Risk Of Femoral Neck Fracture Research Articles

Use of a statistical model of the whole femur in a large scale, multi-model study of femoral neck fracture risk

Interpatient variability is often overlooked in orthopaedic computational studies due to the substantial challenges involved in sourcing and generating large numbers of bone models. A statistical model of the whole femur incorporating both geometric and material property variation was developed as a potential solution to this problem. The statistical model was constructed using principal component analysis, applied to 21 individual computer tomography scans. To test the ability of the statistical model to generate realistic, unique, finite element (FE) femur models it was used as a source of 1000 femurs to drive a study on femoral neck fracture risk. The study simulated the impact of an oblique fall to the side, a scenario known to account for a large proportion of hip fractures in the elderly and have a lower fracture load than alternative loading approaches. FE model generation, application of subject specific loading and boundary conditions, FE processing and post processing of the solutions were completed automatically. The generated models were within the bounds of the training data used to create the statistical model with a high mesh quality, able to be used directly by the FE solver without remeshing. The results indicated that 28 of the 1000 femurs were at highest risk of fracture. Closer analysis revealed the percentage of cortical bone in the proximal femur to be a crucial differentiator between the failed and non-failed groups. The likely fracture location was indicated to be intertrochantic. Comparison to previous computational, clinical and experimental work revealed support for these findings.

Effects of Positioning and Notching of Resurfaced Femurs on Femoral Neck Strength: A Biomechanical Test

To assess the effects of positioning and notching of resurfaced femurs on the mechanical strength of third-generation saw bone (TGSB) femurs using an in vitro analogue bone model. 30 TGSB femurs were equally divided into 6 resurfaced femur groups (intact, anatomic, varus, valgus, anatomically notched, and valgus notched) for testing the load to failure, stiffness, and total energy. Compared to the intact femurs, the load to failure in all resurfaced femurs was significantly decreased by 29 to 57%. Among the resurfaced femurs, valgus and anatomic femurs had the highest load to failure, followed by valgus notched, varus, and anatomically notched femurs. Notching weakened the construct by a further 24 to 30%. To minimise the risk of femoral neck fracture, resurfaced femoral heads should be placed in an anatomic or valgus orientation, and the superior cortex of the femoral neck should remain intact.

A numerical study of failure mechanisms in the cemented resurfaced femur: Effects of interface characteristics and bone remodelling

Failure mechanisms of the resurfaced femoral head include femoral neck fracture in the short-term and stress shielding and implant loosening in the long-term. In this study, finite element simulations of the resurfaced femur considering a debonded implant-cement interface, variable stem-bone interface conditions, and bone remodelling were used to study load transfer within the resurfaced femur and to investigate its relationship with known failure mechanisms. Realistic three-dimensional finite element models of an intact and resurfaced femur were used. Various conditions at the interface between the stem of the prosthesis and the bone were considered. Loading conditions included normal walking and stair climbing. For all stem-bone contact conditions, the tensile stresses in the cement mantle varied between 1 MPa and 5.4 MPa, except near the distal rim of the resurfacing component where they reached 5.4-7MPa. In the case of full stem-bone contact, high von Mises stresses (114-121MPa) were generated in the implant at the stem-cup junction. These stresses were considerably reduced (maximum von Mises stress, 76 MPa) where a gap was present at the stem-bone interface. Resurfacing led to strain shielding of the bone of the femoral head (20-75 per cent strain reductions) and periprosthetic bone resorption (50-80 per cent bone density reductions) for all interface stem-bone contact conditions. In the lateral femoral head and the proximal femoral shaft around the trochantric region, bone density reductions varied between 10 per cent and 50 per cent. Bone apposition was observed in the inferior-medial part of the femoral head and proximal femoral neck region. For full stem-bone contact, more load was transferred through the stem to the surrounding bone, exacerbating strain shielding. Although femoral hip resurfacing conserves bone stock at the primary operation, strain shielding and periprosthetic bone resorption might lead to eventual loosening over time. Post-operatively, the resurfacing procedure generated elevated strains (0.50-0.75 per cent strain) in the proximal femoral neck-component junction irrespective of the variation in interface conditions, indicating an initial risk of femoral neck fracture. Subsequent to bone remodelling, this strain concentration was considerably reduced (0.35-0.50 per cent strain), lowering the risk of neck fracture. In order to reduce the potential risk of neck fracture, patients should avoid activities which might induce high loading of the hip during the early post-operative period to allow the bone around the proximal femoral neck to remodel and heal.

