The relationship between time to diagnose and diagnostic accuracy among internal medicine residents: a randomized experiment.

BACKGROUND: Diagnostic errors have been attributed to cognitive biases (reasoning shortcuts), which are thought to result from fast reasoning. Suggested solutions include slowing down the reasoning process. However, slower reasoning is not necessarily more accurate than faster reasoning. In this study, we studied the relationship between time to diagnose and diagnostic accuracy. METHODS: We conducted a multi-center within-subjects experiment where we prospectively induced availability bias (using Mamede et al.'s methodology) in 117 internal medicine residents. Subsequently, residents diagnosed cases that resembled those bias cases but had another correct diagnosis. We determined whether residents were correct, incorrect due to bias (i.e. they provided the diagnosis induced by availability bias) or due to other causes (i.e. they provided another incorrect diagnosis) and compared time to diagnose. RESULTS: We did not successfully induce bias: no significant effect of availability bias was found. Therefore, we compared correct diagnoses to all incorrect diagnoses. Residents reached correct diagnoses faster than incorrect diagnoses (115 s vs. 129 s, p < .001). Exploratory analyses of cases where bias was induced showed a trend of time to diagnose for bias diagnoses to be more similar to correct diagnoses (115 s vs 115 s, p = .971) than to other errors (115 s vs 136 s, p = .082). CONCLUSIONS: We showed that correct diagnoses were made faster than incorrect diagnoses, even within subjects. Errors due to availability bias may be different: exploratory analyses suggest a trend that biased cases were diagnosed faster than incorrect diagnoses. The hypothesis that fast reasoning leads to diagnostic errors should be revisited, but more research into the characteristics of cognitive biases is important because they may be different from other causes of diagnostic errors.

Does providing the correct diagnosis as feedback after self-explanation improve medical students diagnostic performance?

BACKGROUND: Self-explanation without feedback has been shown to improve medical students' diagnostic reasoning. While feedback is generally seen as beneficial for learning, available evidence of the value of its combination with self-explanation is conflicting. This study investigated the effect on medical students' diagnostic performance of adding immediate or delayed content-feedback to self-explanation while solving cases. METHODS: Ninety-four 3rd-year students from a Canadian medical school were randomly assigned to three experimental conditions (immediate-feedback, delayed-feedback, control). In the learning phase, all students solved four clinical cases by giving i) the most likely diagnosis, ii) two main arguments supporting this diagnosis, and iii) two plausible alternative diagnoses, while using self-explanation. The immediate-feedback group was given the correct diagnosis after each case; delayed-feedback group received the correct diagnoses only after the four cases; control group received no feedback. One week later, all students solved four near-transfer (i.e., same final diagnosis as the learning cases but different scenarios) and four far-transfer cases (i.e., different final diagnosis from the learning cases and different scenarios) by answering the same three questions. Students' diagnostic accuracy (score for the response to the first question only) and diagnostic performance (combined score of responses to the three questions) scores were assessed in each phase. Four one-way ANOVAs were performed on each of the two scores for near and far-transfer cases. RESULTS: There was a significant effect of experimental condition on diagnostic accuracy on near-transfer cases (p < .05). The immediate-feedback and delayed-feedback groups performed equally well, both better than control (respectively, mean = 90.73, standard deviation =10.69; mean = 89.92, standard deviation = 13.85; mean = 82.03, standard deviation = 17.66). The experimental conditions did not significantly differ on far-transfer cases. CONCLUSIONS: Providing feedback to students in the form of the correct diagnosis after using self-explanation with clinical cases is potentially beneficial to improve their diagnostic accuracy but this effect is limited to similar cases. Further studies should explore how more elaborated feedback combined with self-explanation may impact students' diagnostic performance on different cases.

Do patients' disruptive behaviours influence the accuracy of a doctor's diagnosis? A randomised experiment.

