Prior investigations have been primarily conducted in a laboratory to examine the effects of the smartphone use on the neck and head positions, whether these results are applicable to actual conditions is still unknown. This field survey thus analyzed the neck flexion (NF), head flexion (HF), gaze angle (GA), and viewing distance (VD) of smartphone users in public areas in Taipei, Taiwan. Six hundred smartphone users (300 men and 300 women) were photographed sagittally in standing, supported sitting, or unsupported sitting postures while using a smartphone. Results showed that women had significantly less NF and HF and shorter VDs than male users. Regardless of gender, higher NF was observed for standing than for sitting. Women had similar NF and HF while sitting supported and unsupported, but both were significantly lower than those while standing. By contrast, male users had higher NF and HF during unsupported sitting than during supported sitting. The NF (45°–50°) was much greater than the recommended maximum safe NF of 15°. Women may be at higher risk of visual strain because of shorter VD.

Background Total hip arthroplasty (THA) is the treatment of choice for posttraumatic arthritis with failed internal fixation for hip fractures. However, the postoperative prognosis is not clear. Questions/purposes The primary aim of the study is to report the postoperative outcome, prognosis, and complication rates of total hip arthroplasty in posttraumatic hip arthritis after failed internal fixation of fractures around the hip. The secondary aim of the study is to report results among different fracture types around the hip. Patients and methods We enrolled salvage THA patients after failed internal fixation of fractures around the hip and matched control patients undergoing primary THA for hip osteoarthritis. Subgroup analysis was performed to compare the postoperative outcomes, prognosis, and complication rates of salvage THA in posttraumatic hip arthritis after failed internal fixation of different fracture types around the hip. Results A total of 315 THAs (105 salvage THAs and 210 primary THAs) were analyzed. Patients with salvage THA had a longer operative time, lower postoperative hemoglobin (Hb) level, more Hb drop (2.2 ± 1.4 vs. 1.7 ± 1.2 gm/dl, p = 0.002), and delayed ambulation. The salvage THA group also had a higher dislocation rate within 2 months after salvage THA (9.5% vs. 1.9%, p = 0.002), reoperation rate (10.5% vs. 3.8%, p = 0.019, including debridement, open and closed reduction under sedation, revision surgery, surgical fixation for periprosthetic fractures), and revision rate (5.7% vs. 0.5%, p = 0.003) than patients undergoing primary THA. Patients who had failed fixation for acetabular fractures were younger and tended to recover well. Patients with previous intertrochanteric fracture had the longest operative time, more hip pain (83.8%, p = 0.022) and more complications. Conclusion Salvage THA in posttraumatic hip arthritis after failed internal fixation required a longer operative time and led to more blood loss and postoperative complications. The dislocation, reoperation, and revision rates after salvage THA were higher than those after primary THA. Patients with salvage THA after failed internal fixation for intertrochanteric fractures were the most susceptible to more complications compared to those with femoral neck fracture or acetabular fracture. Level of Evidence level III