Treatment of chronic musculoskeletal pain with opioids

Dear Editor, Our letter is inspired by the article of D Choquette, TG McCarthy, JFN Rodrigues, and coauthors [1]. We read it with great interest as it discusses important issues encountered by physicians who deal with chronic nonmalignant pain (CNMP) in the course of musculoskeletal disease. The article specifically relates to the use of opioids in patients with CNMP, with underlying musculoskeletal disease, who do not benefit fully from firstand second-step drugs of the World Health Organization (WHO) pain relief ladder. We have no intention to debate the mentioned article. We write in reference to the commonly expressed opinion that climbing the pain relief ladder in CNMP treatment is often done in a schematic way. In other words, it is believed that the lack of analgesic effect of step 1 and 2 drugs, in a patient whose pain intensity equals to 5 on the numerical pain scale, justifies the introduction of strong opioids. This is an approach which assumes that every kind of chronic pain is similar. It does not differentiate between malignant and osteoarthritic pain. The WHO pain relief ladder, initially created for cancer pain, was also adopted in practice for nonmalignant pain treatment. However, causes and sources of pain should not be ignored in relation to analgesic treatment. A priority in malignancy is to suppress pain and this does not interfere with the treatment of the underlying disease. In CNMP caused by musculoskeletal disease, treatment aims to maximize preservation of motor organ functions. In these patients, the intention to decrease pain is very important but it can sometimes be incompatible with maintaining maximal possible efficiency of motor organs after the termination of treatment. As an example, we show the case of our patient with hip joint pain and high-grade subchondral cysts in the femoral head and iliac acetabulum, awaiting an operation. Pain occurred mainly during movement and applying load to the joint. We may therefore ask whether it is prudent to remove pain and enable activity and loading of the joint, increasing the risk of femoral head fracture. Clinically, we all encounter many such examples. It should be remembered that opioids improve the quality of life but deprive the patient of the warning function of pain. Opioids also have adverse effects. They were discussed by the authors in their article. We would also remark on another adverse effect of opioids, important in treatment planning, which is their sedative potential. The risk of femoral neck fracture among persons taking opioids is increased 1.6-fold [2]. It results from the ability of opioids to impair balance and increase the risk of falls. This risk seems to be even higher among elderly people with advanced musculoskeletal disease. In persons with concomitant osteoporosis and/or atlantooccipital junction instability due to rheumatoid arthritis, falls can have serious consequences [3]. These factors should always be considered by a physician estimating risks and benefits for the patient. Opioids are an important class of drugs in the treatment of CNMP caused by musculoskeletal diseases. Their inclusion in the treatment of CNMP significantly improved the effectiveness of analgesia. They also counteract with mechanisms of pain chronification. Nevertheless, decisions concerning their introduction into CNMP treatment should not be schematic. Thus, as recommended by the American Clin Rheumatol (2008) 27:1473–1474 DOI 10.1007/s10067-008-0987-9

Risk of Periprosthetic Femoral Neck Fracture After Hip Resurfacing Arthroplasty: Valgus Compared with Anatomic Alignment

Early clinical results of hip resurfacing arthroplasty have led to the recommendation to achieve a neck-shaft angle of 140 degrees when inserting the femoral component. In addition, the idea of adhering to an absolute angle when inserting instrumentation in hips with excessive anatomic varus or valgus neck-shaft angles has raised concern. A biomechanical analysis was completed in order to determine if the achieved valgus orientation of the femoral component reduced the risk of periprosthetic fracture. Twenty fresh-frozen cadaveric femora were blindly assigned to be implanted with a neutral or valgus-oriented hip-resurfacing femoral component. Bone mineral density scans were acquired for all femora. All specimens were loaded axially to failure at a rate of 0.21 mm per second. Radiographs of the specimens were measured in order to determine the relative valgus orientation of the femoral components and the change in offset. There was a significant increase in the ultimate failure load for the valgus-oriented components. While the bone density scans revealed that the bone mineral densities measured in the neutral and valgus-oriented femoral components were almost identical, the ultimate failure load was found to be significantly increased for the valgus-oriented components (6955 N) compared with the neutral-oriented components (5254 N). For the valgus-oriented femoral components, two had failure at the subcapital level, seven had vertical shear fractures, and one had an anterior shear fracture. For the neutral-oriented components, five subcapital fractures and five vertical shear failures were observed. The study suggests that a valgus orientation decreases the risk of periprosthetic femoral neck fracture following hip resurfacing. It also brings into question the use of an absolute angle for all patients. Obtaining the maximum possible valgus angle, while avoiding notching, may in fact provide the optimum protection from periprosthetic femoral neck fractures.

