Overcoming the strength-formability trade-off in high strength steels via cryogenic treatment.

High strength steels are becoming more important than ever before for automotive applications to reduce the weight of automobiles and to ensure the safety of passengers. Since increased strength usually results in degraded formability, however, cold forming of high strength steels into final shapes remains a challenge to both automotive manufacturers and suppliers. Here we report novel alloy and processing design concepts that can impart high strength to cold-formable steels, which deviates from the traditional approach of improving the formability of high strength steels. Such designed steel subjected to a designed processing route shows an excellent combination of formability and strength as well as crashworthiness, which is crucial for the safety of passengers in the automobiles. The alloy and processing design concepts used in the present study are based on the utilization of thermally induced austenite to martensite transformation, which imparts high strength to cold-formable austenite by cryogenic treatment.

The outcome following spinal instrumentation in haemodialyzed patients with pyogenic spondylodiscitis.

AIMS: The aim of this study was to evaluate the outcome of spinal instrumentation in haemodialyzed patients with native pyogenic spondylodiscitis. Spinal instrumentation in these patients can be dangerous due to rates of complications and mortality, and biofilm formation on the instrumentation. PATIENTS AND METHODS: A total of 134 haemodialyzed patients aged more than 50 years who underwent surgical treatment for pyogenic spondylodiscitis were included in the study. Their mean age was 66.4 years (50 to 83); 66 were male (49.3%) and 68 were female (50.7%). They were divided into two groups according to whether spinal instrumentation was used or not. Propensity score matching was used to attenuate the potential selection bias. The outcome of treatment was compared between these two groups. RESULTS: A total of 89 patients (66.4%) underwent non-instrumented surgery and 45 (33.5%) underwent instrumented surgery. There were no significant differences in the rates of postoperative complications, except for an increased rate of wound problems in the instrumented group, which was found in the unmatched cohorts (p = 0.034). There were no significant differences in the rate of recurrent infections (p = 0.328 for the unmatched cohort; p = 0.269 for the matched cohort) and mortality rate, including in-hospital (p = 0.713 for the unmatched cohort; p = 0.738 for the matched cohort) and one-year rates (p = 0.363 for the unmatched cohort; p = 0.787 for the matched cohort), between the groups. However, the interval between the initial diagnosis and the first recurrence was significantly longer in the instrumented group (p = 0.008 for the unmatched cohort; p = 0.032 for the matched cohort). CONCLUSION: Instrumented surgery for haemodialyzed patients with pyogenic spondylodiscitis showed similar outcomes, including recurrence and mortality, to non-instrumented surgery, despite the instrumented group having more severe neurological deficit, a larger number of involved levels, and increased kyphotic angle.

Treatment of infection following intramedullary nailing of tibial shaft fractures-results of the ORS/ISFR expert group survey.

OBJECTIVE: The lack of universally accepted treatment principles and protocols to manage infected intramedullary (IM) nails following tibial fractures continues to challenge us, eliciting a demand for clear guidelines. Our response to this problem was to create an ORS/ISFR taskforce to identify potential solutions and trends based on published evidence and practices globally. MATERIALS AND METHODS: A questionnaire of reported treatment methods was created based on a published meta-analysis on the topic. Treatment methods were divided in two groups: A (retained nail) and B (nail removed). Experts scored the questionnaire items on a scale of 1-4 twice, before and after revealing the success rates for each stage of infection. Inter- and intra-observer variability analysis among experts' personal scores and between experts' scores was performed. An agreement mean and correlation degree between experts' scores was calculated. Finally, a success rate report between groups was performed. RESULTS: Experts underestimated success rate of an individual treatment method compared to published data. The mean difference between experts' scores and published results was + 26.3 ± 46 percentage points. Inter-observer agreement mean was poor (< 0.2) for both rounds. Intra-observer agreement mean across different treatment methods showed a wide variability (18.3 to 64.8%). Experts agree more with published results for nail removal on stage 2 and 3 infections. CONCLUSIONS: Experts' and published data strongly agree to retain the implant for stage 1 infections. A more aggressive approach (nail removal) favoured for infection stages 2 and 3. However, literature supports both treatment strategies. EVIDENCE: Clinical Question.

