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Papers by Bart van der Wal

International Journal of Molecular Sciences

Targeted radionuclide therapy (TRT) has been burgeoning worldwide, with several radiopharmaceutic... more Targeted radionuclide therapy (TRT) has been burgeoning worldwide, with several radiopharmaceuticals for the treatment of metastatic cancers being approved for clinical use [...]

Journal of Bone and Joint Infection

Introduction: Debridement, antibiotics and implant retention (DAIR) procedures are effective trea... more Introduction: Debridement, antibiotics and implant retention (DAIR) procedures are effective treatments for acute postoperative or acute hematogenous periprosthetic joint infections. However, literature reporting on the effectiveness of DAIR procedures performed after a one-or two-stage revision because of a prosthetic joint infection (PJI) (PJI-related revision arthroplasty) is scarce. The aim of this study is to retrospectively evaluate the infection control after 1 year of a DAIR procedure in the case of an early postoperative infection either after primary arthroplasty or after PJI-related revision arthroplasty. Materials and methods: All patients treated with a DAIR procedure within 3 months after onset of PJI between 2009 and 2017 were retrospectively included. Data were collected on patient and infection characteristics. All infections were confirmed by applying the Musculoskeletal Infection Society (MSIS) 2014 criteria. The primary outcome was successful control of infection at 1 year after a DAIR procedure, which was defined as the absence of clinical signs, such as pain, swelling, and erythema; radiological signs, such as protheses loosening; or laboratory signs, such as C-reactive protein (CRP) (< 10) with no use of antibiotic therapy. Results: Sixty-seven patients were treated with a DAIR procedure (41 hips and 26 knees). Successful infection control rates of a DAIR procedure after primary arthroplasty (n = 51) and after prior PJI-related revision arthroplasty (n = 16) were 69 % and 56 %, respectively (p = 0.38). The successful infection control rates of a DAIR procedure after an early acute infection (n = 35) and after a hematogenous infection (n = 16) following primary arthroplasty were both 69 % (p = 1.00). Conclusion: In this limited study population, no statistically significant difference is found in infection control after 1 year between DAIR procedures after primary arthroplasty and PJI-related revision arthroplasty.

Medical Imaging 2019: Image Processing, 2019

Purpose: To assess the feasibility of deep learning-based high resolution synthetic CT generation... more Purpose: To assess the feasibility of deep learning-based high resolution synthetic CT generation from MRI scans of the lower arm for orthopedic applications. Methods: A conditional Generative Adversarial Network was trained to synthesize CT images from multi-echo MR images. A training set of MRI and CT scans of 9 ex vivo lower arms was acquired and the CT images were registered to the MRI images. Threefold cross-validation was applied to generate independent results for the entire dataset. The synthetic CT images were quantitatively evaluated with the mean absolute error metric, and Dice similarity and surface to surface distance on cortical bone segmentations. Results: The mean absolute error was 63.5 HU on the overall tissue volume and 144.2 HU on the cortical bone. The mean Dice similarity of the cortical bone segmentations was 0.86. The average surface to surface distance between bone on real and synthetic CT was 0.48 mm. Qualitatively, the synthetic CT images corresponded well with the real CT scans and partially maintained high resolution structures in the trabecular bone. The bone segmentations on synthetic CT images showed some false positives on tendons, but the general shape of the bone was accurately reconstructed. Conclusions: This study demonstrates that high quality synthetic CT can be generated from MRI scans of the lower arm. The good correspondence of the bone segmentations demonstrates that synthetic CT could be competitive with real CT in applications that depend on such segmentations, such as planning of orthopedic surgery and 3D printing.

