Postoperative complications after surgery for lumbar spinal stenosis, assessment using two different data sources.

PURPOSE: Lumbar spinal stenosis (LSS) is a prevalent disorder, and surgery for LSS is a common procedure. Postoperative complications occur after any surgery and impose costs for society and costs and additional morbidity for patients. Since complications are relatively rare, medical registries of large populations may provide valuable knowledge. However, recording of complications in registries can be incomplete. To better estimate the true prevalence of complications after LSS surgery, we reviewed two different sources of data and recorded complications for a sample of Norwegian LSS patients. METHODS: 474 patients treated surgically for LSS during 2015 and 2016 at four hospitals reported to a national spine registry (NORspine). Postoperative complications were recorded by patients in NORspine, and we cross-referenced complications documented in NORspine with the patients´ electronic patient records (EPR) to re-test the complication rates. We performed descriptive statistics of complication rates using the two different data sources above, and analyzed the association between postoperative complications and clinical outcome with logistic regression. RESULTS: The mean (95%CI) patient age was 66.3 (65.3-67.2) years, and 254 (53.6%) were females. All patients were treated with decompression, and 51 (10.7%) received an additional fusion during the index surgery. Combining the two data sources, we found a total rate for postoperative complications of 22.4%, the NORspine registry reported a complication rate of 15.6%, and the EPR review resulted in a complication rate of 16.0%. However, the types of complications were inconsistent across the two data sources. According to NORspine, the frequency of reoperation within 90 days was 0.9% and according to EPR 3.4%. The rates of wound infection were for NORspine 3.1% and EPR review 2.1%. There was no association between postoperative complication and patient reported outcome. CONCLUSION: Postoperative complications occurred in 22% of LSS patients. The frequency of different postoperative complications differed between the two data sources.

Long-term comparison of anterior (ALIF) versus transforaminal (TLIF) lumbar interbody fusion: a propensity score-matched register-based study.

PURPOSE: Anterior (ALIF) and transforaminal (TLIF) lumbar interbody fusion have shown similar clinical outcomes at short- and medium-term follow-ups. Possible advantages of ALIF in the long run could be better disc height and lumbar lordosis and reduced risk of adjacent segment disease. We aimed to study if ALIF could be associated with superior clinical outcomes than TLIF at long-term follow-up. METHODS: We analysed 535 patients treated with ALIF or TLIF of the L5-S1 spinal segment between 2007 and 2017 who completed long-term follow-up in a national spine registry database (NORspine). We defined treatment success after surgery as at least 30% improvement in Oswestry Disability Index (ODI) at long-term follow-up. Patients treated with ALIF and TLIF and who responded at long term were balanced by propensity score matching. The proportions of successfully treated patients within each group were compared by numbers and percentages with corresponding relative risk. RESULTS: The mean (95%CI) age of the total study population was 50 (49-51) years, and 264 (49%) were females. The mean (95%CI) preoperative ODI score was 40 (39-42), and 174 (33%) had previous spine surgery. Propensity score matching left 120 patients in each treatment group. At a median (95%CI) of 92 (88-97) months after surgery, we found no difference in proportions successfully treated patients with ALIF versus TLIF (68 (58%) versus 77 (65%), RR (95%CI) = 0.88 (0.72 to1.08); p = 0.237). CONCLUSIONS: This propensity score-matched national spine register study of patients treated with ALIF versus TLIF of the lumbosacral junction found no differences in proportions of successfully treated patients at long-term follow-up. LEVEL OF EVIDENCE I: Diagnostic: individual cross-sectional studies with the consistently applied reference standard and blinding.

Characteristics and outcomes of patients who did not respond to a national spine surgery registry.

