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Background: Worldwide, the majority of total hip arthroplasties (THAs) placed in patients Methods: All primary THA placed in patients younger than 55 years, registered in the LROI between 2007 and 2019 were included n = 28,516). Kaplan-Meier survival analyses were used to estimate the survival of primary THA by method of fixation. Additionally, survival of revision procedures that changed or did not change in method of fixation were estimated. McNemar’s test was used to assess differences in the proportion of cemented and uncemented fixation between primary and revision THA. Results: In all acetabular revisions, the use of cemented fixation increased statistically significant with 39% (95% CI, 34–45, p Conclusions: There was a significant change towards cemented fixation between primary and revision THA in young patients in the Netherlands, which was especially pronounced in acetabular revisions. No significant difference in short-term survival was found between revision procedures that changed or did not change in method of fixation. Long-term follow-up data are needed to evaluate the effect of this change in fixation method on the outcome of revision procedures in young patients.

Contains fulltext : 220918.pdf (Publisher’s version ) (Open Access) BACKGROUND: Surgical management of displaced midshaft clavicle fractures in adults leads to better union rates, improved early functional outcomes, and increased patient satisfaction compared with nonoperative treatment. However, both intramedullary fixation and plate osteosynthesis are subject to a specific array of disadvantages and complications. The Anser Clavicle Pin is a novel intramedullary device designed to address these disadvantages and complications. The aim of this study was to evaluate the union rate, functional outcomes, and complications of the Anser Clavicle Pin at 1-year follow-up. METHODS: A prospective explorative case series including 20 patients with displaced midshaft clavicle fractures was performed in 2 hospitals. The primary outcomes were union rate, functional outcomes (Constant-Murley score and Disabilities of the Arm, Shoulder and Hand score), and complications. The secondary outcomes were closed reduction rate, operative time, image-intensifier time, hospital stay, incision length, time to radiologic union, postoperative pain reduction, reoperation rate, health-related quality-of-life score, and patient satisfaction. RESULTS: There was a 100% union rate. The Constant-Murley score at 1 year was 96.7 (standard deviation [SD], 5). The Disabilities of the Arm, Shoulder and Hand score was 5.1 (SD, 10). There were no infections, neuropathy of the supraclavicular nerve, or hardware irritation requiring removal of hardware. Three device-related complications (15%) occurred, including plastic deformation, protrusion, and hardware failure. The satisfaction score was 8.9 (SD, 1) on the visual analog scale at the 1-year follow-up. CONCLUSION: Managing displaced midshaft clavicle fractures with the Anser Clavicle Pin results in a 100% union rate and excellent functional outcomes and patient satisfaction. It has a low non-device-related complication rate, and the device-related complications that occurred in this series may be prevented in the future.

Background and purpose — Hip resurfacing (HR) is a treatment option promoted for hip arthritis in young and active patients. However, adverse reactions to metal are a concern and the search for non-metallic bearing options proceeds. We present the first clinical study performed in patients using a newly developed hydrophilic polymer-on-polymer hip resurfacing device. Patients and methods — After performing extensive hip simulator tests, biocompatibility testing and animal tests (ISO 14242-1,3; 10993-3,4,5,10,11), approval was obtained from the IRB committee to enroll 15 patients in the first clinical study in humans using this experimental polymer-on-polymer hip resurfacing device. All surgeries were done by 2 experienced hip resurfacing surgeons. Clinical scores and standard radiographs as well as routine MRIs were obtained at regular intervals. Results — The surgical technique proved feasible with successful implantation of the new device using PMMA cement fixation on both sides without complications. Postoperative imaging revealed a well-positioned and well-fixed polymer resurfacing hip arthroplasty in all 4 initial cases. All 4 patients were free of pain and had good function for the first 2 months. However, in all 4 cases early cup loosening occurred between 8 and 11 weeks after surgery, necessitating immediate closure of the study. All 4 patients had a reoperation and were revised to a conventional THA. Retrieval analyses confirmed early cup loosening at the implant–cement interface in all 4 cases. The femoral components remained well attached to the cement. The periprosthetic tissues showed only small amounts of polymeric wear debris and there was only a very mild inflammatory reaction to this. Interpretation — Early cup loosening mandated a premature arrest of this study. After additional laboratory testing this failure mode was found to be the result of a small, yet measurable contraction in the cup size after exposing these implants to biological fluid divalent ion fluctuations in vivo. Currently used preclinical tests had failed to detect this failure mechanism. Modification of the polymer is essential to overcome these problems and before the potential of a polymer-on-polymer resurfacing arthroplasty may be further evaluated in patients.

