[Flat panel technology in the orthopaedic trauma operating room]. / Flat-panel-Technologie im orthopädisch-unfallchirurgischen Operationssaal.

The advantages of flat panel detector technology with X-ray sensitive semiconductor technology has increasingly gained acceptance in the inpatient setting for diagnostic X-ray imaging in recent years and has replaced conventional X-ray films. For intraoperative imaging C-arms, not least for cost reasons, are still based on conventional image intensifier technology. By improving the robustness of the flat panel technology and cost-effective production, future spread of these technologies in the OR could be expected. Direct digital imaging with improved image quality, with a possible reduction in radiation dose while at the same time enlarging the image field, can affect the procedural quality of surgery. A return on investment can be achieved in part by saving time and avoiding additional postoperative imaging.

Assessment and modification of degenerate qPCR primers that amplify functional genes from etheneotrophs and vinyl chloride-assimilators.

AIMS: Degenerate qPCR primer sets that target the functional genes etnC and etnE in etheneotrophs and vinyl chloride-assimilating bacteria were assessed and modified in an effort to improve performance. METHODS AND RESULTS: Functional gene abundance in four pure cultures was estimated by qPCR using novel (MRTC and MRTE) and existing (RTC and RTE) degenerate primer sets and compared to abundances estimated with nondegenerate gene-specific primers (GSPs). Functional gene abundance in groundwater DNA extracted from several contaminated sites was also estimated with MRTC and MRTE primers. CONCLUSIONS: MRTC primers displayed significantly improved etnC quantification in both pure cultures and environmental samples. SIGNIFICANCE AND IMPACT OF THE STUDY: Application of MRTC and MRTE primer sets will enhance microbial ecology studies involving etheneotrophs and qPCR analyses that support vinyl chloride bioremediation strategies.

Screw loosening after posterior dynamic stabilization--review of the literature.

PURPOSE OF THE STUDY: The malposition of pedicle screws in the lumbar spine is associated with a potential risk of iatrogenic injury of neurological structures but also with a decrease of biomechanical stability. The correct position of the pedicle screws of a dynamic stabilization device, as a long-term implant, seems to be of great importance. A high incidence of screw loosening could influence both the rate of revision surgeries and the clinical results.We compared screw loosening in our own patients with published data after navigated and non-navigated implantation of Dynesys. MATERIAL AND METHODS: Posterior instrumentation with the Dynesys system was performed in 19 patients after improvement of facet joint infiltrations. Seven (37%) patients underwent conventional surgery (group I), five (26%) were operated on using a CT-based navigation (group II) and seven (37%) using a fluoroscopic-based navigation (group III). Pre-operatively, the "Oswestry Low Back Pain Disability Questionnaire (OQ)" and the "Short Form 36 Health Survey Questionnaire (SF-36)" were used to obtain pain and functional scores. Furthermore, radiographs, MRI and CT examinations were performed before surgery. Screw position was analyzed on post-operative CT scans. At a minimum follow-up of twelve months, clinical examination, plain and dynamic X-rays were performed, and pain and functional scores (OQ, SF-36) were obtained. RESULTS: Pedicle perforation of minimum 2 mm was detected in two group I patients, in one group II and in two group III patients. Regarding OQ and SF-36, an improvement was observed in all patients, except for one column of SF-36. One patient (group I) underwent revision surgery due to symptomatic screw loosening and another patient (group III) due to persistent pain without signs of screw loosening. DISCUSSION: In former publications the majority of patients improved after Dynesys implantation with or without the use of navigation methods.Malposition of screws was not always followed by screw loosening. Revision surgery due to screw loosening, but without clinical symptoms, was not necessary in the majority of cases. CONCLUSIONS: It still remains unclear if screw loosening after Dynesys implantation influences the clinical results or the rate of revision surgery and if malposition of screws will be followed by a higher rate of screw loosening.

[Perioperative morbidity of lumbar stabilisation with Dynesys]. / Perioperative Morbidität bei Dynesys-Instrumentierung der Lendenwirbelsäule.

