Acromioclavicular joint suture button repair leads to coracoclavicular tunnel widening.

PURPOSE: Biomechanical evaluation of three different suture button devices used in acromioclavicular joint repair and analysis of their effect on post-testing tunnel widening. METHODS: Eighteen human shoulder girdles were assigned into three groups with a similar mean bone mineral density. Three different single-tunnel acromioclavicular repair devices were tested: (1) AC TightRope® with FiberWire; (2) AC Dog Bone™ Button with FiberTape; (3) Low Profile AC Repair System. Biomechanical testing was performed simulating the complex movement of the distal clavicle as follows. A vertical load of 80 N was applied continuously. The rotation of the clavicle about its long axis was set at 10° anterior and 30° posterior for 2500 cycles at 0.25 Hz. The horizontal translation of the clavicle was set at 6 mm medial and 6 mm lateral for 10,000 cycles at 1 Hz. The coracoclavicular distance was measured before and after testing. After testing, each sample underwent micro-CT analysis. Following 3D reconstruction, the area of the bone tunnels was measured at five defined cross sections. RESULTS: In TightRope® and Dog Bone™ groups, all samples completed testing, whereas in the Low Profile group, three out of six samples showed system failure. The mean absolute difference of coracoclavicular distance after testing was significantly greater in the Low Profile group compared to TightRope® and Dog Bone™ groups (4.3 ± 1.3 mm vs 1.9 ± 0.7 mm vs 1.9 ± 0.8 mm; p = 0.001). Micro-CT analysis of the specimens demonstrated significant tunnel widening in the inferior clavicular and superior coracoid regions in all three groups (p < 0.05). CONCLUSION: Significant tunnel widening can be observed for all devices and is primarily found in the inferior parts of the clavicle and superior parts of the coracoid. The Low Profile AC Repair System showed inferior biomechanical properties compared to the AC TightRope® and AC Dog Bone™ devices. Therefore, clinicians should carefully select the type of acromioclavicular repair device used and need to consider tunnel widening as a complication.

Vaginal laceration leading to air embolism during consensual sexual intercourse.

Vaginal injuries with clinical complications apart from local bleeding following sexual intercourse are thought to be rare events that have recently fostered a discussion on the topic. We report a case of a vaginal laceration resulting in death caused by air embolism in a non-pregnant woman during consensual sexual intercourse with digital and penile penetration. Hysterectomy and a preexisting vaginal injury were additional risk factors present in this case. Besides case history and autopsy findings, histological examination of the vaginal lesion and postmortem computer tomography (PMCT) helped in diagnosing the cause of death and underlying pathophysiological mechanisms.

Determinants of health-related quality of life among homeless individuals during the COVID-19 pandemic.

OBJECTIVE: To clarify which variables are associated with the health-related quality of life (HRQoL) among homeless individuals during the COVID-19 pandemic. STUDY DESIGN: Cross-sectional research. METHODS: Data were taken from the Hamburg survey of homeless individuals (n = 151). HRQoL was assessed using the EQ-5D tool. More precisely, the EQ-5D-5L questionnaire was used to quantify problems in five health dimensions (i.e. mobility, self-care, usually activities, pain/discomfort, anxiety/depression), and its visual analog scale (EQ-VAS) was used to record the according self-rated health status. Explanatory variables include sex, age, education, marital status, country of origin, health insurance, and chronic alcohol consumption. RESULTS: With regard to HRQoL, most frequently, problems were reported as pain/discomfort (47.3%), followed by anxiety/depression (32.4%), mobility (29.7%), usual activities (20.7%) and self-care (4.6%). The mean EQ-VAS score was 75.34 (SD 22.23; range 1-100), and the mean EQ-5D-5L index was 0.84 (SD 0.23; range 0.32-1). Regressions showed increasing problems in mobility and self-care with higher age, whereas EQ-VAS was positively associated with younger age. Furthermore, EQ-5D-5L index was positively associated with younger age and higher education. Summarized, among this cohort, a higher age is associated with a lower HRQoL. CONCLUSION: Remarkably high EQ-VAS values and rather few problems in the five dimensions investigated here were reported among the homeless individuals during the COVID-19 pandemic particularly compared with the general population. Moreover, study findings particularly stress the link between higher age and lower HRQoL among homeless individuals. This knowledge is important to address homeless individuals at risk of poor HRQoL. Longitudinal studies are required to confirm the given findings.

