BACKGROUND/AIM:Type II odontoid fractures in elderly patients are associated with high rates of nonunion and substantial morbidity. However, the clinical relevance of radiographic nonunion following anterior odontoid screw fixation remains unclear. This study aimed to evaluate long-term functional outcomes and health-related quality of life, with particular focus on the impact of fracture healing. PATIENTS AND METHODS:This retrospective single-center study included 82 patients (mean age 75.7 years) treated with anterior odontoid screw fixation between 2011 and 2019. Radiographic union was assessed using postoperative imaging. Patient-reported outcome measures (PROMs), including Visual Analog Scale (VAS), Neck Disability Index (NDI), EQ-5D-5L, and SF-36, were obtained at long-term follow-up. Outcomes were compared between patients with and without radiographic union. RESULTS:Radiographic nonunion was observed in 44% of patients. A total of 27 patients completed follow-up assessments. Overall outcomes were favorable, with low pain levels (mean VAS score of 2), minimal disability (NDI mean 7), and good quality of life (EQ-5D-5L mean 0.79). Patients with nonunion demonstrated consistently worse PROMs; however, differences did not reach statistical significance. A significant difference was observed in the EQ-5D-5L anxiety/depression domain (p=0.018), indicating increased psychological burden in the nonunion group. CONCLUSION:Anterior odontoid screw fixation provides satisfactory long-term clinical outcomes in elderly patients with type II odontoid fractures. Despite a high rate of radiographic nonunion, functional outcomes and quality of life were not significantly impaired. These findings suggest that mechanical stability may be more clinically relevant than complete osseous union. Larger prospective studies are required to confirm these results.

Background Inflammatory joint destruction releases intracellular components like ATP and triggers an acidic microenvironment. Detection of ATP and ischemia by sensory neurons leads to pain sensation, but little is known about the presence of purinoceptors and regulating factors in synovial tissue. The current study investigates the presence of ATP-receptor P2X5, acid-sensing ion channel ASIC3, and ATP degrading ectonucleotidases NTPDase1 (CD39) and NTPDase2 in human rheumatoid arthritis (RA) and osteoarthritis (OA) synovial tissue. Methods H&E and immunofluorescent staining on 8 rheumatoid arthritis (2 male, 6 female) and 8 osteoarthritis specimens (1 male, 7 female) were analyzed. Results Synovitis score was significantly higher in RA compared to OA (p=0.0002*, 7.38 ± 1.30 versus 2.75 ± 1.28 points, mean±SD). ASIC3 and P2X5 as well as NTPDase1 and NTPDase2 show a very high, significant correlation in synovial tissue of RA lining and sublining layer (r>93%, double staining in 11.2-24.6% of all cells, single staining in 0.5-10%). A high correlation for NTPDase1 and NTPDase2 was observed also in OA sublining layer (r>94%, double staining in 15.2-37.6% of cells, 0.8-8.1% single staining). Conclusions ASIC3 and P2X5 together with NTPDase1 and NTPDase2 indicate a tightly regulated purinergic microenvironment in RA and OA synovial tissue. Data suggests that nucleotide turnover, including ATP breakdown and subsequent adenosine generation, modulates inflammatory and nociceptive processes and purinergic signaling pathways in synovitis.