BACKGROUND: Loss to follow-up may bias outcome assessments in medical registries. This cohort study aimed to analyze and compare patients who failed to respond with those that responded to the Norwegian Registry for Spine Surgery (NORspine). METHODS: We analyzed a cohort of 474 consecutive patients operated for lumbar spinal stenosis at four public hospitals in Norway during a two-year period. These patients reported sociodemographic data, preoperative symptoms, and Oswestry Disability Index (ODI), numerical rating scales (NRS) for back and leg pain to NORspine at baseline and 12 months postoperatively. We contacted all patients who did not respond to NORspine after 12 months. Those who responded were termed responsive non-respondents and compared to 12 months respondents. RESULTS: One hundred forty (30%) did not respond to NORspine 12 months after surgery and 123 were available for additional follow-up. Sixty-four of the 123 non-respondents (52%) responded to a cross-sectional survey done at a median of 50 (36-64) months after surgery. At baseline, non-respondents were younger 63 (SD 11.7) vs. 68 (SD 9.9) years (mean difference (95% CI) 4.7 years (2.6 to 6.7); p = < 0.001) and more frequently smokers 41 (30%) vs. 70 (21%) RR (95%CI) = 1.40 (1.01 to 1.95); p = 0.044. There were no other relevant differences in other sociodemographic variables or preoperative symptoms. We found no differences in the effect of surgery on non-respondents vs. respondents (ODI (SD) = 28.2 (19.9) vs. 25.2 (18.9), MD (95%CI) = 3.0 ( -2.1 to 8.1); p = 0.250). CONCLUSION: We found that 30% of patients did not respond to NORspine at 12 months after spine surgery. Non-respondents were somewhat younger and smoked more frequently than respondents; however, there were no differences in patient-reported outcome measures. Our findings suggest that attrition bias in NORspine was random and due to non-modifiable factors.

Impact of the number of previous lumbar operations on patient-reported outcomes after surgery for lumbar spinal stenosis or lumbar disc herniation.

Repeated lumbar spine surgery has been associated with inferior clinical outcomes. This study aimed to examine and quantify the impact of this association in a national clinical register cohort. This is a population-based study from the Norwegian Registry for Spine surgery (NORspine). We included 26,723 consecutive cases operated for lumbar spinal stenosis or lumbar disc herniation from January 2007 to December 2018. The primary outcome was the Oswestry Disability Index (ODI), presented as the proportions reaching a patient-acceptable symptom state (PASS; defined as an ODI raw score ≤ 22) and ODI raw and change scores at 12-month follow-up. Secondary outcomes were the Global Perceived Effect scale, the numerical rating scale for pain, the EuroQoL five-dimensions health questionnaire, occurrence of perioperative complications and wound infections, and working capability. Binary logistic regression analysis was conducted to examine how the number of previous operations influenced the odds of not reaching a PASS. The proportion reaching a PASS decreased from 66.0% (95% confidence interval (CI) 65.4 to 66.7) in cases with no previous operation to 22.0% (95% CI 15.2 to 30.3) in cases with four or more previous operations (p < 0.001). The odds of not reaching a PASS were 2.1 (95% CI 1.9 to 2.2) in cases with one previous operation, 2.6 (95% CI 2.3 to 3.0) in cases with two, 4.4 (95% CI 3.4 to 5.5) in cases with three, and 6.9 (95% CI 4.5 to 10.5) in cases with four or more previous operations. The ODI raw and change scores and the secondary outcomes showed similar trends. We found a dose-response relationship between increasing number of previous operations and inferior outcomes among patients operated for degenerative conditions in the lumbar spine. This information should be considered in the shared decision-making process prior to elective spine surgery.

Predictors for failure after surgery for lumbar spinal stenosis: a prospective observational study.

