Search

Abstract Background Peripheral arterial disease (PAD) is common in older people. An ankle-brachial index (ABI) < 0.9 can be used as an indicator of PAD. Patients with low ABI have increased mortality and a higher risk of serious cardiovascular morbidity. However, because 80% of the patients are asymptomatic, PAD remains unrecognised in a large group of patients. The aims of this study were 1) to examine the prevalence of reduced ABI in subjects aged 80 and over, 2) to determine the diagnostic accuracy of the medical history and clinical examination for reduced ABI and 3) to investigate the difference in functioning and physical activity between patients with and without reduced ABI. Methods A cross-sectional study embedded within the BELFRAIL study. A general practitioner (GP) centre, located in Hoeilaart, Belgium, recruited 239 patients aged 80 or older. Only three criteria for exclusion were used: urgent medical need, palliative situation and known serious dementia. The GP recorded the medical history and performed a clinical examination. The clinical research assistant performed an extensive examination including Mini-Mental State Examination (MMSE), Geriatric Depression Scale (GDS-15), Activities of Daily Living (ADL), Tinetti test and the LASA Physical Activity Questionnaire (LAPAQ). ABI was measured using an automatic oscillometric appliance. Results In 40% of patients, a reduced ABI was found. Cardiovascular risk factors were unable to identify patients with low ABI. A negative correlation was found between the number of cardiovascular morbidities and ABI. Cardiovascular morbidity had a sensitivity of 65.7% (95% CI 53.4-76.7) and a specificity of 48.6% (95% CI 38.7-58.5). Palpation of the peripheral arteries showed the highest negative predictive value (77.7% (95% CI 71.8-82.9)). The LAPAQ score was significantly lower in the group with reduced ABI. Conclusion The prevalence of PAD is very high in patients aged 80 and over in general practice. The clinical examination, cardiovascular risk factors and the presence of cardiovascular morbidity were not able to identify patients with a low ABI. A screening strategy for PAD by determining ABI could be considered if effective interventions for those aged 80 and over with a low ABI become available through future research.

Study Design: Multicentre comparative analysis of explanted Spine Magnetically Controlled Growing Rods (MCGRs)., Objectives: MAGEC X, the latest commercially available generation, was recalled in 2020 due to the risk of post-implantation separation of an actuator end-cap component. Currently, the supply of all MAGEC rods was temporarily suspended in the UK and the EU. Objective of this study is to compare the performance of the MAGEC X MCGR to the earlier MAGEC 1.3 design iteration, by means of retrieval analysis., Methods: Fifteen of both MAGEC X and MAGEC 1.3 rods were consecutively collected from five different hospitals following removal surgery and matched by time to removal. Clinical and implant data was collected for all MCGRs. Analysis comprised visual assessments of external damage, plain radiograph evaluations, force and elongation testing, MAGEC X end-cap torque testing and disassembly. Mann-Whitney U tests were used to statistically compare groups., Results: Rod distraction reached in vivo was significantly higher in the MAGEC 1.3 ( P = .002). There was no statistically significant difference in the total external damage score ( P = .870), maximum force produced ( P = .695) or distraction reached during force test ( P = .880). No pin fracture was detected. Elongation of stroke was mildly higher ( P = .051) for the MAGEC X implants. One MAGEC X had evident end cap component loosening. Internal damage scores were mildly lower in the MAGEC X group., Conclusion: MAGEC X showed similar performance results than the previous design iteration MAGEC 1.3. End-cap component loosening was observed, with no major consequences on the internal mechanism., Competing Interests: Declaration of Conflicting InterestsThe author(s) declared the following potential conflicts of interest with respect to the research, authorship, and/or publication of this article: Authors HH and AH receive institutional support from NuVasive to independently collect and analyse retrieved MAGEC rods. Authors MS, ST and EB use MAGEC rods in their clinical practice.