Radiofrequency ablation (RFA) has become an important minimally invasive option for the treatment of painful spinal tumors and benign bone lesions. While its effectiveness within the vertebral body is well established, there is ongoing concern about unintended heat exposure of nearby neural structures. Experimental data describing how heat propagates beyond the vertebra during spinal RFA are still limited. This experimental in vitro study aims to assess the extravertebral temperature exposure during spinal radiofrequency ablation as a surrogate parameter for potential neural injury risk under controlled conditions. This experimental in vitro study was performed on four fresh-frozen human lumbar spines. Radiofrequency ablation was carried out using a commercially available system and standard clinical protocols. Two anatomical configurations were examined: ablation within the vertebral body and ablation within the pedicle. Temperatures were measured at predefined locations outside the vertebra, including the spinal canal and cortical boundaries, using multiple thermocouples. To aid interpretation of radiofrequency-related measurement artifacts, an additional control setup using an electrothermal heating system without radiofrequency energy was included. Temperature data were evaluated descriptively. In the control experiments, temperature profiles were consistent across all measurement sites, and no values exceeded 42 °C. During radiofrequency ablation, temperature recordings showed pronounced fluctuations related to electromagnetic interference. In the pedicle configuration, temperatures rose gradually during energy delivery and decreased after the procedure, with maximum values reaching up to 44 °C. Although temperatures above 42 °C occurred intermittently, no sustained exposure above 45 °C was observed at any extravertebral location. Under controlled in vitro conditions and with intact cortical bone, spinal radiofrequency ablation led to limited heat propagation beyond the vertebral body and pedicle. Temperature levels commonly associated with irreversible neural injury were not reached or were exceeded only briefly. These findings suggest a low risk of clinically relevant thermal injury to adjacent neural structures when spinal RFA is performed with appropriate probe placement and preserved osseous integrity. Caution is warranted when applying these results to clinical situations involving cortical destruction or altered vertebral anatomy.

This systematic review aims to evaluate the effectiveness of low-frequency (LF) whole-body electromyostimulation (WB-EMS) in reducing pain and improving function in patients with nonspecific chronic back pain (NSCBP). Given the global prevalence of NSCBP and the limitations of conventional exercise due to time constraints and comorbidities, LF WB-EMS, a time-efficient and joint-friendly intervention, has emerged as a potential alternative. All prior PubMed studies on WB-EMS and back pain have exclusively investigated LF-EMS (0-999 Hz), and this review assesses its efficacy compared to a passive control group (PCG) or active control group (ACG), addressing a gap in understanding its clinical utility for NSCBP management. Following Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines, PubMed and Physiotherapy Evidence Database (PEDro) were systematically searched for clinical trials from database inception to the present using inclusion criteria encompassing adults with NSCBP (pain >12 weeks, no specific cause), WB-EMS interventions, and randomized controlled trials (RCTs) or controlled clinical trials (CCTs) reporting pain and function outcomes. Data were extracted by two independent reviewers using a standardized form, and quality was assessed with the PEDro Scale. A narrative synthesis described study characteristics, while a meta-analysis using IBM SPSS Statistics software, version 22 (IBM Corp., Armonk, NY), employed an inverse variance-weighted method to pool standardized mean differences (SMD) with 95% confidence intervals, assessing heterogeneity with I². Studies lacking a distinct non-WB-EMS control group or with mixed control groups not clearly assignable to passive or active controls were excluded from comparative analysis but included in within-group analysis where appropriate. Six studies (n = 677, WB-EMS: 278, controls: 329) were included, comprising four RCTs, one CCT, and one meta-analysis (2017-2023). LF WB-EMS (20-minute sessions, once a week, eight to 16 weeks, 50-85 Hz) significantly reduced pain (-0.60 to -1.58 Numeric Rating Scale (NRS)/Visual Analog Scale (VAS)) and improved function (+7.19 kg to -15.8 Oswestry Disability Index (ODI)) within groups. Meta-analysis of five studies showed a pooled pain reduction of -0.87 (95% CI (-1.02, -0.72), I² = 70%) and functional SMD of 0.84 (95% CI (0.68, 0.99), I² = 76%). Against passive controls (n = 15/group), effect sizes were 0.75 (pain) and 0.85 (function), while versus active controls, pooled effects were 0.33 (pain, I² = 96%) and 0.28 (function, I² = 92%), with high heterogeneity. The results indicate that LF WB-EMS can reduce pain and improve function in NSCBP, with within-group effects of -0.87 NRS and 0.84 SMD and comparative effects of 0.75/0.85 vs. PCG and 0.33/0.28 vs. ACG, indicating potential benefits despite high heterogeneity and modest effect sizes. WB-EMS shows comparable efficacy to established methods, offering a promising option for patients with time or mobility constraints, supported by its safety and joint-friendly nature. However, limitations, including a small PCG sample (n=15) and limited research on medium-frequency WB-EMS, necessitate larger trials and further studies to optimize protocols and confirm long-term efficacy.