BACKGROUND/CONTEXT: Some patients do not improve after surgery for lumbar spinal stenosis (LSS), and surgical treatment implies a risk for complications and deterioration. Patient selection is of paramount importance to improve the overall clinical results and identifying predictive factors for failure is central in this work. PURPOSE: We aimed to explore predictive factors for failure and worsening after surgery for LSS. STUDY DESIGN /SETTING: Retrospective observational study on prospectively collected data from a national spine registry with a 12-month follow-up. PATIENT SAMPLE: We analyzed 11,873 patients operated for LSS between 2007 and 2017 in Norway, included in the Norwegian registry for spine surgery (NORspine). Twelve months after surgery, 8919 (75.1%) had responded. OUTCOME MEASURES: Oswestry Disability Index (ODI) 12 months after surgery. METHODS: Predictors were assessed with uni- and multivariate logistic regression, using backward conditional stepwise selection and a significance level of 0.01. Failure (ODI>31) and worsening (ODI>39) were used as dependent variables. RESULTS: Mean (95%CI) age was 66.6 (66.4-66.9) years, and 52.1% were females. The mean (95%CI) preoperative ODI score was 39.8 (39.4-40.1). All patients had decompression, and 1494 (12.6%) had an additional fusion procedure. Twelve months after surgery, the mean (95%CI) ODI score was 23.9 (23.5-24.2), and 2950 patients (33.2%) were classified as failures and 1921 (21.6%) as worse. The strongest predictors for failure were duration of back pain > 12 months (OR [95%CI]=2.24 [1.93-2.60]; p<.001), former spinal surgery (OR [95%CI]=2.21 [1.94-2.52]; p<.001) and age>70 years (OR (95%CI)=1.97 (1.69-2.30); p<.001). Socioeconomic variables increased the odds of failure (ORs between 1.36 and 1.62). The strongest predictors for worsening were former spinal surgery (OR [95%CI]=2.04 [1.77-2.36]; p<.001), duration of back pain >12 months (OR [95%CI]=1.83 [1.45-2.32]; p<.001) and age >70 years (OR [95%CI]=1.79 [1.49-2.14]; p<.001). Socioeconomic variables increased the odds of worsening (ORs between 1.33-1.67). CONCLUSIONS: After surgery for LSS, 33% of the patients reported failure, and 22% reported worsening as assessed by ODI. Preoperative duration of back pain for longer than 12 months, former spinal surgery, and age above 70 years were the strongest predictors for increased odds of failure and worsening after surgery.

Total Hip Arthroplasty Leads to Better Results After Low-Energy Displaced Femoral Neck Fracture in Patients Aged 55 to 70 Years: A Randomized Controlled Multicenter Trial Comparing Internal Fixation and Total Hip Arthroplasty.

BACKGROUND: The optimal treatment of displaced femoral neck fractures in patients 55 to 70 years old remains controversial. The aim of the present study was to assess the effect of closed reduction and internal fixation with cannulated screws (IF) compared with total hip arthroplasty (THA) on hip pain and function, with use of data for outcome measures, complications, and reoperations. METHODS: This multicenter randomized controlled trial included all patients 55 to 70 years old who presented with a low-energy displaced femoral neck fracture between December 2013 and December 2018. Patients were randomly allocated to undergo either IF or THA. The primary outcome was the Harris Hip Score (HHS) at 12 months postoperatively. Secondary outcomes were the HHS at 4 and 24 months postoperatively, Oxford Hip Score (OHS), Hip Disability and Osteoarthritis Outcome Score (HOOS), health-related quality of life (EQ-5D-3L [EuroQol 5 Dimensions 3 Levels] index score and EQ-VAS [visual analogue scale]), VAS for pain, and VAS for patient satisfaction at 4, 12, and 24 months postoperatively. Complications and reoperations were continuously monitored. The primary analyses were performed according to the intention-to-treat principle. RESULTS: A total of 102 patients with a mean (± standard deviation) age of 63.7 ± 4.2 years were allocated to IF (n = 51) or THA (n = 51). The mean difference in the primary outcome, the HHS at 12 months postoperatively (5.3; 95% confidence interval, 0.9 to 9.7; p = 0.017), was below the predefined minimal clinically important difference of 10 points. However, patients who underwent THA had a significantly higher HHS at 4 and 12 months, better OHS at 4 and 12 months, and better HOOS at 4, 12, and 24 months postoperatively. Patients who underwent THA also reported better health-related quality of life at 4 months postoperatively and reported greater satisfaction and less pain at 4 and 12 months postoperatively. A total of 26 patients in the IF group (51%; 95% confidence interval, 37% to 65%) and 2 patients in the THA group (4%; 95% confidence interval, 0.5% to 13%) underwent a major reoperation. CONCLUSIONS: In this randomized controlled trial, we showed that patients between 55 and 70 years old who underwent THA for a low-energy displaced femoral neck fracture experienced better outcomes than those who underwent closed reduction and internal fixation. LEVEL OF EVIDENCE: Therapeutic Level I . See Instructions for Authors for a complete description of levels of evidence.