Summary Objective A hallmark of osteoarthritis (OA) is degradation of articular cartilage proteoglycans. In isolated human OA chondrocytes, the anti-inflammatory cytokine Interleukin-37 (IL-37) lowers the expression of the proteolytic MMP and ADAMTS enzymes, which mediate this degradation. Therefore, we investigated if IL-37 protects against proteoglycan loss in freshly obtained human OA explants. Material and methods Human OA cartilage explants were incubated with IL-37. Release of sulphated proteoglycans (sGAGs) was measured with the dimethylmethylene-blue assay. Production and degradation of newly synthesized proteoglycans was measured using 35S-sulphate. Proteoglycan and proteolytic enzyme expression were analyzed by qPCR and Western Blot. Proteolytic activity was determined by measuring MMP- and ADAMTS-generated aggrecan neo-epitopes with ELISA and by using MMP-3-, MMP-13- or ADAMTS-5-inhibitors. Results Over time, a linear release of sGAGs from OA cartilage was measured. IL-37 reduced this release by 87 μg/ml (24%) 95%CI [21.04–141.4]. IL-37 did not affect 35S-sulphate incorporation or proteoglycan gene expression. In contrast, IL-37 reduced loss of 35S-sulphate labeled GAGs and reduced MMP-3 protein expression, indicating that IL-37 inhibits proteoglycan degradation. Remarkably, we observed two groups of patients; one group in which MMP-3-inhibition lowered sGAG release, and one group in which ADAMTS5-inhibition had this effect. Remarkably, IL-37 was only functional in the group of patients that responded to MMP-3-inhibition. Conclusion We identified a relationship between IL-37 and reduced sGAG loss in OA cartilage. Most likely, this effect is mediated by inhibition of MMP-3 expression. These results suggest that IL-37 could be applied as therapy in a subgroup of OA patients, in which cartilage degradation is mediated by MMP-3.

Introduction Untreated unilateral developmental dysplasia of the hip (DDH) results in asymmetry of gait and hip strength and may lead to early osteoarthritis, which is commonly treated with a total hip arthroplasty (THA). There is limited knowledge about the obtained symmetry of gait and hip strength after the THA. The objectives of this cross-sectional study were to: a) identify asymmetries between the operated and non-operated side in kinematics, kinetics and hip strength, b) analyze if increased walking speed changed the level of asymmetry in patients c) compare these results with those of healthy subjects. Methods Women (18-70 year) with unilateral DDH who had undergone unilateral THA were eligible for inclusion. Vicon gait analysis system was used to collect frontal and sagittal plane kinematic and kinetic parameters of the hip joint, pelvis and trunk during walking at comfortable walking speed and increased walking speed. Furthermore, hip abductor and extensor muscle strength was measured. Results Six patients and eight healthy subjects were included. In the patients, modest asymmetries in lower limb kinematics and kinetics were present during gait, but trunk lateral flexion asymmetry was evident. Patients' trunk lateral flexion also differed compared to healthy subjects. Walking speed did not significantly influence the level of asymmetry. The hip abduction strength asymmetry of 23% was not statistically significant, but the muscle strength of both sides were significantly weaker than those of healthy subjects. Conclusions In patients with a DDH treated with an IBG THA modest asymmetries in gait kinematics and kinetics were present, with the exception of a substantial asymmetry of the trunk lateral flexion. Increased walking speed did not result in increased asymmetries in gait kinematics and kinetics. Hip muscle strength was symmetrical in patients, but significantly weaker than in healthy subjects. Trunk kinematics should be included as an outcome measure to assess the biomechanical benefits of the THA surgery after DDH.