Total Hip Resurfacing in Patients Who Are Sixty Years of Age or Older

Metal-on-metal total hip resurfacing arthroplasty has been associated with excellent early results in patients who are younger than sixty years of age, but it remains controversial whether this procedure is appropriate in older patients. The purpose of the present study was to compare the clinical and radiographic outcomes after hip resurfacing in two cohorts of patients: those who were sixty years of age or older, and those who were younger than sixty years of age. Between November 2002 and August 2005, thirty-five patients (forty hips) who were sixty years of age or older were managed with metal-on-metal total hip resurfacing arthroplasty. The outcomes of these patients were compared with those of 130 patients (153 hips) who were younger than sixty years of age but otherwise had similar preoperative parameters and who had resurfacing arthroplasty performed during the same time interval and by the same surgeon. We evaluated Harris hip scores, Short Form-12 scores, and complications as well as radiographic alignment and radiolucencies. At a mean follow-up time of thirty-six months, the mean Harris hip scores improved from 52 points to 94 points in the older patient cohort and from 53 points to 92 points in the younger patient cohort. The final Short Form-12 scores of the two groups were also similar. Two patients who were sixty years or older and five of the younger patients required conversion to a conventional total hip arthroplasty. Femoral neck fracture was the reason for one conversion in each group. There were no impending radiographic failures in either cohort. Although national registries indicate that the risk of femoral neck fracture is higher in older patients, the present study found that these patients had excellent clinical outcomes that were similar to those of patients who were younger. We await longer follow-up results to determine further outcomes in these patients.

Response of serum carboxylated and undercarboxylated osteocalcin to alendronate monotherapy and combined therapy with vitamin K2 in postmenopausal women

Alendronate decreases the risk of femoral neck fracture by suppressing bone turnover, and also decreases the serum total osteocalcin level. A low serum carboxylated osteocalcin level or high undercarboxylated osteocalcin level could be risk factors for femoral neck fracture. Vitamin K mediates the carboxylation of osteocalcin, but the effect of alendronate therapy with or without vitamin K(2) supplementation remains unknown. Forty-eight postmenopausal women were enrolled in a 1-year prospective randomized trial and assigned to alendronate monotherapy (5 mg/day) (group A, n = 26) or vitamin K(2) (45 mg/day) plus alendronate (5 mg/day) (group AK, n = 22). Bone mineral density was measured by dual-energy X-ray absorptiometry at 0 and 12 months; bone turnover parameters were measured at 0, 3, and 12 months. Four patients discontinued alendronate therapy, and we analyzed the remaining 44 patients (23 in group A and 21 in group AK) who completed 1 year of treatment. Alendronate decreased undercarboxylated osteocalcin; carboxylated osteocalcin was not affected. Addition of vitamin K(2) enhanced the decrease of undercarboxylated osteocalcin levels and led to a greater increase of femoral neck bone mineral density. Alendronate monotherapy does not decrease carboxylation of osteocalcin, and combination of vitamin K(2) and alendronate brings further benefits on both osteocalcin carboxylation and BMD of femoral neck in postmenopausal women with osteoporosis.

