Antonio Lobo-Escolar

Predictive factors for cutting-out in femoral intramedullary nailing

BACKGROUND Femoral intramedullary nailing is currently one of the most frequent surgical treatments for extracapsular hip-fracture fixation. Cutting-out of the lag screw is the main complication of this technique, but only few studies have approached the cutting-out focussed on femoral nailing. The aim of this study was to confirm in patients treated with intramedullary nailing not only with regard to previous reports about the association of cutting-out with technical factors, but also with regard to clinical factors not previously studied. METHODS Case-control study of all patients sustaining a cut-out of the femoral nail was carried out and a control sample was randomly selected among all extracapsular hip-fracture patients during the study period (2005-2008). All clinical and technical variables were collected from medical records. Orthopaedic Trauma Association (AO/OTA) fracture classification, Singh Osteoporosis Index of the contralateral hip and the American Society of Anaesthesiology (ASA) criteria for preoperative clinical status were used. Statistical assessment included bivariant analysis and multivariant logistic regression analysis. RESULTS A total of 916 hip-fracture cases were treated in the study period: 33 of them (3.6%) were identified as suffering cutting-out, and 315 controls fulfilling inclusion criteria were also recruited. No statistical differences were found in age, sex or other socio-demographic variables between the two groups. Bivariant analysis showed significant differences between groups in technical variables (tip-apex distance, suboptimal placement of lag screw, fracture diastasis, inadequate fixation quality and distal static locking) and in clinical variables (osteoporosis severity, right hip affected, better previous ability for walking and better preoperative ASA status). Multivariant logistic regression analysis showed significant association only for tip-apex distance and inadequate fixation quality. Differences in distal static locking were close to statistical significance. CONCLUSIONS The strongest predictor of cutting-out in femoral nailing is tip-apex distance. This study suggests that distal static locking and other clinical conditions play an important role in this fixation failure.

Male osteoporosis: A review.

Osteoporosis in men is a heterogeneous disease that has received little attention. However, one third of worldwide hip fractures occur in the male population. This problem is more prevalent in people over 70 years of age. The etiology can be idiopathic or secondary to hypogonadism, vitamin D deficiency and inadequate calcium intake, hormonal treatments for prostate cancer, use of toxic and every disease or drug use that alters bone metabolism.Risk factors such as a previous history of fragility fracture should be assessed for the diagnosis. However, risk factors in men are very heterogeneous. There are significant differences in the pharmacological treatment of osteoporosis between men and women fundamentally due to the level of evidence in published trials supporting each treatment. New treatments will offer new therapeutic prospects. The goal of this work is a revision of the present status knowledge about male osteoporosis.

Somatic and psychiatric comorbidity in the general elderly population: Results from the ZARADEMP Project

OBJECTIVE In a representative sample of the elderly population in a southern European city, we tested the hypothesis that there is an association between general somatic and general psychiatric morbidity. METHODS A stratified random sample of 4803 individuals aged > or =55 years was selected for the baseline study in the ZARADEMP Project. The elderly were assessed with standardized Spanish versions of instruments, including the Geriatric Mental State (GMS)-AGECAT. Psychiatric cases were diagnosed according to GMS-AGECAT criteria, and somatic morbidity was documented with the EURODEM Risk Factors Questionnaire. RESULTS General comorbidity clustered in 19.9% of the elderly when hypertension was removed from the somatic conditions category, with 33.5% of the sample remaining free from both somatic and psychiatric illnesses. General comorbidity was associated with age, female gender, and limited education, but did not increase systematically with age. The frequency of psychiatric illness was higher among the somatic cases than among noncases, and the frequency of somatic morbidity among the psychiatric cases was higher than among noncases. This association between somatic and psychiatric morbidity remained statistically significant after controlling for age, gender, and education [odds ratio (OR)=1.61; confidence interval (CI)=1.38-1.88]. Most somatic categories were associated with psychiatric illness, but after adjusting for demographic variables and individual somatic illnesses, the association remained statistically significant only for cerebrovascular accidents (CVAs) (OR=1.47; CI=1.09-1.98) and thyroid disease (OR=1.67; CI=1.10-2.54). CONCLUSION This is the first study to document that there is a positive and statistically significant association between general somatic morbidity and general psychiatric morbidity in the (predominantly) elderly population. CVAs and thyroid disease may have more weight in this association.