Seit der Veröffentlichung der ersten Empfehlungen der Deutschen Gesellschaft für Orthopädie und Traumatologie zu Sport bei Skoliose sind mehr als 3 Jahrzehnte vergangen und die Operationsmethoden haben sich in dieser Zeit stärker verändert als dies die nichtoperativen Verfahren getan haben. Das Vertrauen in die modernen Pedikelschraubenkonstrukte bei dorsalen Korrekturspondylodesen hat zu einer deutlich früheren und auch umfangreicheren Freigabe sportlicher Aktivitäten nach Korrekturoperationen geführt, während der intellektuell einleuchtende Vorteil neuerer, beweglichkeitserhaltender Verfahren noch nicht ausreichend bewiesen ist. Zumindest für Leitungssportler scheint auch im kurzfristigen Verlauf nach Operation ein Wiedererreichen der Leistungsfähigkeit vor der Operation möglich. Die Kürze der Nachbeobachtungszeiten vieler Studien zu Sport nach Skolioseoperationen führt aber möglicherweise zu einer Unterschätzung der langfristigen Nachteile von Fusionen bis in die LWS, wie eine japanische Studie mit einem Nachbeobachtungszeitraum von mindestens 10 Jahren nahelegt. Auch eventuelle länger anhaltende Effekte spezifischer Physiotherapierichtungen, wie z.B. der Schroth-Therapie, sind weiterhin nicht untersucht und damit nicht evident.

More than three decades have passed since the German Society for Orthopaedics and Traumatology published its first recommendations on sports participation for scoliosis patients. During this period, surgical techniques have changed more substantially than non-surgical procedures. Confidence in modern pedicle screw constructs for posterior spinal correction and fusion has led to an earlier and more extensive return to sporting activities after corrective surgery, whereas the theoretically plausible advantage of newer, mobility-preserving procedures has not yet been sufficiently proven. At least for elite athletes, a return to pre-operative performance appears achievable even in the short term after surgery. However, the short follow-up periods of many studies on sports participation after scoliosis surgery may lead to an underestimation of the long-term disadvantages of fusions extending into the lumbar spine, as suggested by a Japanese study with a follow-up period of at least 10 years. Potential long-term effects of specific physiotherapeutic approaches, such as Schroth therapy, have not yet been investigated and are therefore not evident.

Monitoring of bone mineral density (BMD) is used to assess pharmacological osteoporosis therapy. This study examined the real-life effects of antiresorptive and osteoanabolic treatments on volumetric BMD (vBMD) of the spine by quantitative computed tomography (QCT). Patients aged ≥ 50 years with a vBMD < 120 mg/ml had ≥ 2 QCT. For analysis of therapy effects, the pharmacological treatment and the duration of each therapy were considered. Identical vertebrae were evaluated in all vBMD measurements for each patient. A linear mixed model with random intercepts was used to estimate the effects of pharmacological treatments on vBMD. A total of 1145 vBMD measurements from 402 patients were analyzed. Considering potential confounders such as sex, age, and prior treatment, a reduction in trabecular vBMD was estimated for oral bisphosphonates (− 1.01 mg/ml per year; p < 0.001), intravenous bisphosphonates (− 0.93 mg/ml per year; p = 0.015) and drug holiday (− 1.58 mg/ml per year; p < 0.001). Teriparatide was estimated to increase trabecular vBMD by 4.27 mg/ml per year (p = 0.018). Patients receiving denosumab showed a statistically non-significant decrease in trabecular vBMD (− 0.44 mg/ml per year; p = 0.099). Compared to non-treated patients, pharmacological therapy had positive effects on trabecular vBMD (1.35 mg/ml; p = 0.001, 1.43 mg/ml; p = 0.004, 1.91 mg/ml; p < 0.001, and 6.63 mg/ml; p < 0.001 per year for oral bisphosphonates, intravenous bisphosphonates, denosumab, and teriparatide, respectively). An increase in trabecular vBMD by QCT was not detected with antiresorptive agents. Patients treated with teriparatide showed increasing trabecular vBMD. Non-treatment led to a larger decrease in trabecular vBMD than pharmacological therapy.