Genetics and Genomics for Clinicians

ADVANCES IN GENETICS AND GENOMICS ARE REVOLUtionizing biomedical science and providing great promise for the future of clinical practice. The magnitude, scope, and pace of discovery in genetics and genomics research are at unprecedented levels and continue to increase exponentially. Progress in basic science resulting from the sequencing of the human genome and new approaches for genomics analyses have accelerated and continue to expand, resulting in new knowledge, mechanisms, and techniques for examining the genetic basis of disease. These discoveries have important implications for understanding disease processes and pathophysiology, for predicting disease susceptibility and progression, and for refining and individualizing treatments—all of which ultimately have the potential to improve health and to increase both quality of life and longevity. Given the pace of discovery and the promise in translating these scientific discoveries to clinical application, physicians and other health care professionals must have a keen awareness about ongoing research and advances in genetics and genomics. This theme issue of JAMA is intended to provide information on genetics and genomics that is relevant and accessible for clinicians, yet also should be of interest to physician-scientists and other investigators involved in genetics and genomics research. A total of 121 manuscripts were submitted for this theme issue, resulting in far too many articles to publish in one issue. Therefore, a number of articles on genetics and genomics will be published in upcoming issues of JAMA. In addition, several members of our family of Archives Journals also are publishing theme issues on genetics and genomics, including the March and April issues of Archives of Neurology and the March issues of Archives of Dermatology, Archives of Ophthalmology, and Archives of Surgery. Additional articles on genomics and genetics are included in the March issues of Archives of General Psychiatry, Archives of Internal Medicine, and Archives of Otolaryngology–Head & Neck Surgery. In this issue of JAMA, 5 articles provide new information on genetics and genomics for common diseases and conditions, including cardiovascular disease, osteoporosis, posttraumatic stress disorder, venous thromboembolism, and cancer. In an elegant, comprehensive study, Bhattacharyya and colleagues examined the relationship among genotype, generelated functional activity, and clinical outcomes in 1399 patients who had undergone coronary angiography. The authors found consistent associations among paraoxonase 1 (PON1) genotypes, levels of PON1 activity and systemic indices of oxidant stress, and prevalent cardiovascular disease as well as recurrent and incident cardiovascular events. In an ambitious multicenter collaborative investigation that included individual-level data from 37 534 individuals from Europe and North America, van Meurs and colleagues studied the relationship between polymorphisms of the gene encoding low-density lipoprotein receptorrelated protein 5 (LRP5) and bone mineral density and fracture risk. The authors report evidence for an association of common variants of the LRP5 gene with alterations in bone mineral density and risk of lumbar spine fractures and femoral neck fractures. In an investigation designed to increase understanding of genetic and environmental risk factors and their potential interactions with development of posttraumatic stress disorder (PTSD) symptoms, Binder and colleagues examined psychological risk factors combined with single nucleotide polymorphism (SNP) genotyping in 762 primarily lowincome, African American men and women. Four SNPs of the FKBP5 gene had significant interactions with severity of child abuse as a predictor of symptoms of PTSD in adults, suggesting the possibility of a gene–childhood environment interaction for adult PTSD. In an analysis designed to examine genetic factors associated with deep vein thrombosis, Bezemer and colleagues analyzed 3 large case-control studies. SNPs in several genes, including CYP4V2, were associated with deep vein thrombosis and with coagulation factor XI levels, suggesting that common genetic variation is an important factor in venous thrombotic disease. As Bovill points out in an insightful accompanying editorial, studies such as this hold the promise that risk profiles with significant predictive value ultimately may be developed to help guide clinical practice.

Osteoprotegerin Lys3Asn Polymorphism and the Risk of Fracture in Older Women

Osteoprotegerin (OPG) is a soluble decoy receptor for receptor activator nuclear factor kappa-beta that blocks osteoclastic bone resorption. We investigated the association between a Lys3Asn polymorphism in the OPG gene and bone mineral density (BMD), and the risk of fracture in 6695 women aged 65 yr and older participating in the Study of Osteoporotic Fractures. BMD was measured using either single-photon absorptiometry (Osteon Osteoanalyzer; Dove Medical Group, Los Angeles, CA) or dual-energy x-ray absorptiometry (Hologic QDR 1000; Hologic, Inc., Bedford, MA). Incident fractures were confirmed by physician adjudication of radiology reports. Genotyping was performed using an immobilized probe-based assay. Women who were homozygous for the minor G (Lys) allele had significantly lower BMD at the intertrochanter, distal radius, lumbar spine, and calcaneus than those with the C (Asn) allele. There were 701 incident hip fractures during 13.6-yr follow-up (91,249 person-years), including 362 femoral neck and 333 intertrochanteric hip fractures. Women with the C/C (Asn-Asn) genotype had a 51% higher risk of femoral neck fracture (95% confidence interval, 1.13-2.02) and 26% higher risk of hip fracture (95% confidence interval, 1.02-1.54) than those with the G/G (Lys-Lys) genotype. These associations were independent of BMD. Intertrochanteric fractures were not associated with the Lys3Asn polymorphism. These results require confirmation but suggest a role for the OPG Lys3Asn polymorphism in the genetic susceptibility to hip fractures among older white women.