BACKGROUND: Literature suggests that patients who display disruptive behaviours in the consulting room fuel negative emotions in doctors. These emotions, in turn, are said to cause diagnostic errors. Evidence substantiating this claim is however lacking. The purpose of the present experiment was to study the effect of such difficult patients' behaviours on doctors' diagnostic performance. METHODS: We created six vignettes in which patients were depicted as difficult (displaying distressing behaviours) or neutral. Three clinical cases were deemed to be diagnostically simple and three deemed diagnostically complex. Sixty-three family practice residents were asked to evaluate the vignettes and make the patient's diagnosis quickly and then through deliberate reflection. In addition, amount of time needed to arrive at a diagnosis was measured. Finally, the participants rated the patient's likability. RESULTS: Mean diagnostic accuracy scores (range 0-1) were significantly lower for difficult than for neutral patients (0.54 vs 0.64; p=0.017). Overall diagnostic accuracy was higher for simple than for complex cases. Deliberate reflection upon the case improved initial diagnostic, regardless of case complexity and of patient behaviours (0.60 vs 0.68, p=0.002). Amount of time needed to diagnose the case was similar regardless of the patient's behaviour. Finally, average likability ratings were lower for difficult than for neutral-patient cases. CONCLUSIONS: Disruptive behaviours displayed by patients seem to induce doctors to make diagnostic errors. Interestingly, the confrontation with difficult patients does however not cause the doctor to spend less time on such case. Time can therefore not be considered an intermediary between the way the patient is perceived, his or her likability and diagnostic performance.

Why patients' disruptive behaviours impair diagnostic reasoning: a randomised experiment.

BACKGROUND: Patients who display disruptive behaviours in the clinical encounter (the so-called 'difficult patients') may negatively affect doctors' diagnostic reasoning, thereby causing diagnostic errors. The present study aimed at investigating the mechanisms underlying the negative influence of difficult patients' behaviours on doctors' diagnostic performance. METHODS: A randomised experiment with 74 internal medicine residents. Doctors diagnosed eight written clinical vignettes that were exactly the same except for the patients' behaviours (either difficult or neutral). Each participant diagnosed half of the vignettes in a difficult patient version and the other half in a neutral version in a counterbalanced design. After diagnosing each vignette, participants were asked to recall the patient's clinical findings and behaviours. Main measurements were: diagnostic accuracy scores; time spent on diagnosis, and amount of information recalled from patients' clinical findings and behaviours. RESULTS: Mean diagnostic accuracy scores (range 0-1) were significantly lower for difficult than neutral patients' vignettes (0.41 vs 0.51; p<0.01). Time spent on diagnosing was similar. Participants recalled fewer clinical findings (mean=29.82% vs mean=32.52%; p<0.001) and more behaviours (mean=25.51% vs mean=17.89%; p<0.001) from difficult than from neutral patients. CONCLUSIONS: Difficult patients' behaviours induce doctors to make diagnostic errors, apparently because doctors spend part of their mental resources on dealing with the difficult patients' behaviours, impeding adequate processing of clinical findings. Efforts should be made to increase doctors' awareness of the potential negative influence of difficult patients' behaviours on diagnostic decisions and their ability to counteract such influence.

[Classification of haematogenous and post-traumatic osteomyelitis]. / Klassifikation der Osteomyelitis und Osteitis.

A classification of osteomyelitis must reflect the complexity of the disease and, moreover, provide conclusions for the treatment. The classification is based on the following eight parameters: source of infection (OM [osteomyelitis]/OT [post-traumatic OM]), anatomic region, stability of affected bone (continuity of bone), foreign material (internal fixation, prosthesis), range of infection (involved structures), activity of infection (acute, chronic, quiescent), causative microbes (unspecific and specific bacteria, fungi) and comorbidity (immunosuppressive diseases, general and local). In the long version of the classification, which was designed for scientific studies, the parameters are named by capital letters and specified by Arabic numbers, e.g., an acute, haematogenous osteomyelitis of a femur in an adolescent with diabetes mellitus, caused by Staphylococcus aureus, multi-sensible is coded as: OM2 Lo33 S1a M1 In1d Aa1 Ba2a K2a. The letters and numbers can be found in clearly arranged tables or calculated by a freely available grouper on the internet (www.osteomyelitis.exquit.net). An equally composed compact version of the classification for clinical use includes all eight parameters, but without further specification. The above-mentioned example in the compact version is: OM 3 S a Ba2 K2. The short version of the classification uses only the first six parameters and excludes causative microbes and comorbidity. The above mentioned example in the short version is: OM 3 S a. The long version of the classification describes an osteomyelitis in every detail. The complexity of the patient's disease is clearly reproducible and can be used for scientific comparisons. The for clinical use suggested compact and short versions of the classification include all important characteristics of an osteomyelitis, can be composed quickly and distinctly with the help of tables and provide conclusions for the individual treatment. The freely available grouper (www.osteomyelitis.exquit.net) creates all three versions of the classification in one step.

