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Background: We developed iodine-coated titanium implants to suppress microbial activity and prevent periprosthetic joint infection (PJI); their efficacy was demonstrated in animal and in vitro models. The iodine content in iodine-coated implants naturally decreases in vivo. However, to our knowledge, the effect of reduced iodine content on the implant's antimicrobial activity has not been evaluated to date.Questions/purposes: (1) How much does the iodine content on the implant surface decrease after 4 and 8 weeks in vivo in a rat model? (2) What effect does the reduced iodine content have on the antimicrobial effect of the implant against multiple bacteria in an in vitro model?Methods: This experiment was performed in two parts: an in vivo experiment to determine attenuation of iodine levels over time in rats, and an in vitro experiment in which we sought to assess whether the reduced iodine content observed in the in vivo experiment was still sufficient to deliver antimicrobial activity against common pathogens seen in PJI. For the in vivo experiment, three types of titanium alloy washers were implanted in rats: untreated (Ti), surface-anodized to produce an oxide film (Ti-O), and with an iodine layer on the oxidation film (Ti-I). The attenuation of iodine levels in rats was measured over time using inductively coupled plasma-mass spectrometry. Herein, only the Ti-I washer was used, with five implanted in each rat that were removed after 4 or 8 weeks. For the 4- and 8-week models, two rats and 15 washers were used. For the in vitro study, to determine the antibacterial effect, three types of washers (Ti, Ti-O, and Ti-I) (nine washers in total) were implanted in each rat. Then, the washers were removed and the antibacterial effect of each washer was examined on multiple bacterial species using the spread plate method and fluorescence microscopy. For the spread plate method, six rats were used, and five rats were used for the observation using fluorescence microscopy; further, 4- and 8-week models were made for each method. Thus, a total of 22 rats and 198 washers were used. Live and dead bacteria in the biofilm were stained, and the biofilm coverage percentage for quantitative analysis was determined using fluorescence microscopy in a nonblinded manner. Ti-I was used as the experimental group, and Ti and Ti-O were used as control groups. The total number of rats and washers used throughout this study was 24 and 213, respectively.Results: Iodine content in rats implanted with Ti-I samples decreased to 72% and 65% after the in vivo period of 4 and 8 weeks, respectively (p = 0.001 and p < 0.001, respectively). In the in vitro experiment, the Ti-I implants demonstrated a stronger antimicrobial activity than Ti and Ti-O implants in the 4- and 8-week models. Both the median number of bacterial colonies and the median biofilm coverage percentage with live bacteria on Ti-I were lower than those on Ti or Ti-O implants for each bacterial species in the 4- and 8-week models. There was no difference in the median biofilm coverage percentage of dead bacteria. In the 8-week model, the antibacterial activity using the spread plate method had median (interquartile range) numbers of bacteria on the Ti, Ti-O, and Ti-I implants of 112 (104 to 165) × 105, 147 (111 to 162) × 105, and 55 (37 to 67) × 105 of methicillin-sensitive Staphylococcus aureus (Ti-I versus Ti, p = 0.026; Ti-I versus Ti-O, p = 0.009); 71 (39 to 111) × 105, 50 (44 to 62) × 105, and 26 (9 to 31)× 105 CFU of methicillin-resistant S. aureus (Ti-I versus Ti, p = 0.026; Ti-I versus Ti-O, p = 0.034); and 77 (74 to 83) × 106, 111 (95 to 117) × 106, and 30 (21 to 45) × 106 CFU of Pseudomonas aeruginosa (Ti-I versus Ti, p = 0.004; Ti-I versus Ti-O, p = 0.009). Despite the decrease in the iodine content of Ti-I after 8 weeks, it demonstrated better antibacterial activity against all tested bacteria than the Ti and Ti-O implants.Conclusion: Iodine-coated implants retained their iodine content and antibacterial activity against methicillin-sensitive S. aureus, methicillin-resistant S. aureus, and P. aeruginosa for 8 weeks in vivo in rats. To evaluate the longer-lasting antibacterial efficacy, further research using larger infected animal PJI models with implants in the joints of both males and females is desirable.Clinical Relevance: Iodine-coated titanium implants displayed an antibacterial activity for 8 weeks in rats in vivo. Although the findings in a rat model do not guarantee efficacy in humans, they represent an important step toward clinical application. [ABSTRACT FROM AUTHOR]