Disproportional geometry of the proximal femur in patients with Turner syndrome: a cross‐sectional study

Patients with Turner syndrome (TS) have altered growth and increased risk of osteoporosis due to oestrogen deficiency and possibly a host of other factors. Thus, TS patients have a 4.9-fold increased risk of femoral neck fractures. Most patients are treated with oestrogen during puberty and adolescence to facilitate pubertal development and prevent secondary osteoporosis. The geometry of the hip is a predictor for hip fractures independent of bone mineral density (BMD). The purpose of the present study was to investigate the variation of the geometry of the hip in patients with TS in comparison with healthy controls. The study population comprised 58 patients with TS (aged 22-67 years) and 60 age-matched healthy women (aged 21-65 years). Hip axis length (HAL), neck width (NW), neck shaft angle (NSA), and femoral head-radius (HR) on dual-energy X-ray absorptiometry (DXA) screen images. These parameters related to age of oestrogen supplementation, menarche, and duration of oestrogen exposure. Height was 146.6 +/- 6.9 cm and 167.1 +/- 6.2 cm (P < 0.1) and weight 57.4 +/- 13.9 kg and 62.3 +/- 8.3 kg (P < 0.001) in patients and controls, respectively. After adjustment for differences in height, HAL was not significantly different (9.4 +/- 0.5 vs. 9.5 +/- 0.5 cm; NS) in TS compared with controls while NW was significantly increased (3.5 +/- 0.4 cm vs. 3.3 +/- 0.2 cm, P < 0.001), NSA was similar (129 +/- 4 degrees vs. 130 +/- 4 degrees , NS), and HR was significantly decreased (4.1 +/- 0.4 vs. 4.5 +/- 0.3 cm, P < 0.001). The duration of oestrogen exposure was significantly shorter among TS, but did not correlate significantly with the geometrical parameters in either TS or controls. Our data demonstrates that hip geometry is disproportionate in TS compared with normal controls. The altered hip geometry, however, cannot explain the increased risk of hip fracture in TS.

Investigation into the effect of varus–valgus orientation on load transfer in the resurfaced femoral head: A multi-femur finite element analysis

Femoral head resurfacing is a popular procedure for younger active hip replacement patients. Whilst the current generation of metal-on-metal resurfacing arthroplasties appear to have cured the osteolysis problems that plagued earlier resurfacing implants, fracture of the femoral head and aseptic loosening are still factors of concern in its survivorship. Several studies have shown a tendency towards failure in resurfaced femurs where the implant has been set at a varus angle. This work aims to investigate the influence of varus-valgus orientation on load transfer within the resurfaced proximal femur. This study uses Computer Tomography based finite element analysis to determine the effect of implant orientation on load transfer in the proximal femur with respect to the intact femur. A group of 16 femurs were studied to take into account inter-patient variation; four models were produced for each femur, one of the intact femur, one resurfaced with the implant set inline with the femoral neck and one each representing varus and valgus implant alignment. Results showed the valgus aligned resurfaced femur to produce strain patterns more akin to the intact femur. As the implant's angle to the femoral shaft increases from varus to valgus the strains in the superior femoral neck are reduced while those in the inferior neck are increased. The study concluded that valgus alignment of the resurfacing arthroplasty is preferential to varus alignment; as it induces a more physiological strain pattern and reduces the risk of femoral neck fracture. These findings are in line with clinical experience, which has shown an increase of failure with varus implanted prostheses.

Femoral neck structure in hip fracture

Hip fracture occurs relating to fall and decreased mechanical integrity of the femoral neck. Mechanical strength of the femoral neck is determined by both bone mineral density and other factors such as bone quality and hip geometry. Histomorphometrical studies show that cortical thinning, regional hyper-mineralization, decreased osteocyte lacunae and microdamage accumulation occur in aged or fractured subjects, suggesting that bone quality contributes mechanical integrity of femoral neck. Recent dual energy X-ray absorptiometry (DXA) studies revealed that hip axis length, longer in femoral neck fracture patients may contribute to the risk of femoral neck fracture.