Criteria for failure and worsening after surgery for lumbar spinal stenosis: a prospective national spine registry observational study.

BACKGROUND CONTEXT: Criteria for success after surgical treatment of lumbar spinal stenosis (LSS) have been defined previously; however, there are no clear criteria for failure and worsening after surgery as assessed by patient-reported outcome measures (PROMs). PURPOSE: We aimed to quantify changes in standard PROMs that most accurately identified failure and worsening after surgery for LSS. STUDY DESIGN /SETTING: Retrospective analysis of prospective national spine registry data with 12-months follow-up. PATIENT SAMPLE: We analyzed 10,822 patients aged 50 years and older operated in Norway during a decade, and 8,258 (76%) responded 12 months after surgery. OUTCOME MEASURES (PROMS): We calculated final scores, absolute changes, and percentage changes for Oswestry Disability Index (ODI), Numeric Rating Scale (NRS) for back and leg pain (0-10), and EuroQol-5D (EQ-5D). These 12 PROM derivates were compared to the Global Perceived Effect (GPE), a 7-point Likert scale. METHODS: We used ODI, NRS back and leg pain, and EQ-5D 12 months after surgery to identify patients with failure (no effect) and worsening (clinical deterioration). The corresponding GPE at 12-months was graded as failure (GPE=4-7) and worsening (GPE=6-7) and used as an external criterion. To quantify the most accurate cut-off values corresponding to failure and worsening, we calculated areas under the curves (AUCs) of receiver operating characteristics (ROC) curves for the respective PROM derivates. RESULTS: Mean (95% CI) age was 68.3 (68.1 - 68.5) years, and 52% were females. There were 1,683 (20%) failures, and 476 (6%) patients were worse after surgery. The mean (95% CI) pre- and postoperative ODIs were 39.8 (39.5 - 40.2) and 23.7 (23.3 - 24.1), respectively. At 12 months, the mean difference (95% CI) in ODI was 16.1 (15.7 - 16.4), and the mean (95% CI) percentage improvement 38.8% (37.8 - 38.8). The PROM derivates identified failure and worsening accurately (AUC>0.80), except for the absolute change in EQ-5D. The ODI derivates were most accurate to identify both failure and worsening. We found that less than 20% improvement in ODI most accurately identified failure (AUC=0.89 [95% CI: 0.88 to 0.90]), and an ODI final score of 39 points or more most accurately identified worsening (AUC =0.91 [95% CI: 0.90 - 0.92]). CONCLUSIONS: In this national register study, ODI derivates were most accurate to identify both failure and worsening after surgery for degenerative lumbar spinal stenosis. We recommend use of ODI percentage change and ODI final score for further studies of failure and worsening in elective spine surgery.

Acute Paraspinal Compartment Syndrome After Deadlifting: A Case Report.

CASE: A 27-year-old African man was admitted with acute right-sided loin pain that had started 4 hours after deadlifting. Renal colic was suspected, but clinical and radiological examination revealed no pathology of the urinary system. Further investigation revealed rhabdomyolysis. The back pain worsened with flexion, and both loins were hard on palpation 24 hours later. High intracompartmental pressures confirmed acute paraspinal compartment syndrome. CONCLUSIONS: We performed fasciotomy of the back muscles 28 hours after the onset of pain. Eighteen months after surgery, the patient no longer performed deadlifts but returned to pain-free exercise.