WOS: 000444019900009 PubMed ID: 30094972 Diagnostic accuracy of needle-based optical coherence tomography (OCT) for prostate cancer detection by visual and quantitative analysis is defined. 106 three-dimensional (3-D)-OCT data sets were acquired in 20 prostates after radical prostatectomy and precisely matched with pathology. OCT images were grouped per histological category. Two reviewers performed blind assessments of the OCT images. Sensitivity and specificity for malignancy detection were calculated. Quantitative analyses by automated optical attenuation coefficient calculation were performed. OCT can reliably differentiate between fat, cystic, and regular atrophy and benign glands. The overall sensitivity and specificity for malignancy detection was 79% and 88% for reviewer 1 and 88% and 81% for reviewer 2. Quantitative analysis for differentiation between stroma and malignancy showed a significant difference (4.6 mm(-1) versus 5.0 mm(-1) Mann-Whitney U-test p < 0.0001). A Kruskal-Wallis test showed a significant difference in median attenuation coefficient between stroma, inflammation, Gleason 3, and Gleason 4 (4.6, 4.1, 5.9, and 5.0 mm(-1), respectively). However, attenuation coefficient varied per patient and a related-samples Wilcoxon signed-rank test showed no significant difference per patient (p = 0.17). This study confirmed the one to one correlation of histopathology and OCT. Precise matching showed that most histological tissues categories in the prostate could be distinguished by their unique pattern in OCT images. In addition, the optical attenuation coefficient can play a role in the differentiation between stroma and malignancy; however, a per patient analysis of the optical attenuation coefficient did not show a significant difference. (C) The Authors. Published by SPIE under a Creative Commons Attribution 3.0 Unported License. Cure for Cancer Foundation This study was funded by an unrestricted research grant from the Cure for Cancer Foundation.

Contains fulltext : 154213.pdf (Publisher’s version ) (Closed access) PURPOSE: The purpose of this study is predicting the clinical and radiological long-term outcome and identifying prognostic factors of Legg-Calve-Perthes disease (LCPD) in Catterall 2 and 3 hips. METHODS: Sixty hips (59 patients) were diagnosed with LCPD between 1959 to 1974 and were followed prospectively. Forty-two of these 60 hips were classified as Catterall 2 or 3. In 2002, 33 hips (32 patients) with Catterall type 2 or 3 were evaluated clinically and radiographically. In 2010, 27 hips (26 patients) were re-evaluated. RESULTS: In 2002, 15 hips had Catterall 2 type LCPD and 18 hips Catterall 3. Twelve of the 33 hips (36%) had signs of osteoarthritis. In 2010, 14 hips were classified as Catterall 2 and 13 hips as Catterall 3. Catterall 2 hips had a significantly better Harris Hip Score (HHS) (p = 0.001). There were 15 hips (55%) with signs of osteoarthritis. CONCLUSION: The long-term prognosis of LCPD Catterall type 2 and 3 is relatively benign. However, more than 50% of the patients will develop signs of osteoarthritis between the 4th and 5th decades. At the latest follow-up a strong increase in the number of cases with osteoarthritis was seen. Sphericity of the femoral head is an important predicting factor in the development of osteoarthritis.

