The Long-Term Efficacy of Computed Tomography-Navigated Total Hip Arthroplasty: An 18-Year Follow-Up Study.

Backgroumd: There have been few reports on the long-term survival of computed tomography (CT)-navigated total hip arthroplasty (THA), which should lead to a lower incidence of dislocation and loosening. In this study, we examined survivorship, dislocation, and loosening incidence using plain radiographs over a minimum 15-year follow-up after CT-navigated THA. METHODS: We retrospectively reviewed 145 consecutive CT-navigated THAs for >15 years. We surveyed the angles placed in both the acetabular and femoral components, survivorship, the occurrence of dislocation, the revision rate, and the fixation grade of the acetabular component. RESULTS: The mean follow-up duration was 18.4 years. Overall, 73.8% of THAs were within the safe zone of Lewinnek. There were four dislocations (2.8%), with three occurring within 1 month after surgery and the other within 7 years after surgery. Revision THA was performed in one case (0.69%); consequently, the survival rate was 99.3%. The fixation grade was evaluated in 144 hips, and those were evaluated as having "no loosening". CONCLUSIONS: CT-navigated THA was speculated to contribute to long-term survivorship, with a low rate of loosening, even after 18 years of follow-up. It was speculated that the acetabular component was placed at an acceptable insertion angle and a suitable position for stable initial fixation.

Coordinate value of the femoral head center estimated using those of the tip of the greater trochanter and lesser trochanter.

Several studies have reported estimating the femoral head center (FC) from reference points on the pelvis; however, none have reported estimates obtained from those on the femur. In this cross-sectional study, we investigated the estimated point of FC from the coordinate value of the tip of the greater trochanter (GT) and lesser trochanter (LT) using a formula with a three-dimensional measurement technique. We used data from 92 healthy Japanese subjects without any back or knee symptoms and no abnormalities in the hip, knee, or spine on plain radiographs. In our study, the difference in the anteroposterior direction was larger than that in the other directions. We speculate that the accuracy of defining the tip of the LT is difficult in the anteroposterior direction. Moreover, the correlation coefficients were larger for women. The reason for this was unclear because the variation in the proximal femur may be similar in women. We found that the average difference between the actual and calculated values was approximately 2 mm. We considered that the coordinate value of the FC from the tip of the GT could be estimated more accurately using the regression equation compared to previous methods based on pelvic reference points.

Age at the time of hip fracture in patients with rheumatoid arthritis is 4 years greater than it was 10 years before, but is still younger than that of the general population.

Objective: To investigate the characteristics of hip fractures in patients with rheumatoid arthritis (RA).Methods: Between 2012 and 2015, 789 hip fractures were treated at our hospital. Patients with RA were checked and their characteristics were compared with data recorded 10 years before, and with the general population.Results: There were 11 patients with RA, who were all female, and the mean age was 76 ± 7.0 years. The age at the time of hip fracture was 4 years older than that recorded 10 years before (72 ± 4.5 years, p < .05), but was younger than that of the general population (84 ± 8.0 years, p < .001). The mean prednisolone dose of 2.5 ± 2.6 mg/day was lower than that recorded 10 years before (4.8 ± 2.9 mg/day, p < .05). The rate of patients treated with anti-osteoporotic medications at fracture (73%) was higher than 10 years before (42%); however, the difference was not significant. The incidence of secondary fracture was not high compared to the general population. No mortality was recorded at 1 year, and no infective complications occurred.Conclusion: The age at the time of hip fracture in RA patients is increasing, but is still younger than that of the general population.