Journal of Bone and Joint Infection, 2021

Introduction: Two-stage revision surgery is the most frequently performed procedure in patients w... more Introduction: Two-stage revision surgery is the most frequently performed procedure in patients with a chronic periprosthetic joint infection (PJI). The infection eradication rates in the current literature differ between 54 % and 100 %, which could be attributed to different treatment strategies. The aim of this study was to retrospectively evaluate the infection eradication rate in patients with chronic PJI treated with two-stage revision surgery of the hip or knee in primary and re-revision cases. Methods: All patients treated with a two-stage revision for chronic PJI between 2005 and 2011 were analysed. Patient and infection characteristics were retrieved. Primary outcome was successful infection eradication at last follow-up. Successful eradication is specified as no need for subsequent revision surgery or suppressive antibiotic treatment. Results: Forty-seven patients were treated with a two-stage revision. Infection eradication was achieved in 36 out of 47 cases. Thirty-eight patients had positive cultures: 35 monomicrobial infections and 3 polymicrobial infections. Nine cases of culture-negative infections were identified. Accompanying eradication rates were 26 out of 35 cases, 2 out of 3 cases, and 8 out of 9 cases respectively. Mean follow-up was 128 (27-186) months. For hip and knee revisions the eradication rates were 22 out of 31 cases and 14 out of 16 cases respectively. After primary arthroplasty the infection was eradicated in 29 out of 38 cases and after re-revision in 7 out of 9 cases. Conclusion: In this study, the infection eradication rate for two-stage revision surgery after PJI of the hip and knee in primary and re-revision cases was 77 %. No statistically significant patient, infection and microorganism characteristics were found which influence the infection eradication rates at long-term follow-up of 128 (27-186) months.

Orthopaedics & Traumatology: Surgery & Research, 2020

Background: Dislocation is one of the leading causes for early revision surgery after total hip a... more Background: Dislocation is one of the leading causes for early revision surgery after total hip arthroplasty (THA). To address this problem, the dual mobility (DM) cup was developed in the 1970s by the French. Despite the increased and, in some countries, broad use of DM cups, high quality evidence of their effectiveness compared to traditional unipolar (UP) cups is lacking. There are a few well-conducted literature reviews, but the level of evidence of the included studies was moderate to low and the rates of revision were not specifically investigated. Therefore, we did a systematic review to investigate whether there is a difference in the rate of dislocations and revisions after primary THA with a DM cup or a UP cup. Methods: We conducted a systematic literature search in PubMed, Embase and Cochrane databases in July 2019. The articles were selected based upon their quality, relevance and measurement of the predictive factor. We used the MINORS criteria to determine the methodological quality of all studies. Results: The initial search resulted in 702 citations. After application of the inclusion and exclusion criteria, eight articles met our eligibility criteria and were graded. Included studies were of medium to low methodological quality with a mean score of 14/24 (11-16) points following the MINORS criteria. In the case-control studies, a total of 549 DM cups and 649 UP cups were included. In the registry studies, a total of 5.935 DM cups and 217.362 UP cups were included. In the case-control studies, one (0.2%) dislocation was reported for the DM cups and 46 (7.1%) for the UP cup (p = 0.009, IQR = 0.00-7.00). Nine (1.6%) revisions, of which zero due to dislocation, were reported for the DM cup and 39 (6.0%), of which 30 due to dislocation, for the UP cup (p = 0.046, CI = −16.93-5.73). In the registry studies 161 (2.7%) revisions were reported for the DM cup, of which 14 (8.7%) due to dislocation. For the UP cup, 3.332 (1.5%) revisions were reported (p = 0.275, IQR = 41.00-866.25), of which 1.093 (32.8%) due to dislocation (p = 0.050, IQR = 3.50-293.25). Conclusion: This review suggests lower rates of dislocation and lower rates of revision for dislocation in favor of the DM cups. Concluding, DM cups might be an effective solution to reduce dislocation in primary THA. To evaluate the efficacy of DM cups compared to UP cups, an economic evaluation alongside a randomized controlled trial is needed focusing on patient important endpoints. Level of evidence: III, systematic review of level III studies.

