Clinical, imaging, and histopathological characteristics of Vietnamese patients with late-stage avascular necrosis of the femoral head.

INTRODUCTION

Avascular necrosis of the femoral head (AVNFH) causes femoral head (FH) collapse and hip osteoarthritis due to various factors.

OBJECTIVE

The purpose of this study is to report on clinical features, MRI imaging, and histopathology of AVNFH in Vietnamese patients.

METHODS

One hundred fifty patients diagnosed with AVNFH (stage IV, V, or VI according to Steinberg’s classification) were evaluated for clinical symptoms, blood tests, X-rays, and hip MRI. Histopathological was performed on cancellous bone samples from the neck, greater trochanter, and lesser trochanter of the femur.

RESULTS

Patients revealed rapid, persistent onset of pain in all three stages, with 100% exhibiting quadriceps atrophy, gluteal atrophy, and shortened limbs. Risk factors for AVNFH include alcohol/smoking (> 70%). Imaging injuries include bone defects/osteoporosis, femoral neck collapse, and joint space constriction (100%). Synovial edema, congestion, and cartilage separation were prevalent in phases V and VI (76.7–100%). Stage IV showed a wrinkled FH cartilage surface (80%) and partial FH collapse (100%), while stages V and VI revealed a jagged cartilage surface and total FH collapse (80–100%). Bone marrow necrosis, marrow edema, subchondral fractures, dead bone trabeculae, and thickening bone trabeculae occurred in all AVNFH patients. Furthermore, articular cartilage had fewer elastic fibers (stages IV and V), but complete articular cartilage degradation occurs only in stage VI.

CONCLUSIONS

Bone defects/osteophytes, FH collapse, and joint space narrowing are common markers for AVNFH in Vietnamese patients. Hip joint effusion, bone marrow necrosis, edema, subchondral fracture, dead bone trabeculae, and thickening bone trabeculae are common.