[Definition of the Diagnosis Osteomyelitis-Osteomyelitis Diagnosis Score (ODS)]. / Zur Definition der Diagnose Osteomyelitis - Osteomyelitis-Diagnose-Score (ODS).

AIM: The disease "osteomyelitis" is characterised by different symptoms and parameters. Decisive roles in the development of the disease are played by the causative bacteria, the route of infection and the individual defense mechanisms of the host. The diagnosis is based on different symptoms and findings from the clinical history, clinical symptoms, laboratory results, diagnostic imaging, microbiological and histopathological analyses. While different osteomyelitis classifications have been published, there is to the best of our knowledge no score that gives information how sure the diagnosis "osteomyelitis" is in general. METHOD: For any scientific study of a disease a valid definition is essential. We have developed a special osteomyelitis diagnosis score for the reliable classification of clinical, laboratory and technical findings. The score is based on five diagnostic procedures: 1) clinical history and risk factors, 2) clinical examination and laboratory results, 3) diagnostic imaging (ultrasound, radiology, CT, MRI, nuclear medicine and hybrid methods), 4) microbiology, and 5) histopathology. RESULTS: Each diagnostic procedure is related to many individual findings, which are weighted by a score system, in order to achieve a relevant value for each assessment. If the sum of the five diagnostic criteria is 18 or more points, the diagnosis of osteomyelitis can be viewed as "safe" (diagnosis class A). Between 8-17 points the diagnosis is "probable" (diagnosis class B). Less than 8 points means that the diagnosis is "possible, but unlikely" (class C diagnosis). Since each parameter can score six points at a maximum, a reliable diagnosis can only be achieved if at least 3 parameters are scored with 6 points. CONCLUSION: The osteomyelitis diagnosis score should help to avoid the false description of a clinical presentation as "osteomyelitis". A safe diagnosis is essential for the aetiology, treatment and outcome studies of osteomyelitis.

Stress amongst dental students: a systematic review.

The present study was conducted to provide future researchers and dental educators with an overview of stress amongst undergraduate dental students reported in the literature. This overview is needed for the development of a new questionnaire measuring the level of stressors including students, staff and process of dental education. In addition, the review can be used to modify dental curricula to decrease such stress and produce better dentists. Our study consisted of a systematic review of 49 peer-reviewed articles published between 1966 till October 2008 in English, discussing different aspects of stress amongst undergraduate dental students. These aspects are demographic variables of stress, sources of stress, impact of stress, indicators of stress, instruments measuring stress level and management of stress. Major sources of reported stress were related to examinations, clinical requirements and dental supervisors. Studies suggest using signs and symptoms for early detection of stress and proper intervention.

Determinants of effective clinical learning: a student and teacher perspective in Saudi Arabia.

CONTEXT: Graduating clinically competent medical students is probably the principal objective of all medical curricula. Training for clinical competence is rather a complex process and to be effective requires involving all stakeholders, including students, in the processes of planning and implanting the curriculum. This study explores the perceptions of students of the College of Medicine at King Abdul-Aziz Bin Saud University for Health Sciences (KASU-HS), Riyadh, Saudi Arabia of the features of effective clinical rotations by inviting them to answer the question: "Which experiences or activities in your opinion have contributed to the development of your clinical competence? This college was established in 2004 and adopted a problem-based learning curriculum. METHODS: This question was posed to 24 medical students divided into three focus groups. A fourth focus group interview was conducted with five teachers. Transcriptions of the tape-recorded focus group interviews were qualitatively analyzed using a framework analysis approach. FINDINGS: Students identified five main themes of factors perceived to affect their clinical learning: (1) the provision of authentic clinical learning experiences, (2) good organization of the clinical sessions, (3) issues related to clinical cases, (4) good supervision and (5) students' own learning skills. These themes were further subdivided into 18 sub-themes. Teachers identified three principal themes: (1) organizational issues, (2) appropriate supervision and (3) providing authentic experiences. CONCLUSION: Consideration of these themes in the process of planning and development of medical curricula could contribute to medical students' effective clinical learning and skills competency.

