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PURPOSE Despite the fact that new and modern short-stems allow bone sparing and saving of soft-tissue and muscles, we still face the challenge of anatomically reconstructing the femoro-acetabular offset and leg length. Therefore a radiological and clinical analysis of a short-stem reconstruction of the femoro-acetabular offset and leg length was performed. METHODS Using an antero-lateral approach, the optimys short-stem (Mathys Ltd, Bettlach, Switzerland) was implanted in 114 consecutive patients in combination with a cementless cup (Fitmore, Zimmer, Indiana, USA; vitamys RM Pressfit, Mathys Ltd, Bettlach, Switzerland). Pre- and postoperative X-rays were done in a standardized technique. In order to better analyse and compare X-ray data a special double coordinate system was developed for measuring femoral- and acetabular offset. Harris hip score was assessed before and six weeks after surgery. Visual analogue scale (VAS) satisfaction, leg length difference and the existence of gluteal muscle insufficiency were also examined. RESULTS Postoperative femoral offset was significantly increased by a mean of 5.8 mm. At the same time cup implantation significantly decreased the acetabular offset by a mean of 3.7 mm, which resulted in an increased combined femoro-acetabular offset of 2.1 mm. Postoperatively, 81.7 % of patients presented with equal leg length. The maximum discrepancy was 10 mm. Clinically, there were no signs of gluteal insufficiency. No luxation occurred during hospitalization. The Harris hip score improved from 47.3 before to 90.1 points already at six weeks after surgery while the mean VAS satisfaction was 9.1. CONCLUSION The analysis showed that loss of femoro-acetabular offset can be reduced with an appropriate stem design. Consequently, a good reconstruction of anatomy and leg length can be achieved. In the early postoperative stage the clinical results are excellent.

PURPOSE To determine whether particulate debris is present in periprosthetic tissue from revised Dynesys(®) devices, and if present, elicits a biological tissue reaction. METHODS Five Dynesys(®) dynamic stabilization systems consisting of pedicle screws (Ti alloy), polycarbonate-urethane (PCU) spacers and a polyethylene-terephthalate (PET) cord were explanted for pain and screw loosening after a mean of 2.86 years (1.9-5.3 years). Optical microscopy and scanning electron microscopy were used to evaluate wear, deformation and surface damage, and attenuated total reflectance Fourier transform infrared spectroscopy to assess surface chemical composition of the spacers. Periprosthetic tissue morphology and wear debris were determined using light microscopy, and PCU and PET wear debris by polarized light microscopy. RESULTS All implants had surface damage on the PCU spacers consistent with scratches and plastic deformation; 3 of 5 exhibited abrasive wear zones. In addition to fraying of the outer fibers of the PET cords in five implants, one case also evidenced cord fracture. The pedicle screws were unremarkable. Patient periprosthetic tissues around the three implants with visible PCU damage contained wear debris and a corresponding macrophage infiltration. For the patient revised for cord fracture, the tissues also contained large wear particles (>10 μm) and giant cells. Tissues from the other two patients showed comparable morphologies consisting of dense fibrous tissue with no inflammation or wear debris. CONCLUSIONS This is the first study to evaluate wear accumulation and local tissue responses for explanted Dynesys(®) devices. Polymer wear debris and an associated foreign-body macrophage response were observed in three of five cases.