The assessment of three-dimensional bony defects is important to inform the surgical planning of hip reconstruction. Mirroring of the contralateral side has been previously used to measure the hip center of rotation (CoR). However, the contralateral side may not be useful when diseased or replaced. Statistical Shape Models (SSMs) can aid reconstruction of patient anatomy. Previous studies have been limited to computational models only or small patient cohorts. We used SSM as a tool to help derive landmarks that are often absent in hip joints of patients with large acetabular defects. Our aim was to compare the reconstructed pelvis with patients who have previously undergone hip revision. This retrospective cohort study involved 38 patients with Paprosky type IIIB defects. An SSM was built on 50 healthy pelvises and used to virtually reconstruct the native pelvic morphology for all cases. The outcome measures were the difference in CoR for (1) SSM versus diseased hip, (2) SSM versus plan, and (3) SSM versus contralateral healthy hip. The median differences in CoR were 31.17 mm (interquartile range [IQR]: 43.80-19.87 mm), 8.53 mm (IQR: 12.76-5.74 mm), and 7.84 mm (IQR: 10.13-5.13 mm), respectively. No statistical difference (p > 0.05) was found between the SSM versus plan and the SSM versus contralateral CoRs. Our findings show that the SSM model can be used to reconstruct the absent bony landmarks of patients with significant lysis regardless of the defect severity, hence aiding the surgical planning of hip reconstruction and implant design., (© 2023 The Authors. Journal of Orthopaedic Research® published by Wiley Periodicals LLC on behalf of Orthopaedic Research Society.)

Three-dimensional (3D) printing is used to manufacture custom acetabular cups to treat patients with massive acetabular defects. There is a risk of defects occurring in these, often in the form of structural voids. Our aim was to investigate the presence of voids in commercially available cups. We examined 12, final-production titanium custom acetabular cups, that had been 3D-printed by six manufacturers. We measured their mass, then performed micro-computed tomography (micro-CT) imaging to determine their volume and density. The micro-CT data were examined for the presence of voids. In cups that had voids, we computed (1) the number of voids, (2) their volume and the cup volume fraction, (3) their sphericity, (4) size, and (5) their location. The cups had median mass, volume, and density of 208.5 g, 46,471 mm 3 , and 4.42 g/cm 3 , respectively. Five cups were found to contain a median (range) of 90 (58-101) structural voids. The median void volume and cup volume fractions of cups with voids were 5.17 (1.05-17.33) mm 3 and 99.983 (99.972-99.998)%, respectively. The median void sphericity and size were 0.47 (0.19-0.65) and 0.64 (0.27-8.82) mm, respectively. Voids were predominantly located adjacent to screw holes, within flanges, and at the transition between design features; these were between 0.17 and 4.66 mm from the cup surfaces. This is the first study to examine defects within final-production 3D-printed custom cups, providing data for regulators, surgeons, and manufacturers about the variability in final print quality. The size, shape, and location of these voids are such that there may be an increased risk of crack initiation from them., (© 2022 The Authors. Journal of Orthopaedic Research® published by Wiley Periodicals LLC on behalf of Orthopaedic Research Society.)

Background: The mechanisms of fracture in magnetically controlled growing rods (MCGRs) and the risk factors associated with this are poorly understood. This retrospective analysis of explanted MCGRs aimed to add understanding to this subject., Methods: From our cohort of over 120 retrieved MCGRs, we identified 7 rods that had fractured; all were single-rod constructs, retrieved from 6 patients. These were examined and compared with 15 intact single-rod constructs. Retrieval and fractographic analyses were used to determine the failure mode at the fracture site and the implant's functionality. Cobb angle, degree of rod contouring, and the distance between anchoring points were computed on anteroposterior and lateral radiographs., Results: 5/7 versus 3/15 rods had been inserted after the removal of a previously inserted rod, in the fractured versus control groups. All fractured rods failed due to bending fatigue. Fractured rods had greater rod contouring angles in the frontal plane ( P = 0.0407) and lateral plane ( P = 0.0306), and greater distances between anchoring points in both anteroposterior and lateral planes ( P = 0.0061 and P = 0.0074, respectively)., Conclusions: We found all failed due to a fatigue fracture and were virtually all single rod configurations. Fracture initiation points corresponded with mechanical indentation marks induced by the intraoperative rod contouring tool. Fractured rods had undergone greater rod contouring and had greater distances between anchoring points, suggesting that it is preferable to implant double rod constructs in patients with sufficient spinal maturity to avoid this complication., Clinical Relevance: Level III., Competing Interests: H.H. and A.H. receive institutional support from NuVasive to independently collect and analyze retrieved MAGEC rods. The remaining authors declare no conflicts of interest., (Copyright © 2023 The Author(s). Published by Wolters Kluwer Health, Inc.)