Innovations in medical internship: benchmarking and application within the King Saud bin Abdulaziz University for Health Sciences.

INTRODUCTION: While the medical internship (MI) has evolved in some countries into competency-based training with innovative tools for assessment and feedback, the traditional MI is still the norm in many countries. AIM: To describe recent advances in the MI in several countries, to discuss the current MI situation in Saudi Arabia as an example of a country that applies a traditional MI, and to present a Framework for Medical Interns' Competencies (FMIC) implemented within the King Saud bin Abdulaziz University for Health Sciences (KSAU-HS). METHODS: Common electronic databases were searched for the years 1990 to 2008 under keywords related to medical internship education. Information on curricula designed for medical interns or junior doctors in selected countries was obtained by searching relevant websites. At the KSAU-HS, the FMIC was created by first building the case for the urgent need for revising the MI and adapting international approaches to the KSA's needs, followed by dialogue among faculty and leaders, planning, coordination and execution of the framework. RESULTS: Two trends were identified in the recent evolution of the MI. In North America, the first postgraduate year now serves the traditional purpose of the MI. Australia and the United Kingdom have embedded the MI within junior doctor training. These innovative curricula have in common a focus on the domains of medical knowledge, clinical practice, professionalism and communication skills. The FMIC applies innovative principles during the MI years customized to the local medical education setting. CONCLUSION: The evolution in medical education and healthcare systems worldwide has necessitated innovations in the MI. The FMIC is a model whereby innovative curriculum was introduced to enhance the outcomes of the MI in a country that has applied a traditional MI.

Maternal psychological distress and fetal growth trajectories: the Generation R Study.

BACKGROUND: Previous research suggests, though not consistently, that maternal psychological distress during pregnancy leads to adverse birth outcomes. We investigated whether maternal psychological distress affects fetal growth during the period of mid-pregnancy until birth. METHOD: Pregnant women (n=6313) reported levels of psychological distress using the Brief Symptom Inventory (anxious and depressive symptoms) and the Family Assessment Device (family stress) at 20.6 weeks pregnancy and had fetal ultrasound measurements in mid- and late pregnancy. Estimated fetal weight was calculated using head circumference, abdominal circumference and femur length. RESULTS: In mid-pregnancy, maternal distress was not linked to fetal size. In late pregnancy, however, anxious symptoms were related to fetal size after controlling for potential confounders. Anxious symptoms were also associated with a 37.73 g [95% confidence interval (CI) -69.22 to -6.25, p=0.019] lower birth weight. When we related maternal distress to fetal growth curves using multilevel models, more consistent results emerged. Maternal symptoms of anxiety or depression were associated with impaired fetal weight gain and impaired fetal head and abdominal growth. For example, depressive symptoms reduced fetal weight gain by 2.86 g (95% CI -4.48 to -1.23, p<0.001) per week. CONCLUSIONS: The study suggests that, starting in mid-pregnancy, fetal growth can be affected by different aspects of maternal distress. In particular, children of prenatally anxious mothers seem to display impaired fetal growth patterns during pregnancy. Future work should address the biological mechanisms underlying the association of maternal distress with fetal development and focus on the effects of reducing psychological distress in pregnancy.

The intermediate effect and the diagnostic accuracy in clinical case recall of students and experts in dental medicine.

