Estimation of mesenchymal stem cells (mscs) and monocytes in peripheral blood of acute traumatic head and spinal cord injuries in patients with concomitant diaphyseal femoral fractures: a clinical prospective controlled cohort study

There is some clinical evidence to suggest that fractures of long bones heal more rapidly in patients with severe head injury or acute traumatic spinal cord injury. The mechanism underlying this orthopedic phenomenon is not well understood. The aim of the current study was to investigate the bone healing of diaphyseal femoral fractures in patients with concomitant head or spinal cord injuries and to elucidate mechanism of a possible accelerated osteogenesis. The study recruited 52 group (A) patients with head injury, 50 group (B) patients with head injury and 58 femoral shaft fractures, 20 group (C) patients with spinal cord injuries, 21 group (D) patients with spinal cord injuries and 22 femoral shaft fractures, 60 group (E) patients with 69 femoral shaft fractures only, and 50 group (F) healthy subjects. All the femoral fractures in groups (B), (D), and (E) were treated by closed reduction and internal fixation by intramedullary nail. The fracture healing indicators were compared between patients of different groups and patients' blood samples were used to count circulating mesenchymal stem cells (MSCs) and monocytes using the flow cytometry. Results were analysed with statistical package of social sciences SPSS. Mean scores between two groups of patients were compared using chi square and the Student t-test. The study showed that femoral diaphyseal fractures in patients with head or spinal cord injury heal more expectedly, faster and with more callus formation and patients' blood samples showed statistically significant increase in circulating MSCs count and blood monocytes count in groups (A) to (D). The study revealed acceleration of femoral fractures in patients with concomitant head or spinal cord injuries and also demonstrated mobilization of distant bone marrow MSCs, homing early to fracture site and the role of monocytes in providing mediators to accelerate healing.