Midterm Outcomes and Frequency of Osteolysis of Total Hip Arthroplasty Using Cementless Modular Stem for Asian Patients.

BACKGROUND: Modular stems are useful for total hip arthroplasty (THA) in anatomically difficult dysplasia. Here, we present mean 6.8-year outcomes of cementless primary THA using S-ROM-A (modified modular stem for Asian patients) femoral prosthesis in anatomically difficult cases. METHODS: Charts of 373 patients (461 hips) undergoing THA (mean age, 58 years) were reviewed for clinical evaluation of modified Merle d'Aubigné-Postel score and Kaplan-Meier survivorship with revision for any reason as the end point. For radiographic analysis, 331 patients (412 hips) followed up for ≥5 years were included. Bearing couples were metal-on-metal (n = 145), metal-on-polyethylene (n = 120), and ceramic-on-polyethylene (n = 147). Radiography and multiplanar computed tomography were performed. RESULTS: No postoperative dislocation or deep infection occurred. Mean modified Merle d'Aubigné-Postel score improved significantly (10.9 points preoperatively, 16.7 points at last follow-up; P < .001). Cumulative 5- and 10-year stem survival rates were 100% and 84%, respectively (95% confidence interval, 75%-93%). All stems were classified as bone ingrown fixation. Osteolysis occurred in metal-on-metal (42.8%) and metal-on-polyethylene (15.8%) groups. Mean time to osteolysis was ~3 years, with no significant difference between 3 groups (P = .264). In logistic regression, lower cup inclination angle was significantly associated with osteolysis (odds ratio, 0.914; 95% confidence interval, 0.84-0.99; P = .029). CONCLUSION: S-ROM-A femoral prosthesis achieved excellent midterm fixation, and the modular system was useful in primary THA with severe deformity. Bearing couples are potentially associated with adverse reactions to metal debris. S-ROM-A with ceramic-on-polyethylene bearing couples may be an option for anatomically difficult THA.

Detection of total hip prostheses at airport security checkpoints.

BACKGROUND: There have been several reports regarding airport security checks using arched metal detectors in patients with orthopedic implants and/or joint replacement surgery. Implants of different sizes and/or materials are used in total hip arthroplasty (THA), but there have been no reports regarding differences in detection rates between different types of THA implants and materials. We examined detection rates by airport metal detectors among THA patients with different implants. METHODS: We selected 1684 patients from regular outpatients at our hospital from June to December 2016. A questionnaire elicited responses regarding usage of airplanes, flight type (domestic/international), and detection by airport metal detectors. Data were investigated according to unilateral/bilateral THA, femoral stem type, acetabular shell component diameter, femoral head diameter, and femoral head material type. RESULTS: Among 671 patients selected from those who used airplanes, 346 patients reported detection by metal detectors. Detection rates for patients with unilateral THA/domestic flights, unilateral THA/international flights, bilateral THA/domestic flights, and bilateral THA/international flights were 23% (81 of 351 patients), 56% (114 of 186 patients), 75% (140 of 204 patients), and 86% (118 of 138 patients), respectively. Logistic regression analysis indicated that the most effective explanatory variables were cup size and material type of femoral head for domestic flights, and cup size for unilateral THA/international flights. CONCLUSION: Detection rate was lowest for patients with unilateral THA/domestic flights (23%), and highest for bilateral THA/international flights (86%). Statistical analyses of implant data indicated that cup size was the most significant explanatory variable.

Direct anterior versus anterolateral approach in one-stage supine total hip arthroplasty. Focused on nerve injury: A prospective, randomized, controlled trial.