Cementless Hydroxyapatite Coated Hip Prostheses

More than twenty years ago, hydroxyapatite (HA), calcium phosphate ceramics, was introduced as a coating for cementless hip prostheses. The choice of this ceramic is due to its composition being similar to organic apatite bone crystals. This ceramic is biocompatible, bioactive, and osteoconductive. These qualities facilitate the primary stability and osseointegration of implants. Our surgical experience includes the implantation of more than 4,000 cementless hydroxyapatite coated hip prostheses since 1990. The models implanted are coated with HA in the acetabulum and in the metaphyseal area of the stem. The results corresponding to survival and stability of implants were very satisfactory in the long-term. From our experience, HA-coated hip implants are a reliable alternative which can achieve long term survival, provided that certain requirements are met: good design selection, sound choice of bearing surfaces based on patient life expectancy, meticulous surgical technique, and indications based on adequate bone quality.

Association of Hypertension with Depression in Community-Dwelling Elderly Persons: Results from the ZARADEMP Project

National Committee Seventh Report criteria [11] were used for the diagnosis of hypertension. Research psychiatrists individually supervised the standardized interviews of lay interviewers doing the field study, and reassessed the cases considered to be ‘doubtful’ in the elderly homes (n = 159) [12] . A systematic control of the reliability of lay interviewers and psychiatrists was implemented to prevent reliability decay. Psychiatric cases were diagnosed according to GMS-AGECAT criteria. The specific hypothesis of the association of hypertension with depression was tested by means of logistic regression (LR) analysis. Potentially confounding factors ( table 1 ) were selected for the analysis because of their association with depression in previous research and in preliminary, bivariate models calculated here. Standard ethical principles have been maintained, according to Spanish law (article 5, 1992). The analysis of data has been completed in the subjects with full information (n = 4,136), the 667 losses being due to missing data in blood pressure measurements or other variables. Hypertension was documented in 2,523 individuals (61.0%; 41.7% were stage 1 and 19.3% were stage 2 hypertensives), and 314 of them (12.4%) were depressed. Results of LR analysis show, in the unadjusted model, that OR for depression was significantly higher in stage 2 hypertension (OR = 1.46, 95% CI = 1.12–1.90). Potential modifiers/confounders were then included in the model ( table 1 ; models 1–5), the results being similar. Finally, table 1 also shows the results of LR analysis when controlling for all variables (model 5), showing that the estimated risk for depression remains statistically significant for grade 2 hypertension (OR = 1.37, 95% CI = 1.03–1.81). The results support the hypothesized association of hypertension with depression. It might be argued that not all GMS-AGECAT cases of depression fulfill DSM-IV-TR or ICD-10 psychiatric criteria. However, this computerized diagnostic system has been shown to correspond with what psychiatrists recognize as a case for intervention [7] . Subsyndromal depression, which has also been suggested in some reports to be associated with hypertension [1] , was not approached in this study because we were more interested in potential clinical implications. Our findings are rather consistent with the report by Copeland et al. [1] . The British authors used the same GMS-AGECAT standardized diagnostic method and controlled for a number of potential risk factors. However, hypertension was self-reported and cognitive performance was not controlled. Barrett-Connor and Palinkas [4] also found an association with depression scores, but it was limited to DBP, both high and low DBP. However, their paper is not totally comparable to ours, since their sample was limited to men, depression was only assessed by a questionnaire and they only controlled for age and weight loss. The studies by Friedman et al. [2] The empirical literature in population studies does not unequivocally support clinical observations suggesting the association of hypertension with depression. A positive association has been reported in some inquiries [1] but not in others [2, 3] , and the relationship was limited to individuals with diastolic blood pressure (DBP) in some studies [4] . Differences in design make between-study comparisons difficult. Methodological difficulties are observed in previous research: some studies are based on self-reported hypertension, adjustment for potential confounders is not systematic and no studies with the exception of the investigation by Copeland et al. [1] have used a standardized psychiatric diagnosis. This study tests the hypothesis of a positive association between hypertension and depression, and tries to circumvent the described methodological difficulties. It is the baseline, crosssectional study of the ZARADEMP Project, a longitudinal, threewave epidemiological inquiry, the methodology of which has been previously described [5] . A large, stratified random sample of individuals from the census list aged 55 and over was selected. Refusal rate was 20.5%, and 4,803 people were interviewed. Residents of old age homes and other institutions were included in the community sample. An epidemiological screening design was implemented, and standardized Spanish versions of assessment instruments were used, including the Geriatric Mental State (GMS) [6] , its computerized diagnostic program, AGECAT, and the History and Aetiology Schedule [7, 8] . The history of medical diseases was documented by means of the Risk Factor Questionnaire designed by the EURODEM Workgroup [9] . The assessment of blood pressure followed World Health Organization standards, modified by the European Society of Hypertension [10], and Joint Published online: July 25, 2008

