Patient History
67-year-old male with right hip pain and possible avascular necrosis of the right femoral head
Findings
SKELETAL: Extensive geometric and serpiginous areas of heterogeneous signal alteration occupy greater than 80% of the weightbearing femoral head area and volume consistent with avascular necrosis. Mild femoral head flattening without collapse. Contralateral side demonstrates linear and ring patterns of hypointensity compatible with less severe contralateral AVN.
Postsurgical change in the lumbosacral region with evidence of transpedicular screw construct and disc space narrowing. Retrospinal sarcopenia.
PELVIS: Pelvic ring and sacroiliac joints are preserved. But, the symphysis pubis is swollen and the pubic capsule is inflamed or torn with osteoarthritic reaction and spurring best seen on series 9, image 19 and series 5, image 21.
JOINTS: Joint effusion without synovitis. Penetrating posterior acetabular erosions. Prolapsing paralabral cyst extends just outside the lateral iliofemoral capsule on series 8, image 12. Weightbearing articular cartilage joint space narrowing seen from anterior to posterior.
ACETABULUM/LABRUM: Anterosuperior and superolateral labral tear with paralabral cyst formation conspicuous on series 10, image 10 and series 8, image 12. Diminutive appearance of the labrum with paralabral cyst seen on series 9, image 12.
MUSCLES/TENDONS/LIGAMENTS: Irregular shape of the iliofemoral ligament compatible with ligamentous insufficiency or laxity. Frayed ligamentum teres in the fovea capitis.
OTHER/SOFT TISSUE: Severe abductor muscle atrophy and dysfunction, especially severe in the gluteus medius.
Conclusion
Avascular necrosis involving at least 80% of the weightbearing articular surface of the femoral head, confluent and sclerotic without collapse. Predominately ring type avascular necrosis of lesser severity on the contralateral side.