Neben der AO-Klassifikation fur Frakturen im Wachstumsalter (PCCF, „Pediatric Comprehensive Classification of Long-Bone Fractures“) gibt es die LiLa-Klassifikation fur Frakturen der langen Rohrenknochen im Wachstumsalter (LiLa-Klassifikation). Letztere sollte im Rahmen dieser Arbeit unter klinisch relevanten Bedingungen auf ihre Reliabilitat und Praktikabilitat gepruft werden. Prospektiv wurden in einem Kindertraumazentrum uber 12 Monate samtliche Frakturen der langen Rohrenknochen erfasst und unabhangig von Experten und Laien nach der LiLa-Klassifikation kodiert und die Intra-/Interobserverreliabilitat nach Cohen (Kappa, κ) berechnet. Klassifiziert wurden 408 Frakturen. Die Intraobserverreliabilitat fur Frakturlokalisation und Knochensegment ergab ein „almost perfect agreement“ (κ = 0,91–0,95), ebenso die Angabe hinsichtlich Gelenk- oder Schaftfraktur (κ = 0,87–0,93). Aufgrund der oft hohergradigen Einstufung des Dislokationsausmases in der 2. Beurteilung lag bei der Intraobserverbetrachtung insgesamt ein „moderate agreement“ (κ = 0,53–0,58) vor. Die Interobserverreliabilitat fur die Gesamtklassifikation zeigte ein „moderate agreement“ (κ = 0,55); dies war im Wesentlichen der Problematik qualitativ schlechter Rontgenbilder und der Klassifikation seltener Frakturen geschuldet, hinzu kam die unterschiedliche Interpretationen der Lange der Metaphyse. Die LiLa-Klassifikation ist fur die Klassifikation der Frakturen langen Rohrenknochen im Kindesalter geeignet und weitestgehend anwenderfreundlich; einzig die Einschatzung des Dislokationsgrades erfordert spezifische kindertraumatologische Kenntnisse. Die Reliabilitat ist hoher als bei anderen etablierten frakturspezifischen Klassifikationen und vergleichbar mit der AO-Klassifikation fur Frakturen im Wachstumsalter, konnte allerdings durch eine exaktere Definition der Metaphyse noch deutlich erhoht werden. Klassifikationsunabhangige Fehler entstanden durch qualitativ unzureichende Rontgenbilder und seltene, nicht eindeutig zu klassifizierende Frakturen. Insgesamt kann die LiLa-Klassifikation weiterhin als Option zur Klassifikation von Frakturen der Rohrenknochen des Kindesalters gesehen werden.

We report a series of 16 consecutive total knee arthroplasty (TKA) revision procedures for deep infection, treated with a newly developed intraoperatively moulded PMMA cement-prostheses-like spacer (CPLS). The standard treatment consisted of a two-stage protocol with initial explantation of the infected components combined with radical debridement, followed by implantation of a temporary cement spacer and final reimplantation of a new TKA. A sterilizeable Teflon tapered aluminium mould was developed for production of a custom made CPLS during the intervention. Stable implantation of the CPLS was achieved with a second cementation, allowing for correct alignment and ligament balancing. The spacer remained 3.5 months on average until reimplantation of a TKA occurred. At time of reimplantation, patients had an average KSS score of 84.44 points with an average flexion capacity of 102°. There was no recurrent infection during the study period of minimum 2 years. With this new technique, a low friction articulation with good stability, high comfort and a better range of motion compared to handcrafted spacers was achieved. The use of this spacer is a time sparing, cheap and convenient option in 2-stage TKA revision.

Recent developments in clinical radiology have resulted in additional developments in the field of forensic radiology. After implementation of cross-sectional radiology and optical surface documentation in forensic medicine, difficulties in the validation and analysis of the acquired data was experienced. To address this problem and for the comparison of autopsy and radiological data a centralized database with internet technology for forensic cases was created. The main goals of the database are (1) creation of a digital and standardized documentation tool for forensic-radiological and pathological findings; (2) establishing a basis for validation of forensic cross-sectional radiology as a non-invasive examination method in forensic medicine that means comparing and evaluating the radiological and autopsy data and analyzing the accuracy of such data; and (3) providing a conduit for continuing research and education in forensic medicine. Considering the infrequent availability of CT or MRI for forensic institutions and the heterogeneous nature of case material in forensic medicine an evaluation of benefits and limitations of cross-sectional imaging concerning certain forensic features by a single institution may be of limited value. A centralized database permitting international forensic and cross disciplinary collaborations may provide important support for forensic-radiological casework and research.