Bone remodelling inside a cemented resurfaced femoral head

Although the short-term performance of modern resurfacing hip arthroplasty is impressive, the long-term performance is still unknown. It is hypothesised that bone remodelling and the resulting changes in stress/strain distribution within the resurfaced femur influence the risk of fixation failure. Three-dimensional finite element models and adaptive bone remodelling algorithms have been used to predict long-term changes in bone density following cemented femoral head resurfacing. Applied loading conditions include normal walking and stair climbing. The remodelling simulation was validated by comparing the results of an analysis of a proximal femur implanted with a Charnley femoral component with known clinical data in terms of bone density adaptations. Resurfacing caused a reduction of strain of 20-70% in the bone underlying the implant as compared to the intact femur, immediately post operative. Elevated strains, ranging between 0.50 and 0.80% strain, were generated post-operatively around the proximal femoral neck regions, indicating a potential risk of neck fracture. However, this strain concentration was considerably reduced after bone remodelling. After remodelling, bone resorption of 60-90% was observed in the bone underlying the implant. Reduction in bone density of 5-47% occurred in the lateral femoral head. Bone apposition was observed in the proximal-medial cortex, around the inferior edge of the implant. Hardly any changes in bone density occurred in the distal neck or the femoral diaphysis. Although resurfacing has produced encouraging clinical results, bone remodelling within the femoral head might be a concern for long-term fixation. Regions of strain concentration at the head-neck junction, which may increase the initial risk of femoral neck fracture, are reduced with bone remodelling. In order to reduce this risk of femoral neck fracture, patients should avoid activities which induce high loading of the hip during the early rehabilitation period after surgery.

Finite element study of the proximal femur with retained trochanteric gamma nail and after removal of nail

This study aims to evaluate the stress and strain distributions in the healed proximal femur after fixation with a trochanteric gamma nail (TGN) and after TGN removal, using the finite element method. The stress distributions in the proximal femur with retained TGN and after TGN removal were very similar. The strain and the strain energy density in the femoral neck region with retained TGN were much higher than in the lag screw hole at the subtrochanter and the distal locking screw hole at the proximal femur, and even higher after TGN removal. Stair climbing resulted in higher strain and higher strain energy density at the femoral neck than normal walking. The conclusion can be drawn that removal of the TGN may result in high risk of femoral neck fracture.

Intracapsular hip fractures in end-stage renal failure

Patients with end-stage renal failure (ESRF) have metabolic bone disease. This increases the risk of femoral neck fracture and increases the risk of complications associated with fracture fixation such as non-union and avascular necrosis (AVN). We report the results of treatment in a consecutive series of 15 intracapsular fractures of the hip occurring in 13 patients with ESRF over a 5-year period. Six intracapsular hip fractures (of which five were undisplaced) were treated by internal fixation. Five out of these six (mean=83.3%) required conversion to total hip arthroplasty because of non-union or AVN. In all six of these patients, internal fixation was considered adequate post operatively. Of the remaining nine intracapsular hip fractures treated by hemiarthroplasty, only one required conversion to total hip arthroplasty because of stem subsidence (mean=11%). The difference in the revision rate for the two groups i.e. primary fixation versus primary hemiarthroplasty was statistically significant (p-value=0.01). The six patients with undisplaced intracapsular fractures treated by internal fixation required a total of 14 major operations, at an average rate (including initial fracture fixation and revision surgery) of 2.3 per patient. The 9 displaced fractures treated by hemiarthroplasty required just 10 operations in total, at an average rate of 1.1 per patient. (The difference was significant; p-value=0.006.) The 1-year mortality in the whole group (13 patients with 15 fractures) was 44.4%. We suggest that patients with ESRF with an intracapsular fracture of the neck of femur should be treated by replacement arthroplasty irrespective of femoral head displacement because of the high risk of revision surgery associated with internal fixation.