Edge-wear in acetabular cups is known to be correlated with greater volumes of material loss; the location of this wear pattern in vivo is less understood. Statistical shape modelling (SSM) may provide further insight into this. This study aimed to identify the most common locations of wear in vivo, by combining CT imaging, retrieval analysis and SMM. Shape variance was described in 20 retrieved metal-on-metal acetabular surfaces. These were revised after a mean of 90 months, from 13 female and seven male patients. They were positioned with a mean inclination and anteversion of 53° and 30°, respectively. Their orientation, in vivo, was established using their stabilising fins, visible in pre-revision CT imaging. The impact of wear volume, positioning, time, gender and size on the in vivo location of wear was investigated. These surfaces had a mean wear volume of 49.63 mm 3 . The mean acetabular surface displayed superior edge-wear centred 7° within the posterosuperior quadrant, while more of the volumetric wear occurred in the anterosuperior quadrant. Components with higher inclination had greater superior edge-wear scars, while a relationship was observed between greater anteversion angles and more posterosuperior edge-wear. This SSM method can further our understanding of hip implant function, informing future design and may help to refine the safe zone for implant positioning.

Background: 3D printed patient-specific titanium acetabular cups are used to treat patients with massive acetabular defects. These have highly porous surfaces, with the design intent of enhancing bony fixation. Our aim was to characterise these porous structures in commercially available designs., Methods: We obtained 12 final-production, patient-specific 3D printed acetabular cups that had been produced by 6 manufacturers. High resolution micro-CT imaging was used to characterise morphometric features of their porous structures: (1) strut thickness, 2) the depth of the porous layer, (3) pore size and (4) the level of porosity. Additionally, we computed the surface area of each component to quantify how much titanium may be in contact with patient tissue. Statistical comparisons were made between the designs., Results: We found a variability between designs in relation to the thickness of the struts (0.28 to 0.65 mm), how deep the porous layers are (0.57 to 11.51 mm), the pore size (0.74 to 1.87 mm) and the level of porosity (34 to 85%). One manufacturer printed structures with different porosities between the body and flange; another manufacturer had two differing porous regions within the body of the cups. The cups had a median (range) surface area of 756.5 mm 2 (348 - 1724)., Conclusions: There is a wide variability between manufacturers in the porous titanium structures they 3D print. We do not currently know whether there is an optimal porosity and how this variability will impact clinically on the integrity of bony fixation; this will become clearer as post market surveillance data is generated., (© 2022. The Author(s).)

Aims: Acetabular edge-loading was a cause of increased wear rates in metal-on-metal hip arthroplasties, ultimately contributing to their failure. Although such wear patterns have been regularly reported in retrieval analyses, this study aimed to determine their in vivo location and investigate their relationship with acetabular component positioning., Methods: 3D CT imaging was combined with a recently validated method of mapping bearing surface wear in retrieved hip implants. The asymmetrical stabilizing fins of Birmingham hip replacements (BHRs) allowed the co-registration of their acetabular wear maps and their computational models, segmented from CT scans. The in vivo location of edge-wear was measured within a standardized coordinate system, defined using the anterior pelvic plane., Results: Edge-wear was found predominantly along the superior acetabular edge in all cases, while its median location was 8° (interquartile range (IQR) -59° to 25°) within the anterosuperior quadrant. The deepest point of these scars had a median location of 16° (IQR -58° to 26°), which was statistically comparable to their centres (p = 0.496). Edge-wear was in closer proximity to the superior apex of the cups with greater angles of acetabular inclination, while a greater degree of anteversion influenced a more anteriorly centred scar., Conclusion: The anterosuperior location of edge-wear was comparable to the degradation patterns observed in acetabular cartilage, supporting previous findings that hip joint forces are directed anteriorly during a greater portion of walking gait. The further application of this novel method could improve the current definition of optimal and safe acetabular component positioning. Cite this article: Bone Joint Res  2021;10(10):639-649.