Cross-Table Lateral Radiographs Accurately Predict Displacement in Valgus-Impacted Femoral Neck Fractures.

BACKGROUND: Femoral neck fractures are classified as nondisplaced (Garden types I and II) or displaced (Garden types III and IV) on the basis of anteroposterior radiographs. Cross-table lateral radiographs are important in the assessment of Garden type-I and II fractures as posterior tilt of the femoral head may influence treatment results. A posterior tilt of >20° has been associated with an increased risk of treatment failure after internal fixation, although the precision of these measurements has not been validated. Therefore, the purpose of the present study was to compare cross-table lateral radiographs with 3-dimensional computed tomographic (3D-CT) reconstructions of Garden type-I and II femoral neck fractures. METHODS: Twenty-three patients presenting with Garden type-I and II femoral neck fractures that were verified on anteroposterior radiographs underwent CT scanning immediately after radiographic examination. 3D models of the fractured and uninjured femora were reconstructed from the CT images, and displacement of the 3D models was determined by superimposing the fractured and uninjured femora. We defined a coordinate system with its origin at the center of the uninjured femoral head with the x axis oriented medially; the y axis, posteriorly; and the z axis, cranially. Correlations between lateral radiographs and 3D models were assessed with the Spearman rank coefficient, mean difference, and limits of agreement. RESULTS: Posterior tilt of the femoral head on lateral radiographs was strongly correlated with displacement of the femoral head along the y axis of the 3D models, with a correlation coefficient of 0.86 (p < 0.001). Correlations between the findings on lateral radiographs and displacements along the x or z axis were weak, with coefficients of -0.30 (p = 0.18) and 0.21 (p = 0.34), respectively. The mean difference between displacement on lateral radiographs and displacement along the y axis of the 3D models was smaller, and demonstrated a smaller limits-of-agreement interval, compared with the x or z axis. CONCLUSIONS: Our results demonstrated a strong correlation between posterior displacement of the femoral head on lateral radiographs and displacement along the y axis in 3D models of Garden type-I and II femoral neck fractures. This finding indicates that lateral radiographs provide an accurate assessment of posterior tilt.

Screw Fixation Versus Hemiarthroplasty for Nondisplaced Femoral Neck Fractures in Elderly Patients: A Multicenter Randomized Controlled Trial.