This study investigated the influence of the rotation of innominate bone on anterior pelvic plane (APP) tilt, the angle formed by the APP, and coronal plane of the body to determine whether the provision of proper information about the sagittal balance of the body by the value of the APP tilt (APPT). In total, 244 patients (171 females, 73 males) who were candidates for total hip or knee arthroplasty, periacetabular osteotomy, or shelf arthroplasty were included. The rotational angle of the innominate bone was quantified using computed tomography images at the level of the anterior superior, and anterior inferior iliac spine, and ischiopubic portion. Clustering analysis was performed to identify subtypes of innominate bone rotation. High, intermediate, and low internal rotational alignment groups were identified in females, characterized by rotational angles. Males were treated as one group, and no intergroup differences were observed in sacral slope (SS) and pelvic incidence. However, intergroup differences in APPT were found, indicating a variation in APPT irrespective of sagittal body balance. A negligible relationship between SS and APPT was observed in the high‐internal‐rotation group, intermediate‐internal‐rotation group, and male group, whereas a moderate correlation found in the low‐internal‐rotation group (r =.59). The results could suggest surgeons that the value of the APPT provides no information on the sagittal balance; therefore, it may be ignored for acetabular component positioning during preoperative planning for total hip arthroplasty. [ABSTRACT FROM AUTHOR]

Purpose: To investigate whether anatomic and straight stems could reproduce the anteroposterior distance (AD) of the native femoral head and evaluate the effect of AD of the femoral head on range of motion (ROM) and bony impingement.Methods: This retrospective simulation study included 64 patients who had undergone primary total hip arthroplasty between 2012 and 2014. Using computed tomography (CT)-based templating software, anatomic and straight stems were inserted with same alignment. AD of the head centre was compared between the two stems and native anatomy. Furthermore, post-operative ROM was calculated, and correlation between AD and ROM was assessed.Results: There was a strong positive correlation between native anteversion (mean 21.9°) and anatomic stem anteversion (mean 22.5°) (R = 0.975, P < 0.001). There was no significant difference in AD between the native and anatomic stems (mean 37.7 and 38.8 mm, respectively), but AD of the straight stem was significantly lower than that of the native and anatomic stems. The straight stem showed a significantly lower ROM in flexion and internal rotation angles with 90° flexion (IR) than the anatomic stem (P < 0.05 and P < 0.001, respectively). AD showed a stronger correlation with ROM of IR than with stem anteversion.Conclusions: The anatomic stem could reproduce AD of the native femoral head centre, but the head centre of the straight stem in the same anteversion with anatomic stem translated significantly posterior, significantly decreasing the ROM of flexion and IR and increasing bony impingement of IR. To avoid bony impingement and acquire sufficient ROM, reproducing AD was important. [ABSTRACT FROM AUTHOR]

Background: Anterior overhang of the acetabular component is associated with iliopsoas impingement, which may cause groin pain and functional limitations after THA. However, little is known about the relationship between component overhang and functional alignment of the acetabular component. CT-based image simulation may be illuminating in learning more about this because CT images are more effective than radiographs for evaluating the component's overhang and position.Questions/purposes: Using CT simulations based on preoperative data of nondysplastic and dysplastic hips, we asked: (1) What are the differences in the amount of component overhang, defined as the mediolateral distance from the component's edge to the native acetabular bony boundary on axial images (axial overhang), and as the AP distance on sagittal images (sagittal overhang) among pelvises with neutral and posterior tilt (in which the cephalad portion of the pelvis is more posterior than the caudad portion in the sagittal plane) in patients with dysplastic hips and those with nondysplastic hips? (2) Are increments in the amount of component overhang associated with a difference in the likelihood that the iliopsoas tendon will impinge against the edge of the acetabular component, after controlling for native acetabular abduction and anteversion and the presence of dysplasia?Methods: A total of 128 hips (dysplastic group: 73 hips; nondysplastic group: 55 hips) were evaluated. We defined a dysplastic hip as one with a lateral center-edge angle of less than 20° on AP radiographs. Pelvic models with neutral (0°) and 10° and 20° of posterior tilt were created from CT data. In simulations, acetabular component models were implanted into the true acetabulum with a tilt-adjusted orientation angle that was defined as the component's angle based on a reference for the functional