Weight Bearing as Tolerated After Intramedullary Nailing of the Femur: A Retrospective Analysis of Clinical and Radiographic Outcomes

Intramedullary nailing of femur fractures has become the standard of care, with high union rates. Few high-level studies have discussed the effect that early weight bearing has on the healing of these fractures, regardless of nail size or fracture pattern. The goal of this study was to determine the clinical and radiographic outcomes of femoral shaft fractures for patients allowed immediate weight bearing after intramedullary nailing. We performed a retrospective review of 341 femoral shaft fractures, with 131 allowed immediate weight bearing, 99 allowed partial weight bearing, and 111 kept non-weight bearing. Demographic, intraoperative, and postoperative variables were collected and analyzed. Increased fracture complexity was associated with higher likelihood of delayed weight bearing. No significant difference was found for nail size or rate of failure with different nail sizes. A total of 50 nonunions were noted (14.7%), with no difference in nonunion rates between weight bearing cohorts. The only significant predictor of nonunion was Orthopaedic Trauma Association (OTA) classification of OTA32B fractures (P=.02), which were 2 times and 4 times as likely to occur compared with OTA32A and OTA32C fractures, respectively. Failure of interlocking screws occurred among 15 patients (4.4%) and was more common with older patients, osteoporotic bone, and larger diameter nails. In summary, unilateral intramedullary nailing of adult femoral shaft fractures does not show a difference in fracture union rates or implant failure with unrestricted, immediate weight bearing, regardless of nail characteristics. [Orthopedics. 2022;45(3):e148-e153.].

Decrease of CD4(+)FOXP3(+) T regulatory cells in the peripheral blood of human subjects undergoing a mental stressor

We have previously shown that acute psychological stress alerts the adaptive immune response causing an increase in antigen-experienced effector T cells in the peripheral blood. T regulatory cells (Tregs) play a central role in maintaining self-tolerance and controlling autoimmune responses. Here, we analyzed for the first time the behaviour of Tregs in the context of a stress-induced activation of the adaptive immune response. 31 healthy young males underwent a brief laboratory stressor and, in a crossover design, served as their own unstressed controls. We quantified effects of acute stress on CD4(+)FOXP3(+) T regulatory cells and other T cell subpopulations using flow cytometry. In addition, the expression of Treg-related effector molecules and stress hormone receptors were analyzed in the subjects' peripheral T cells. We confirmed our previous observation of a stress-induced decrease in CD45RA(+)CCR7(+) "naïve" and CD45RA(-)CCR7+ "central memory" T cells while CD45RA(-)-CCR7(-) "memory effector" and CD45RA(+)CCR7(-) "terminally differentiated" effector T cells remained stable or increased. Importantly, we found acute psychological stress to cause a concomitant decrease in CD4(+)FOXP3(+) Tregs and in CD4(+) T cells expressing Treg-related effector molecules cytotoxic T-lymphocyte antigen-4 (CTLA-4) and latency associated peptide (LAP). Finally, we observed beta(1)-adrenergic and glucorticoid alpha receptors to be overexpressed in Tregs, suggesting that these molecules might mediate stress-related effects on Tregs. In conclusion, inhibiting components of the adaptive immune response, like Tregs, are down-regulated during a stress-induced activation of the adaptive immune response. In situations of chronic stress, this scenario might result in an exacerbation of inflammatory conditions such as autoimmune diseases.

Acute psychological stress alerts the adaptive immune response: Stress-induced mobilization of effector T cells

Influences of psychological stress on the acquired immune system have not consequently been investigated. We found acute psychological stress to cause an increase in CD56+ and CCR5+ effector T cells in the peripheral blood of healthy human subjects (N=22), while skin-homing CLA+ T cells decreased. At the same time, we observed a stress-induced decrease in CD45RA+/CCR7+ naive and CD45RA-/CCR7+ central memory T cells, while CD45RA-/CCR7- effector memory and CD45RA+/CCR7- terminally differentiated T cells increased. This T cell redistribution translated into an increase in T cells expressing perforin/granzyme B and in Epstein-Barr virus-specific, cytomegalovirus-specific and influenza virus-specific CD8+ T cells. Thus, acute stress seems to promote the retention of less mature T cells within lymphoid tissue or skin while effector-type T cells are mobilized into the blood in order to be able to rapidly migrate into peripheral tissues.