Chemically linked metal-matrix nanocomposites of boron nitride nanosheets and silver as thermal interface materials.

Herein, novel hybrid nanocomposite thermal interface materials (TIMs) relying on the chemical linkage of silver, boron nitride nanosheets (BNNSs), and organic ligands are reported. These TIMs were prepared using a co-electrodeposition/chemisorption approach where the electrolytic reduction of silver ions into silver nano-/micro-crystals was coupled with the conjugation of ligand-coated nanosheets onto silver crystals. Furthermore, the influence of the bond strength of silver/nanosheet links on the thermal, mechanical, and structural properties is investigated using a combination of techniques including laser flash analysis, phase-sensitive transient thermoreflectance, nanoindentation, and electron microscopy. The internal nanostructure was found to be strongly dependent on the linker chemistry. While the chemical grafting of 4-cyano-benzoyl chloride (CBC) and 2-mercapto-5-benzimidazole carboxylic acid (MBCA) on BNNSs led to the uniform distribution of functionalized-nanosheets in the silver crystal matrix, the physical binding of 4-bromo-benzoyl chloride linkers on nanosheets caused the aggregation and phase separation. The thermal conductivity was 236-258 W m-1 K and 306-321 W m-1 K for physically and chemically conjugated TIMs, respectively, while their hardness varied from 400-495 MPa and from 240 to 360 MPa, respectively. The corresponding ratio of thermal conductivity to hardness, which is a critical parameter controlling the performance of TIMs, was ultrahigh for the chemically conjugated TIMs: 1.3 × 10-6 m2 K-1 s for MBCA-BNNS and 8.5 × 10-7 m2 K-1 s for CBC-BNNS. We anticipate that these materials can satisfy some of the emerging thermal management needs arising from the improved performance and efficiency, miniaturization, and/or high throughput of electronic devices, energy storage devices, energy conversion systems, light-emitting diodes, and telecommunication components.

The association between whole body sagittal balance and risk of falls among elderly patients seeking treatment for back pain.

OBJECTIVES: The objective of this study was to assess the association between whole body sagittal balance and risk of falls in elderly patients who have sought treatment for back pain. Balanced spinal sagittal alignment is known to be important for the prevention of falls. However, spinal sagittal imbalance can be markedly compensated by the lower extremities, and whole body sagittal balance including the lower extremities should be assessed to evaluate actual imbalances related to falls. METHODS: Patients over 70 years old who visited an outpatient clinic for back pain treatment and underwent a standing whole-body radiograph were enrolled. Falls were prospectively assessed for 12 months using a monthly fall diary, and patients were divided into fallers and non-fallers according to the history of falls. Radiological parameters from whole-body radiographs and clinical data were compared between the two groups. RESULTS: A total of 144 patients (120 female patients and 24 male patients) completed a 12-month follow-up for assessing falls. A total of 31 patients (21.5%) reported at least one fall within the 12-month follow-up. In univariate logistic regression analysis, the risk of falls was significantly increased in older patients and those with more medical comorbidities, decreased lumbar lordosis, increased sagittal vertical axis, and increased horizontal distance between the C7 plumb line and the centre of the ankle (C7A). Increased C7A was significantly associated with increased risk of falls even after multivariate adjustment. CONCLUSION: Whole body sagittal balance, measured by the horizontal distance between the C7 plumb line and the centre of the ankle, was significantly associated with risk of falls among elderly patients with back pain.Cite this article: J. Kim, J. Y. Hwang, J. K. Oh, M. S. Park, S. W. Kim, H. Chang, T-H. Kim. The association between whole body sagittal balance and risk of falls among elderly patients seeking treatment for back pain. Bone Joint Res 2017;6:-344. DOI: 10.1302/2046-3758.65.BJR-2016-0271.R2.

Successful outcome with minimally invasive plate osteosynthesis for periprosthetic tibial fracture after total knee arthroplasty.