Introduction: Recent clinical studies confirmed that whole -body electromyostimulation (WB-EMS) training is a safe and time -efficient therapeutic method for patients with nonspecific chronic back pain (NSCBP). However, significant variations in initial pain intensity among subjects in these studies have been observed. This study aims to determine if patients with differing initial pain intensities experience varying degrees of benefit from WB-EMS and to assess the overall correlation between initial pain levels and pain reduction. Methods: Pain intensity datasets from two studies were combined. The pooled data included 121 NSCBP patients (38 males and 83 females) with an average age of 55.1 years (+/- 11.8 years). Data was categorized by baseline pain intensity on the numeric rating scale (NRS) into seven groups: 0 to 2, >2 to 3, >3 to 4, >4 to 5, >5 to 6, >6 to 7, and >7. Both absolute and relative changes were analyzed. Additionally, a Spearman rho correlation test was performed on the entire dataset to evaluate the relationship between initial pain level and pain reduction. Results: Significant improvements were noted across all NRS11 categories, with strong effect sizes (p) in all classes above 2, ranging from 0.56 to 0.90. The >7 category exhibited the highest rate of clinically significant changes (80%) and an average improvement of 3.72 points. The overall group from >1 to 10 showed an average improvement of 1.33 points, with 37% of the participants experiencing clinically significant improvements. The Spearman rho correlation test revealed a moderate positive relationship between initial pain level and pain reduction (r_s = 0.531, p < 0.001), indicating that, generally, higher initial pain levels are associated with greater pain reduction. Conclusion: The findings support the hypothesis that NSCBP patients with higher baseline NRS values benefit more substantially from WB-EMS. Those with NRS values above 7 show the greatest improvement and highest rate of clinical significance. The overall positive correlation between initial pain intensity and pain reduction further underscores the efficacy of WB-EMS in managing NSCBP across different pain intensities.

Objective Distances and angles measured from long-leg radiographs (LLR) are important for surgical decision-making. However, projectional radiography suffers from distortion, potentially generating differences between measurement and true anatomical dimension. These phenomena are not uniform between conventional radiography (CR) digital radiography (DR) and fan-beam technology (EOS). We aimed to identify differences between these modalities in an experimental setup. Materials and methods A hemiskeleton was stabilized using an external fixator in neutral, valgus and varus knee alignment. Ten images were acquired for each alignment and each modality: one CR setup, two different DR systems, and an EOS. A total of 1680 measurements were acquired and analyzed. Results We observed great differences for dimensions and angles between the 4 modalities. Femoral head diameter measurements varied in the range of > 5 mm depending on the modality, with EOS being the closest to the true anatomical dimension. With functional leg length, a difference of 8.7% was observed between CR and EOS and with the EOS system being precise in the vertical dimension on physical-technical grounds, this demonstrates significant projectional magnification with CR-LLR. The horizontal distance between the medial malleoli varied by 20 mm between CR and DR, equating to 21% of the mean. Conclusions Projectional distortion resulting in variations approaching 21% of the mean indicate, that our confidence on measurements from standing LLR may not be justified. It appears likely that among the tested equipment, EOS-generated images are closest to the true anatomical situation most of the time.

BACKGROUND:Over the last 50 years arthroplasty became the gold-standard treatment for disabling conditions of the coxofemoral joint. Variations of anterior, lateral, and dorsal incision have been applied, but as each approach requires the incision and reflection of various muscles to gain adequate exposure of the joint results are still controversial.OBJECTIVE:The purpose of this study was to develop a minimal-invasive, tissue-sparing approach in sheep with reduced risks in animal testing.METHODS:12 mature sheep underwent hip surgery as part of a study to evaluate a hip resurfacing system. In line with the preliminary cadaveric tests a modified, minimal-invasive, musclepreserving surgical approach was sought after.RESULTS:We developed a surgical approach to the coxofemoral joint in sheep using only blunt tissue dissection after skin incision without any limitations in joint exposure or increased blood loss/duration of surgery.CONCLUSION:Even though limitations occur and femoral orientation in sheep differs from man, joint forces have similar relative directions to the bone with similar bony and vascular anatomy. Therefore, this minimal-invasive muscle preserving approach might be a safe and comparable alternative in still inevitable animal testing.