Revue de Chirurgie Orthopédique et Traumatologique, 2020

Abstract Background Dislocation is one of the leading causes for early revision surgery after tot... more Abstract Background Dislocation is one of the leading causes for early revision surgery after total hip arthroplasty (THA). To address this problem, the dual mobility (DM) cup was developed in the 1970's by the French. Despite the increased and, in some countries, broad use of DM cups, high quality evidence of their effectiveness compared to traditional unipolar (UP) cups is lacking. There are a few well conducted literature reviews, but the level of evidence of the included studies was moderate to low and the rate of revision was not specifically investigated. Therefore, we did a systematic review to investigate whether there is a difference in the rate of dislocations and revisions after primary total hip arthroplasty THA with a DM cup or a UP cup. Methods We conducted a systematic literature search in PubMed, Embase and Cochrane databases in July 2019. The articles were selected based upon their quality, relevance and measurement of the predictive factor. We used the MINORS criteria to determine the methodological quality of all studies. Results The initial search resulted in 702 citations. After application of the inclusion and exclusion criteria, eight articles met our eligibility criteria and were graded. Included studies were of medium to low methodological quality with a mean score of 14/24 (11–16) points following the MINORS criteria. In the case-control studies, a total of 549 DM cups and 649 UP cups were included. In the registry studies, a total of 5935 DM cups and 217.362 UP cups were included. In the case-control studies, 1 (0.2%) dislocation was reported for the DM cups and 46 (7.1%) for the UP cup (p = 0.009, IQR = 0.00–7.00). Nine (1.6%) revisions, of which 0 due to dislocation, were reported for the DM cup and 39 (6.0%), of which 30 due to dislocation, for the UP cup (p = 0.046, CI = − 16.93–5.73). In the registry studies, 161 (2.7%) revisions were reported for the DM cup, of which 14 (8.7%) due to dislocation. For the UP cup, 3332 (1.5%) revisions were reported (p = 0.275, IQR = 41.00–866.25), of which 1093 (32.8%) due to dislocation (p = 0.050, IQR = 3.50–293.25). Conclusion This review suggests lower rates of dislocation and revision for dislocation in favor of the DM cups. DM cups might be an effective solution to reduce dislocation in primary THA. To evaluate the efficacy of DM cups compared to UP cups, an economic evaluation alongside a randomized controlled trial is needed focusing on patient important endpoints. Level of evidence III, systematic review of level III studies. Prospero registry number CRD42018091921.

Implant-associated Staphylococcus aureus infections are difficult to treat because of biofilm for... more Implant-associated Staphylococcus aureus infections are difficult to treat because of biofilm formation. Bacteria in a biofilm are often insensitive to antibiotics and host immunity. Monoclonal antibodies (mAbs) could provide an alternative approach to improve the diagnosis and/or treatment of biofilm-related infections. Here we show that mAbs targeting common surface components of S. aureus can recognize clinically relevant biofilm types. We identify two groups of antibodies: one group that uniquely binds S. aureus in biofilm state and one that recognizes S. aureus in both biofilm and planktonic state. In a mouse model, we show that mAb 4497 (recognizing wall teichoic acid (WTA)) specifically localizes to biofilm-infected implants. In conclusion, we demonstrate the capacity of several human mAbs to detect S. aureus biofilms in vitro and in vivo. This is an important first step to develop mAbs for imaging or treating S. aureus biofilms.

PLOS ONE, 2020

Background Implant associated infections such as periprosthetic joint infections are difficult to... more Background Implant associated infections such as periprosthetic joint infections are difficult to treat as the bacteria form a biofilm on the prosthetic material. This biofilm complicates surgical and antibiotic treatment. With rising antibiotic resistance, alternative treatment options are needed to treat these infections in the future. The aim of this article is to provide proof-ofprinciple data required for further development of radioimmunotherapy for non-invasive treatment of implant associated infections. Methods Planktonic cells and biofilms of Methicillin-resistant staphylococcus aureus are grown and treated with radioimmunotherapy. The monoclonal antibodies used, target wall teichoic acids that are cell and biofilm specific. Three different radionuclides in different doses were used. Viability and metabolic activity of the bacterial cells and biofilms were measured by CFU dilution and XTT reduction. Results Alpha-RIT with Bismuth-213 showed significant and dose dependent killing in both planktonic MRSA and biofilm. When planktonic bacteria were treated with 370 kBq of 213 Bi-RIT 99% of the bacteria were killed. Complete killing of the bacteria in the biofilm was seen at 185 kBq. Beta-RIT with Lutetium-177 and Actinium-225 showed little to no significant killing. Conclusion Our results demonstrate the ability of specific antibodies loaded with an alpha-emitter Bismuth-213 to selectively kill staphylococcus aureus cells in vitro in both planktonic and biofilm