INTRODUCTION: The incidence of periprosthetic fractures after total knee arthroplasty (TKA) is increasing, and treatment is becoming more necessary. In periprosthetic tibial fractures, the stem of the tibial component largely occupies the medullary canal of the proximal tibia, which limits the selection of implants. The purpose of this study was to evaluate the effectiveness of the minimally invasive plate osteosynthesis (MIPO) technique with locking plates for periprosthetic tibial fractures after TKA. MATERIALS AND METHODS: Sixteen patients with periprosthetic tibial fracture after TKA were included. There were 6 type II and 10 type III fractures according to the Felix classification. Ten patients had fractures in the proximal metaphysis, and 6 in the diaphysis. MIPO using locking plates was performed on the medial side in 4 cases, the lateral side in 2 cases, and both in 10 cases. Radiographic results included time to union, alignment, and malunion. Clinical results included range of motion (ROM), functional activity data, Knee Society scores, and complications. RESULTS: Fourteen of 16 fractures achieved union at 17.1 weeks (range, 14-24) postoperatively. There were 2 failures that required a secondary procedure. Except one for 1 case with varus malunion, all had acceptable alignment. Mean ROM at the final follow-up was 108.8° (range, 15-135°), and 15 patients recovered pre-injury knee joint activity. Mean knee and function scores were 88.9 (range, 77-100) and 83.3 (range, 60-100), respectively. Knees with fewer than 8 cortices giving purchase to screws in the proximal segment showed higher failure rates (P=0.025). DISCUSSION: MIPO with locking plates can achieve satisfactory results for periprosthetic tibial fractures after TKA. Rigid fixation of the proximal segment may be necessary for successful outcome. LEVEL OF EVIDENCE: IV.

Increased sagittal vertical axis is associated with less effective control of acute pain following vertebroplasty.

OBJECTIVES: Although vertebroplasty is very effective for relieving acute pain from an osteoporotic vertebral compression fracture, not all patients who undergo vertebroplasty receive the same degree of benefit from the procedure. In order to identify the ideal candidate for vertebroplasty, pre-operative prognostic demographic or clinico-radiological factors need to be identified. The objective of this study was to identify the pre-operative prognostic factors related to the effect of vertebroplasty on acute pain control using a cohort of surgically and non-surgically managed patients. PATIENTS AND METHODS: Patients with single-level acute osteoporotic vertebral compression fracture at thoracolumbar junction (T10 to L2) were followed. If the patients were not satisfied with acute pain reduction after a three-week conservative treatment, vertebroplasty was recommended. Pain assessment was carried out at the time of diagnosis, as well as three, four, six, and 12 weeks after the diagnosis. The effect of vertebroplasty, compared with conservative treatment, on back pain (visual analogue score, VAS) was analysed with the use of analysis-of-covariance models that adjusted for pre-operative VAS scores. RESULTS: A total of 342 patients finished the 12-week follow-up, and 120 patients underwent vertebroplasty (35.1%). The effect of vertebroplasty over conservative treatment was significant regardless of age, body mass index, medical comorbidity, previous fracture, pain duration, bone mineral density, degree of vertebral body compression, and canal encroachment. However, the effect of vertebroplasty was not significant at all time points in patients with increased sagittal vertical axis. CONCLUSIONS: For single-level acute osteoporotic vertebral compression fractures, the effect of vertebroplasty was less favourable in patients with increased sagittal vertical axis (> 5 cm) possible due to aggravation of kyphotic stress from walking imbalance.Cite this article: Y-C. Kim, D. H. Bok, H-G. Chang, S. W. Kim, M. S. Park, J. K. Oh, J. Kim, T-H. Kim. Increased sagittal vertical axis is associated with less effective control of acute pain following vertebroplasty. Bone Joint Res 2016;5:544-551. DOI: 10.1302/2046-3758.511.BJR-2016-0135.R1.

Second to fourth digit ratio: a predictor of adult testicular volume.

