Validation of a novel testing machine for the investigation of the biomechanical properties of lumbar vertebrae in an osteoporotic rat model

BACKGROUND

For the investigation of the biomechanical properties of bone, various testing devices have been described. However, only a limited number have been developed to test the vertebral body of small animals. The aim of this study was to develop and validate a new bone testing device, which investigates the different biomechanical properties in small-animal vertebrae as a whole, three-dimensional unit, respecting its anatomical structure.

METHODS

Thirty-five twelve-week-old female Sprague Dawley rats were utilized. Group 1 was composed of 17 rats with a normal bone metabolism without osteoporosis, while Group 2 consisted of 18 rats with manifest osteoporosis, 8 weeks after ovariectomy. The 5th lumbar vertebra of each animal was tested using the new bone testing device. This device has the ability to be adjusted to the slanted nature of each individual vertebral body and fix the vertebra in a natural position to allow for a non-dislocating axial force application. The device is designed to respect the anatomical three-dimensional shape of the vertebral body, thus avoiding the application of non-anatomic, non-physiological forces and thus preventing a distortion of the biomechanical testing results. The parameters investigated were stiffness, yield load, maximum load and failure load, and the results were compared to current literature values.

RESULTS

The conduction of the biomechanical bone testing of the vertebral bodies with the new device was conductible without any instances of dislocation of the vertebrae or machine malfunctions. Significant differences were found for stiffness, maximum load and failure load between groups, with a lower value in the osteoporotic rats in each parameter tested. The yield load was also lower in the osteoporotic group, however not significantly. The values achieved correlate with those in current literature.

CONCLUSIONS

This study demonstrates that the newly developed testing machine is easy to handle and produces valid data sets for testing biomechanical bone parameters of whole vertebral bodies in an established small animal model. Therefore, it can be utilized, also as reference data, to test different structural properties and changes in vertebral bone, for example, in different metabolic settings or under the influence of different pharmaceutical entities in further studies.

[Postoperative implant-associated osteomyelitis of the shoulder: Hardware-retaining revision concept using temporary drainage]

BACKGROUND

Posttraumatic and postoperative osteomyelitis (PPO) is a subgroup of bone infections with increasing importance. However, to date no standardized reoperation concept exists particularly for patients with PPO of the shoulder region. Therefore the purpose of this study was to evaluate a revision concept including débridement, irrigation, and insertion of temporary drainage with hardware retention until healing.

PATIENTS AND METHODS

A total of 31 patients with PPO were included with a proximal humerus fracture (n = 14), clavicle fracture (n = 10), or AC-joint separation (n = 7). In all, 27 of these patients could be followed for > 1 year.

RESULTS

Hardware retention until fracture or ligament healing could be achieved in > 83%. Six patients required follow-up débridement due to recurrent infections, but then were unremarkable. Clinical outcome showed excellent Constant scores (91.6 ± 2.8).

CONCLUSION

A cost-efficient, simple, and successful revision concept for patients with PPO of the shoulder region is described.

The ATLS(®) classification of hypovolaemic shock: a well established teaching tool on the edge?

Uncontrolled bleeding is the leading cause of shock in trauma patients and delays in recognition and treatment have been linked to adverse outcomes. For prompt detection and management of hypovolaemic shock, ATLS(®) suggests four shock classes based upon vital signs and an estimated blood loss in percent. Although this classification has been widely implemented over the past decades, there is still no clear prospective evidence to fully support this classification. In contrast, it has recently been shown that this classification may be associated with substantial deficits. A retrospective analysis of data derived from the TraumaRegister DGU(®) indicated that only 9.3% of all trauma patients could be allocated into one of the ATLS(®) shock classes when a combination of the three vital signs heart rate, systolic blood pressure and Glasgow Coma Scale was assessed. Consequently, more than 90% of all trauma patients could not be classified according to the ATLS(®) classification of hypovolaemic shock. Further analyses including also data from the UK-based TARN registry suggested that ATLS(®) may overestimate the degree of tachycardia associated with hypotension and underestimate mental disability in the presence of hypovolaemic shock. This finding was independent from pre-hospital treatment as well as from the presence or absence of a severe traumatic brain injury. Interestingly, even the underlying trauma mechanism (blunt or penetrating) had no influence on the number of patients who could be allocated adequately. Considering these potential deficits associated with the ATLS(®) classification of hypovolaemic shock, an online survey among 383 European ATLS(®) course instructors and directors was performed to assess the actual appreciation and confidence in this tool during daily clinical trauma care. Interestingly, less than half (48%) of all respondents declared that they would assess a potential circulatory depletion within the primary survey according to the ATLS(®) classification of hypovolaemic shock. Based on these observations, a critical reappraisal of the current ATLS(®) classification of hypovolaemic seems warranted.

Characteristics of bone metabolism markers during the healing of osteoporotic versus nonosteoporotic metaphyseal long bone fractures: a matched pair analysis

PURPOSE

The activity and metabolism of fracture healing can be monitored quantitatively by measuring bone turnover markers (BTMs) in serum or urine. However, in osteoporotic bone, the exact metabolism processes during the healing of metaphyseal fractures remain unknown. There is no diagnostic approach which currently allows dynamic insight into the fracture healing processes in order to monitor the progression of healing and to assist in therapeutic decision making.

METHODS

Between March 2007 and February 2009, 30 patients over 50 years of age who suffered a metaphyseal fracture were included in our study. The levels of the osteoanabolic marker BAP (bone-specific alkaline phosphatase) and osteocatabolic marker β-CTX [crosslinked C-(CTX)-telopeptide-of-type-I-collagen] were monitored during the fracture healing of osteoporotic and nonosteoporotic fractures for a duration of 8 weeks.