Whole-Body Electromyostimulation (WB-EMS) is a training technology that enables simultaneous stimulation of all the main muscle groups with a specific impulse intensity for each electrode. The corresponding time-efficiency and joint-friendliness of WB-EMS may be particularly attractive for people unable or unmotivated to conduct (intense) conventional training protocols. However, due to the enormous metabolic and musculoskeletal impact of WB-EMS, particular attention must be paid to the application of this technology. In the past, several scientific and newspaper articles reported severe adverse effects of WB-EMS. To increase the safety of commercial non-medical WB-EMS application, recommendations “for safe and effective whole-body electromyostimulation” were launched in 2016. However, new developments and trends require an update of these recommendations to incorporate more international expertise with demonstrated experience in the application of WB-EMS. The new version of these consensus-based recommendations has been structured into 1) “general aspects of WB-EMS”, 2) “preparation for training”, recommendations for the 3) “WB-EMS application” itself and 4) “safety aspects during and after training”. Key topics particularly addressed are 1) consistent and close supervision of WB-EMS application, 2) mandatory qualification of WB-EMS trainers, 3) anamnesis and corresponding consideration of contraindications prior to WB-EMS, 4) the participant’s proper preparation for the session, 5) careful preparation of the WB-EMS novice, 6) appropriate regeneration periods between WB-EMS sessions and 7) continuous interaction between trainer and participant at a close physical distance. In summary, we are convinced that the present guideline will contribute to greater safety and effectiveness in the area of non-medical commercial WB-EMS application.

IntroductionDual-energy X-ray absorptiometry (DXA) is considered the gold standard for the diagnosis of osteoporosis and assessment of fracture risk despite proven limitations. Quantitative computed tomography (QCT) is regarded as a sensitive method for diagnosis and follow-up. Pathologic fractures are classified as the main clinical manifestation of osteoporosis. The objective of the study was to compare DXA and QCT to determine their sensitivity and discriminatory power.Materials and methodsPatients aged 50 years and older were included who had DXA of the lumbar spine and femur and additional QCT of the lumbar spine within 365 days. Fractures and bone mineral density (BMD) were retrospectively examined. BMD measurements were analyzed for the detection of osteoporotic fractures. Sensitivity and receiver operating characteristic curve were used for calculations. As an indication for a second radiological examination was given, the results were compared with control groups receiving exclusively DXA or QCT for diagnosis or follow-up.ResultsOverall, BMD measurements of 404 subjects were analyzed. DXA detected 15 (13.2%) patients having pathologic fractures (n = 114) with normal bone density, 66 (57.9%) with osteopenia, and 33 (28.9%) with osteoporosis. QCT categorized no patients having pathologic fractures with healthy bone density, 14 (12.3%) with osteopenia, and 100 (87.7%) with osteoporosis. T-score DXA, trabecular BMD QCT, and cortical BMD QCT correlated weakly. Trabecular BMD QCT and cortical BMD QCT classified osteoporosis with decreased bone mineral density (AUC 0.680; 95% CI 0.618-0.743 and AUC 0.617; 95% CI 0.553-0.682, respectively). T-score DXA could not predict prevalent pathologic fractures. In control groups, each consisting of 50 patients, DXA and QCT were significant classifiers to predict prevalent pathologic fractures.ConclusionOur results support that volumetric measurements by QCT in preselected subjects represent a more sensitive method for the diagnosis of osteoporosis and prediction of fractures compared to DXA.

