There have been many studies regarding nongeriatric femoral neck fractures (FNFs), which included patients of a wide age range (between 20 and 60 years old). We aimed to determine whether internal fixation provided acceptable outcomes for middle-aged patients with displaced FNFs, and identify predictors of successful internal fixation. A total of 117 patients, aged 50–60 years and who underwent closed reduction and unilateral internal fixation using cannulated screws, were included. The outcomes were classified as either “complications” (varus malunion, femoral neck shortening, non-union/early collapse, avascular necrosis, or arthroplasty during the follow-up) or “optimal outcomes” (no complications). Patients with displaced FNFs (Garden stages III–IV, n = 69) were categorized according to whether they experienced acceptable or unacceptable reduction. We evaluated whether patients’ clinical characteristics could predict optimal outcomes. Patients with displaced FNFs generally experienced complications (84.1%). Twenty-two percent of patients experienced optimal outcomes when acceptable reduction was achieved. Patients with unacceptable reductions experienced complications. Optimal outcomes were positively associated with Pauwels’ type II fracture (OR: 8.67, p = 0.025) and negatively associated with excessive alcohol consumption (p = 0.045). Compared with the younger age group, complication rates are higher in middle-aged patients with displaced FNFs treated using cannulated screws. If internal fixation is to be used for a displaced FNF, patient selection is essential. Care must be taken to avoid selecting patients with excessive alcohol consumption, while successful internal fixation may be more likely for patients with Pauwels’ type II fracture.

Background: Titanium (Ti) is one of the most popular implant materials, and its surface titanium dioxide (TiO₂) provides good biocompatibility. The coagulation of blood on Ti implants plays a key role in wound healing and cell growth at the implant site; however, researchers have yet to fully elucidate the mechanism underlying this process on TiO₂. Methods: This study examined the means by which blood coagulation was affected by the crystal structure of TiO₂ thin films (thickness < 50 nm), including anatase, rutile, and mixed anatase/rutile. The films were characterized in terms of roughness using an atomic force microscope, thickness using an X-ray photoelectron spectrometer, and crystal structure using transmission electron microscopy. The surface energy and dielectric constant of the surface films were measured using a contact angle goniometer and the parallel plate method, respectively. Blood coagulation properties (including clotting time, factor XII contact activation, fibrinogen adsorption, fibrin attachment, and platelet adhesion) were then assessed on the various test specimens. Results: All of the TiO₂ films were similar in terms of surface roughness, thickness, and surface energy (hydrophilicity); however, the presence of rutile structures was associated with a higher dielectric constant, which induced the activation of factor XII, the formation of fibrin network, and platelet adhesion. Conclusions: This study provides detailed information related to the effects of TiO₂ crystal structures on blood coagulation properties on Ti implant surfaces.