AIM: Several non-fusion technologies have been developed as an alternative to fusion procedures in the past decades, in order to avoid typical problems related to fusion. The Dynesys (Zimmer, USA), which was inaugurated 7 years ago, consists of pedicle screws, flexible spacers and cords and is intended to control segmental motion and to realign the lumbar spine. Since this device is new, it was the goal of this study to analyse the perioperative morbidity of lumbar stabilisation with Dynesys retrospectively. METHOD: 136 patients (74 men and 62 women) underwent posterior stabilisation of the lumbar spine with Dynesys between January 2002 and April 2006. We acquired retrospectively several patient-related variables, e.g. the number of instrumented and decompressed segments, the perioperative blood loss, the operation duration, prior surgeries and technical and general complications. RESULTS: The average age of the patients was 61.2 years (range: 33-84). 1.6 segments (range: 1-3) were instrumented and 1.2 segments (range: 0-3) were decompressed on average. The mean perioperative blood loss was 1100 ml (range: 50-3400) and the mean operation duration was 127.1 minutes (range: 30-270). Eighteen patients (13.2 %) had a urinary tract infection and 5 patients (3.7 %) had cardiovascular complications. Dura lesions were seen in 11 patients (8.1 %) with 1 patient having persistent bladder symptoms. Revision surgery was necessary in 3 patients (2.2 %) due to screw malposition with neurological deficits and radicular pain. Five patients (3.7 %) were revised due to postoperative seroma, 2 of them developing superficial infection. CONCLUSION: The perioperative morbidity of lumbar stabilisation with Dynesys seems to be similar to posterior fusion techniques. However, an additional morbidity due to interbody fusion, which may necessitate also autogenous bone, is avoided.

[The impact of preoperative function and pain on early patient-centred outcome after total hip arthroplasty]. / Der Einfluss von präoperativem Funktionsstatus und Schmerz auf das patientenzentrierte Frühergebnis nach Hüftendoprothesen-Implantation.

AIM: It was the purpose of this prospective study to investigate the impact of preoperative functional status and pain on the early patient-centred outcome after total hip arthroplasty (THA). METHODS: 67 consecutive patients scheduled for THA were included in this study. Outcome was analysed with the Western Ontario and McMaster Universities' (WOMAC) Osteoarthritis Index preoperatively and after ten days and 12 weeks, respectively. Patients were grouped with regard to their preoperative function and pain according to the WOMAC Osteoarthritis Index. Statistical analysis was performed using a multivariate regression model considering further confounding variables (age, gender, affected side, duration of surgery, and anchorage of THA). RESULTS: All patients showed a significant functional improvement both at ten days postoperatively and after three months, respectively. Patients with a higher degree of disability preoperatively had a larger relative functional improvement according to their WOMAC score compared to patients who initially were less deteriorated. However, the latter had the better absolute scores postoperatively. Multiple regression analysis revealed gender (OR: -11.85, 95% CI: -22.65 to -1.06, p=0.03) and preoperative WOMAC score (OR: 0.34, 95% CI: 0.09 to 0.59, p<0.01) to be significant prognostic variables at ten days postoperatively. After three months, age (OR: 0.43, 95% CI: 0.04 to 0.82, p=0.03) was the only variable predicting the patient-centred outcome. CONCLUSION: In our study sample, patient-related variables did significantly influence the patient-centred outcome after ten days (gender and WOMAC) and at three months postoperatively (age) whereas procedure-related variables did not have any impact.

On the outcome of computer-assisted total knee replacement.

A number of studies have reported a significant improvement of the postoperative alignment, when computer-navigated total knee arthroplasty (TKA) was compared with conventional techniques. However, no studies are available on the functional and patient-relevant outcomes after computer-assisted knee replacement. In a prospective, randomized trial comparing 27 computer-assisted TKAs with 25 conventional implantations, the Knee Society Score was used to assess functional status, and the WOMAC questionnaire was used to record the disease-specific, patient-relevant outcome. At a twelve-month follow-up no significant difference was detected between the two patient groups in either the scores or the number of complications and range of postoperative knee flexion. The results are in agreement with those reported in other studies on the effect of conventional TKA. With the patient group of this size it can be concluded that computer-navigated TKA gives short-term resuits comparable with those achieved by conventional methods of implantation.

[Differential diagnoses of avascular necrosis of the femoral head. Articular groin pain in adults]. / Differentialdiagnosen der aseptischen Hüftkopfnekrose. Artikulärer Leistenschmerz des Erwachsenen.

