Inferior Radiographic and Functional Outcomes With Modular Stem in Metal-on-Metal Total Hip Arthroplasty

Background

Data on the association between stem type and metal-on-metal (MoM) total hip arthroplasty (THA) performance are limited. The aim of this study is to investigate the effect of stem type on the prevalence of osteolysis and radiolucency, blood metal ion levels, and functional outcomes in patients with Articular Surface Replacement THA (ASR XL), a type of MoM THA.

Infrared spectroscopy indicates altered bone turnover and remodeling activity in renal osteodystrophy

Renal osteodystrophy alters metabolic activity and remodeling rate of bone and also may lead to different bone composition. The objective of this study was to characterize the composition of bone in high‐turnover renal osteodystrophy patients by means of Fourier transform infrared spectroscopic imaging (FTIRI). Iliac crest biopsies from healthy bone (n = 11) and patients with renal osteodystrophy (ROD, n = 11) were used in this study. The ROD samples were from patients with hyperparathyroid disease. By using FTIRI, phosphate‐to‐amide I ratio (mineral‐to‐matrix ratio), carbonate‐to‐phosphate ratio, and carbonate‐to‐amide I ratio (turnover rate/remodeling activity), as well as the collagen cross‐link ratio (collagen maturity), were quantified. Histomorphometric analyses were conducted for comparison. The ROD samples showed significantly lower carbonate‐to‐phosphate (p < .01) and carbonate‐to‐amide I (p < .001) ratios. The spatial variation across the trabeculae highlighted a significantly lower degree of mineralization (p < .05) at the edges of the trabeculae in the ROD samples than in normal bone. Statistically significant linear correlations were found between histomorphometric parameters related to bone‐remodeling activity and number of bone cells and FTIRI‐calculated parameters based on carbonate‐to‐phosphate and carbonate‐to‐amide I ratios. Hence the results suggested that FTIRI parameters related to carbonate may be indicative of turnover and remodeling rate of bone. © 2010 American Society for Bone and Mineral Research     

Challenges related to human papillomavirus (HPV) vaccine uptake in Minnesota: clinician and stakeholder perspectives

Background

Human papillomavirus (HPV) vaccination rates among adolescents are increasing in Minnesota (MN) but remain below the Healthy People 2020 goal of 80% completion of the series. The goal of this study was to identify messaging and interventions impacting HPV vaccine uptake in MN through interviews with clinicians and key stakeholders.

Methods

We conducted semi-structured key participant interviews with providers and stakeholders involved in HPV vaccination efforts in MN between 2018 and 2019. Provider interview questions focused on messaging around the HPV vaccine and clinic-based strategies to impact HPV vaccine uptake. Stakeholder interview questions focused on barriers and facilitators at the organizational or state level, as well as initiatives and collaborations to increase HPV vaccination. Responses to interviews were recorded and transcribed. Thematic content analysis was used to identify themes from interviews.

Results

14 clinicians and 13 stakeholders were interviewed. Identified themes were grouped into 2 major categories that dealt with messaging around the HPV vaccine, direct patient–clinician interactions and external messaging, and a third thematic category involving healthcare system-related factors and interventions. The messaging strategy identified as most useful was promoting the HPV vaccine for cancer prevention. The need for stakeholders to prioritize HPV vaccination uptake was identified as a key factor to increasing HPV vaccination rates. Multiple providers and stakeholders identified misinformation spread through social media as a barrier to HPV vaccine uptake.

Conclusion

Emphasizing the HPV vaccine’s cancer prevention benefits and prioritizing it among healthcare stakeholders were the most consistently cited strategies for promoting HPV vaccine uptake. Methods to combat the negative influence of misinformation about HPV vaccines in social media are an urgent priority.

     

Hedonic responses as predictors of food choice: flexibility and self-prediction

The association between liking and choices of six cheeses was examined. Particular attention was in hedonic flexibility, i.e. the range of liking ratings, within an individual, leading to a choice. Second, the ability of respondents to predict their future liking and choices was studied. Respondents (62 females, 20-64 years) initially tasted and rated the cheeses blind and then chose three cheeses, 150 g piece of each, for home-use during the following week. They also predicted how their ratings of liking and choices would be next time, after a week. They returned to the laboratory to repeat the tasks twice, with one-week intervals, thus a total of nine choices were made. Expectedly, the association between initial liking and frequencies of choice was strong (aggregate level correlation 0.70). Self-prediction of liking was less successful initially (r=0.56) than in the second session (r=0.68). In the first session, three choices were made within 1.3 points (mean) at the upper end of a 7-point scale, while nine choices were made within 2.7 points of initial ratings. Thus, the choices extended towards the initially less-liked cheeses in the second and third session. Although poor at precise prediction of their choices, the respondents fairly accurately knew which cheeses they would not choose. Hence, an important strategy in food choice may be to screen out unacceptable options and then alternate among the acceptable ones.     