Lumbar spinal stenosis is a frequent indication for spinal surgery. The predictive quality of treadmill testing and MRI for diagnostic verification is not yet clearly defined. Aim of the current study was to assess correlations between treadmill testing and MRI findings in the lumbar spine. Twenty-five patients with lumbar spinal stenosis were prospectively examined. Treadmill tests were performed and the area of the dural sac and neuroforamina was examined with MRI for the narrowest spinal segment. VAS and ODI were used for clinical assessment. The median age of the patients was 67 years. In the narrowest spinal segment the median area of the dural sac was 91 mm(2). The median ODI was 66 per cent. The median walking distance in the treadmill test was 70 m. The distance reached in the treadmill test correlated with the area of the dural sac (Spearman's rho = 0.53) and ODI (rho = -0.51), but not with the area of the neuroforamina and VAS. The distance reached in the treadmill test predicts the grade of stenosis in MRI but has a limited diagnostic importance for the level of clinical symptoms in lumbar spinal stenosis.

A literature review of the nine most widely used, condition-specific, self-administered assessment questionnaires for low back pain has been undertaken. General and historic aspects, reliability, responsiveness and minimum clinically important difference, external validity, floor and ceiling effects and available languages were analysed for the nine most-used outcome tools. When considering which condition-specific measure to employ, the present overview on assessment tools should provide the necessary information to define the technical aspects of the nine questionnaires. These criteria, however, are only part of the consideration. In part II the construction of these scales in relationship to the measurement domains will be evaluated.

Retrospective case review. In the present study, the neurological outcome, retirement and prognostic factors of patients with spinal cord injury without radiographic abnormality (SCIWORA) were evaluated. Swiss national work accident insurance database. The medical histories of 32 patients who were insured by the Swiss Accident Insurance Fund (SUVA) and had SCIWORA between 1995 and 2004 were evaluated thoroughly. Moreover, all available magnetic resonance imaging (MRI) scans were evaluated. At the last follow-up, none of the patients had complete spinal cord injury, only 4 patients had severe deficits and 12 patients had normal motor and sensory function in the neurological examination. However, only 7 out of 32 patients had returned to full-time work and 10 out of 32 patients were fully retired. Both the presence of spinal cord change (ρ=0.51) and higher maximum spinal cord compression (ρ=0.57) in MRI scan correlated with the likelihood for retirement; older age (ρ=0.38) and physical load of work (ρ=0.4) correlated with retirement to a lesser extent. Although the neurological outcome of SCIWORA is mostly good, the retirement rate is high. Presence of spinal cord change and severity of cord compression are the best predictors for the degree of retirement.

For treatment of total knee prosthesis infections, a two-stage protocol with explantation of the infected components, antibiotic cement spacer implantation, and secondary reimplantation of the prosthesis after curing the infection is the accepted standard procedure (Wilde and Ruth 1988, Pitto and Spika 2004). The cement spacer is antibiotic-loaded, maintains the articular distance between femur and tibia, stabilizes the knee, and allows passive motion of the knee (Scott et al. 1993). Different techniques have been used for fabrication of this spacer, including intraoperative molding. The results of handcrafted spacers are unsatisfactory because such spacers have a rough surface and are not congruent. As a result, instability, limited range of motion, and excessive wear have been reported (Goksan and Freeman 1992, Hanssen et al. 1994). We have developed a tapered aluminium mold for production of a custom made PMMA spacer like prostheses (CLSP) during the intervention. We consider the use of the CSLP as a promising approach for the treatment of complicated deep TKA infections since this technique is time sparing, cheap and easy to apply in all surgical theatres. Construction of the spacer mold The 2 molds were produced in a computerized numerical-control sinking machine (DMU 70eV-process) based on the design of the balanSys knee system (size B; D) (Mathys AG, Bettlach, Switzerland). The mold for the femoral spacer consists of 3 parts and for the tibial spacer, of 2. It is made of high-strength aluminium (AA7075 T6 3.4365; density 2.8 kg/dm3 and tensile strength 520–560 Nm/mm2) and coated with Altef. In this process, the surface of the base material is converted into a ceramic coating in which Teflon is integrated. Half of the coating penetrates into the base material, which results in an increase of 25 µm, leading to a standard coating thickness of 50 µm. The mold can be cleaned and sterilized for re-use (Figure 1 and ​and22). Figure 3. Implantation of the intraoperative molded PMMA knee spacer. Figure 1. Femoral mold, composed of 3 parts. It can be filled through 2 channels with tubes. Figure 2. The 2 parts of the tibial mold. Surgical technique and postoperative protocol The first step includes explantation of the prosthetic components and removal of the cement mantle. An extensive debridement of the infected joint is performed. Biopsies are taken for microbiological culture and histology. The appropriate size for the components is assessed on conventional AP and lateral knee radiographs. The parts of the femoral mold component are mounted with 2 screws. If necessary, special antibiotics can be added to the cement, based on the cultures and antibiogram. The mold is filled through 2 channels on the upper side, using a 20-mL tube. After polymerization of the cement, the screws, which interlink the mold, are opened and the femoral spacer component can be easily removed from the mold. Since the cement expands during polymerization, pressure inside the closed mold rises and creates a smooth surface on the final cement spacer. The femoral component is implanted first with a small portion of additional cement. Then the distance between the tibia and the femur is measured in neutral position. The tibial mold is filled with PMMA cement according to the distance measured. After polymerization of the cement, the tibial part of the spacer is removed from the mold and the mounting cement on the posterior and lateral side of the spacer is removed with a Luer pincer. The tibial component is then implanted with a small portion of cement (Figure 3). The stability and range of motion is tested, and then the wound can be closed (Figures 4). Figure 4. After implantation of the PMMA spacer. Depending on the agent and the intraoperative findings, an individual protocol of intravenous and oral antibiotics is indicated. Continuous passive motion is started 24 h postoperatively, with no limitations. Ambulation is started (with two crutches and partial weight bearing of 20 kg) on the third day after surgery.