It has been suggested that second to fourth digit ratio (digit ratio) may correlate with male reproductive system function or disorders. This hypothesis is based on finding that the Hox genes control finger development and differentiation of the genital bud during embryogenesis. Thus, we investigated the association between digit ratio and adult testicular volume. A total of 172 Korean men (aged 20-69 years) hospitalized for urological surgery were prospectively enrolled. Patients with conditions known to strongly influence testicular volume were excluded. Before determining testicular volume, the lengths of the second and fourth digits of the right hand were measured by a single investigator using a digital vernier calliper. Using orchidometry, the testes were measured by an experienced urologist who had no information about the patient's digit ratio. To identify the independent predictive factors influencing testicular volume, univariate and multivariate analyses were performed using linear regression models. Age, height, serum testosterone and free testosterone level were not correlated with testicular volume. Digit ratio, along with weight, was significantly correlated with testicular volume (right testicular volume: r = -0.185, p = 0.015; left testicular volume: r = -0.193, p = 0.011; total testicular volume: r = -0.198, p = 0.009). Multivariate analysis using linear regression models showed that only digit ratio was the independent factor to predict all (right, left and total) testicular volumes (right testicular volume: ß = -0.174, p = 0.023; left testicular volume: ß = -0.181, p = 0.017; total testicular volume: ß = -0.185, p = 0.014). Our findings demonstrated that digit ratio is negatively associated with adult testicular volume. This means that men with a higher digit ratio may be more likely to have smaller testis compared to those with a lower digit ratio.

Bone transport with an external fixator and a locking plate for segmental tibial defects.

Although gradual bone transport may permit the restoration of large-diameter bones, complications are common owing to the long duration of external fixation. In order to reduce such complications, a new technique of bone transport involving the use of an external fixator and a locking plate was devised for segmental tibial bone defects. A total of ten patients (nine men, one woman) with a mean age at operation of 40.4 years (16 to 64) underwent distraction osteogenesis with a locking plate to treat previously infected post-traumatic segmental tibial defects. The locking plate was fixed percutaneously to bridge proximal and distal segments, and was followed by external fixation. After docking, percutaneous screws were fixed at the transported segment through plate holes. At the same time, bone grafting was performed at the docking site with the external fixator removed. The mean defect size was 5.9 cm (3.8 to 9.3) and mean external fixation index was 13.4 days/cm (11.8 to 19.5). In all cases, primary union of the docking site and distraction callus was achieved, with an excellent bony result. There was no recurrence of deep infection or osteomyelitis, and with the exception of one patient with a pre-existing peroneal nerve injury, all achieved an excellent or good functional result. With short external fixation times and low complication rates, bone transport with a locking plate could be recommended for patients with segmental tibial defects.

Cardiac markers of EIH athletes in ultramarathon.

This study aimed to investigate effects of a 100-km ultramarathon on cardiac markers of exercise-induced-hypertensive marathoners. 10 marathoners with exercise-induced hypertension and 10 normal marathoners participated in the study. Their blood samples were collected before starting, at 50 km, and after finishing the course (100 km). Creatinine kinase was more significantly increased in the exercise-induced-hypertensive group than in the normal group at 100 km (P<0.05). N-terminal pro-brain nutriuretic peptide was significantly increased in the exercise-induced-hypertensive group at 50 km and 10 km (P<0.05) which was significant being doubled compared to the normal group (P<0.05). Exercise-induced-hypertensive marathoners showed a significant triple-increase in C-Reactive protein at 100 km (P<0.05). In conclusion, although the exercise-induced-hypertensive runners did not have myocardial damage during the 100 km ultramarathon, they had higher myocardial stress and more damage in active muscles due to a bloodstream disability.

Plating of humeral shaft fractures: comparison of standard conventional plating versus minimally invasive plating.

PURPOSE: This study compared clinical outcomes and complications in patients with humeral shaft fractures treated using two methods of fixation by plating. METHODS: Minimally invasive plate osteosynthesis (MIPO, n=29) was prospectively performed from around the middle of the study period, while open reduction and plate osteosynthesis (ORPO, n=30) had been the original standard method. Locking compression plate was used in these two groups. Major characteristics of the two groups were similar in terms of fracture type, fracture location, age, associated injuries and numbers of open fractures. RESULTS: Primary union was achieved in 28 of 29 in the MIPO and in 27 of 30 in the ORPO. Mean time to union was similar in the two groups. Mean operation time in the MIPO (110min) was shorter than in the ORPO (169min) (P<0.05). Bone grafting was performed in five patients of in the ORPO, but in no patient in the MIPO (P<0.0001). There was one case of deep infection in the ORPO. Functional outcome was satisfactory in both groups. CONCLUSIONS: Minimally invasive plate osteosynthesis may achieve comparable results with the open plate osteosynthesis method in simple as well as complex fractures of humeral shaft. Although MIPO potentially has the radiation hazard, it may reduce the perioperative complications with a shortened operation time. LEVEL OF EVIDENCE: Level III. Case-control study.