Item does not contain fulltext OBJECTIVE: To rescue chondrogenic differentiation of human mesenchymal stem cells (hMSCs) in osteoarthritic conditions by inhibition of protein kinases. METHODS: hMSCs were cultured in pellets. During early chondrogenic differentiation, these were exposed to osteoarthritic synovium-conditioned medium (OAS-CM), combined with the Janus kinase (JAK)-inhibitor tofacitinib and/or the transforming growth factor beta-activated kinase 1 (TAK1)-inhibitor oxozeaenol. To evaluate effects on chondrogenesis, the glycosaminoglycan (GAG) content of the pellets was measured at the time that chondrogenesis was manifest in control cultures. Moreover, mRNA levels of matrix molecules and enzymes were measured during this process, using real-time polymerase chain reaction (RT-PCR). Initial experiments were performed with hMSCs from a fetal donor, and results of these studies were confirmed with hMSCs from adult donors. RESULTS: Exposure to OAS-CM resulted in pellets with a much lower GAG content, reflecting inhibited chondrogenic differentiation. This was accompanied by decreased mRNA levels of aggrecan, type II collagen, and Sox9, and increased levels of matrix metalloproteinase (MMP)1, MMP3, MMP13, ADAMTS4, and ADAMTS5. Both tofacitinib (JAK-inhibitor) and oxozeaenol (TAK1 inhibitor) significantly increased the GAG content of the pellets in osteoarthritis (OA)-like conditions. The combination of both protein kinase inhibitors showed an additive effect on GAG content. In agreement with this, in the presence of OAS-CM, both tofacitinib and oxozeaenol increased mRNA expression of sox9. The expression of aggrecan and type II collagen was also up-regulated, but this only reached significance for aggrecan after TAK1 inhibition. Both inhibitors decreased the mRNA levels of MMP1, 3, and 13 in the presence of OAS-CM. Moreover, oxozeaenol also significantly down-regulated the mRNA levels of aggrecanases ADAMTS4 and ADAMTS5. When combined, the inhibitors caused additive reduction of OA-induced MMP1 mRNA expression. Counteraction of OAS-CM-induced inhibition of chondrogenesis by these protein kinase inhibitors was confirmed with hMSCs of two different adult donors. Both tofacitinib and oxozeaenol significantly improved GAG content in cell pellets from these adult donors. CONCLUSIONS: Tofacitinib and oxozeaenol partially prevent the inhibition of chondrogenesis by factors secreted by OA synovium. Their effects are additive. This indicates that these protein kinase inhibitors can potentially be used to improve cartilage formation under the conditions occurring in osteoathritic, or otherwise inflamed, joints.

Contains fulltext : 173999.pdf (Publisher’s version ) (Closed access) Objective.: A crucial feature of OA is cartilage degradation. This process is mediated by pro-inflammatory cytokines, among other factors, via induction of matrix-degrading enzymes. Interleukin 37 (IL37) is an anti-inflammatory cytokine and is efficient in blocking the production of pro-inflammatory cytokines during innate immune responses. We hypothesize that IL37 is therapeutic in treating the inflammatory cytokine cascade in human OA chondrocytes and can act as a counter-regulatory cytokine to reduce cartilage degradation in OA. Methods.: Human OA cartilage was obtained from patients undergoing total knee or hip arthroplasty. Immunohistochemistry was applied to study IL37 protein expression in cartilage biopsies from OA patients. Induction of IL37 expression by IL1beta, OA synovium-conditioned medium and TNFalpha was investigated in human OA chondrocytes. Adenoviral overexpression of IL37 followed by IL1beta stimulation was performed to investigate the anti-inflammatory potential of IL37. Results.: IL37 expression was detected in cartilage biopsies of OA patients and induced by IL1beta. After IL1beta stimulation, increased IL1beta, IL6 and IL8 expression was observed in OA chondrocytes. Elevated IL37 levels diminished the IL1beta-induced IL1beta , IL6 and IL8 gene levels and IL1beta and IL8 protein levels. In addition to the reduction in pro-inflammatory cytokine expression, IL37 reduced MMP1 , MMP3 , MMP13 and disintegrin and metalloproteinase with thrombospondin motifs 5 gene levels and MMP3 and MMP13 protein levels. Conclusion.: IL37 is induced by IL1beta, and IL37 itself reduced IL1beta, IL6 and IL8 production, indicating that IL37 is able to induce a counter-regulatory anti-inflammatory feedback loop in chondrocytes. In addition, IL37 dampens catabolic enzyme expression. This supports IL37 as a potential therapeutic target in OA.