Aims: The aim of this study was to present the first retrieval analysis findings of PRECICE STRYDE intermedullary nails removed from patients, providing useful information in the post-market surveillance of these recently introduced devices., Methods: We collected ten nails removed from six patients, together with patient clinical data and plain radiograph imaging. We performed macro- and microscopic analysis of all surfaces and graded the presence of corrosion using validated semiquantitative scoring methods. We determined the elemental composition of surface debris using energy dispersive x-ray spectroscopy (EDS) and used metrology analysis to characterize the surface adjacent to the extendable junctions., Results: All nails were removed at the end of treatment, having achieved their intended lengthening (20 mm to 65 mm) and after regenerate consolidation. All nails had evidence of corrosion localized to the screw holes and the extendable junctions; corrosion was graded as moderate at the junction of one nail and severe at the junctions of five nails. EDS analysis showed surface deposits to be chromium rich. Plain radiographs showed cortical thickening and osteolysis around the junction of six nails, corresponding to the same nails with moderate - severe junction corrosion., Conclusion: We found, in fully united bones, evidence of cortical thickening and osteolysis that appeared to be associated with corrosion at the extendable junction; when corrosion was present, cortical thickening was adjacent to this junction. Further work, with greater numbers of retrievals, is required to fully understand this association between corrosion and bony changes, and the influencing surgeon, implant, and patient factors involved. Cite this article: Bone Jt Open  2021;2(8):599-610.

Aims: The optimum clearance between the bearing surfaces of hip arthroplasties is unknown. Theoretically, to minimize wear, it is understood that clearances must be low enough to maintain optimal contact pressure and fluid film lubrication, while being large enough to allow lubricant recovery and reduce contact patch size. This study aimed to identify the relationship between diametrical clearance and volumetric wear, through the analysis of retrieved components., Methods: A total of 81 metal-on-metal Pinnacle hips paired with 12/14 stems were included in this study. Geometrical analysis was performed on each component, using coordinate and roundness measuring machines. The relationship between their as-manufactured diametrical clearance and volumetric wear was investigated. The Mann-Whitney U test and unpaired t -test were used, in addition to calculating the non-parametric Spearman's correlation coefficient, to statistically evaluate the acquired data., Results: The hips in this study were found to have had a median unworn diametrical clearance of 90.31 μm (interquartile range (IQR) 77.59 to 97.40); 32% (n = 26) were found to have been below the manufacturing tolerance. There was no correlation found between clearance and bearing (r s = -0.0004, p = 0.997) or taper (r s = 0.0048, p = 0.966) wear rates. The wear performance of hips manufactured within and below these specifications was not significantly different (bearing: p = 0.395; taper: p = 0.653). Pinnacles manufactured from 2007 onwards had a greater prevalence of bearing clearance below tolerance (p = 0.004)., Conclusion: The diametrical clearance of Pinnacle hips did not influence their wear performance, even when below the manufacturing tolerance. The optimum clearance for minimizing hip implant wear remains unclear.Cite this article: Bone Joint Res 2020;9(8):515-523., (© 2020 Author(s) et al.)

Background: To assess the relationship between mechanical wear and the failure of the internal lengthening mechanism in retrieved MAGnetic Expansion Control (MAGEC) growing rods., Methods: This study included 34 MAGEC rods retrieved from 20 patients. The state of the internal mechanism and mechanical wear were assessed in all the rods using plain radiographs and visual inspection. Metrology was then performed to assess the topography and mechanical wear of the telescopic bars, using a Talyrond 365 (Taylor Hobson, Leicester, UK) roundness measuring machine., Results: Plain radiographs showed evidence of a broken internal mechanism in 29% of retrieved rods. Single-side wear marks were found in 97% of retrieved rods. Material loss was found to significantly increase in rods with a damaged internal mechanism (p < 0.05) and rods with longer time in situ (r = 0.692, p < 0.05)., Conclusions: We found an association between damage to the internal mechanism of the rods and (1) patterns of single-side longitudinal wear marks and (2) increased material loss. As the material loss was also found to increase over time of rod in situ, we emphasise the importance of early detection and revision of failed MAGEC rods in clinical practice.