pelvic plane (coronal plane of the body) in each pelvic model. Axial and sagittal component overhang were measured on CT images. Axial overhang of at least 12 mm and sagittal overhang of at least 4 mm were defined as thresholds increasing the likelihood of iliopsoas impingement according to previous studies. When determining the amount of overhang of the acetabular component, we controlled for abduction and anteversion of the native acetabulum and the presence of dysplasia by performing a multivariable logistic regression analysis.Results: In dysplastic hips, axial overhang increased by a mean ± SD of 5 ± 1 mm (Bonferroni adjusted p < 0.001; 95% CI, 4.7-5.1) from 0° to 10° of posterior tilt and by 5 ± 1 mm (p < 0.001; 95% CI, 4.9-5.3) from 10° to 20° of posterior tilt. Sagittal overhang increased by 1 ± 0 mm (p < 0.001; 95% CI, 1.0-1.0) from 0° to 10° of posterior tilt and by 1 ± 0 mm (p < 0.001; 95% CI, 1.0-1.0) from 10° to 20° of posterior tilt. In nondysplastic hips, axial overhang increased by a mean of 5 ± 0 mm (p < 0.001; 95% CI, 4.7-5.0) from 0° to 10° of posterior tilt and by 5 ± 1 mm (p < 0.001; 95% CI, 4.6-5.0) from 10° to 20° of posterior tilt. Sagittal overhang increased by 1 ± 0 mm (p < 0.001; 95% CI, 1.0-1.1) from 0° to 10° of posterior tilt and by 1 ± 0 mm (p < 0.001; 95% CI, 1.0-1.1) from 10° to 20° of posterior tilt. After controlling for the presence of dysplasia, we found that native acetabular abduction and anteversion and posterior pelvic tilt, presence of dysplasia (p = 0.030; adjusted odds ratio [OR], 2.2; 95% CI, 1.1-4.6), native acetabular anteversion (p < 0.001; adjusted OR, 1.4; 95% CI, 1.3-1.5), and 10° and 20° of backward tilt compared with 0° of tilt (10° of posterior tilt: p < 0.001; adjusted OR, 15; 95% CI, 5.5-41; 20° of posterior tilt: p < 0.001; adjusted OR, 333; 95% CI, 96-1157) were independently associated with axial overhang of at least 12 mm; the model showed high goodness of fit (Nagelkerke's r = 0.68). In contrast, native acetabular anteversion (p < 0.001; adjusted OR, 1.2; 95% CI, 1.1-1.2) and 20° of backward tilt compared with 0° of tilt (p = 0.015; adjusted OR, 2.2; 95% CI, 1.2-4.0) were independently associated with sagittal overhang of at least 4 mm; the model had low goodness of fit (Nagelkerke's r = 0.20).Conclusions: Acetabular component overhang is more severe when the pelvis tilts posteriorly. Moreover, posterior pelvic tilt, the presence of dysplasia, and higher native acetabular anteversion were independently associated with an increased risk of component overhang. When 20° of posterior tilt was adjusted, the risk of severe overhang was especially increased.Clinical Relevance: Based on these results, surgeons can attempt to prevent severe overhang in patients with posterior pelvic tilt by increasing component anteversion and abduction; when component anteversion is increased by 8° and abduction is increased by 2° from the target angle of 15° of anteversion and 40° of abduction in patients with posterior tilt of 20°, the risk of severe overhang is reduced to by approximately one-twentieth. However, it is still unclear how much the degree of component anteversion should be increased when surgeons attempt to prevent anterior prosthetic dislocation at the same time. Future studies such as prospective clinical trials evaluating both prosthetic dislocation and iliopsoas impingement in patients with posterior tilt might clarify this issue. [ABSTRACT FROM AUTHOR]

Objectives: Although both sarcopenia and hip disease decrease physical function, few studies have investigated the association. We investigated the prevalence of sarcopenia in patients awaiting total hip arthroplasty for osteoarthritis and examined the impact of sarcopenia on pre- and postoperative outcomes., Methods: This prospective study included 96 females. Participants were classified using two criteria. Cases defined as having sarcopenia by the Asian Working Group for Sarcopenia (AWGS) criteria were categorized as the AWGS-sarcopenia (A-S) group, and others were categorized as the AWGS-non-sarcopenia (A-NS) group. Those classified by hand grip strength (HGS) constituted the lower-HGS (L-H) and normal-HGS (N-H) groups. Patient demographics, physical function, and Japanese Orthopaedic Association (JOA) score were compared between each group., Results: The prevalence of the AWGS sarcopenia was 33.3%. In the pre- and postoperative analyses, the L-H group had significantly poorer physical function and JOA score than the N-H group. Postoperatively, the A-S group only demonstrated poorer HGS., Conclusion: Preoperative physical function and JOA score was significantly poorer in the L-H group; physical function was significantly poorer even postoperatively. A HGS test is useful for detecting a decline in the pre- and postoperative physical function in females with hip osteoarthritis., (© 2021 Japan College of Rheumatology.)