Item does not contain fulltext OBJECTIVE: S100A8 and S100A9 are two Ca(2+) binding proteins classified as damage-associated molecular patterns or alarmins that are found in high amounts in the synovial fluid of osteoarthritis (OA) patients. The purpose of this study was to investigate whether S100A8 and/or S100A9 can interact with chondrocytes from OA patients to increase catabolic mediators. METHODS: Using immunohistochemistry, we stained for S100A8 and S100A9 protein, matrix metalloproteinases (MMPs), and a cartilage-breakdown epitope specific for MMPs (VDIPEN) in cartilage from OA donors. Isolated chondrocytes or explants from OA and non-OA donors were stimulated with S100A8 and/or S100A9. Messenger RNA and protein levels of MMPs, cytokines, and cartilage matrix molecules were determined with quantitative reverse transcription-polymerase chain reaction and Luminex techniques, respectively. For receptor blocking studies, specific inhibitors for Toll-like receptor 4 (TLR-4), receptor for advanced glycation end products (RAGE), and carboxylated glycans were used. RESULTS: In cartilage from OA patients, the expression of S100A8 and S100A9 protein close to chondrocytes was associated with proteoglycan depletion and expression of MMP-1, MMP-3, and VDIPEN. Stimulation of chondrocytes with S100A8 and S100A9 caused a strong up-regulation of catabolic markers (MMPs 1, 3, 9, and 13, interleukin-6 [IL-6], IL-8, and monocyte chemotactic protein 1) and down-regulation of anabolic markers (aggrecan and type II collagen), thereby favoring cartilage breakdown. Blocking TLR-4, but not carboxylated glycans or RAGE, inhibited the S100 effect. The catabolic S100 effect was significantly more pronounced in chondrocytes from OA patients as compared to those from non-OA patients, possibly due to higher TLR-4 expression. CONCLUSION: S100A8 and S100A9 have a catabolic effect on human chondrocytes that is TLR-4 dependent. OA chondrocytes are more sensitive than normal chondrocytes to S100 stimulation. 01 mei 2012

Purpose We investigated the hypothesis that many total hip arthroplasty revisions that are classified as aseptic are in fact low-grade infections missed with routine diagnostics.Methods In 7 Dutch ...

Contains fulltext : 80087.pdf (Publisher’s version ) (Closed access) OBJECTIVE: Wnt signaling pathway proteins are involved in embryonic development of cartilage and bone, and, interestingly, developmental processes appear to be recapitulated in osteoarthritic (OA) cartilage. The present study was undertaken to characterize the expression pattern of Wnt and Fz genes during experimental OA and to determine the function of selected genes in experimental and human OA. METHODS: Longitudinal expression analysis was performed in 2 models of OA. Levels of messenger RNA for genes from the Wnt/beta-catenin pathway were determined in synovium and cartilage, and the results were validated using immunohistochemistry. Effects of selected genes were assessed in vitro using recombinant protein, and in vivo by adenoviral overexpression. RESULTS: Wnt-induced signaling protein 1 (WISP-1) expression was strongly increased in the synovium and cartilage of mice with experimental OA. Wnt-16 and Wnt-2B were also markedly up-regulated during the course of disease. Interestingly, increased WISP-1 expression was also found in human OA cartilage and synovium. Stimulation of macrophages and chondrocytes with recombinant WISP-1 resulted in interleukin-1-independent induction of several matrix metalloproteinases (MMPs) and aggrecanase. Adenoviral overexpression of WISP-1 in murine knee joints induced MMP and aggrecanase expression and resulted in cartilage damage. CONCLUSION: This study included a comprehensive characterization of Wnt and Frizzled gene expression in experimental and human OA articular joint tissue. The data demonstrate, for the first time, that WISP-1 expression is a feature of experimental and human OA and that WISP-1 regulates chondrocyte and macrophage MMP and aggrecanase expression and is capable of inducing articular cartilage damage in models of OA.

Item does not contain fulltext OBJECTIVE: The aim of the present study was to identify independent preoperative hip function characteristics sensitive for preoperative intervention that are predictive of an extended length of hospital stay (LOS) after primary total hip arthroplasty (THA). DESIGN: This is a longitudinal cohort study. A retrospective chart analysis was conducted on prospectively collected data of patients (158) who underwent unilateral primary elective cemented THA in a 4-yr period. The main outcome measure was LOS after primary THA. RESULTS: The median LOS was 6.0 days. The authors found an 18.5% increased chance of requiring an LOS of more than 6 days (odds ratio, 2.15; 95% confidence interval, 1.03-4.50) for the patients who needed to use a walking aid preoperatively and a 23.6% increased chance (odds ratio, 2.74; 95% confidence interval, 1.31-5.74) for the patients who had difficulties managing stairs. Sex, age, body mass index, comorbidity, and preoperative pain did not reach the level of significance in the multivariate analysis. CONCLUSIONS: Patients who are at risk for a longer stay in the hospital after THA can be identified preoperatively on simple physical function characteristics. These findings enable the identification of appropriate patients for preoperative training to improve functional recovery and decrease the LOS after primary THA.