BACKGROUND: Elderly patients with a displaced femoral neck fracture treated with hip arthroplasty may have better function than those treated with internal fixation. We hypothesized that hemiarthroplasty would be superior to screw fixation with regard to hip function, mobility, pain, quality of life, and the risk of a reoperation in elderly patients with a nondisplaced femoral neck fracture. METHODS: In a multicenter randomized controlled trial (RCT), Norwegian patients ≥70 years of age with a nondisplaced (valgus impacted or truly nondisplaced) femoral neck fracture were allocated to screw fixation or hemiarthroplasty. Assessors blinded to the type of treatment evaluated hip function with the Harris hip score (HHS) as the primary outcome as well as on the basis of mobility assessed with the timed "Up & Go" (TUG) test, pain as assessed on a numerical rating scale, and quality of life as assessed with the EuroQol-5 Dimension-3 Level (EQ-5D) at 3, 12, and 24 months postsurgery. Results, including reoperations, were assessed with intention-to-treat analysis. RESULTS: Between February 6, 2012, and February 6, 2015, 111 patients were allocated to screw fixation and 108, to hemiarthroplasty. At the time of follow-up, there was no significant difference in hip function between the screw fixation and hemiarthroplasty groups, with a 24-month HHS (and standard deviation) of 74 ± 19 and 76 ± 17, respectively, and an adjusted mean difference of -2 (95% confidence interval [CI] = -6 to 3; p = 0.499). Patients allocated to hemiarthroplasty were more mobile than those allocated to screw fixation (24-month TUG = 16.6 ± 9.5 versus 20.4 ± 12.8 seconds; adjusted mean difference = 6.2 seconds [95% CI = 1.9 to 10.5 seconds]; p = 0.004). Furthermore, screw fixation was a risk factor for a major reoperation, which was performed in 20% (22) of 110 patients who underwent screw fixation versus 5% (5) of 108 who underwent hemiarthroplasty (relative risk reduction [RRR] = 3.3 [95% CI = 0.7 to 10.0]; number needed to harm [NNH] = 6.5; p = 0.002). The 24-month mortality rate was 36% (40 of 111) for patients allocated to internal fixation and 26% (28 of 108) for those allocated to hemiarthroplasty (RRR = 0.4 [95% CI = -0.1 to 1.1]; p = 0.11). Two patients were lost to follow-up. CONCLUSIONS: In this multicenter RCT, hemiarthroplasty was not found to be superior to screw fixation in reestablishing hip function as measured by the HHS (the primary outcome). However, hemiarthroplasty led to improved mobility and fewer major reoperations. The findings suggest that certain elderly patients with a nondisplaced femoral neck fracture may benefit from being treated with a latest-generation hemiarthroplasty rather than screw fixation. LEVEL OF EVIDENCE: Therapeutic Level I. See Instructions for Authors for a complete description of levels of evidence.

Calcar screws and adequate reduction reduced the risk of fixation failure in proximal humeral fractures treated with a locking plate: 190 patients followed for a mean of 3 years.

BACKGROUND: Fixation of proximal humeral fractures (PHF) with locking plates has gained popularity over conservative treatment, but surgery may be complicated with infection, non-union, avascular necrosis (AVN) of the humeral head and fixation failure. Failure to achieve structural support of the medial column has been suggested to be an important risk factor for fixation failure. The aims of this study were to examine the effect of calcar screws and fracture reduction on the risk of fixation failure and to assess long-term shoulder pain and function. METHODS: This was a single-centre retrospective study of 190 adult PHF patients treated with a locking plate between 2011 and 2014. Reoperations due to fixation failure were the primary outcome. Risk factors for fixation failure were assessed using the Cox regression analysis. Postoperative shoulder pain and function were assessed by the Oxford Shoulder Score (OSS). RESULTS: Thirty-one of 190 (16%) patients underwent a reoperation: 14 (7%) due to fixation failure, 10 (5%) due to deep infection and 2 (1%) due to AVN. The absence of calcar screws and fixation with residual varus malalignment (head-shaft angle < 120°) both increased the risk of fixation failure with an adjusted hazard ratio (95% CI) of 8.6 (1.9-39.3; p = 0.005) and 4.9 (1.3-17.9; p = 0.02), respectively. The median (interquartile range) OSS was 40 (27-46). CONCLUSION: The use of calcar screws, as well as the absence of postoperative varus malalignment, significantly reduced the risk of fixation failure. We, therefore, recommend the use of calcar screws and to avoid residual varus malalignment to improve the medial support of proximal humeral fractures treated with a locking plate.

Bilateral symmetrical comparison of the proximal femur using 3D-CT models.