Purpose: Total knee arthroplasty (TKA) disturbs patellar blood flow, an unintended accompaniment to TKA that may be a cause of postoperative anterior knee pain. We examine whether disrupted patellar blood flow correlates with anterior knee pain following TKA. Methods: In 50 patients (21 men, 29 women) undergoing TKA, we compared patellar blood flow at flexions 0° to 30°, 60°, 90°, and 110° before and after medial parapatellar arthrotomy to pre- and postoperative anterior knee pain scores by means of a laser Doppler flowmeter (LDF) probe. Anterior knee pain was assessed using the pain intensity numeric rating scale (NRS) of 0-10 (0-no, 10-worst pain). Based on the NRS pain values, patients were divided into two main groups: group A (n=34) with no pain or discomfort (NRS range 0-4) and group B (n=16) with anterior knee pain (NRS range 5-10). Results: Patients of group B demonstrated a significant decrease in blood flow before arthrotomy at flexions from 0° to 90°, and 110° and from 0° to 60°, 90°, and 110° after arthrotomy. For group A, a significant decrease in blood flow was detected at flexions from 0° to 90°, and 110° before and after arthrotomy. For both groups, medial arthrotomy did not have a statistically significant influence on patellar blood flow (margin of significance P

Vertebroplasty and kyphoplasty are well-established minimally invasive treatment options for compression fractures of osteoporotic vertebral bodies. Possible procedural disadvantages, however, include incomplete fracture reduction or a significant loss of reduction after balloon tamp deflation, prior to cement injection. A new procedure called "vertebral body stenting" (VBS) was tested in vitro and compared to kyphoplasty. VBS uses a specially designed catheter-mounted stent which can be implanted and expanded inside the vertebral body. As much as 24 fresh frozen human cadaveric vertebral bodies (T11-L5) were utilized. After creating typical compression fractures, the vertebral bodies were reduced by kyphoplasty (n = 12) or by VBS (n = 12) and then stabilized with PMMA bone cement. Each step of the procedure was performed under fluoroscopic control and analysed quantitatively. Finally, static and dynamic biomechanical tests were performed. A complete initial reduction of the fractured vertebral body height was achieved by both systems. There was a significant loss of reduction after balloon deflation in kyphoplasty compared to VBS, and a significant total height gain by VBS (mean +/- SD in %, p < 0.05, demonstrated by: anterior height loss after deflation in relation to preoperative height [kyphoplasty: 11.7 +/- 6.2; VBS: 3.7 +/- 3.8], and total anterior height gain [kyphoplasty: 8.0 +/- 9.4; VBS: 13.3 +/- 7.6]). Biomechanical tests showed no significant stiffness and failure load differences between systems. VBS is an innovative technique which allows for the possibly complete reduction of vertebral compression fractures and helps maintain the restored height by means of a stent. The height loss after balloon deflation is significantly decreased by using VBS compared to kyphoplasty, thus offering a new promising option for vertebral augmentation.