Journal of Bone and Joint Infection, 2020

Background: Diagnosis of periprosthetic joint infection (PJI) can be troublesome. Sonication can ... more Background: Diagnosis of periprosthetic joint infection (PJI) can be troublesome. Sonication can be a helpful tool in culturing bacteria that are difficult to detect with standard tissue cultures. Aim of this study is to evaluate the clinical importance of our standardized sonication protocol in detecting periprosthetic joint infection. Materials and methods: All patients with revision surgery of a hip or knee prosthesis between 2011 and 2016 were retrospectively reviewed and divided in two groups: clinically suspected of infection or not suspected of infection. For both tissue culture and implant sonication, calculations of sensitivity and specificity were performed. Clinical relevance of sonication was evaluated by calculating in which percentage of patients' sonication influenced clinical treatment. Results: 226 patients with revision of a total hip prosthesis (122 patients) or a total knee prosthesis (104 patients) were included. Sensitivity of perioperatively taken tissue cultures was 94.3% and specificity was 99.3%. For sonication sensitivity was 80.5% and specificity was 97.8%. In the infection group eight patients (9%) with only one positive tissue culture and a positive sonication fluid culture with the same pathogen were found. Interpretation: Although sensitivity and specificity of sonication was lower compared to tissue cultures, periprosthetic joint infection could only be established in 8 patients (9%) suspected of infection because of a positive result of the sonication fluid culture. Sonication leads to clinically relevant changes in treatment and seems therefore to be a helpful diagnostic tool in clinical practice.

Journal of Orthopaedic Research, 2019

ABSTRACTThe clinical impact of bacterial infections on bone regeneration has been incompletely qu... more ABSTRACTThe clinical impact of bacterial infections on bone regeneration has been incompletely quantified and documented. As a result, controversy exists about the optimal treatment strategy to maximize healing of a contaminated defect. Animal models are extremely useful in this respect, as they can elucidate how a bacterial burden influences quantitative healing of various types of defects relative to non‐infected controls. Moreover, they may demonstrate how antibacterial treatment and/or bone grafting techniques facilitate the osteogenic response in the harsh environment of a bacterial infection. Finally, it a well‐known contradiction that osteomyelitis is characterized by uncontrolled bone remodeling and bone loss, but at the same time, it can be associated with excessive new bone apposition. Animal studies can provide a better understanding of how osteolytic and osteogenic responses are related to each other during infection. This review discusses the in vivo impact of bacterial...

Journal of Bone and Joint Surgery, 2019

Background: Anterior glenohumeral instability with >20% glenoid bone loss is a disorder that c... more Background: Anterior glenohumeral instability with >20% glenoid bone loss is a disorder that can be treated with the Latarjet stabilizing procedure; however, complications are common. The purposes of this study were to (1) evaluate the effect of an anatomic-specific titanium implant produced by 3-dimensional (3D) printing as a treatment option for recurrent shoulder instability with substantial glenoid bone loss and (2) compare the use of that implant with the Latarjet procedure. Methods: Ten fresh-frozen cadaveric shoulders (mean age at the time of death, 78 years) were tested in a biomechanical setup with the humerus in 30° of abduction and in neutral rotation. The shoulders were tested under 5 different conditions: (1) normal situation, (2) creation of an anterior glenoid defect, (3) implantation of an anatomic-specific titanium implant produced by 3D printing, and the Latarjet procedure (4) with and (5) without 10 N of load attached to the conjoined tendon. In each condition,...