RESULTS

After an initial decrease of BAP in the first week, the BAP level steadily increased through the fourth week in both groups. The levels of BAP in the osteoporotic group surpassed the healthy group. β-CTX steadily increased in healthy bone up to the fourth week; in osteoporotic bone, β-CTX first increased and, thereafter, decreased from the first week onwards.

CONCLUSIONS

In this work, the first molecular biological aspects of osteoporotic fracture healing have been uncovered, helping to explain the mechanisms of delayed fracture healing in osteoporotic bone. The early decrease of reduced β-CTX as well as elevated BAP during the healing process may be the first aspects within the delayed healing of osteoporotic bone. Further studies are necessary in order to achieve more detailed insight to fracture healing and to ascertain the progression of fracture healing as being essential (criteria) for therapeutic decision making.

[The Ludwigshafen Osteoporosis Screening Questionnaire (LOS Questionnaire): result of the evaluation of anamnestic risk factors in osteoporosis diagnostics]

BACKGROUND

Osteoporosis is a major health problem worldwide and is included in the WHO list of the top ten major diseases. However, it is often undiagnosed until the first fracture occurs, due to inadequate patient education and lack of insurance coverage for screening tests.

METHODS AND MATERIAL

In our study of 78 patients with metaphyseal long bone fractures, we searched for a correlation between anamnestic risk factors, bone-specific laboratory values, and the bone morphogenic density (BMD). Each indicator was examined as a possible diagnostic instrument for osteoporosis. The secondary aim of this study was to demonstrate the high prevalence of osteoporosis in patients with metaphyseal fractures.

RESULTS

Of our fracture patients 76.9% had decreased bone density and 43.6% showed manifest osteoporosis in DXA (densitometry) measurements. Our modified LOS Questionnaire, identifying anamnestic risk factors, correlated highly significantly (p=0.01) with reduced BMD, whereas seven bone-specific laboratory values (p=0.046) correlated significantly.

CONCLUSION

Anamnestic risk factors correlate with pathological BMD more than bone-specific laboratory values. The LOS Questionnaire used in this study would therefore function as a cost-effective primary diagnostic instrument for identification of osteoporosis patients.

[How to become a trauma surgeon: analysis of the current situation and concepts for career development in the new common field of orthopaedics and trauma surgery--part I]

The lack of clinical residents especially in the surgical domains, including orthopaedics and trauma surgery, is not only omnipresent but also a topic of lively discussions. This lack originates from sociopolitical and healthcare policy issues as well as from a loss of attractiveness of all surgical disciplines. The loss is caused by the high workload and disadvantageous working hours especially in those disciplines with a high rate of emergencies, e.g. trauma surgery. Moreover, it is caused by the poorly structured and unpredictable period of residency. In order to anticipate the bottleneck in supply due to the lack of trainees, a number of structural and contextual measures have to be taken to improve both undergraduate und postgraduate surgical training. Due to the numerous facets of the topic the first part of this analysis refers to the period until the trainee decides on the field of training.A basic insight into the field of orthopaedics and trauma surgery can already be offered far before the period of medical studies itself. During undergraduate medical education the existing structures should be modified, the characteristics of the discipline should be emphasized and the charm of combining theory and practical skills should be highlighted in order to enhance student's perception of the discipline. This might begin during preclinical training and should be continued throughout clinical training and elective courses (basic wound care, TEAM approach, AO course for students and seminars for M.D. candidates). Contextual and structural improvements of the practical year are indispensable to arouse students' interest in our discipline. These options conjoined with the actual offers for students provided by our scientific society, such as guided tours during the annual congress, travelling grants and the recently inaugurated summer school, might provide the basis for clearly structured information and offer a distinct stimulus to apply for residency in our field.

[Medical care reality in trauma surgical clinics in Germany. A survey of the professional committee of the German Society for Trauma Surgery]

Due to revised conditions of medical care in Germany, in particular the introduction of the newly designated specialist for orthopaedics and trauma surgery, the working conditions in trauma surgical clinics in Germany has changed. In May 2008 the professional committee of the German Trauma Society conducted a survey at the 729 trauma surgical clinics and departments in order to establish the true level of care at these particular sites. The results of the 90,000 variables presented in the following article, reflect the changes in trauma care as well as in the medical care structures and emphasize the increased work load. In particular the lack of qualified candidates underlines the main explanation for vacant posts and is also evaluated in this article.

[Physicians in traumatology. Critically endangered? Results of an inquiry]

INTRODUCTION

The aim of this investigation was to describe the current situation and atmosphere among residents and consultants in traumatology, using the results of a questionnaire. Wishes and needs concerning training programs in traumatology were addressed.

METHODS

A questionnaire consisting of 25 items was distributed among members of the German Society of Traumatology (DGU) to document basic data concerning the state of residency and physicians' current workload. The participants were also asked about their personal interests and aims within traumatology. Finally, questions concerning educational programs, compensation, and work-life balance were addressed. The results were analysed descriptively.

RESULTS

The final analysis included 549 questionnaires. The mean age of the participants was 36 years (SD +/-7.5). Sixty percent (329) were residents, and 16% (88) served as consultants. The mean workload per week was 61 h (SD +/-10.8 h), and participants were on call seven times (SD +/-5.6) a month. The work-life balance was rated a mean of only 5 ("mediocre"). The majority of participants rejected working longer in order to reduce the duration of their educational program. On the other hand, most of the participants would also reject a reduction in working time accompanied by a reduced salary. Nevertheless, 78% (428) of the participants would, in retrospect, choose the same profession, and 85% (466) would even choose the same specialty.

DISCUSSION

The study reports on the atmosphere among residents and consultants in traumatology. Despite European regulations, the individual workload is exceptionally high. It is a clear task of hospital administrators to increase the attractiveness of hospital jobs in order to ensure qualified personnel in the future.