Low back pain (LBP) is currently the most prevalent and costly musculoskeletal problem in modern societies. Screening instruments for the identification of prognostic factors in LBP may help to identify patients with an unfavourable outcome. In this systematic review screening instruments published between 1970 and 2007 were identified by a literature search. Nine different instruments were analysed and their different items grouped into ten structures. Finally, the predictive effectiveness of these structures was examined for the dependent variables including "work status", "functional limitation", and "pain". The strongest predictors for "work status" were psychosocial and occupational structures, whereas for "functional limitation" and "pain" psychological structures were dominating. Psychological and occupational factors show a high reliability for the prognosis of patients with LBP. Screening instruments for the identification of prognostic factors in patients with LBP should include these factors as a minimum core set.

With an official life time of over 5 years, Spine Tango can meanwhile be considered the first international spine registry. In this paper we present an overview of frequency statistics of Spine Tango for demonstrating the genesis of questionnaire development and the constantly increasing activity in the registry. Results from two exemplar studies serve for showing concepts of data analysis applied to a spine registry. Between 2002 and 2006, about 6,000 datasets were submitted by 25 centres. Descriptive analyses were performed for demographic, surgical and follow-up data of three generations of the Spine Tango surgery and follow-up forms. The two exemplar studies used multiple linear regression models to identify potential predictor variables for the occurrence of dura lesions in posterior spinal fusion, and to evaluate which covariates influenced the length of hospital stay. Over the study period there was a rise in median patient age from 52.3 to 58.6 years in the Spine Tango data pool and an increasing percentage of degenerative diseases as main pathology from 59.9 to 71.4%. Posterior decompression was the most frequent surgical measure. About one-third of all patients had documented follow-ups. The complication rate remained below 10%. The exemplar studies identified "centre of intervention" and "number of segments of fusion" as predictors of the occurrence of dura lesions in posterior spinal fusion surgery. Length of hospital stay among patients with posterior fusion was significantly influenced by "centre of intervention", "surgeon credentials", "number of segments of fusion", "age group" and "sex". Data analysis from Spine Tango is possible but complicated by the incompatibility of questionnaire generations 1 and 2 with the more recent generation 3. Although descriptive and also analytic studies at evidence level 2++ can be performed, findings cannot yet be generalised to any specific country or patient population. Current limitations of Spine Tango include the low number and short duration of follow-ups and the lack of sufficiently detailed patient data on subgroup levels. Although the number of participants is steadily growing, no country is yet represented with a sufficient number of hospitals. Nevertheless, the benefits of the project for the whole spine community become increasingly visible.

The objectives of this study were to develop and validate a tool for assessing pain in population-based observational studies and to develop three subscales for back/neck, upper extremity and lower extremity pain. Based on a literature review, items were extracted from validated questionnaires and reviewed by an expert panel. The initial questionnaire consisted of a pain manikin and 34 items relating to (i) intensity of pain in different body regions (7 items), (ii) pain during activities of daily living (18 items) and (iii) various pain modalities (9 items). Psychometric validation of the initial questionnaire was performed in a random sample of the German-speaking Swiss population. Analyses included tests for reliability, correlation analysis, principal components factor analysis, tests for internal consistency and validity. Overall, 16,634 of 23,763 eligible individuals participated (70%). Test-retest reliability coefficients ranged from 0.32 to 0.97, but only three coefficients were below 0.60. Subscales were constructed combining four items for each of the subscales. Item-total coefficients ranged from 0.76 to 0.86 and Cronbach's alpha were 0.75 or higher for all subscales. Correlation coefficients between subscales and three validated instruments (WOMAC, SPADI and Oswestry) ranged from 0.62 to 0.79. The final Pain Standard Evaluation Questionnaire (SEQ Pain) included 28 items and the pain manikin and accounted for the multidimensionality of pain by assessing pain location and intensity, pain during activity, triggers and time of onset of pain and frequency of pain medication. It was found to be reliable and valid for the assessment of pain in population-based observational studies.

