Twenty-two patients with unreduced hip dislocation or fracture dislocation were prospectively evaluated. Intraosseous aspiration, marrow fluid analysis and core biopsy histological analysis was performed from the supero-lateral (test group) and central part (control group) of the femoral head. After appropriate surgical treatment and postoperative management, they were followed up for 2 years by clinical, radiological and magnetic resonance imaging evaluation. Eight patients eventually developed avascular necrosis (AVN) of the femoral head. The analysis of test samples revealed that 9 patients had an aspirate volume of < 1 cc ; marrow morphology of 11 hips showed necrotic cells; 12 patients had a core biopsy histology suggestive of dead osseous fragments and necrotic osteocytes. In contrast, all the control samples had an aspirate volume of > 1cc and showed viable cells on histology. Intra-operative assessment of marrow-aspirate volume (< 1cc), marrow morphology and core biopsy histology from the superolateral part of femur head can fairly predict the development of subsequent ONFH after trauma; the correlation is statistically significant (p < 0.05).