The biomechanical performance of locking plate fixation with intramedullary fibular strut graft augmentation in the treatment of unstable fractures of the proximal humerus.

We evaluated the biomechanical properties of two different methods of fixation for unstable fractures of the proximal humerus. Biomechanical testing of the two groups, locking plate alone (LP), and locking plate with a fibular strut graft (LPSG), was performed using seven pairs of human cadaveric humeri. Cyclical loads between 10 N and 80 N at 5 Hz were applied for 1,000,000 cycles. Immediately after cycling, an increasing axial load was applied at a rate of displacement of 5 mm/min. The displacement of the construct, maximum failure load, stiffness and mode of failure were compared. The displacement was significantly less in the LPSG group than in the LP group (p = 0.031). All maximum failure loads and measures of stiffness in the LPSG group were significantly higher than those in the LP group (p = 0.024 and p = 0.035, respectively). In the LP group, varus collapse and plate bending were seen. In the LPSG group, the humeral head cut out and the fibular strut grafts fractured. No broken plates or screws were seen in either group. We conclude that strut graft augmentation significantly increases both the maximum failure load and the initial stiffness of this construct compared with a locking plate alone.

Clonorchis sinensis infection is positively associated with atopy in endemic area.

BACKGROUND: Epidemiologic studies have suggested that helminth infections play a protective role against allergy; this inverse association, however, has not been consistent. Clonorchis sinensis, the liver fluke of human, is prevalent in the Far East. The association between C. sinensis infection and allergy has not yet been reported. OBJECTIVE: We evaluated the association between clonorchiasis and atopy or allergic diseases in adults in endemic areas of clonorchiasis. METHODS: A total of 1116 subjects (males 419, females 697; age range, 30-86; mean age=61 years) were recruited from two endemic areas of C. sinensis in Korea. Clonorchiasis was confirmed by stool examination. Allergic symptoms were evaluated with a modified ISAAC questionnaire, and atopy was defined by skin prick test for common inhalant allergens. Total serum IgE and C. sinensis-specific IgE level was measured by ELISA and methacholine bronchial provocation test was performed to evaluate airway hyperresponsiveness (AHR). RESULTS: Clonorchiasis was positively associated with atopy [odds ratio (OR), 1.856; 95% confidence interval (CI), 1.199-2.873] and high levels of total serum IgE (OR, 1.455; 95% CI, 1.050-2.016). Higher association with clonorchiasis was shown in subjects who showed both atopy and high total serum IgE levels (OR, 2.540; 95% CI, 1.448-4.455). Clonorchiasis had no association with wheezing, AHR, asthma or allergic rhinitis. CONCLUSION AND CLINICAL RELEVANCE: Clonorchiasis was positively associated with atopy in adults in endemic area.

Population attributable fraction of infection-related cancers in Korea.

BACKGROUND: A number of infectious agents have been classified as human carcinogens. The purpose of the current study was to provide an evidence-based assessment of the burden of infection-related cancers in the Korean population. MATERIALS AND METHODS: The population attributable fraction was calculated using infection prevalence data from 1990 or earlier, relative risk estimates from meta-analyses using mainly Korean studies and national data on cancer incidence and mortality for the year 2007. RESULTS: The fractions of all cancers attributable to infection were 25.1% and 16.8% for cancer incidence in men and women, and 25.8% and 22.7% of cancer mortality in men and women, respectively. Among infection-related cancers, Helicobacter pylori was responsible for 56.5% of cases and 45.1% of deaths, followed by hepatitis B virus (HBV) (23.9% of cases and 37.5% of deaths) and human papillomavirus (HPV) (11.3% of cases and 6% of deaths) and then by hepatitis C virus (HCV) (6% of cases and 9% of deaths). Over 97% of infection-related cancers were attributable to infection with H. pylori, HBV, HCV and HPV. CONCLUSION: Up to one-quarter of cancer cases and deaths would be preventable through appropriate control of infectious agents in Korea.