Contains fulltext : 108265.pdf (Publisher’s version ) (Open Access) BACKGROUND: Bone grafts from bone banks might be mixed with bisphosphonates to inhibit the osteoclastic response. This inhibition prevents the osteoclasts to resorb the allograft bone before new bone has been formed by the osteoblasts, which might prevent instability. Since bisphosphonates may not only inhibit osteoclasts, but also osteoblasts and thus bone formation, we studied different bisphosphonate concentrations combined with allograft bone. We investigated whether locally applied alendronate has an optimum dose with respect to bone resorption and formation. Further, we questioned whether the addition of demineralized bone matrix (DBM), would stimulate bone formation. Finally, we studied the effect of high levels of antibiotics on bone allograft healing, since mixing allograft bone with antibiotics might reduce the infection risk. METHODS: 25 goats received eight bone conduction chambers in the cortical bone of the proximal medial tibia. Five concentrations of alendronate (0, 0.5 mg/mL, 1 mg/mL, 2 mg/mL, and 10 mg/mL) were tested in combination with allograft bone and supplemented with cefazolin (200 mug/mL). Allograft not supplemented with alendronate and cefazolin served as control. In addition, allograft mixed with demineralized bone matrix, with and without alendronate, was tested. After 12 weeks, graft bone area and new bone area were determined with manual point counting. RESULTS: Graft resorption decreased significantly (p < 0.001) with increasing alendronate concentration. The area of new bone in the 1 mg/mL alendronate group was significantly (p = 0.002) higher when compared to the 10 mg/mL group. No differences could be observed between the group without alendronate, but with demineralized bone, and the control groups. CONCLUSIONS: A dose-response relationship for local application of alendronate has been shown in this study. Most new bone was present at 1 mg/mL alendronate. Local application of cefazolin had no effect on bone remodelling.

The most important complications occurring with joint replacement prostheses are aseptic loosening and infection, both of which often present with pain at the prosthesis site. Since these conditions often require major surgery and the surgical approaches toward these problems are very different, it is important to confirm loosening and differentiate aseptic from septic loosening before surgery. Nuclear medicine techniques can be helpful in this differentiation: a normal bone scan virtually excludes loosening, and combined imaging of bone marrow and 111In-labeled white blood cells is the current best practice for the assessment of suspected prosthetic infections. Several other radiotracers that are easier to prepare than labeled white cells have been studied, such as 111In-labeled human polyclonal IgG and 99mTc-labeled anti-granulocyte antibodies. Three-dimensional techniques such as SPECT and PET may improve imaging of prostheses even further. 18F-fluorodeoxyglucose PET has already been reported to have a high accuracy for prosthesis loosening and infection. The characteristics of these techniques are described in this chapter.

Clinical practice guidelines are being used in many countries throughout the world to improve the quality of patient care. The Dutch Orthopaedic Association has a long tradition of guideline develo...

Item does not contain fulltext BACKGROUND: Little is known about the functional performance of patients after revision total hip arthroplasty with major acetabular bone impaction grafting. In general, these patients are assumed to perform worse due to a more advanced stage of periarticular tissue degeneration and multiple surgeries compared with patients with primary total hip arthroplasty (THA). OBJECTIVE: The main purpose of this study was to quantify the differences in performance of the sit-to-stand (STS) movement between patients with primary THA and patients with revision THA. DESIGN AND METHODS: In this study, the STS movement was analyzed kinematically (knee and hip angular extension velocity) and kinetically (loading symmetry ratio). Ten patients after primary THA and 10 patients after revision THA with acetabular bone impaction grafting were compared using these 3 rising parameters. RESULTS: The patients with revision THA performed the STS movement comparably to the patients with primary THA; there were no differences in knee and hip velocity or leg asymmetry during rising. LIMITATIONS: The study focused only on kinetic and kinematic aspects, and only patients who were satisfied with their THA were involved. CONCLUSIONS: This study showed that patients after a revision THA with acetabular bone impaction grafting and cement did not perform the STS movement differently, either kinematically or kinetically, compared with patients with a primary THA.