Reproducibility and agreement of micro-CT and histomorphometry in human trabecular bone with different metabolic status

The use of micro-computed tomography (micro-CT) to study bone microstructure is continuously increasing. Thus, it is important to ensure that micro-CT can differentiate healthy and pathological bone. This study aimed to determine whether the reproducibility of bone histomorphometry and micro-CT, and agreement between the techniques, vary in bone samples with different metabolic status. Iliac crest biopsies (n = 36) were obtained from healthy subjects (n = 10) and from patients with osteoporosis (OP) (n = 15) or renal osteodystrophy (ROD) (n = 11). Micro-CT and histomorphometry analyses were repeated twice. Results were analyzed in separate groups and after pooling the data. Bone histomorphometry detected generally known differences between the diseases, whereas micro-CT did not detect differences between normal and ROD samples as effectively. Repeated measurements for BV/TV, Tb.Th, Tb.N, and Tb.Sp exhibited linear correlation coefficients (ρ) of 0.87–0.92 [coefficients of variations (CV), 8.3–27.2%] for histomorphometry and of 0.66–0.94 (CV, 4.4–23.4%) for micro-CT. There were no significant differences in reproducibility among samples from different study groups. Correlations between BV/TV (micro-CT) and mineralized bone volume (Md.V/TV, histomorphometry) were weaker than between BV/TV (micro-CT) and BV/TV (histomorphometry). When comparing the techniques, BV/TV, Tb.Th, and Tb.N displayed moderate correlations (ρ = 0.39–0.62, P < 0.05), and the agreement for BV/TV was highest in OP samples. The agreement between the techniques using clinical bone samples was moderate. Especially, micro-CT was less effective than bone histomorphometry in differentiating ROD from normal samples. The reproducibility was not affected by the health status of bone. Histomorphometry is still needed in clinical practice to study the remodeling balance in bone, and the methods are complementary.     

Does cup position differ between trabecular metal and titanium cups? A radiographic propensity score matched study of 300 hips

Background and purpose — The use of trabecular metal cups in primary total hip arthroplasty (THA) is increasing, despite the survival of Continuum cups being slightly inferior compared with other uncemented cups in registries. This difference is mainly explained by a higher rate of dislocation revisions. Cup malpositioning is a risk factor for dislocation and, being made of a highly porous material, Continuum cups might be more difficult to position. We evaluated whether Continuum cups had worse cup positioning compared with other uncemented cups.Patients and methods — Based on power calculation, 150 Continuum cups from 1 center were propensity score matched with 150 other uncemented cups from 4 centers. All patients had an uncemented stem, femoral head size of 32 mm or 36 mm, and BMI between 19 and 35. All operations were done for primary osteoarthrosis through a posterior approach. Patients were matched using age, sex, and BMI. Cup positioning was measured from anteroposterior pelvic radiograph using the Martell Hip Analysis Suite software.Results — There was no clinically relevant difference in mean inclination angle between the study group and the control group (43° [95% CI 41–44] and 43° [CI 42–45], respectively). The study group had a larger mean anteversion angle compared with the control group, 19° (CI 18–20) and 17° (CI 15–18) respectively.Interpretation — Continuum cups had a greater anteversion compared with the other uncemented cups. However, the median anteversion was acceptable in both groups and this difference does not explain the larger dislocation rate in the Continuum cups observed in earlier studies.

Trabecular metal (TM) has become an increasingly popular implant material in both primary and revision total hip arthroplasty (THA) (Laaksonen et al. 2017, 2018). Its highly porous surface provides good initial stability and improves bone ingrowth (Bobyn et al. 1999, Beckmann et al. 2014). Continuum cups (Zimmer Biomet, Warsaw, IN, USA) with TM surface have showed higher revision rates than other uncemented cups after primary THA in some register studies mainly due to a higher dislocation rate (Laaksonen et al. 2018, Hemmilä et al. 2019).Dislocation is one of the most common postoperative complications leading to revision surgery (AOANJRR 2017, Finnish Arthroplasty Register [FAR] 2017). Risk for recurrent dislocation and periprosthetic joint infection increases after revision surgery and therefore prevention of the first dislocation is vital (Ezquerra et al. 2017). Potential risk factors for dislocation are posterior approach, small femoral head size, fracture as the indication for surgery, female sex, and suboptimal acetabular cup positioning (Hailer et al. 2012, Zijlstra et al. 2017). Optimal cup positioning to avoid dislocation is traditionally defined by Lewinnek safe zones. According to this definition optimal cup inclination angle is 40° ± 10° and optimal anteversion angle is 15° ± 10° (Lewinnek et al. 1978. Slight modifications to optimize the stability have also been presented (Danoff et al. 2016). In particular, lower anteversion has been associated with increased dislocation rate (Seagrave et al. 2017a). We theorized that the higher dislocation rate for Continuum cups compared with other uncemented cups may be caused by suboptimal cup positioning due to difficulties in optimizing the acetabular cup position with this highly porous material.In this observational multicenter cohort study, we analyzed whether there is a difference in acetabular implant positioning while using Continuum acetabular cups compared with other uncemented acetabular cups in primary total hip arthroplasty.