Prevalence of osteoporotic vertebral fracture in Spanish women over age 45

The aim of this work is to study the prevalence of osteoporotic vertebral fractures in Spanish women over 45 years of age, based on the selection of a nationwide sample. An observational, cross-sectional, multicenter study was conducted during 2006, in all of Spains regions. The sample analyzed was of 5000 individuals, representative of the female population over age 45 in Spain. A questionnaire was used to determine which factors are most often associated with vertebral fractures. We also assessed whether the Prevalent Vertebral Fracture Index, proposed by Vogt, is useful in indicating a possible osteoporotic vertebral fracture. Five hundred orthopedic surgeons, from various Spanish regions, were trained in different aspects of the study: inclusion and exclusion criteria, management of the risk factor questionnaire, and implementation of the Vogt questionnaire. The number of fracture cases was 1549 (31.79%). 528 Women (34.08%) had a single vertebral fracture, and 1021 (65.92%) had multiple vertebral fractures. The following factors were statistically significantly associated with vertebral fracture: age, late menarche, early menopause, diabetes mellitus, hyperparathyroidism, rheumatoid arthritis, height loss, daily physical activity, corticosteroid therapy, personal history of osteoporotic fracture and previous diagnosis of osteoporosis. The differences in Vogt score according to age and fracture status were statistically significant. The conclusion of the study is that vertebral osteoporotic fracture in the female Spanish population is frequent. The high prevalence in the Spanish population older than 60 years is probably related to malnutrition in the period from 1936 to 1952.

Applications of finite element simulation in orthopedic and trauma surgery

Research in different areas of orthopedic and trauma surgery requires a methodology that allows both a more economic approach and the ability to reproduce different situations in an easy way. Simulation models have been introduced recently in bioengineering and could become an essential tool in the study of any physiological unity, regardless of its complexity. The main problem in modeling with finite elements simulation is to achieve an accurate reproduction of the anatomy and a perfect correlation of the different structures, in any region of the human body. Authors have developed a mixed technique, joining the use of a three-dimensional laser scanner Roland Picza captured together with computed tomography (CT) and 3D CT images, to achieve a perfect reproduction of the anatomy. Finite element (FE) simulation lets us know the biomechanical changes that take place after hip prostheses or osteosynthesis implantation and biological responses of bone to biomechanical changes. The simulation models are able to predict changes in bone stress distribution around the implant, so allowing preventing future pathologies. The development of a FE model of lumbar spine is another interesting application of the simulation. The model allows research on the lumbar spine, not only in physiological conditions but also simulating different load conditions, to assess the impact on biomechanics. Different degrees of disc degeneration can also be simulated to determine the impact on adjacent anatomical elements. Finally, FE models may be useful to test different fixation systems, i.e., pedicular screws, interbody devices or rigid fixations compared with the dynamic ones. We have also developed models of lumbar spine and hip joint to predict the occurrence of osteoporotic fractures, based on densitometric determinations and specific biomechanical models, including approaches from damage and fracture mechanics. FE simulations also allow us to predict the behavior of orthopedic splints applied to the correction of deformities, providing the recovering force-displacement and angle-moment curves that characterize the mechanical behavior of the splint in the overall range of movement.