All-suture anchor pullout results in decreased bone damage and depends on cortical thickness.

PURPOSE: To evaluate the influence of cortical and cancellous bone structure on the biomechanical properties of all-suture and conventional anchors and compare the morphological bone damage after their failure. The hypothesis of the study is that all-suture anchor pullout is less invasive and that the pullout force is influenced by the cortical thickness. METHODS: Thirty human humeri were biomechanically tested as follows: starting with a load cycle from 20 to 50 N, a stepwise increase of the upper peak force by 0.05 N for each cycle at a rate of 1 Hz was performed. Analysis included maximum pullout strength for three different anchor implantation angles (45°, 90°, 110°) of the two anchor types. After anchor pullout, every sample underwent micro-CT analysis. Bone mineral density (BMD) and cortical thickness were determined at the anchor implantation site. Furthermore, the diameter of the cortical defect and the volume of the bone cavity were identified. RESULTS: The maximum pullout strength of all-suture anchors demonstrates a strong correlation to the adjacent cortical thickness (r = 0.82, p ≤ 0.05) with at least 0.4 mm needed to withstand 200 N. No correlation could be seen in conventional anchors. Moreover, no correlation could be detected for local BMD in both anchors. All-suture anchors show a significantly narrower cortical defect as well as a smaller bone cavity following pullout (4.3 ± 1.3 mm vs. 5.3 ± 0.9 mm, p = 0.037; 141 mm3 vs. 212 mm3; p = 0.009). The cortical defect is largest if the anchors are placed at a 45° angle. CONCLUSION: In contrast to conventional anchors, the pullout force of all-suture anchors depends on the thickness of the humeral cortex. Furthermore, all-suture anchors show a significantly smaller cortical defect as well as decreased bone damage in the case of pullout. Therefore, the clinical implication of this study is that all-suture anchors are advantageous due to their bone preserving ability. Also, intraoperative decortication should not be performed and cortical thickness should be preoperatively evaluated to decrease the risk of anchor failure.

Cartilage calcification is associated with histological degeneration of the knee joint: a highly prevalent, age-independent systemic process.

OBJECTIVES: To investigate if cartilage calcification (CC) is a systemic process, the purpose of this study was to determine the prevalence and the amount of meniscal/hyaline CC of the knee joint in the general population by high-resolution imaging (DCR) and to evaluate the association between CC with cartilage degeneration and age. METHODS: Cross-sectional DCR-study of 180 knee joints of 90 donors (42 female/48 male, mean age 62.3y). Histological hyaline (OARSI) and meniscal (Krenn) cartilage degeneration was determined of all knees. RESULTS: CC was observed in 100% of the donors (bilaterally in 98%), hyaline cartilage calcification (HCC) in 92% and meniscal calcification (MC) in 100%. CC was detected in more than three out of six distinct cartilage areas in 84.4% of all knees. The mean amount of CC correlated between both sides of donors, the different analyzed areas of the knee joint and between the various types of cartilage structures. There was more calcification in meniscal than in hyaline cartilage (factor 5.3) and in the medial than the lateral compartment (factor 1.2). HCC/MC were already detectable with only mild cartilage lesions and the amount correlated with histological cartilage degeneration, but not with age. CONCLUSIONS: The present study provides evidence that meniscal and hyaline CC occurs in a pattern that is compatible with CC being a systemically driven process and that meniscal fibrocartilage is more prone to calcification than hyaline cartilage. Furthermore, the age-independent association between the amount of CC and the grade of degeneration in both hyaline and meniscal cartilage, suggests that CC is an obligatory early event in initiating cartilage degeneration.

Age-related changes of micro-morphological subchondral bone properties in the healthy femoral head.