This article reports about the internet based, second multicenter study (MCS II) of the spine study group (AG WS) of the German trauma association (DGU). It represents a continuation of the first study conducted between the years 1994 and 1996 (MCS I). For the purpose of one common, centralised data capture methodology, a newly developed internet-based data collection system ( http://www.memdoc.org ) of the Institute for Evaluative Research in Orthopaedic Surgery of the University of Bern was used. The aim of this first publication on the MCS II was to describe in detail the new method of data collection and the structure of the developed data base system, via internet. The goal of the study was the assessment of the current state of treatment for fresh traumatic injuries of the thoracolumbar spine in the German speaking part of Europe. For that reason, we intended to collect large number of cases and representative, valid information about the radiographic, clinical and subjective treatment outcomes. Thanks to the new study design of MCS II, not only the common surgical treatment concepts, but also the new and constantly broadening spectrum of spine surgery, i.e. vertebro-/kyphoplasty, computer assisted surgery and navigation, minimal-invasive, and endoscopic techniques, documented and evaluated. We present a first statistical overview and preliminary analysis of 18 centers from Germany and Austria that participated in MCS II. A real time data capture at source was made possible by the constant availability of the data collection system via internet access. Following the principle of an application service provider, software, questionnaires and validation routines are located on a central server, which is accessed from the periphery (hospitals) by means of standard Internet browsers. By that, costly and time consuming software installation and maintenance of local data repositories are avoided and, more importantly, cumbersome migration of data into one integrated database becomes obsolete. Finally, this set-up also replaces traditional systems wherein paper questionnaires were mailed to the central study office and entered by hand whereby incomplete or incorrect forms always represent a resource consuming problem and source of error. With the new study concept and the expanded inclusion criteria of MCS II 1, 251 case histories with admission and surgical data were collected. This remarkable number of interventions documented during 24 months represents an increase of 183% compared to the previously conducted MCS I. The concept and technical feasibility of the MEMdoc data collection system was proven, as the participants of the MCS II succeeded in collecting data ever published on the largest series of patients with spinal injuries treated within a 2 year period.

Problem: A suspected high proportion of unnecessary blood transfusions occur in patients undergoing total joint replacement. Design: Prospective before and after study evaluating the impact of a one page flow chart aimed at reducing the use of blood transfusions. Setting: Orthopaedic tertiary care centre in Winterthur, Switzerland. 208 patients underwent primary total joint replacement of hips or knees during the control period (October 1998 to September 1999) and 217 during the intervention period (October 1999 to September 2000). Key measures for improvement: Proportion of patients receiving allogeneic blood transfusions. Strategies for change: A simple one page flow chart, which summarised graphically the perioperative decision pathways for anaemic patients, was placed in all charts of patients undergoing total joint replacement and handed out to medical staff from 4 October 1999 onwards. The implementation of the flow chart focused on its endorsement by chief physicians and the development of a sense of "ownership" among physicians and nurses. Effects of change: The proportion of patients receiving allogeneic blood decreased from 35.0% to 19.8% (absolute difference –15.2%, 95% confidence interval –23.3 to –7.0%). The percentage of patients donating and receiving autologous blood also decreased. This led to overall savings of about £23 000 ($42 470; €34 441) (£103.50 per patient undergoing total joint replacement). Differences became more pronounced after adjustment for confounding factors. Lessons learnt: Allogeneic blood transfusions in primary hip and knee replacement surgery may be reduced cost effectively by implementing a one page flow chart. Five key elements may have contributed: simplicity; wide distribution; no requirement for major changes; endorsement by local opinion leaders; and development of a sense of ownership. These elements may be used in other contexts to achieve sustained change of clinical practice.

A literature review of the most widely used, condition-specific, self-administered assessment questionnaires for low back pain has been undertaken. In part I, technical issues such as validity, reliability, availability and comparability were analyzed for the nine most widely used outcome tools. This second part focuses on the content and wording of questions and answers in each of the nine questionnaires, and an analysis of the different score results is performed. The issue of score bias is discussed and suggestions are given in order to increase the construct validity in the practical use of the individual questionnaires.