I had mri that said subchrondral low signal noted in left femoral head consistent with avascular neurosis and maybe on tight hip. what does that mean ?

Femoral head AVN: The earliest findings of avascular necrosis (AVN) of the femoral head are not seen on conventional x-rays but are seen on an MRI of the hip. Increased signal within the femoral head on the MRI may be indicative of early avascular necrosis. As long as there is no loss of sphericity of the femoral head this is likely an earlier finding that may be responsive to less invasive surgical treatment.