Combined effect of socioeconomic status, viral hepatitis, and lifestyles on hepatocelluar carcinoma risk in Korea.

BACKGROUND: The independent and combined effects of socioeconomic status (SES), viral hepatitis, and other lifestyle factors on hepatocellular carcinoma (HCC) risk have not been investigated among Koreans. METHODS: From the National Cancer Center Hospital, 207 HCC cases and 828 age- and gender-matched controls aged 30 years or older were recruited. Socio-demographic and behavioural risk factors were ascertained through personal interview, and infection with hepatitis B and C viruses was determined by their serologic markers. Multivariate logistic regression and synergy index methods were applied for statistical analysis. RESULTS: HB surface antigen (HbsAg) and anti-HCV-positive rates were 149.3 and 185.1 times higher in cases than controls, respectively. Lifetime alcohol consumption (odds ratio: 2.96, 95% CI: 1.29-6.79), cigarette smoking (OR: 3.53, 95% CI: 1.31-9.52), and family income (OR: 17.07, 95% CI: 4.27-68.25) were independently associated with the risk of HCC in subjects with or without viral hepatitis. Synergistic interaction on HCC risk was observed between low income and HBsAg positivity (SI: 3.12, 95% CI: 1.51-6.47) and between low income and heavy alcohol intake (SI: 2.93, 95% CI: 1.24-6.89). CONCLUSION: The inverse association with SES suggests SES as an independent and synergistic predictor of HCC. Heavy alcohol intake also showed a combined effect with low SES on HCC risk.

Preoperative NT-proBNP and CRP predict perioperative major cardiovascular events in non-cardiac surgery.

OBJECTIVE: To investigate whether simple and non-invasive measurement of N-terminal pro-brain natriuretic peptide (NT-proBNP) and/or C-reactive protein (CRP) can predict perioperative major cardiovascular event (PMCE). DESIGN: Prospective, single-centre, cohort study. SETTING: A 1900-bed tertiary-care university hospital in Seoul, Korea Design and PATIENTS: The predictive power of NT-proBNP, CRP and Revised Cardiac Risk Index (RCRI) for the risk of PMCE (myocardial infarction, pulmonary oedema or cardiovascular death) were evaluated from a prospective cohort of 2054 elective major non-cardiac surgery patients. Optimal cut-off values were derived from receiver operating characteristic curve (ROC) analysis. MAIN OUTCOME MEASUREMENT: PMCE (myocardial infarction, pulmonary oedema or cardiovascular death) within postoperative 30 days. RESULTS: PMCE developed in a total of 290 patients (14.1%). Each increasing quartile of NT-proBNP or CRP level was associated with a greater risk of PMCE after adjustment for traditional clinical risk factors. The relative risk (RR) of highest versus lowest quartile was 5.2 for NT-proBNP (p<0.001) and 3.7 for CRP (p<0.001). Both NT-proBNP (cut-off = 301 ng/l) and CRP (cut-off = 3.4 mg/l) predicted PMCE better than RCRI (cut-off = 2) by ROC analysis (p<0.001). Moreover, the predictive power of RCRI (adjusted RR = 1.5) could be improved significantly by addition of CRP and NT-proBNP to RCRI (adjusted RR 4.6) (p<0.001). CONCLUSIONS: High preoperative NT-proBNP or CRP is a strong and independent predictor of perioperative major cardiovascular event in non-cardiac surgery. The predictive power of current clinical risk evaluation system would be strengthened by these biomarkers.

Retrodiaphragmatic portion of the lung: how deep is the posterior costophrenic sulcus on posteroanterior chest radiography?

