with 4-5 small vessels (0.5-0.8mm diameter) penetrating into the fibrotic areas, indicating ongoing inflammatory activity despite the patient's age. The vascular pattern is less chaotic compared to younger patients with hemophilic arthropathy, possibly reflecting the slower disease tempo in acquired hemophilia. The fat pad demonstrates moderately reduced compressibility on probe pressure compared to expected in elderly patients, indicating significant fibrotic component. Dynamic examination during knee flexion reveals impaired mobility of the fat pad with restricted anterior displacement, contributing to anterior knee pain and impingement symptoms. The degree of fibrosis appears disproportionate for only 30 months of disease duration, suggesting that pre-existing age-related fat pad changes (fibrofatty involution commonly seen in elderly patients) may have been accelerated and exacerbated by the superimposed hemorrhagic episodes. Areas of the fat pad adjacent to the patellar ligament and tibial plateau show increased echogenicity and thickening, consistent with chronic mechanical stress and inflammation. No discrete calcifications or ossifications are identified, which is typical for the relatively short disease duration despite patient's age.

Findings: Mild tendon thickening with general preservation of normal parallel fibrillar echostructure. Presence of focal area of heterogeneity (8x3mm) in the lateral portion of the tendon, approximately 2cm proximal to patellar insertion, compatible with outcome of previous intratendinous edema/hematoma. Minimal scattered punctate calcifications (<1mm). Insertion on patellar base is regular without signs of enthesopathy. Doppler shows mild localized increase in vascularization in the heterogeneous area.