Einleitung Eine fehlerhaft diagnostizierte Knochendichte birgt das Risiko eine Osteoporose zu verschleiern. Vor allem die Unterschätzung der Ausprägung kann zu vermeidbaren Frakturen führen. Dual Energy X-Ray Absorptiometry (DXA) gilt trotz nachweislicher Einschränkungen weiterhin als Goldstandard zur Diagnose der Osteoporose nach WHO-Klassifikation, während Messungen mit der quantitativen Computertomografie (QCT) bei stark erniedrigter Knochendichte zur Frakturrisikoeinschätzung herangezogen werden sollen.

BACKGROUND:Surgical decompression is the intervention of choice for lumbar spinal stenosis (LSS) when non-operative treatment has failed. Apart from acute complications such as hematoma and infections, same-level recurrent lumbar stenosis and adjacent-segment disease (ASD) are factors that can occur after index lumbar spine surgery.OBJECTIVE:The aim of this retrospective case series was to evaluate the outcome of surgery and the odds of necessary revisions.METHODS:Patients who had undergone either decompressive lumbar laminotomy or laminotomy and spinal fusion due to lumbar spinal stenosis (LSS) between 2000 and 2011 were included in this analysis. Demographic, perioperative and radiographic data were collected. Clinical outcome was evaluated using numeric rating scale (NRS), the symptom subscale of the adapted version of the german Spinal Stenosis Measure (SSM) and patient-sreported ability to walk.RESULTS:Within the LSS- cohort of 438 patients, 338 patients underwent decompression surgery only, while instrumentation in addition to decompression was performed in 100 cases (22.3%). 38 patients had prior spinal operations (decompression, disc herniation, fusion) either at our hospital or elsewhere. Thirty-five intraoperative complications were documented with dural tear with CSF leak being the most common (33/35; 94.3%). Postoperative complications were defined as complications that needed surgery and differentiated between immediate postoperative complications (⩽ 3 weeks post operation) and complications that needed revisions surgery at a later date. Within all patients 51 revisions were classified as immediate complications of the index operation with infections, neurological deficits and hematoma being the most common. Within this group only 22 patients had fusion surgery in the first place, while 29 were treated by decompression. Revision surgery was indicated by 53 patients at a later date. While 4 patients decided against surgery, 49 revision surgeries were planned. 28 were performed at the same level, 10 at the same level plus an adjacent level, and 10 were executed at index level with indications of adjacent level spinal stenosis, adjacent level spinal stenosis plus instability and stand-alone instability. Pre- operative VAS score and ability to walk improved significantly in all patients.CONCLUSIONS:While looking for predictors of revision surgery due to re-stenosis, instability or same/adjacent segment disease none of these were found. Within our cohort no significant differences concerning demographic, peri-operative and radiographic data of patients with or without revision wer noted. Patients, who needed revision surgery were older but slightly healthier while more likely to be male and smoking. Surprisingly, significant differences were noted regarding the distribution of intraoperative and early postoperative complications among the 6 main surgeons while these weren't obious within the intial index group of late revisions.

Einleitung Die Quantitative Computertomografie (QCT) findet im klinischen Alltag auf Grund der dreidimensionalen Einschätzung des Knochenmineralgehalts (BMD) und der separaten Beurteilung von trabekulärer und kortikaler Struktur häufig Anwendung. Ein Ausschluss von Wirbelkörpern mit sklerotischen trabekulären Arealen erlaubt eine präzise Densitometrie.

Background: Sufficient primary stability is mandatory for successful bony prosthetic incorporation. Therefore, defined micromotion values of 150 pm should not be exceeded as higher values might compromise the ingrowth of bone trabeculae to the implant surface. The aim of this study was to evaluate the primary stability of different cementless disc prosthesis in a cadaver model. Methods: Four different implants with different anchoring and bearing concept were tested with a target level of L4/5. 26 specimens were randomly allocated to 1 of the 4 different implants with 6 speciments in each group. Two groups were formed depending on the anchoring (spikes vs. fin) and bearing concept (non -/semi-vs. constrained). Each implant was tested regarding primary stability in a hydraulic simulator allowing simultaneous polyaxial segment movements and axial loading. The measurements were recorded on the lower plate of the prosthesis. Findings: The majority of the implants showed micromotion values below 200 pm in all planes. Only one prosthesis presented borderline longitudinal amplitudes that were significant higher than the other planes. Furthermore, significant differences were observed in the sagittal plane when comparing spike and keel anchoring. Spike anchoring implants showed superior tresults to keel anchoring implants (40 pm vs. 55 pm; p = .039), while the non-/semi-constrained bearing concept was more advantageous compared to constrained group (40 pm vs. 63 pm; p = .001). Interpretation: Spike anchoring and non-constrained implants might provide better primary stability.