OBJECTIVE: Alterations in the subchondral bone (SCB) are likely to play a decisive role in the development of osteoarthritis (OA). Since aging represents a major risk factor for OA, the aim of the current study was to assess the microstructural changes of the subchondral bone in the femoral head during aging. DESIGN: Femoral heads and matched iliac crest biopsies of 80 individuals (age 21-99 years) were collected post-mortem. The bone microstructure of the subchondral trabecular bone as well as the cartilage thickness (Cg.Th) and subchondral bone plate thickness (SCB.Th) were quantified using histomorphometry. The different subregions of the SCB were also imaged by quantitative backscattered electron imaging (qBEI) in 31 aged cases to assess the bone mineral density distribution (BMDD). RESULTS: The detected linear decline of bone volume per tissue volume (BV/TV) in the femoral head with aging (Slope, 95% CI: -0.208 to -0.109 %/yr.) was primarily due to a decrease in trabecular thickness (Tb.Th, Slope, 95% CI: -0.774 to -0.343 µm/yr). While SCB.Th declined with aging (Slope, 95% CI: -1.941 to -0.034 µm/yr), no changes in Cg.Th were detected (Slope, 95% CI: -0.001 to 0.005 mm/yr). The matrix mineralization of the subchondral bone was lower compared to the trabecular bone and also decreased with aging. CONCLUSIONS: Regular changes of the SCB during aging primarily involve a reduction of Tb.Th, SCB.Th and matrix mineralization. Our findings facilitate future interpretations of early and late OA specimens to decipher the role of the SCB in OA pathogenesis.

[Postmortem imaging of the lung in cases of COVID-19 deaths]. / Postmortale Bildgebung der Lunge bei COVID-19-Todesfällen.

CLINICAL/METHODOLOGICAL ISSUE: COVID-19 is a new viral disease that is associated with inflammatory pulmonary changes which can be detected in computed tomography (CT). So far postmortem CT (PMCT) has not been used as a screening instrument for the evaluation of deaths with and without autopsy. In this respect, its validity has to be proved in comparison to clinical-radiological experiences. STANDARD RADIOLOGICAL METHODS: Postmortem CT METHODICAL INNOVATIONS: So far, PMCT can be regarded as a methodological innovation that has not yet been sufficiently evaluated for pneumonia. PERFORMANCE: CT in clinical routine has a high sensitivity for pneumonia. However, to what extent postmortem artifacts are relevant to PMCT still has to be determined. ACHIEVEMENTS: There is still no standard procedure for the postmortem radiological diagnosis of COVID-19 disease. Despite postmortem artifacts, PMCT can provide valuable information about the presence of pneumonia with interstitial character, especially without autopsy. PRACTICAL RECOMMENDATIONS: PMCT is particularly useful in the assessment of suspected cases of COVID-19 pneumonia for morphological assessment in the context of monitoring deaths in the current pandemic situation.

Prospective study of device-related complications in intensive care unit detected by virtual autopsy.

BACKGROUND: There has been increasing use of invasive techniques, such as extracorporeal organ support, in intensive care units (ICU), and declining autopsy rates. Thus, new measures are needed to maintain high-quality standards. We investigated the potential of computed tomography (CT)-based virtual autopsy to substitute for medical autopsy in this setting. METHODS: We investigated the potential of virtual autopsy by post-mortem CT to identify complications associated with medical devices in a prospective study of patients who had died in the ICU. Clinical records were reviewed to determine the number and types of medical devices used, and findings from medical and virtual autopsies, related and unrelated to the medical devices, were compared. RESULTS: Medical and virtual autopsies could be performed in 61 patients (Group M/V), and virtual autopsy only in 101 patients (Group V). In Group M/V, 41 device-related complications and 30 device malpositions were identified, but only with a low inter-method agreement. Major findings unrelated to a device were identified in about 25% of patients with a high level of agreement between methods. In Group V, 8 device complications and 36 device malpositions were identified. CONCLUSIONS: Device-related complications are frequent in ICU patients. Virtual and medical autopsies showed clear differences in the detection of complications and device malpositions. Both methods should supplement each other rather than one alone for quality control of medical devices in the ICU. Further studies should focus on the identification of special patient populations in which virtual autopsy might be of particular benefit. CLINICAL TRIAL REGISTRATION: NCT01541982.

Articular cartilage calcification of the hip and knee is highly prevalent, independent of age but associated with histological osteoarthritis: evidence for a systemic disorder.