INTRODUCTION: The extensive knowledge of experts facilitates the solving of domain-specific problems. In general, this is due to the fact that experts recall more detailed information than do novices or even advanced students. However, if physicians of different expertise levels are asked to write down the details of a given case, advanced medical students recall more information than experts. This phenomenon was called the 'intermediate effect' and is considered to be a specific feature of medical expertise. The aim of the here presented study was to examine this observation in the domain of dental medicine. MATERIALS AND METHODS: Sixty-one students and 20 specialised dentists participated in this study. Three clinical case descriptions were presented and afterwards the participants were told to write down all concrete information they remembered. Finally, they had to come up with a diagnosis. Interrater agreement, diagnostic accuracy and the recall explanation protocols were analysed statistically in comparison to state-of-the-art (canonical) explanations of the clinical cases. RESULTS: The mean interrater agreement was 96.2 +/- 3.37%. It was shown statistically that the more experienced the participants, the more accurate their diagnoses were (P < 0.001). The statistical analysis using the Games-Howell test demonstrated significant more written recall of the 5th-year students compared with 3rd- and 4th-year students and experts (P < 0.05). CONCLUSION: The results of this study suggest the existence of the intermediate effect in clinical case recall in dental medicine and thereby corroborate its importance and general applicability for different medical domains.

Strategies for the analysis of osteitic bone defects at the diaphysis of long bones.

Septic diseases of the bone and the immediate surrounding soft tissue, i.e., osteitis, belong to the most alarming findings in recent traumatology and orthopedic surgery. The paramount goal of this therapy is to preserve the stable weight-bearing bones while maintaining a correct axis and proper working muscles and joints, in order to avoid permanent disability in the patient. "State-of-the-art" therapy of osteitis/osteomyelitis therapy has two priorities: eradication of the infection and reconstruction of bone and soft tissue. Surgical treatment of the affected bone segments and soft tissue, followed by reconstructive methods, continues to be the main basic therapy. It is often extremely difficult to decide whether the affected bone segment has to be resected, or whether bone continuity can be preserved. The following paper provides strategies and guidance to help guide decisions in this complex and challenging area.

The role of pathophysiological explanations in clinical case representations of dental students and experts.

INTRODUCTION: Teaching of biomedical knowledge lays the foundations for the understanding and treatment of diseases. However, the representation of pathophysiological explanations in the management of clinical cases differs for various levels of medical expertise and different theories have been proposed to explain this phenomenon. The present study investigated for the first time how biomedical knowledge is used in clinical reasoning in dental medicine. MATERIALS AND METHODS: In an experimental study 20 experts in the field of Periodontology and 61 students of different levels of training produced written pathophysiological explanations after having studied three different clinical cases. By comparing the written protocols to a visualised expert-made 'canonical' explanation the concepts used in the pathophysiological explanation were counted and classified as well as the links between concepts. RESULTS: The statistical analysis by MANOVA showed significant differences between third- and fourth-year students, students of intermediate expertise level (fifth-year) and experts for various parameters qualifying concepts or links of the written pathophysiological explanations. The participants of intermediate expertise level produced a high rate of concepts and links; however, characteristic findings for knowledge encapsulation in the different levels of expertise were not evident. The analysis showed that the design of the clinical cases and of the canonical explanations significantly influenced the outcomes. CONCLUSION: The present study demonstrated the pathophysiological representations of clinical cases in dental students and experts to be different from other medical disciplines. It could be assumed that this observation is based on different contents for teaching of practical skills and diagnostic procedures in dental compared with medical education.

Criteria for a good referral system for psychiatric patients: the view from Saudi Arabia.

The development and implementation of quality referral systems reflects sound national health planning. This review appraised the data on referral systems, in particular psychiatric referrals, with special reference to Saudi Arabia. A computer search was made of relevant literature in the past 2 decades. The rate and process of referring patients through referral letters varies globally across practice settings and is initiated by an array of factors linked with health consumers, health providers and delivery systems. Referral systems, including consultation-liaison services, are an essential component of any health care organization for offering a complete range of good quality, specialized health services.

