Long-Term Outcomes and a Radiological Assessment of Hydroxyapatite-Tricalcium Phosphate-Coated Total Hip Arthroplasty (Trilogy/Zimmer): A Long-Term Follow-Up Study.

Background and Objectives: Favorable short- and mid-term results for hydroxyapatite (HA)-tricalcium phosphate (TCP)-coated total hip arthroplasty (THA) (Trilogy/Zimmer) have been reported in the literature; however, the long-term results beyond 15 years have not been documented. Therefore, this study evaluated the long-term postoperative results, radiological bone changes, and implant fixation of the acetabular component of HA-TCP-coated THA. Materials and Methods: This is a retrospective cohort study of 212 patients who underwent primary HA-TCP-coated THA (Trilogy/Zimmer) at our institution between 1 October 2002, and 31 March 2008; 166 who were available for follow-up at least 15 years postoperatively were included (capture rate: 78.3%). All implants were Trilogy/Zimmer. We investigated the survival rate, with aseptic loosening as the endpoint. Clinical evaluations included the presence of dislocation and a modified Harris Hip Score (mHHS) preoperatively and at the final observation. Results: The mean age at surgery and at the follow-up period were 57.7 ± 9.6 and 17.1 ± 1.5 years, respectively. The survival rate was 99.4% (165/166), with aseptic loosening as the endpoint. Dislocation was observed in 4/166 (2.4%) patients. The mHHS improved significantly from 46.1 points preoperatively to 82.2 points during the last survey (p < 0.05). The results revealed that fixation was favorable in all cases except for one case of aseptic loosening. The Trilogy implant coated with HA-TCP was highly effective in bone induction, and bone ingrowth was considered to have occurred without failure, further indicating its usefulness. The long-term results of cementless THA using an HA-TCP coating (Trilogy/Zimmer), with a mean follow-up period of 17.1 years, revealed a commendable survival rate of 99.4%, considering aseptic loosening as the endpoint. Conclusions: HA-TCP-coated THA (Trilogy/Zimmer) had good long-term results. However, further long-term observation is required in patients who have undergone this surgery, and the stem side should be evaluated and investigated, including comorbidities.

A decrease in the number and incidence of osteoporotic hip fractures among elderly individuals in Niigata, Japan, from 2010 to 2015.

We investigated the incidence of hip fracture in patients aged ≥50 years in 2015 in Niigata Prefecture, Japan. We also determined the long-term trend in hip fracture incidence from 1985 to 2015. In 2015, 3214 hip fractures occurred in Niigata Prefecture. The crude incidence rate of hip fracture was 282.7 per 100,000 persons per year (122.9 in men and 416.4 in women). The incidence of hip fracture decreased from 2010 to 2015 in all age groups except in men aged 65-69 years and women aged 60-64 years. The percentage of patients who took anti-osteoporotic medication before their hip fractures increased from 10.2% in 2010 to 14.9% in 2015. The age-specific incidence in women tended to increase until 2010, but significantly decreased from 2010 to 2015 (p < 0.001). Similarly, the incidence in men decreased from 2010 to 2015 but was not significantly different from that in 1994 (p = 0.633); this incidence had been increasing since 1999. In conclusion, a generally increasing trend was observed in the incidence of hip fractures for 30 years in both men and women in Niigata Prefecture; however, it turned into a descending trend beginning in 2010.

Sex- and age-specific differences in femoral head coverage and acetabular morphology among healthy subjects-derivation of normal ranges and thresholds for abnormality.

OBJECTIVE: We aimed to clarify sex- and age-specific differences in three-dimensional and anatomic characteristics of femoral head coverage and acetabular morphology in healthy subjects. MATERIALS AND METHODS: The study included 120 healthy subjects (57 male, 63 female), stratified into groups according to age and sex. We used computed tomography data to measure various anatomic alignment parameters describing femoral head coverage and acetabular morphology. RESULTS: The lateral sector angle in the coronal plane, anterior sector angle in the sagittal plane, and posterior sector angles in the axial plane, which characterize femoral head coverage, did not differ significantly between males and females. However, the Sharp angle in the coronal plane and acetabular anteversion in both the sagittal and axial planes were significantly larger in females than in males. Overall, the age-specific trends were similar between male and female subjects. Specifically, for both males and females, the values for parameters of femoral head coverage were significantly lower in younger subjects (<50 years) than in older subjects (≥50 years); the only exception was the posterior sector angle among females; regarding acetabular morphology, younger subjects showed significantly higher values for the acetabular roof obliquity and Sharp angle, but no difference between younger and older subjects was noted regarding acetabular anteversion in the sagittal or axial plane. CONCLUSION: Our data regarding sex- and age-specific differences and estimated normal ranges for parameters characterizing femoral head coverage and acetabular morphology among healthy subjects can be used to predict normal hip morphology.

The Three-Dimensional Criteria of Developmental Dysplasia of the Hip Using the Functional Pelvic Plane Is More Useful Than That Using the Anterior Pelvic Plane.

Background: This retrospective cross-sectional study investigated the cutoff values (COVs) for developmental dysplasia of the hip (DDH) using a three-dimensional (3D) pelvic model reconstructed using computed tomography (CT). We included 107 healthy Japanese participants and 73 patients who had undergone curved periacetabular osteotomy (CPO) for DDH between 2012 and 2017. Methods: The hip CT images were adjusted to the anterior pelvic plane (APP), functional pelvic plane (FPP), sagittal anterior center-edge angle (ACEA), and sagittal posterior center-edge angle (PCEA). The lateral center-edge angle (LCEA), acetabular roof obliquity (ARO), anterior acetabular sector angle (AASA), and posterior acetabular sector angle (PASA) were measured. Receiver operating characteristic (ROC) curves were used to calculate the COVs, and the association between the parameters was analyzed using multiple logistic regression. Results: The ARO (≥10.2°) and LCEA (≤22.2°) were independent influencing factors for the APP, whereas the AASA (≤53.1°) and LCEA (≤24.5°) were independent influencing factors for the FPP. Conclusions: The 3D criteria for the diagnosis of DDH in Japanese individuals can identify DDH with insufficient anterior coverage, which anteroposterior plain radiographs cannot visualize, and can help determine indications for acetabular osteotomy.

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.