OBJECTIVES: Based on the concept of a systemic predisposition for articular cartilage calcification (CC), the aim of this study was to determine the prevalence and amount of bilateral CC of hip and knee joints in an unselected sample cohort by high-resolution digital contact radiography (DCR) and to analyze the association of CC with histological OA. METHODS: Both hip and knee joints of 87 donors (48 m and 39 f; mean age 62) were analyzed by DCR in this post-mortem study of an unselected cohort of donors. Histological OA (OARSI) of the main load bearing area of femoral heads and medial femoral condyles was determined. RESULTS: The prevalence of CC of the femoral head was 96.6%, of the knee 94.3%. Bilateral calcification was detected in 79.3% of hips and 86.2% of knees. Concomitant CC of all four joints was detected in 69.0% of donors. There was no difference between the amount of CC of hips and knees (P = 0.47). The amount of CC of any given hip or knee correlated with that of the contralateral hip (rs = 0.54, P < 0.001) or knee (rs = 0.50, P < 0.001). There was a correlation between the amount of CC and histological OA (hips rs = 0.48, P < 0.001, knees rs = 0.30, P = 0.004), but not between CC and age (hips rs = -0.09, P = 0.42; knees rs = 0.10, P = 0.34). CONCLUSIONS: These data support the concept that articular CC occurs as the result of a systemic disorder. CC appears to be an early element of hip and knee OA pathogenesis independent of age.

Optimising magnetic resonance imaging-based evaluation of the ossification of the medial clavicular epiphysis: a multi-centre study.

Evaluation of the ossification of the medial clavicular epiphysis plays a key role in forensic age estimation, particularly in determining whether the age of 18 has been attained. A key research objective in the forensic age estimation field at present is to establish non-X-ray methods for investigating the clavicle. This paper looks at the use of magnetic resonance imaging for evaluating the developmental state of the medial clavicular epiphysis. Clavicle specimens obtained from autopsies of 125 female and 270 male subjects aged from 10 to 30 were examined using a 3-T magnetic resonance scanner. One FFE-3D-T1 gradient echo sequence and one 2D-T2 turbo spin echo sequence were acquired. In each case, two investigators undertook a consensual determination of the ossification stage of the medial clavicular epiphysis using recognised classification systems. To determine intra-observer and inter-observer agreement, 80 clavicle specimens were subjected to repeat evaluation. We present statistics relating to the ossification stages. The inclusion of established sub-stages of clavicular ossification offers an additional option for determining whether a subject has attained the age of 18 which is applicable in both sexes. For both sexes, the minimum ages for ossification stages 4 and 5 allow conclusions to be drawn about a subject's age at a point in time lying several years in the past. Magnetic resonance imaging is a valid investigatory procedure for determining the ossification stage of the medial clavicular epiphysis. This paper makes a contribution to expanding the range of methods available for forensic age estimation.

[Mortui vivos docent : The dead teach the living]. / Mortui vivos docent : Die Toten lehren die Lebenden.

There are considerable similarities and intersections between forensic medicine and emergency medicine. This applies especially to frustraneously resuscitated patients or other lethal clinical courses of traumatized patients who are subject to latter forensic autopsy. Cooperation between departments of emergency and forensic medicine not only has emergency medical training potential, but also the possibility of retrospective evaluation of medical emergency measures - both in individual cases and with regard to epidemiological aspects. In particular, the widespread registration of autopsied pre-hospital trauma deaths that occurred despite on-scene resuscitation attempts is useful. The pre-hospital situation represents a hotspot, but also a blind spot in the overall trauma mortality. In recent clinical registers, preclinical deaths go mostly unrecorded, despite the undisputed benefits of clinical registers.

The role of patient-mode high-resolution peripheral quantitative computed tomography indices in the prediction of failure strength of the elderly women's thoracic vertebral body.

UNLABELLED: The correlations between the failure load of 20 T12 vertebral bodies, their patient-mode high-resolution peripheral quantitative computed tomography (HR-pQCT) indices, and the L1 areal bone mineral density (aBMD) were investigated. For the prediction of the T12 vertebral failure load, the T12 HR-pQCT microarchitectural parameters added significant information to that of L1 aBMD and to that of cortical BMD, but not to that of T12 vertebral BMD and not to that of T12 trabecular BMD. INTRODUCTION: HR-pQCT is a new in vivo imaging technique for assessing the three-dimensional microarchitecture of cortical and trabecular bone at the distal radius and tibia. But little is known about this technique in the direct measurement of vertebral body. METHODS: Twenty female donors with the mean age of 80.1 (7.6) years were included in the study. Dual X-ray absorptiometry of the lumbar spine and femur was performed. The spinal specimens (T11/T12/L1) were dissected, scanned using HR-pQCT scanner, and mechanically tested under 4° wedge compression. The L1 aBMD, T12 patient-mode HR-pQCT indices, and T12 vertebral failure loads were analyzed. RESULTS: For the prediction of vertebral failure load, the inclusion of BV/TV into L1 aBMD was the best model (R (2) = 0.52), Tb.N and Tb.Sp added significant information to the L1 aBMD and to the cortical BMD, but none of the vertebral microarchitectural parameters yielded additional significant information to the trabecular BMD (or BV/TV) and to the vertebral BMD. CONCLUSION: Vertebral microarchitectural parameters obtained from the patient-mode HR-pQCT analysis provide significant information on bone strength complementary to that of aBMD and to that of cortical BMD, but not to that of vertebral BMD and not to that of trabecular BMD.