Criteria for a good referral system for psychiatric patients: the view from Saudi Arabia

The development and implementation of quality referral systems reflects sound national health planning. This review appraised the data on referral systems, in particular psychiatric referrals, with special reference to Saudi Arabia. A computer search was made of relevant literature in the past 2 decades. The rate and process of referring patients through referral letters varies globally across practice settings and is initiated by an array of factors linked with health consumers, health providers and delivery systems. Referral systems, including consultation-liaison services, are an essential component of any health care organization for offering a complete range of good quality, specialized health services

Are specialist certification examinations a reliable measure of physician competence?

High stakes postgraduate specialist certification examinations have considerable implications for the future careers of examinees. Medical colleges and professional boards have a social and professional responsibility to ensure their fitness for purpose. To date there is a paucity of published data about the reliability of specialist certification examinations and objective methods for improvement. Such data are needed to improve current assessment practices and sustain the international credibility of specialist certification processes. To determine the component and composite reliability of the Fellowship examination of the College of Physicians of South Africa, and identify strategies for further improvement, generalizability and multivariate generalizability theory were used to estimate the reliability of examination subcomponents and the overall reliability of the composite examination. Decision studies were used to identify strategies for improving the composition of the examination. Reliability coefficients of the component subtests ranged from 0.58 to 0.64. The composite reliability of the examination was 0.72. This could be increased to 0.8 by weighting all test components equally or increasing the number of patient encounters in the clinical component of the examination. Correlations between examination components were high, suggesting that similar parameters of competence were being assessed. This composite certification examination, if equally weighted, achieved an overall reliability sufficient for high stakes examination purposes. Increasing the weighting of the clinical component decreased the reliability. This could be rectified by increasing the number of patient encounters in the examination. Practical ways of achieving this are suggested.

Performance of academically at-risk medical students in a problem-based learning programme: a preliminary report.

INTRODUCTION: Racially segregated schooling, a legacy of Apartheid policies, continues to hamper education in South Africa. Students entering university from suboptimal circumstances are at significant risk of demonstrating poor academic performance and dropping out of their programmes. Attempts to address the educational needs of these students have included the introduction of extended medical programmes at several universities. Such a programme, the Academic Development Programme (ADP), was implemented at the University of Cape Town in 1991. Over the past decade the programme has graduated more than 100 students. Upon implementation of a new problem-based learning (PBL) programme in 2002, the ADP was discontinued and all students were entered directly into the new PBL programme. Students who demonstrate a need for additional academic support by the end of the first semester enter the Intervention Programme for 1 year before proceeding to the second semester of the PBL programme. An interim analysis was performed to compare the retention rates and academic performance of academically at-risk students in the new PBL programme and the ADP. METHODS: The records of all academically at-risk students entering the ADP (1991-2000) and the new PBL programme (2002) were reviewed. Retention rates for all years of study, and academic performance in the fourth year clerkship courses of the respective programmes were compared. RESULTS: A total of 239 academically at-risk students in the ADP and 43 at-risk students in the new PBL programme were studied. The median retention rates, per year of study, for at-risk students in the PBL programme was significantly better than for at-risk students in the ADP (p<0.02). Academic performance of the at-risk students in all the fourth year clinical clerkship courses of the PBL programme was significantly better than the mean performance over 10 years for at-risk students in the same fourth year courses in the ADP. CONCLUSION: The introduction of PBL at the University of Cape Town has not had a deleterious effect on the performance of academically at-risk medical students. Interim analysis suggests that retention rates and academic performance in the PBL programme are better than those achieved in the extended traditional programme.

[Effects of problem-based medical education: 16 Dutch curriculum comparisons]. / Effecten van probleemgestuurd medisch onderwijs; 16 Nederlandse curriculumvergelijkingen.

The effects of problem-based medical education on student performance were studied by curriculum comparison in 16 Dutch studies. The results suggest that students and graduates of the problem-based medical curriculum of Maastricht University in the Netherlands perform better on tests of diagnostic reasoning ability, in the area of interpersonal skills and in practical medical skills such as physical examination. No differences were found with respect to acquired medical knowledge. However, differential drop-out rates of students from the curricula compared may have masked the effects in this area.

[Principles of OSG arthrodesis in cases of joint infection]. / Prinzipien der OSG-Arthrodese bei Gelenkinfekt.