BACKGROUND: The difference in clinical results between the direct anterior approach (DAA) and the anterolateral approach (ALA) for total hip arthroplasty (THA) is still unclear. The purpose of this study was to compare clinical results, including nerve injuries, between DAA and ALA in one-stage bilateral THA in a prospective, randomized controlled trial. METHODS: Thirty patients were recruited for primary bilateral THAs from 2014 to 2016. The left and right hips of each patient were randomly assigned to DAA and the others to ALA. We prospectively compared the clinical results, incidence of lateral femoral cutaneous nerve (LFCN) injury, and tensor fascia lata (TFL) atrophy considered to be related to superior gluteal nerve injury between both approaches. RESULTS: No significant difference was found in the clinical results between both sides at postoperative 1 year. Temporary symptom of LFCN injury was observed only in DAA sides (7/30, 23.3%). The ratio of 3-month postoperative to preoperative cross-sectional area of TFL on computed tomography was significantly lower on the side subjected to DAA (DAA side, 78.8 ± 22.8%) than on the side subjected to ALA (ALA side, 90.7 ± 17.7%) (p < 0.01). In magnetic resonance imaging at postoperative 1 year, the mean grade of fatty atrophy of TFL by Goutalier classification was significantly higher in DAA sides (2.00 ± 1.6) than in ALA sides (1.1 ± 1.3) (p = 0.03). CONCLUSIONS: Excellent clinical results for both DAA and ALA were achieved. LFCN injury was found only in DAA sides. Although TFL atrophy was found in both approaches, it was found significantly more in DAA sides. Our study suggested that ALA should be used rather than DAA in terms of the risk of nerve injuries.

Improvement of cold injury-induced mouse brain edema by endothelin ETB antagonists is accompanied by decreases in matrixmetalloproteinase 9 and vascular endothelial growth factor-A.

Brain edema is a potentially fatal pathological state that often occurs after brain injuries such as ischemia and trauma. However, therapeutic agents that fundamentally treat brain edema have not yet been established. We previously found that endothelin ETB receptor antagonists attenuate the formation and maintenance of vasogenic brain edema after cold injury in mice. In this study, the effects of ETB antagonists on matrixmetalloproteinase (MMP)9 and vascular endothelial growth factor (VEGF)-A expression were examined in the cold injury model. Cold injury was performed in the left brain of male ddY mice (5-6 weeks old) for the induction of vasogenic edema. Expression of MMP9 and VEGF-A mRNA in the mouse cerebrum was increased by cold injury. Immunohistochemical observations showed that the MMP9 and VEGF-A were mainly produced in reactive astrocytes in the damaged cerebrum. Intracerebroventricular administration of BQ788 (10 µg) or IRL-2500 (10 µg) (selective ETB antagonists) attenuated brain edema and disruption of the blood-brain barrier after cold injury. BQ788 and IRL-2500 reversed the cold injury-induced increases in MMP9 and VEGF-A expression. The induction of reactive astrocytes producing MMP9 and VEGF-A in the damaged cerebrum was attenuated by BQ788 and IRL-2500. These results suggest that attenuations of astrocytic MMP9 and VEGF-A expression by ETB antagonists may be involved in the amelioration of vasogenic brain edema.

Delayed Administration of BQ788, an ETB Antagonist, after Experimental Traumatic Brain Injury Promotes Recovery of Blood-Brain Barrier Function and a Reduction of Cerebral Edema in Mice.

Traumatic brain injury (TBI) is induced by immediate physical disruption of brain tissue, and causes death and disability. Studies on experimental TBI animal models show that disruption of the blood-brain barrier (BBB) underlies brain edema and neuroinflammation during the delayed phase of TBI. In neurological disorders, endothelin-1 (ET-1) is involved in BBB dysfunction and brain edema. In this study, the effect of ET antagonists on BBB dysfunction and brain edema were examined in a mouse focal TBI model using lateral fluid percussion injury (FPI). ET-1 and ETB receptors were increased at 2-7 days after FPI, which was accompanied by extravasation of Evans blue (EB) and brain edema. Repeated intracerebroventricular administration of BQ788 (15 nmol/day), an ETB antagonist, from 2 days after FPI promoted recovery of EB extravasation and brain edema, while FR 139317, an ETA antagonist, had no effect. Delayed intravenous administration of BQ788 also promoted recovery from FPI-induced EB extravasation and brain edema. While FPI caused decreases in claudin-5, occludin, and zonula occludens-1 proteins, BQ788 reversed FPI-induced reductions of them. Immunohistochemical observation of the cerebrum after FPI showed that ETB receptors are predominantly expressed in glial fibrillary acidic protein (GFAP)-positive astrocytes. BQ788 reduced FPI-induced increases in GFAP-positive astrocytes. GFAP-positive astrocytes produced vascular endothelial growth factor-A (VEGF-A) and matrix metalloproteinase-9 (MMP9). FPI-induced increases in VEGF-A and MMP-9 production were reversed by BQ788. These results suggest that ETB receptor antagonism during the delayed phase of focal TBI promotes recovery of BBB function and reduction of brain edema.