Early diagnosis and therapy of hip joint complaints in the young adult are often crucial for the prognosis of the joint. Besides avascular necrosis of the femoral head several differential diagnoses are possible, which if left untreated frequently lead to early osteoarthritis. The necessity of joint replacement in middle age often could be avoided by initiating adequate therapy as early as possible. The early diagnosis of aseptic necrosis of the femoral head at an early stage is possible with MRI. Especially in consideration of decreasing budgets MRI is dispensable for other diagnosis, e.g. hip dysplasia, femoroacetabular impingement or coxitis. On the other hand para-articular causes and non-orthopaedic diseases must also be considered, which remain hidden to classic orthopaedic diagnostics. Important differential diagnoses of groin pain in the adult, with emphasis on articular illnesses, are described.

[Predictive factors of perioperative morbidity in revision total hip arthroplasty]. / Prädiktoren der perioperativen Morbidität in der Revisionshüftendoprothetik.

AIM: The awareness and prevention of perioperative morbidity are essential in revision total hip arthroplasty [THA]. Therefore, it was the purpose of this study to assess the rate of perioperative complications following revision THA in order to evaluate the impact of patient- and procedure-related variables. METHODS: 169 consecutive patients with a mean age of 71.7 years suffering from aseptic loosening of their THA were included in this retrospective study. Multivariate logistic regression models with estimation of the odds ratio [OR] and 95% confidence interval [CI] served to analyze the influence of operation duration, gender, revision status, ASA classification, and type of fixation of the primary implant on the perioperative morbidity. RESULTS: 68.6% of the cases were primary revisions, and 31.4% secondary or multiple revisions. 49.7% of the operations involved exchange of the complete implant whereas 39.1% comprised exchange of the cup and 11.2% exchange of the stem only. Mean operation duration was 130 minutes [min] (range: 40-260 min), and mean intraoperative blood loss was 2.6 L (0.5 to 12 L). The rate of intraoperative complications was 10.1 % with a 6.5 % fracture rate. Postoperatively the complication rate was 25.4% with an 8.3% rate of luxations. 11.8% of the patients had revision within the first three weeks after surgery. Regression models showed the significant impact of revision status (primary vs. secondary or multiple: OR 2.90, 95% CI 1.42-5.92) and operation duration (per min starting from the mean operation time: OR 1.01, 95% CI 1.00-1.02) on the resulting complication rate. Analysis of the perioperative complication rate following primary revisions revealed a significant difference (p = 0.03) between patients with cemented (15/36, 41.7%) and non-cemented (8/45, 17.8%) implants. CONCLUSIONS: Revision status with a three-fold increase in patients with multiple revisions as well as operation duration with a 1 % increase per min starting from the mean operation time significantly influence the perioperative morbidity. Patients with a first revision, furthermore, seem to be at greater risk for an adverse event perioperatively if their implant is fully cemented. These findings should be taken into account prior to initiating surgery.

Cement leakage during vertebroplasty: an underestimated problem?

Overall, vertebroplasty has a low complication rate. Nevertheless, severe complications can occur. The majority of these are related to cement extrusion. The rate of cement leakage is often obtained by X-ray, with only a single leak registration per vertebra. Detection rate of leaks in comparison with CT and inter-observer reliability for X-ray is, in large parts, unknown. We conducted this study to determine the value of fluoroscopy and X-ray used to detect cement leakage as compared to CT scans. Intraoperative findings in lateral fluoroscopy by the surgeon, and postoperative findings in X-rays by two orthopaedic surgeons, were compared with CT scans for the same study group. Multiple cement leakage was considered, and agreement rate was determined. The detection rate for leaks was 34% for lateral X-ray and 48% for lateral and AP view. Additional AP views only enhanced the detection of leaks in the segmental veins. The agreement rate between fluoroscopy/X-ray and CT scans ranged between 66% and 74%, while inter-observer reliability showed only fair agreement. The rate of cement leaks in vertebroplasty is high if multiple leaks are considered in CT scans. Detection rates using X-rays are low and complicated by only fair inter-observer agreement. Leaks in the basivertebral veins are frequently misinterpreted and can lead to severe complications. Therefore, CT scans should be obtained to calculate the exact leakage rate and to assess persistent or new pain occurring postoperatively.