Unilateral laminoplasty with lateral mass screw fixation for less invasive decompression of the cervical spine: a biomechanical investigation.

PURPOSE: To compare the stabilization behavior of additional unilateral mass screw fixation with current standard procedures in patients with cervical spondylotic myelopathy (CSM) in a biomechanical study. METHODS: Ten human C2-C7 cervical specimens were tested under various segment conditions: native (NAT), laminoplasty (LP), laminoplasty with unilateral (LPU) or bilateral (LPB) stabilization, laminectomy with bilateral stabilization (LCB), and laminectomy. The instrumented level was from C3 to C6. For each segment condition, in vitro flexibility tests were performed using a spinal simulator and an applied load of ±2.5 Nm. The three-dimensional kinematics of the entire cervical segment in three main loading directions [flexion-extension (FE), lateral bending (LB), and axial rotation (AR)] was measured with an ultrasonic motion analysis system. Analysis of variance followed by a post hoc test was used to determine differences under the specific segment conditions to assess the parameters range of motion (ROM) and neutral zone (NZ). RESULTS: For FE, the total ROM of laminoplasty (-6.3% difference to NAT) and laminectomy (+6.4%) remained at the level of native (p > 0.56), whereas the instrumentations LPU (-37.1%), LPB (-44%), and LCB (-43.2%) lead to significant reductions (p < 0.01) without significant differences in LPU to LPB and LCB (p > 0.38). The same results were found with LB. For AR, the stabilization of all instrumentations was less pronounced, but had the same tendency seen for FE and AR. The results for the NZ showed equivalent values as that for ROM. CONCLUSION: The degree of stabilization was as expected for LC and LCB; namely, no stabilization for LC and maximal stabilization for LCB. LPU exhibited almost the same degree of stabilization as LCB. LPU could be a new treatment option for less invasive decompression for multilevel CSM.

[Periprosthetic and interimplant femoral fractures: Biomechanical analysis]. / Periprothetische und interimplantäre Femurfrakturen : Biomechanische Analyse.

BACKGROUND: The requirements for treatment of femoral fractures are increasing with the rising age of the patients. The aim of this study was to evaluate femoral stiffness and the fracture risk after inserting different implants and implant combinations. METHODS: A total of 48 cadaveric femors were harvested and 8 groups were randomized on the basis of the bone mineral density (BMD). Different osteosyntheses following prosthetic stem implantation (hip and knee prostheses) were performed and compared with native femurs. All specimens were biomechanically tested in a four-point bending until fracture. RESULTS: The insertion of a femoral stem decreases the stiffness by approximately 33%. Ipsilateral retrograde nailing reduces the force to failure even more. This instable situation can be stabilized by a lateral locking compression plate. The most stable situation occurred in the presence of two cemented stems. CONCLUSION: Taken together these results clearly indicate that a hip prosthesis significantly weakens the femur, whereas two stems produce the most stable situation at all. The situation of a hip prosthesis and an retrograde nail should be avoided or covered by a bridging-osteosynthesis. In clinical practice an extramedullary fixation technique for distal femoral fractures should be preferred.

A low-radiation exposure protocol for 3D QCT of the spine.