Irradiating the groin nodes without breaking a leg: A comparison of techniques for groin node irradiation

The purpose of this study was to determine the optimal technique for delivering postoperative radiotherapy for vulvar cancer and other tumors requiring treatment of the inguinal nodes. This project compared tumor coverage and normal tissue sparing for the 5 main radiotherapy techniques that are used to treat vulvar cancer. The intensity-modulated radiation therapy (IMRT) plan was undesirable because it resulted in an excessive dose to portions of the central pelvic structures. The photon thunderbird with skin match was unacceptable because it underdosed a portion of the groin region. The electron thunderbird was ideal for thin patients but was not applicable for most patients because of excessive dose to the skin and subcutaneous tissues. The photon through-and-through and the photon thunderbird with deep match were acceptable in most situations. In thin patients, where the depth of the inguinal vessels is less than 3 cm, the electron thunderbird is the technique of choice. In the average-sized patient, both the photon through-and-through and the photon thunderbird with deep match are reasonable options. The available literature suggests that the risk of femoral neck fracture or necrosis of the femoral head is approximately 11% at 5 years using the photon through-and-through technique. In our opinion, this is an acceptable price to pay for reliable node coverage, setup simplicity, and zero risk of overdose at field junctions.

Defining the role of raloxifene as a therapeutic agent for postmenopausal osteoporosis: focus on its pharmacological properties

In this semiar, I propose to describe the pharmacological properties of raloxifene that provide a basis for its role in the treatment of postmenopausal osteoporosis. These pharmacological properties can be described as providing therapeutic benefits in the following three areas: 1) reduction in bone turnover, 2) increases in bone mineral density, and 3) risk reduction in fractures. While reloxifene shares these effects with conventional bisphosphonates that are in common use for postmenopausal osteoporosis, it exerts its antiresorptive effects through a different mechanism of action from those of the bisphosphonates. Furthermore, raloxifene exerts its stimulatory or inhibitory effects on estrogen in a tissue-specific fashion as a selective estrogen-receptor-modulator (SERM), thereby providing a wide range of clinical benefits that result from its ability to exert estrogen-like beneficial effects in tissues other than bone while at the same time inhibiting estrogen-like deleterious effects in other tissues. I therefore propose to define the role of raloxifene as a viable therapeutic option in the treatment of postmenopausal osteoporosis in light of these unique pharmacological features. Current data suggests that raloxifene can be positioned somewhere in between hormone replacement therapy (HRT) and bisphosphonates, and is highly likely to be suitable for use in patients between the ages of 55 and 70, while other agents may be indicated in special populations, such as premenopausal patients, postmenopausal patients with hot flushes, or elderly patients who may be placed at accelerated risk of developing femoral neck fractures. Thus, as a novel therapeutic option with unique clinical benefits, a far greater role may be expected for raloxifene in the treatment of postmenopausal osteoporosis than for other conventional therapeutic agents.

A new software for prediction of femoral neck fractures.

Femoral neck fractures are an important clinical, social and economic problem. Even if many different attempts have been carried out to improve the accuracy predicting the fracture risk, it was demonstrated in retrospective studies that the standard clinical protocol achieves an accuracy of about 65%. A new procedure was developed including for the prediction not only bone mineral density but also geometric and femoral strength information and achieving an accuracy of about 80% in a previous retrospective study. Aim of the present work was to re-engineer research-based procedures and develop a real-time software for the prediction of the risk for femoral fracture. The result was efficient, repeatable and easy to use software for the evaluation of the femoral neck fracture risk to be inserted in the daily clinical practice providing a useful tool for the improvement of fracture prediction.

Toward an expanded understanding of the role of the periosteum in skeletal health.

Toward an expanded understanding of the role of the periosteum in skeletal health.

A New Approach for Improving the Prediction of Femoral Neck Fracture

Femoral neck fractures are an important clinical, social, and economical issue. Much effort has been made to improve the accuracy of prediction of fracture risk. However, at present the DEXA standard clinical protocol achieves an accuracy of about 65% in retrospective studies. A new procedure for prediction was developed including not only bone mineral density but also geometric and femoral bone strength information. The retrospective clinical validation has shown an improved accuracy to 80% in classifying 200 patients. The procedure has been employed in efficient, repeatable, and easy to use software for evaluation of femoral neck fracture risk. The software characteristics make it suitable for use in daily clinical practice, providing a useful tool for the improvement of femoral neck fracture prediction.