Purpose We investigated the hypothesis that many total hip arthroplasty revisions that are classified as aseptic are in fact low-grade infections missed with routine diagnostics. Methods In 7 Dutch hospitals, 176 consecutive patients with the preoperative diagnosis of aseptic loosening of their total hip arthroplasty were enrolled. During surgery, between 14 and 20 tissue samples were obtained for culture, pathology, and broad-range 16S rRNA PCR with reverse line blot hybridization. Patients were classified as either not being infected, suspected of having infection, or infected according to strict, predefined criteria. Each patient had a follow-up visit after 1 year. Results 7 patients were classified as infected, 4 of whom were not identified by routine culture. 15 additional patients were suspected of having infection. 20 of these 22 patients received a cemented prosthesis, fixated with antibiotic-loaded bone cement. All 22 patients received prophylactic systemic antibiotics. 7 of them reported complaints one year after surgery, but only one showed signs of early loosening. However, additional surgery was not performed in any of the patients. Interpretation Although the proportions were not as high as previously reported in the literature, between 4% and 13% of patients with the preoperative diagnosis of aseptic loosening were infected. However, as thorough debridement was performed during surgery and prophylactic antibiotics were used, the diagnosis of infection did not have any obvious clinical consequences, as most patients performed well at the 1-year follow-up. Whether this observation has implications for long-term implant survival remains to be seen.

We present descriptions of two human Mycobacterium microti infections: one of a patient with pulmonary disease and one of a patient with osteomyelitis of the hip. Both patients had acid-fast bacilli and a positive Mycobacterium tuberculosis complex PCR from clinical specimens, but mycobacterial cultures remained negative. The microbiological diagnosis was established by molecular methods.

Portable equipment for active measurements of push-off force and ice friction was developed. The equipment consists of a pair of skates with three measuring elements between the shoe and the skate blade to register force in both fore/aft and normal direction. A portable computer samples the friction force and normal force signals during one or more strokes, calculates the mean coefficient of ice friction, and stores the sampled data in memory. The push-off force and ice friction force were measured. The peak push-off forces reach values of up to 140% of body weight. The magnitude of the coefficient of ice friction varies, depending on the weather conditions and preparatory method, generally between 0.003 and 0.007 when skating the straightaway. During the skating of the curves the coefficient of ice friction is 35% higher, most likely due to the different skating technique in the curves.

Cardiovascular response to fast posture change can be used to model individual orthostatic response under normal circumstances and after spaceflight. We set out to construct a computer-controlled tilt table suitable for repeated sinusoidal tilt motion as well as fast, single head-up tilt (HUT). The movement profile of the table was designed to prevent muscle tensing and limit vestibular stimulation.On the new table, 20 healthy subjects underwent a protocol of fast HUT and sinusoidal tilt motion at 2.5 tilts per minute. BP was measured non-invasively (Finapres). Time domain dynamic response to HUT and frequency domain response to sinusoidal tilts were derived from the beat-to-beat BP and from interbeat-interval (IBI) series.Tilt motion did not induce dizziness and was experienced by all subjects as smooth. The systolic BP response to fast HUT correlated mildly with the systolic BP spectral power at the sinusoidal tilt frequency (R = 0.47). The IBI response to fast HUT correlated well with the IBI power at the sinusoidal tilt frequency (R = 0.74).In this study we presented a computer controlled tilt table capable of fast posture change and sinusoidal tilts. An exploratory protocol demonstrated that the table is suitable for obtaining cardiovascular response to posture change for modeling purposes.

We took core biopsies from the acetabulum in 8 patients (at reoperation) after a previous revision with impacted cancellous allograft chips in combination with cement. Except for one biopsy specimen, the graft showed different stages of incorporation. In the specimens taken at 4 months, revascularization of the graft was found. Osteoclasts had removed parts of the graft, while woven bone had formed on the remnants of the graft and in the stroma that was invading the graft. Subsequent specimens showed that this mixture of graft and new bone was in due time remodeled into a normal trabecular bony structure with viable bone marrow that contained little or no remnants of the original graft. The graft-cement interface was present in 4 biopsies taken at 1, 22, 28, and 72 months. The specimen obtained 28 months after revision showed vital bone locally in direct contact with the cement layer; however, a soft tissue interface predominated.