SUMMARY: Cadaver and phantom measurements and simulations confirmed that radiation exposure in 3D QCT of the spine can be reduced if 80 kV instead of 120 kV protocols are used; 120 mAs and slice thicknesses of 1-1.3 mm should be usable but obese patient will require higher milliampere-second settings. PURPOSE: To develop a low-radiation exposure CT acquisition protocol for 3D QCT of the thoracolumbar spine. METHODS: Twenty-six cadavers were scanned with a standard protocol of 120 kV, 100 mAs and with a low-dose protocol using 90 kV, 150 mAs. The scan range included the vertebrae T6 to L4. Each vertebra was segmented and the integral volume and BMD of the total vertebral body were determined. Effective dose values were estimated. The impact of milliampere-second reduction on image quality was simulated by adding noise. RESULTS: One hundred ninety-six vertebrae were analyzed. Integral volume as well as integral BMD correlated significantly (p < 0.001) between standard and low-dose protocols (volume, r (2) = 0.991, residual root mean square (RMS) error, 0.77 cm(3); BMD, r (2) = 0.985, RMS error, 4.21 mg/cm(3)). The slope significantly differed from 1 for integral BMD but not for volume hinting at residual field inhomogeneity differences between the two voltage settings that could be corrected by cross-calibration. Compared to the standard protocol, effective dose was reduced by over 50 % in the low-dose protocol. Adding noise in the 90 kV images to simulate a reduction from 150 to 100 mAs did not affect the results for integral volume or BMD. CONCLUSIONS: For 3D QCT of the spine, depending on scanner type, 80 or 90 kV instead of 120 kV protocols may be considered as an important option to reduce radiation exposure; 120 mAs and slice thicknesses of 1-1.5 mm are usable if segmentation is robust to noise. In obese patients, higher milliampere-second settings will be required.

Accuracy of trabecular structure by HR-pQCT compared to gold standard µCT in the radius and tibia of patients with osteoporosis and long-term bisphosphonate therapy.

UNLABELLED: Despite an increasing use of high-resolution peripheral quantitative computed tomography (HR-pQCT) to evaluate bone morphology in vivo, there are reservations about its applicability in patients with osteoporosis and antiresorptive therapy. This study shows that HR-pQCT provides acceptable in vivo accuracy for bone volume fraction (BV/TV) in patients with osteoporosis and bisphosphonate (BP) treatment. INTRODUCTION: The primary aim was to analyze agreement of trabecular structure between HR-pQCT and gold standard microtomography (µCT) in patients with osteoporosis and long-term BP therapy. METHODS: In the BioAsset study, we analyzed cadaver radii and tibiae of 34 postmenopausal females (81.1 ± 7.1 years) with osteoporosis (no BP n = 22, 1-5 years BP n = 5, >5 years BP n = 7). Two HR-pQCT protocols (patient-mode and µCT-mode) were compared with gold standard µCT after image registration. Undecalcified histological sections were obtained to quantify nonmineralized bone matrix. Bland-Altman plots illustrated methodological agreement. Multiple regression analysis was used to test for variables associated with method agreement. RESULTS: In the radius and tibia, patient-mode HR-pQCT derived indices including bone volume fraction, trabecular number, and trabecular separation correlated well with gold standard µCT (R(2) = 0.78 - 0.88) except for trabecular thickness (R(2) = 0.11). Bland-Altman plots illustrated adequate agreement for bone volume fraction. Lower agreement of trabecular number and trabecular separation improved with decreasing structural impairment at the tibia only. Trabecular thickness was not appropriately assessed with HR-pQCT at both skeletal sites. Higher agreement for bone volume fraction was associated with increasing tissue mineral density in the tibia. CONCLUSIONS: HR-pQCT provides acceptable in vivo accuracy for BV/TV in patients with osteoporosis and BP treatment. Higher TMD was associated with higher BV/TV accuracy in vivo. Overall, methodological agreement got less accurate with increasing structural impairment in the tibia.

Effects of long-term alendronate treatment on bone mineralisation, resorption parameters and biomechanics of single human vertebral trabeculae.