AIM: To determine the depth of the posterior costophrenic sulcus (CPS) on posteroanterior (PA) chest radiography in relation to the diaphragmatic dome and lateral CPS. MATERIALS AND METHODS: Five hundred and forty consecutive PA chest radiographs that were performed for general health screenings were retrospectively reviewed. Among them 282 radiographs were selected that met the following criteria: visualization of the inferior boundary of the posterior CPS behind the right hemidiaphragm; and no abnormal findings that affected the shape and level of the diaphragm. The selected chest radiographs were from 155 men and 127 women with a mean age of 40.7+/-8.4 years. On 282 PA chest radiographs, the distances between the right diaphragmatic dome and posterior CPS (total diaphragmatic height), the diaphragmatic dome and lateral CPS (diaphragmatic dome height), and the lateral and posterior CPS (posterior CPS depth) were measured. In addition levels of the right lateral and posterior CPS were scored in relation to levels of the thoracic and lumbar spines. The relationships between the posterior CPS depth and demographic and physical data and other radiographic measurements were analysed. RESULTS: The mean right posterior CPS depth was 29.2+/-15.6 mm. The average level of the posterior CPS in relation to the spine was 13.5+/-0.6, i.e., the level of lower half of the L1 vertebral body. The posterior CPS depth had a tendency to be deeper in those participants who were taller (r=0.17, p<0.01), had a higher body mass index (BMI; r=0.25, p<0.01), longer total diaphragmatic height (r=0.55, p<0.01), and shorter diaphragmatic dome height (r=-0.18, p<0.01). CONCLUSION: As the posterior CPS is deeper than the lateral CPS by approximately 3 cm, and reaches, on average, to L1, the standard chest PA radiograph must include >3 cm below the level of lateral CPS, or should include the L1 spine.

Arthrodesis of the knee using cannulated screws.

We retrospectively evaluated eight patients who underwent arthrodesis of the knee using cannulated screws. There were six women and two men, with a mean age of 53 years. The indications for arthrodesis were failed total knee arthroplasty, septic arthritis, tuberculosis, and recurrent persistent infection. Solid union was achieved in all patients at a mean of 6.1 months. One patient required autogenous bone graft for delayed union. One suffered skin necrosis which was treated with skin grafting. The mean limb-length discrepancy was 3.1 cm. On a visual analogue scale, the mean pain score improved from 7.9 to 3.3. According to the Knee Injury and Osteoarthritis Outcome score quality of life items, the mean score improved from 38.3 pre-operatively to 76.6 at follow-up. Cannulated screws provide a high rate of union in arthrodesis of the knee with minimal complications, patient convenience, and a simple surgical technique.

Left ventricular diastolic functional reserve during exercise in patients with impaired myocardial relaxation at rest.

BACKGROUND: Patients with similar grade diastolic dysfunction at rest may have a spectrum of alterations in diastolic function during exercise. OBJECTIVE: To evaluate (a) whether exercise could unmask further diastolic abnormalities not evident during rest; (b) whether diastolic functional reserve during exercise is associated with exercise capacity. METHODS: 141 subjects (77 male, mean (SD) age 62 (9)) with abnormal left ventricular (LV) relaxation (mitral E/A <0.75) and/or deceleration time >240 ms, underwent graded supine bicycle exercise with simultaneous respiratory gas analysis and two-dimensional and Doppler echocardiographic study. Mitral inflow and annular velocities were measured at rest and during exercise. The LV diastolic function reserve index (DFRI) was calculated. RESULTS: Patients were classified into two groups: group 1 (n = 64), DFRI <13.5; group 2 (n = 77), DFRI >or=13.5. The ratio of E/E' to stroke volume was used as an index of ventricular elastance (Ed). No significant differences between the groups in mitral inflow and annular velocities at rest were found. Mean (SD) Ed was not significantly different at rest between the groups (0.19 (0.07) vs 0.18 (0.06), p = 0.29). Ed was significantly higher during exercise in group 1 than in group 2 (25 W, 0.21 (0.09) vs 0.14 (0.04), p<0.001; 50 W, 0.22 (0.10) vs 0.15 (0.04), p<0.001). Group 1 subjects had a shorter exercise duration (8.2 (2.7) vs 9.4 (3.7) min, p = 0.04) and lower peak oxygen consumption (17.5 (4.5) vs 20.2 (5.4) ml/kg/min, p = 0.005). CONCLUSIONS: Despite similar mitral flow and annular velocities at rest, different responses to exercise were seen in patients with abnormal LV relaxation at rest. Lower LV diastolic functional reserve was associated with higher ventricular elastance during exercise, and reduced exercise capacity.