PURPOSE: Superimposed three-dimensional (3D)-models obtained from CT-images have been used to evaluate displacement of femoral neck fractures, but this method assumes symmetrical anatomy of normal femurs. The present study aimed to compare the spatial orientation of the left and right proximal femur, thus establishing if 3D models can be used as a reference standard for the evaluation of fracture displacement. METHODS: We generated 3D-CT-models of 20 patients with no skeletal pathology of the proximal femurs. Three observers independently determined the positions of the fovea and the femoral head, and a vector intersecting the centre points of the fovea and the femoral head defined the rotation. Differences in positions and rotations were determined by superimposing the 3D-CT-models of both femurs. RESULTS: The mean distance (95% CI) between positions of the left and right fovea was 3.1 mm (2.7-3.4) and between the left and right femoral head 2.8 mm (2.6-3.0). The minimal detectable change was 2.8 for the fovea and 2.3 for the femoral head, and the repeatability coefficients between 2.1-2.7 and 1.0-2.9, respectively. Mean difference in rotation of the femoral head was 6° (5.3-6.6) with a minimal detectable change of 8.8 and repeatability coefficients ranging from 5.8 to 10.0. CONCLUSIONS: Distances between the left and right femoral heads were larger than what could be explained by measurement error alone, suggesting that there may be minor side-to-side differences. However, these differences are small, and 3D-CT-models can be used as a reference standard to evaluate displacement of femoral neck fractures.

Eight orthopedic surgeons achieved moderate to excellent reliability measuring the preoperative posterior tilt angle in 50 Garden-I and Garden-II femoral neck fractures.

BACKGROUND: Studies of elderly patients with Garden-I and Garden-II femoral neck fractures (FNFs) suggest that a preoperative posterior tilt of the femoral head of at least 20° increases the risk of fixation failure. A recently published treatment algorithm recommended hemiarthroplasty over internal fixation for elderly patients with Garden-I and Garden-II FNFs and a preoperative posterior tilt of at least 20°. However, the reliability of the method used to measure the posterior tilt has not been assessed according to recommended standards for reliability trials. METHODS: Four orthopedic registrars and four consultants measured the posterior tilt angle in 50 preoperative lateral radiographs at two occasions six weeks apart. We estimated inter- and intrarater reliability by intraclass correlation coefficient (ICC). We also assessed repeatability by the repeatability coefficient (RC) and agreement by the minimal detectable change (MDC). Based on the suggested cutoff value of 20°, we reported the overall percentage and specific agreement for the choice of implant. RESULTS: Inter- and intrarater reliability for all raters was excellent with an ICC (95% CI) of 0.77 (0.69-0.85) and 0.77 (0.67-0.86), respectively. The RC was 13.9 and the MDC 14.1. Specific agreement for choosing arthroplasty was 61.3 and 54.6% for the first and second test occasion, respectively. CONCLUSIONS: Eight orthopedic surgeons measured the posterior tilt in 50 Garden-I and Garden-II FNFs and achieved excellent inter- and intrarater reliability. However, variations in repeated measurements and variations in measurements made by different raters, as assessed by the RC and the MDC respectively, ranged from 13.9° to 14.1°. The variations in posterior tilt measurements should be taken into account when choosing the type of implant for elderly patients with Garden-I and Garden-II femoral neck fractures.

The influence of the hips position on measurements of posterior tilt in a valgus-impacted femoral neck fracture.

INTRODUCTION: Lateral radiographs are important for the evaluation of Garden I and II femoral neck fractures. These fractures appear undisplaced in the anteroposterior view, but posterior tilt of the femoral head may still be present in the lateral view. The influence of posterior tilt is, however, debated, which could be caused by the use of non-standardized cross-table radiographs in the conflicting reports. The aim of this bone-model study was therefore to evaluate the influence of the hips position on measurements of posterior tilt. MATERIALS AND METHODS: We generated models of a Garden I-II femoral neck fracture and the non-injured contralateral femur from CT reconstructions with a 3D-printer. Lateral radiographs of the models were obtained in positions ranging from 90° internal rotation (IR) to 90° external rotation (ER) and 0-80° flexion. Two investigators independently measured posterior tilt on 27 lateral radiographs obtained from each model. RESULTS: The inter-tester ICC was 0.91 (0.84-0.94), standard error of measurement (SEM) 2.6, and minimal detectable change (MDC) 7.2. The median (range) posterior tilt for the fracture model was 21.9° (5.0, 33.8) and 23.6° (2.2, 28.6) for observer 1 and observer 2, respectively. The corresponding posterior tilt within the range of 10° IR to 40° ER and 0 to 30° flexion of the fracture model, was 27.3° (24.0, 33.8) and 26.3° (24.8, 28.6). DISCUSSION: The range of posterior tilt measurements for positions of the proximal femur restricted from 10° IR to 40° ER and 0 to 30° flexion, was above the MDC for observer 1, and below the MDC for observer 2. These findings indicate that rotation and flexion affect measurements of posterior tilt, but the influence may be negligible for positions of the injured extremity that are clinically relevant during cross-table lateral radiographs. A larger study that accounts for variations in anatomy and fracture displacement is required to confirm these findings.