Abstract Background High primary stability is the key prerequisite for safe osseointegration of cementless intervertebral disc prostheses. The aim of our study was to determine the primary stability of intervertebral disc prostheses with two different anchoring concepts – keel and spike anchoring. Methods Ten ActivL intervertebral disc prostheses (5 x keel anchoring, 5 x spike anchoring) implanted in human cadaver lumbar spine specimens were tested in a spine movement simulator. Axial load flexion, extension, left and right bending and axial rotation motions were applied on the lumbar spine specimens through a defined three-dimensional movement program following ISO 2631 and ISO/CD 18192-1.3 standards. Tri-dimensional micromotions of the implants were measured for both anchor types and compared using Student’s T-test for significance after calculating 95 % confidence intervals. Results In the transverse axis, the keel anchoring concept showed statistically significant (p < 0.05) lower mean values of micromotions compared to the spike anchoring concept. The highest micromotion values for both types were observed in the longitudinal axis. In no case the threshold of 200 micrometers was exceeded. Conclusions Both fixation systems fulfill the required criteria of primary stability. Independent of the selected anchorage type an immediate postoperative active mobilization doesn’t compromise the stability of the prostheses.

Despite the high potential of healthy bone to regenerate, the reconstruction of large bone defects remains a challenge. Due to the lack of mechanical stability of existing bone substitutes, recently developed degradable metallic alloys are an interesting alternative providing higher load-bearing capabilities. Degradable iron-based alloys therefore might be an attractive innovation. To test the suitability of a newly-designed iron-based alloy for such applications, an animal experiment was performed. Porous iron-based degradable implants with two different densities and a control group were tested. The implants were positioned in the proximal tibia of Merino sheep. Over a period of 6 and 12 months, blood and histological parameters were monitored for signs of inflammation and degradation. In the histological evaluation of the implants` environment we found degraded alloy particles, but no inflammatory reaction. Iron particles were also found within the popliteal lymph nodes on both sides. The serum blood levels of phosphorus, iron and ferritin in the long term groups were elevated. Other parameters did not show any changes. Iron-based degradable porous bone replacement implants showed a good biocompatibility in this experiment. For a clinical application, however, the rate of degradation would have to be significantly increased. Biocompatibility would then have to be re-evaluated.

m an go sto ck / sto ck .ad ob e.c om (S ym bo lb ild m it Fo to m od ell en ) Neben lumbalen Schmerzen beschreibt der Patient, dass die Beschwerden auch in die Leiste und das Ab­ domen ausstrahlen. Die Einnahme von Ibuprofen 600 mg habe keine Linderung gebracht. Bei bekann­ tem arteriellen Hypertonus, Diabetes mellitus, PAVK sowie koronarer Herkrankheit (KHK) finden sich fol­ gende klinische Befunde: Patient wach und ansprech­ bar, deutlich schwitzend; Blutdruck 170/100 mmHg, Herzfrequenz 95, Atemfrequenz 14; Druckschmerz über der unteren Lendenwirbelsäule (LWS); Lasègue beidseits negativ; diffuse Hypästhesie beider Unter­ schenkel; kein eindeutiges motorisches Defizit; Hüften bewegungseingeschränkt, jedoch nicht schmerzhaft. Auf dem Röntgenbild der LWS zeigen sich multiple Osteochondrosen und Spondylarthrosen sowie eine Wirbelkörperfraktur.