Arndt-Peter Schulz

Is non-union of tibial shaft fractures due to nonculturable bacterial pathogens? A clinical investigation using PCR and culture techniques

BackgroundNon-union continues to be one of the orthopedist’s greatest challenges. Despite effective culture methods, the detection of low-grade infection in patients with non-union following tibial fracture still presents a challenge. We investigated whether “aseptic” tibial non-union can be the result of an unrecognized infection.MethodsA total of 23 patients with non-union following tibial shaft fractures without clinical signs of infection were investigated. Intraoperative biopsy samples obtained from the non-union site were examined by means of routine culture methods and by polymerase chain reaction (PCR) for the detection of 16 S ribosomal RNA (rRNA). Control subjects included 12 patients with tibial shaft fractures.Results23 patients (8 women and 15 men; mean age: 47.4 years) were included into this study. Preoperative C-reactive protein levels (mean: 20.8 mg/l) and WBC counts (mean: 8,359/μl) in the study group were not significantly higher than in the control group. None of the samples of non-union routine cultures yielded microorganism growth. Bacterial isolates were found by conventional culturing methods in only 1 case of an open fracture from the control group. In this case, PCR yielded negative results. 16 S rRNA was detected in tissue specimens from 2 patients (8.7%) with non-union. The analysis of these variable species-specific sequences enabled the identification of specific microorganisms (1x Methylobacterium species, 1x Staphylococcus species). Both PCR-positive patients were culture-negative.ConclusionsThe combination of microbiological culture and broad-range PCR seems to substantially add to the number of microbiological diagnoses obtained and may improve the clinican’s ability to tailor therapy to the individual patient’s needs.

Importance of work–life balance among German medical students who wish to become gynecologists

Work–life balance is a crucial upcoming issue, not only for working physicians. Our future colleagues from generation Y, who are born after 1981, are known to attach much more importance to having good working conditions and meaningful lives outside work. The well-conducted review of Hancke et al. [1], presenting a national survey of gynecologists recently published in Arch Gynecol Obstet, provided sufficient evidence to underline the importance of work–life balance. Up to of the gynecologists in this survey state that work life and private life are equally important to them. The results of this survey are startling, as only 50 % of gynecologists are actually satisfied with their work–life balance. The Committee of Medical Education (CME) of the DGOU also addressed the issue of work–life balance and conducted an online survey among medical students to ask their opinion on this topic in 2012. The questionnaire used in this national survey consists of approximately 160 items, and was completed by 465 German medical students from all 36 medical faculties who stated that they aspired to become gynecologists. Most questions were answered using a fivepoint Likert scale. This survey and the study of Hancke et al. [1] provide important insights regarding the importance of work–life balance for gynecologists and medical students. In our survey, the group of future gynecologists consisted of 98 preclinical, 282 clinical, and 85 last-year (Praktisches Jahr, PJ) students. A total of 96 % of the students wishing to become gynecologists were born after 1980 and hence belonged to Generation Y. There was a strong predominance of female students with only 32 men (6.9 %) intending to specialize in gynecology [2, 3]. In analyzing this subgroup, we found the impact of work–life balance to be the #1 topic for choosing job choice/ employer and being satisfied with the job as a gynecologist (mean 4.63, SD 0.63).At the same time, the expectation to actually have a good work–life balance on the job was lowest among students wishing to become gynecologists and it was lower in more advanced students with a significant group difference (mean 1.68, SD 1.15, p = 0.036). We found this to be alarming as the importance of work– life balance contrasts sharply with the expectation that this wish will not come true. Hospitals wishing to attract skilled young physicians need to offer work environments allowing them to reconcile work with their ideas of living.

Deltoid muscular flap transfer for the treatment of irreparable rotator cuff tears

The purpose of this study was to evaluate the outcome of deltoid muscle flap transfer for the treatment of irreparable rotator cuff tears. In a retrospective study 20 consecutive patients were evaluated. The index procedure took place between 2000 and 2003. Fifteen patients were male, mean age was 62 years. Inclusion criterion was a rotator cuff defect Bateman grade IV. Exclusion criteria were smaller defects, shoulder instability and fractures of the injured shoulder. An open reconstruction with acromioplasty and a pedicled delta flap was performed. Follow up period was mean 42 months. Follow-up included clinical examination, Magnetic Resonance Imaging (MRI) and the Constant and Simple (CS) shoulder tests. According to the Constant shoulder test the results were good in 13 patients, fair in 5 and unsatisfactory in 2. The pre-operative Constant Score improved from mean 25.7 points (±5.3) to 72.3 (±7.8) at follow-up. The mean values for the subcategories of CS increased significantly from 3.9 to 14.4 points for pain and from 4.2 to 15.9 points for activities daily routine (p<0.05). The change in range of motion and strength were not significant (p>0.05). Results of the Simple Shoulder Test showed a significant increase of the mean values from pre-operative 4.3 to 14.7 points post-operatively. MRI showed a subacromial covering of the defect in all cases, all flaps where intact on MRI but always the flap showed marked fatty degeneration. In conclusion, the delta flap is a simple method for the repair of large defects of the rotator cuff leading to satisfying medium results.

Bone plates for osteosynthesis - a systematic review of test methods and parameters for biomechanical testing.

Abstract Bone plates for osteosynthesis are subject to biomechanical testing for safety and regulatory purposes. International standards applicable for those devices are designed for bone plates used in the surgical fixation of the skeletal system but not necessarily for all device variants available. We intend to summarize the test methods and parameters presented in the literature to evaluate bone plates in a clinical environment, especially for modern anatomically shaped implants. We conducted a systematic review on published biomechanical studies for lower and upper extremities (clavicle, humerus, ulna, radius, metacarpal, femur, tibia, fibula, metatarsal). The search process led to the identification of 159 relevant articles containing 330 individual tests, which were analyzed concerning various test criteria including test methods and parameters per bone segment for static and dynamic loading tests, as well as number of cycles, chosen bone model and outcome variables. The biomechanical literature for bone plates is diverse, inconsistent and heterogeneous. Test methods are not commonly applied per bone plate location and test parameters are not uniformly specified and displayed. They vary in particular for bending and torsion tests as well as for the number of loading cycles for dynamic testing. Outcome variables are not commonly applied nor defined. Consequently this paper is the first in a planned chronological series of three to identify the need (this publication), to develop a systematic procedural approach (2. publication) and to apply the process exemplary on a bone plate sample (3. publication).

Bone plate-screw constructs for osteosynthesis – recommendations for standardized mechanical torsion and bending tests

Abstract This paper follows up on a recent systematic review of test methods and parameters for biomechanical testing of bone plates and it is the first study that contains recommendations for standardized mechanical testing of bone plate-screw constructs for osteosynthesis. Following the testing philosophy of ASTM F382 and ISO 9585, we have developed standardized quasi-static and dynamic testing methods for straight linear and anatomically shaped plates, including locked type and conventional systems. The test specification comprises torsion and bending tests along the implant axis and therefore modifies and extends the methods proposed by ASTM F382. We present specific test setups in order to determine product-specific characteristics of the mechanical construct, consisting of the bone plate with corresponding screws (such as construct stiffness, yield strength, ultimate strength and fatigue properties) under the condition that it is rigidly fixed to “healthy bone”. We also address specific testing requirements that are important for the purpose of standardization, such as the positioning of the construct for testing or the number of screws in the diaphysis and metaphysis. Finally, we define the outcome parameters and associated failure criteria related to quasi-static and dynamic testing for comparative purposes. This paper does not intend to replace biomechanical testing of those devices under physiological loading conditions.