A chronic empyema of the ankle joint often develops after an open fracture or surgery. In the case of the destruction of the joint due to an infection, an arthrodesis should be performed. Normally we use an external fixator with two bone-nails placed into the calcaneus and two into the tibia. The arthrodesis is distracted and Septopal is permanently implemented. At 4-6 weeks after surgery the Septopal is removed, with distraction being reduced and a cancellous bone-graft taken from the dorsal iliac crest is performed to fill the bony defect. After bone healing, the external fixator is removed and the patient mobilized in a brace. Initially, weight-bearing is limited to 10 kg but is increased gradually to full weight. The brace is used for 6-9 months; later the patient is mobilized in orthopaedic shoes. In difficult cases, also in combination with a malposition which has to be corrected or a lengthening of the lower limb, we use the Ilizarov fixator. From 1993 to 2003 we performed arthrodeses of the ankle joint due to infectious destruction in 107 cases. In 82.2%, the empyema was caused by a fracture of the ankle joint and the following treatment. In 58% of the patients, we saw associated diseases such as obesity, alcohol abuse, diabetes and malposition of the foot. In 55% we found Staphylococcus aureus. In 86%, we used the external AO-fixator, in 14% the Ilizarov fixator. The patient retained the fixator for an average of 128 days. In our study, 92.1% of the 101 patients who had completed therapy showed a good stability an average of 4.5 years after the arthrodesis. In 5% we found partial stability, while three patients had to be amputated. In 57 patients (56.4), an arthrosis of the tarsal bones was found, and 38 patients (54.3%) of the 70 patients who at the time of the arthrodesis were still working could return to work.

Facile synthesis of cyclopropene analogues of aluminum and an aluminum pinacolate, and the reactivity of LAl[eta(2)-C(2)(SiMe(3))(2)] toward unsaturated molecules (L=HC[(CMe)(NAr)](2), Ar=2,6-i-Pr(2)C(6)H(3)).

Reduction of LAlI(2) (1) (L = HC[(CMe)(NAr)](2), Ar = 2,6-i-Pr(2)C(6)H(3)) with potassium in the presence of alkynes C(2)(SiMe(3))(2), C(2)Ph(2), and C(2)Ph(SiMe(3)) yielded the first neutral cyclopropene analogues of aluminum LAl[eta(2)-C(2)(SiMe(3))(2)] (3), LAl(eta(2)-C(2)Ph(2)) (4), and LAl[eta(2)-C(2)Ph(SiMe(3))] (5), respectively, whereas reduction of 1 in the presence of Ph(2)CO gave an aluminum pinacolate LAl[O(2)(CPh(2))(2)] (6), irrespective of the amount of Ph(2)CO employed. The unsaturated molecules CO(2), Ph(2)CO, and PhCN inserted into one of the Al-C bonds of 3 leading to ring enlargement to give novel aluminum five-membered heterocyclic systems LAl[OC(O)C(2)(SiMe(3))(2)] (7), LAl[OC(Ph)(2)C(2)(SiMe(3))(2)] (8), and LAl[NC(Ph)C(2)(SiMe(3))(2)] (9) in high yields. In contrast, 3 reacted with t-BuCN, 2,6-Trip(2)C(6)H(3)N(3) (Trip = 2,4,6-i-Pr(3)C(6)H(2)), and Ph(3)SiN(3) resulting in the displacement of the alkyne moiety to afford LAl[N(2)(Ct-Bu)(2)] (10) with an unprecedented aluminum-containing imidazole ring, and the first monomeric aluminum imides LAlNC(6)H(3)-2,6-Trip(2) (11) and LAlNSiPh(3) (12). All compounds have been characterized spectroscopically. The variable-temperature (1)H NMR studies of 3 and ESR measurements of 3 and 4 suggest that the Al-C-C three-membered-ring systems can be best described as metallacyclopropenes. The (27)Al NMR resonances of 2 and 3 are reported and compared. Molecular structures of compounds 3, 4, 6.OEt(2), 8.OEt(2), and 9 were determined by single-crystal X-ray structural analysis.