Due to their well-established fracture risk reduction, bisphosphonates are the most frequently used therapeutic agent to treat osteoporosis. Bisphosphonates reduce fracture risk by suppressing bone resorption, but the lower bone turnover could have a negative impact on bone quality at the tissue level. Here, we directly assess the structural and mechanical characteristics of cancellous bone from the lumbar vertebrae (L5) in non-treated osteoporotic controls (n=21), mid-term alendronate-treated osteoporotic patients (n=6), and long-term alendronate-treated osteoporotic patients (n=7). The strength and toughness of single trabeculae were evaluated, while the structure was characterised through measurements of microdamage accumulation, mineralisation distribution, and histological indices. The alendronate-treated cases had a reduced eroded surface (ES/BS, p<0.001) and a higher bone mineralisation in comparison to non-treated controls (p=0.037), which is indicative of low turnover associated with treatment. However, the amount of microdamage and the mechanical properties were similar among the control and treatment groups. As the tissue mineral density (TMD) increased significantly with alendronate treatment compared to non-treated osteoporotic controls, the reduction in resorption cavities could counterbalance the higher TMD allowing the alendronate-treated bone to maintain its mechanical properties and resist microdamage accumulation. A multivariate analysis of the possible predictors supports the theory that multiple factors (e.g., body mass index, TMD, and ES/BS) can impact the mechanical properties. Our results suggest that long-term alendronate treatment shows no adverse impact on mechanical cancellous bone characteristics.

[Causes, injuries, therapy and possibilities of prevention of equine-related accidents. Results of a 2-center-study]. / Ursachen, Verletzungen, Therapie und Präventionsmöglichkeiten von Unfällen im Reitsport. Ergebnisse einer 2-Center-Studie.

BACKGROUND: Horse riding is associated with a high rate of injuries. The possibilities of prevention are limited because of deficient knowledge about the causes and mechanisms of equine-related accidents. In the present study 198 equine-related accidents were analyzed and based on these data risk groups were identified and guidelines to improve safety in horse riding were formulated. MATERIAL AND METHODS: In this 2-center study the accidents of 169 riders over a period of 12 months were analyzed. Data on equine-related patterns of injury and the resulting treatment were collated from the clinical records. Additionally, a questionnaire was completed on the day of trauma by the patients, which covered age, gender, the cause and mechanism of injury and the use of safety equipment at the time of the accident. RESULTS: There were 169 (85.5%) female and 29 (14.5%) male riders with a median age of 27.2 years (range 5-74 years). Of the riders 55 (27.8%) were aged 18 years or younger, 134 (67.7%) riders were treated as outpatients while 64 (32.3%) required hospitalization, 51 (25.8%) required surgical treatment, 66 (33.3%) used a helmet and 14 (7.1%) a body protector at the time of accident. DISCUSSION: Equestrians wear helmets increasingly more when riding but the willingness to wear body protectors is disappointing. Protective headgear has been proven to reduce the risk of injuries but based on these data a positive effect of body protectors could not be shown. In this study safety vest users suffered from injuries of the upper body more often than those who did not wear a body protector. Children and adolescents often overestimate their skills; therefore, teaching and supervision of inexperienced young riders along with the use of protective equipment can prevent major injuries.

[Ligament bracing--augmented cruciate ligament sutures: biomechanical studies of a new treatment concept]. / "Ligament bracing"--die augmentierte Kreuzbandnaht: Biomechanische Grundlagen für ein neues Behandlungskonzept.

BACKGROUND: In the context of acute knee dislocations, suture repair of ruptured cruciate ligaments leads to good clinical results in 80% of cases. Disadvantages are low primary stability and subsequently secondary elongation of the sutured ligaments. In the present study, we compared primary stability of suture repair, reinforced by different suture augments, to cruciate ligament reconstruction. OBJECTIVE: The concept of ligament bracing with transosseous suture repair of the cruciate ligaments and additional suture augmentation is biomechanically superior to cruciate ligament reconstruction. MATERIAL AND METHODS: A total of 42 porcine knee joints divided into seven groups were examined. The stability of four different suture/augmentation combinations were compared to cruciate ligament reconstruction with human hamstring tendons. The investigational setup consisted of testing 1000 cycles with 20 N to 154 N load in a.-p. translation and 60° flexion. Elongation and load to failure were measured. RESULTS: Neither reconstruction (3.13 ± 1.65 mm; 362 ± 51 N) nor augmented suture repair (1.89-2.5 mm; 464-624 N) achieved the primary stability of the intact cruciate ligament (0.63 ± 0.34 mm, 1012 ± 91 N). In comparison to ligament reconstruction, all four augmented suture repairs showed minor elongation in the cyclic test and a higher load to failure. The isolated suture repair showed poor results (6.79 ± 4.86 mm, 177 ± 73 N). CONCLUSION: Augmented suture repair provides significantly higher stability compared with isolated suture repair and reconstruction with hamstring tendons. The concept of ligament bracing could be a promising future treatment option in acute knee dislocations. Clinical results remain to be seen.