Clinical Orthopaedics & Related Research, 2017

Background The aseptic lymphocyte vasculitis-associated lesion (ALVAL) score and the modified Oxf... more Background The aseptic lymphocyte vasculitis-associated lesion (ALVAL) score and the modified Oxford ALVAL score are frequently used scoring methods to evaluate the morphologic features of periprosthetic tissues around metal-on-metal (MoM) hip implants. Except for the initial studies of these two morphology scoring methods, to our knowledge, no other studies have reported on intraclass correlation coefficient (ICC) values for interobserver reliability of these scoring methods. Questions/purposes Are the ALVAL and Oxford ALVAL scores reproducible? Methods The periprosthetic tissue of 37 revisions of 36 patients with failed MoM THAs were independently scored by three experienced pathologists using ALVAL and Oxford ALVAL scoring methods. All patients were included who underwent revision surgery in our hospital until January 2013, with a large-head MoM prosthesis and also met the criteria: blood serum cobalt levels, available MRI scan, and intraarticular cobalt levels. The population included 26 patients with pseudotumors diagnosed by two radiologists using the method described by Matthies et al. The ALVAL describes morphologic features of the synovial lining, tissue organization, and inflammatory cell infiltrate in periprosthetic tissues. The Oxford-ALVAL score uses a semiquantitative measure of the immune response which should be easier to score. Results The ALVAL score showed an ICC of 0.38 (95% CI, 0.18-0.58) (fair) for the sum score and this improved up to 0.50 (95% CI, 0.31-0.68) (moderate) using the modified Oxford ALVAL score. The individual parameters of the ALVAL score showed an ICC for the scoring of Each author certifies that he or she, or a member of his or her immediate family, has no funding or commercial associations (eg, consultancies, stock ownership, equity interest, patent/licensing arrangements, etc) that might pose a conflict of interest in connection with the submitted article. All ICMJE Conflict of Interest Forms for authors and Clinical Orthopaedics and Related Research 1 editors and board members are on file with the publication and can be viewed on request. Clinical Orthopaedics and Related Research 1 neither advocates nor endorses the use of any treatment, drug, or device. Readers are encouraged to always seek additional information, including FDAapproval status, of any drug or device prior to clinical use. The scientific committee of the Leiden University Medical Centre and the ethical committee in the Meander Medical Centre waived approval for the human protocol for this investigation, and each author certifies that all investigations were conducted in conformity with ethical principles of research.

Hip International, 2006

Proximal bone resorption and an increased fracture rate in the ABG-I stem has been shown. For the... more Proximal bone resorption and an increased fracture rate in the ABG-I stem has been shown. For these reasons the ABG-I stem design was changed to the ABG-II. In this study periprosthetic bone loss around the ABG-I vs ABG-II is compared to verify if the design changes resulted in improved proximal bone preservation. Methods: 51 patients were randomised to either the ABG-I or ABG-II hip prosthesis. Periprosthetic BMD change at various time points was measured using DEXA. Between the two groups (age, gender, weight etc.) no statistical difference was encountered. Compared to the baseline at two years the ABG-II preserved bone better proximally (e.g. zone 7: ABG-II:-3.7%, ABG-I:-11.9%, p=0.05) than the ABG-I. Distally, the trend was opposite and less bone loss was measured for the ABG-I than the ABG-II in zones 3, 4 and 5 (n.s.). Conclusion: this study confirms the philosophy behind the design changes from the ABG-I to ABG-II stem where increased elasticity, more proximal HA-coating, a shorter and distally polished stem, were meant to reduce proximal bone resorption. In future this may lead to fewer periprosthetic fractures and to less complicated revision surgery.

International orthopaedics, 2015

Recently, concerns have arisen about metal-on-metal (MoM) total hip arthroplasty (THA). Therefore... more Recently, concerns have arisen about metal-on-metal (MoM) total hip arthroplasty (THA). Therefore, the purpose of this cross-sectional cohort study was to describe the incidence of pain, pseudotumours, revisions and the relation between elevated metal ion levels, functional outcome and quality of life after MoM THA. In 351 patients, 377 MoM THA with a fixed-size 38-mm head were evaluated with a mean follow-up of 30 months (range 11-58). Evaluation included pain, serum metal ions, patient-reported questionnaires (Short Form-36 [SF-36], Hip disability and Osteoarthritis Outcome Score [HOOS] and the Oxford Hip Score [OHS]) and radiological imaging. Sixteen patients did not participate in the screening. One hundred and eighteen (35 %) patients reported pain and showed significantly higher cobalt and chromium levels compared to patients without pain. Median serum cobalt levels were 4.4 μg/l (interquartile range [IQR] 6.6) and chromium levels were 3.6 μg/l (IQR 4.8). Patients with cobalt ...