Delayed union in pediatric forearm fractures.

Background: The aim of this study was to assess the predictive factors of delayed union in pediatric forearm fractures. Few previous reports have approached this complication, but contrary to these studies we excluded cases with known pathogenic factors and included in the sample cases treated with conservative methods. Methods: This is a case-control study of all pediatric shaft forearm fractures presenting delayed union in a minimum follow-up period of 12 months, from 2003 through 2009, in a hospital covering a health area. Exclusion criteria were fracture dislocations, infection, suboptimal osteosynthesis, greenstick, open, pathologic, and associated radial head fractures. Statistical assessment included bivariate and multivariate linear regression analysis. Results: Four hundred and forty-one complete, both-bone forearm fractures were treated during the study period: 14 of them (3.2%) were identified as suffering delayed union; and 63 controls fulfilling inclusion criteria were randomly selected. Bivariate analysis showed significant differences between “union delay” and “control” groups in age, need of surgical treatment, open versus closed reduction, and mean time to hardware removal. However, open reduction of the fracture, more frequent in the “union delay” group, was the only variable that remained associated with time to consolidation in the multivariate analysis. Conclusions: The strongest predictor of union delay in pediatric forearm fractures is open reduction. Based on our results, we recommend to avoid when possible the open reduction of the fracture in patients undergoing surgery and to use instead closed reduction and internal fixation. Level of Evidence: A case-control study. Therapeutic level III.

Long-Term Outcomes of a New Model of Anatomical Hydroxyapatite-Coated Hip Prosthesis

This prospective study was designed to evaluate 196 Anatomique Benoist Giraud (ABG II) total hip arthroplasties which were implanted between September 1999 and December 2000. A minimum 11 years follow up was completed in 183 cases. The bearing surfaces were polyethylene-zirconia in 84 cases, polyethylene-metal in 42 and ceramic-ceramic in 57. Changes in the femoral stem design, in relation to the previous ABG I model, have led to a significant improvement in stress-shielding. Polyethylene wear rate was lower by more than 50% compared with non-crosslinked polyethylene. Excellent and good results were obtained in 90.32% of cases, and implant survival was 98.39% at the end of follow-up.

A mechanical model for predicting the probability of osteoporotic hip fractures based in DXA measurements and finite element simulation

BackgroundOsteoporotic hip fractures represent major cause of disability, loss of quality of life and even mortality among the elderly population. Decisions on drug therapy are based on the assessment of risk factors for fracture, from BMD measurements. The combination of biomechanical models with clinical studies could better estimate bone strength and supporting the specialists in their decision.MethodsA model to assess the probability of fracture, based on the Damage and Fracture Mechanics has been developed, evaluating the mechanical magnitudes involved in the fracture process from clinical BMD measurements. The model is intended for simulating the degenerative process in the skeleton, with the consequent lost of bone mass and hence the decrease of its mechanical resistance which enables the fracture due to different traumatisms. Clinical studies were chosen, both in non-treatment conditions and receiving drug therapy, and fitted to specific patients according their actual BMD measures. The predictive model is applied in a FE simulation of the proximal femur. The fracture zone would be determined according loading scenario (sideway fall, impact, accidental loads, etc.), using the mechanical properties of bone obtained from the evolutionary model corresponding to the considered time.ResultsBMD evolution in untreated patients and in those under different treatments was analyzed. Evolutionary curves of fracture probability were obtained from the evolution of mechanical damage. The evolutionary curve of the untreated group of patients presented a marked increase of the fracture probability, while the curves of patients under drug treatment showed variable decreased risks, depending on the therapy type.ConclusionThe FE model allowed to obtain detailed maps of damage and fracture probability, identifying high-risk local zones at femoral neck and intertrochanteric and subtrochanteric areas, which are the typical locations of osteoporotic hip fractures.The developed model is suitable for being used in individualized cases. The model might better identify at-risk individuals in early stages of osteoporosis and might be helpful for treatment decisions.