Multimodality Imaging Findings of Nail–Patella Syndrome: The Utility of Cross-Sectional Imaging in Identifying Soft Tissue Abnormalities

Nail–patella syndrome (NPS; Fong's disease) is a rare condition, caused by a defect in LMX1B, especially when diagnosed in the adult age. NPS may present with skeletal deformities such as nail abnormalities, absent or hypoplastic patella, iliac horns, or elbow dysplasia, as well as kidney disease, hearing loss, and ophthalmic involvement. We present the case of a 54-year-old female with chronic knee pain whose diagnosis was supported by multimodality imaging. Radiographically, X-ray demonstrates classic findings of hypoplastic or rudimentary patellae, which can be displaced upward and laterally. Magnetic resonance imaging further identified hypoplastic tendons and a unique fibrous band extending from the Hoffa fat pad to the trochlea. The patient was managed conservatively with physical therapy. While osseous hallmarks like iliac horns confirm the diagnosis of NPS, this case report highlights the utility of cross-sectional imaging in identifying intra-articular soft-tissue abnormalities (i.e., infrapatellar fibrous band) that dictate biomechanical and degenerative pathways of the patellofemoral space.