Virchows Archiv, 2000

Nesidioblastosis is rare in adults and accounts for 0.5-5% of cases of organic hyperinsulinemia. ... more Nesidioblastosis is rare in adults and accounts for 0.5-5% of cases of organic hyperinsulinemia. The diagnosis of nesidioblastosis should be considered when peroperative imaging modalities fail to localize a lesion in patients with hyperinsulinism. Two female patients, aged 55 and 16 years, with hyperinsulinemic hypoglycemia are reported. Somatostatin receptor scintigraphy showed slight focal activity in both patients. The first patient underwent a Whipple procedure and became diabetic. The second patient underwent a distal hemi-pancreatectomy and suffered from recurrent hypoglycemic episodes 3 months after surgery, for which she is presently being treated with octreotide. Histological examination of the resected pancreata revealed focally increased islet tissue and a number of slightly hypertrophic beta cells. Such histological abnormalities have been related to functional changes of β-cells. In infantile nesidioblastosis, a proportion of cases has been associated with mutations in one of several genes. Whether such mutations, leading to hyperinsulinism, also play a role in adult nesidioblastosis is presently unknown.

International Orthopaedics, 2006

Recently it was shown that the design changes from the ABG-I to ABG-II hip stem resulted in a bet... more Recently it was shown that the design changes from the ABG-I to ABG-II hip stem resulted in a better, although not significant, proximal bone preservation. Our hypothesis was that by matching patients for preoperative bone quality, statistical power would increase and that the trend of better proximal bone preservation in ABG-II might become significant. Twenty-four ABG-II patients were compared to two different ABG-I groups: (1) 25 patients from our earlier prospective study and (2) a group of 24 patients selected to perfectly match the ABG-II group regarding gender, age and preoperative bone quality. Postoperative changes in periprosthetic bone mineral density (BMD) were quantified at 2 years postoperatively using DEXA scanning. Bone preservation (less BMD loss) was better for the ABG-II than the ABG-I (all two groups) in the proximal zones 1 and 7. In Gruen zone 7, a statistically significant difference was found for group B (p=0.03). By matching patients for preoperative bone quality and gender, a statistical significant difference was found in proximal bone preservation in favour of ABG-II. In future comparative bone remodelling studies using DEXA, patients should be matched for preoperative bone quality and gender. Résumé Il a été démontré, récemment, que le changement de la pièce fémorale entre l'ABG-1 et l'ABG-2 entraînait une amélioration de la préservation du stock osseux mais ceci n'était pas significatif. En étudiant une série de patients, nous avons souhaité démontrer l'inverse. 24 patients avec une prothèse ABG-2 ont été comparés à différents groupes de patients avec une prothèse ABG-1: (1) 25 patients de notre étude prospective et (2) un groupe de 24 patients sélectionnés, avec une série parfaitement cohérente en termes de sexe, d'âge et de qualité osseuse préopératoire. Les modifications de la densité minérale osseuse (BMD) ont été mesurées à deux ans post opératoires en utilisant la technique DEXA. La préservation du capital osseux est meilleure dans l'ABG-2 que dans l'ABG-1 (y compris dans les deux groupes) au niveau de la partie proximale en zones 1 et 7. Dans la zone 7 de Gruen une différence significative a été trouvée pour le groupe B (p=0.03). Cette étude montre qu'avec une bonne sélection de patients on peut mettre en évidence que la conservation osseuse est meilleure pour l'ABG-2. Dans une étude ultérieure, nous essayerons d'évaluer, selon la technique DEXA le capital osseux en sélectionnant des patients en préopératoire selon la qualité de l'os et le sexe.