Preoperative posterior tilt of at least 20° increased the risk of fixation failure in Garden-I and -II femoral neck fractures.

Background and purpose - It has been suggested that preoperative posterior tilt of the femoral head may increase the risk of fixation failure in Garden-I and -II femoral neck fractures. To investigate this association, we studied a cohort of 322 such patients. Patients and methods - Patients treated with internal fixation between 2005 and 2012 were retrospectively identified using hospital records and the digital image bank. 2 raters measured the preoperative posterior tilt angle and categorized it into 3 groups: < 10°, 10-20°, and ≥ 20°. The inter-rater reliability (IRR) was determined. Patients were observed until September 2013 (with a minimum follow-up of 18 months) or until failure of fixation necessitating salvage arthroplasty. The risk of fixation failure was assessed using competing-risk regression analysis, adjusting for time to surgery. Results - Patients with a posterior tilt of ≥ 20° had a higher risk of fixation failure: 19% (8/43) as compared to 11% (14/127) in the 10-20° category and 6% (9/152) in the < 10° category (p = 0.03). Posterior tilt of ≥ 20° increased the risk of fixation failure, with an adjusted hazard ratio of 3.4 (95% CI: 1.3-8.9; p = 0.01). The interclass correlation coefficient for angular measurements of posterior tilt was 0.90 (95% CI: 0.87-0.92), and the IRR for the categorization of posterior tilt into 3 groups was 0.76 (95% CI: 0.69-0.81). Interpretation - Preoperative posterior tilt of ≥ 20° in Garden-I and -II femoral neck fractures increased the risk of fixation failure necessitating salvage arthroplasty. The reliability of the methods that we used to measure posterior tilt ranged from good to excellent.

Personality traits and types predict medical school stress: a six-year longitudinal and nationwide study.

OBJECTIVES: Personality types (combinations of traits) that take into account the interplay between traits give a more detailed picture of an individual's character than do single traits. This study examines whether both personality types and traits predict stress during medical school training. METHODS: We surveyed Norwegian medical students (n = 421) 1 month after they began medical school (T1), at the mid-point of undergraduate Year 3 (T2), and at the end of undergraduate Year 6 (T3). A total of 236 medical students (56%) responded at all time-points. They were categorised according to Torgersen's personality typology by their combination of high and low scores on the 'Big Three' personality traits of extroversion, neuroticism and conscientiousness. We studied the effects of both personality types (spectator, insecure, sceptic, brooder, hedonist, impulsive, entrepreneur and complicated) and traits on stress during medical school. RESULTS: There was a higher level of stress among female students. The traits of neuroticism (P = 0.002) and conscientiousness (P = 0.03) were independent predictors of stress, whereas female gender was absorbed by neuroticism in the multivariate model. When controlled for age and gender, 'brooders' (low extroversion, high neuroticism, high conscientiousness) were at risk of experiencing more stress (P = 0.02), whereas 'hedonists' (high extroversion, low neuroticism, low conscientiousness) were more protected against stress (P = 0.001). CONCLUSIONS: This is the first study to show that a specific combination of personality traits can predict medical school stress. The combination of high neuroticism and high conscientiousness is considered to be particularly high risk.