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Recently epidemiological studies suggest females lose neuroprotection from neurodegenerative diseases as they go through menopause. It has been hypothesized that this neuroprotection is hormone-dependent. The current study characterized cell signaling molecules downstream of estrogen receptor beta that are known to play a role in memory, PKC, ERK, and connexin-43, in regions of the brain associated with memory decline in an attempt to elucidate significant changes that occur post-estrus. Total whole cell lysates were compared to isolated mitochondrial protein because mitochondrial function is known to be altered during aging. As hypothesized, protein concentrations differed depending on age, gender, and brain region. Additionally, many of these changes occurred within mitochondria but not within whole cell lysates indicating that these are epigenetic alterations. These findings accentuate the complexity of aging and provide insight into the gender-specific cellular processes that occur throughout this process.

Objective: To report upon a series of patients who have experienced the backout of distal interlocking screws after retrograde femoral nailing with the DePuy Synthes RFN-Advanced Retrograde Femoral Nailing System (DePuy Synthes, Raynham, MA). Design: Retrospective case series. Patients: Twenty-seven skeletally mature patients with femoral shaft or distal femur fractures who underwent operative fixation with the DePuy Synthes RFN-Advanced Retrograde Femoral Nailing System with 8 patients subsequently experiencing backout of distal interlocking screws. Intervention: The study intervention included retrospective review of patient charts and radiographs. Main Outcome Measure: The incidence rate of distal interlocking screw backout. Results: Thirty percent of patients experienced the backout of at least 1 distal interlocking screw (mean: 1.625) after undergoing retrograde femoral nailing with the RFN-Advanced system. Thirteen total screws backed out postoperatively. Screw backout was identified an average of 61 days postoperatively (range: 30–139 days). All patients complained of implant prominence and pain along the medial or lateral aspect of the knee. Five patients elected to return to the operating room to remove the symptomatic implant. The oblique distal interlocking screws comprised 62% of screw backouts. Conclusions: Given the high incidence rate of this complication, the associated costs of reoperation, and patient discomfort, we believe that a further investigation into this implant complication is warranted. Level of Evidence: Therapeutic Level IV. See Instructions for Authors for a complete description of levels of evidence.