International Journal of Cancer, 1997

This study used a co-culture system with Transwell tissue-culture inserts to investigate the role... more This study used a co-culture system with Transwell tissue-culture inserts to investigate the role of primary cultures of rat peritoneal mesothelial cells on the proliferation of rat colon-carcinoma cells (CC531 cells). Mesothelial cells significantly inhibited the growth of CC531 cells, while, conversely, CC531 cells stimulated the growth of mesothelial cells. Receptor-binding studies demonstrated the presence of high-affinity IGF-I receptors on the mesothelial and CC531 cells. Both cell types also produced IGF-I, as measured by radioimmunoassay. IGF-I stimulated DNA synthesis in mesothelial cells, but had no effect on the growth of CC531 cells. In co-culture, it was found that IGF-I potentiated the inhibitory effect of mesothelial cells on CC531 cells. The effect of IGF-I on mesothelial-cell proliferation was additive to the stimulatory effect of CC531 cells. TGF-beta had no effect on the growth of the CC531 cells, suggesting that this growth (-inhibitory) factor is not involved in the inhibitory effect of mesothelial cells on CC531 cell growth. The study provides evidence for the existence of a paracrine loop between mesothelial and colon-carcinoma cells, giving more insight into the basic cellular mechanisms that may modulate the growth of intraperitoneal colon carcinoma. Inhibition of CC531-cell proliferation by rat mesothelial cells might explain the earlier finding that tumour cells grow poorly in a surgically uncompromised abdomen.

Archives of Orthopaedic and Trauma Surgery, 2007

In a consecutive series of 64 patients with an ABG-II stem, we analyzed whether the tightness of ... more In a consecutive series of 64 patients with an ABG-II stem, we analyzed whether the tightness of the fit of the prosthesis affected bone remodeling and if there was a relation between clinical and radiological results. Radiographic analysis of bone remodeling in different Gruen zones was done. Bone density changes were graded as present or absent in the AP and lateral radiographs as compared with the previous sets of radiographs. Bone remodeling was compared to literature values of the ABG-I stem. Three stem levels were defined. The proximal level was set at the upper border of the lesser trochanter, the mid-stem level at halfway the stem and the distal level 1 cm above the tip of the prosthesis. Femoral fit was defined as tight when the ratio of the fit was &amp;gt;/=0.8 and as non-tight if the fit was &amp;lt;0.8. The incidence of thigh pain was scored using the Merle d&amp;#39;Aubigne (MdA) hip score. Proximal bone resorption in Gruen zone 1 was 26.6% and in zone 7, 34.4% compared to 48 and 45% for the ABG-I stem after 5 years. No correlation was found between femoral fit and radiological changes. Proximal and distal fit was significantly lower for patients with thigh pain than without thigh pain. Patients with a non-tight proximal fit produced significantly more varus (17/30 = 56.7%) than patients with a tight proximal fit (2/34 = 5.9%; P &amp;lt; 0.01). Femoral fit in ABG-II does not predict certain radiological changes, but less proximal bone resorption confirms the design changes from ABG-I to ABG-II. A non-tight proximal fit is correlated with varus position of the stem. Thigh pain is correlated with a poor fit and fill of the femoral stem.

Acta orthopaedica Belgica, 2005

As a result of the rising threats of terrorism, airport security has become a major issue. Patien... more As a result of the rising threats of terrorism, airport security has become a major issue. Patients with orthopaedic implants are concerned that they may activate alarms at airport security gates. A literature overview showed that the activation rate of the alarm by hand-held detectors is higher than for arch detectors (100% versus 56%). Arch detection rate has significantly increased from 0% before 1995 up to 83.3% after 1994. Reported factors which influence detection rates are implant mass, implant combinations, implant volume, transfer speed, side of implant, detector model, sensitivity settings, material and tissue masking. Detection rate has been improved by more sensitive devices and improved filter software. Doctors should be able to objectively inform patients. A form is presented which will easily inform the airport security staff.