Towards a Non-Invasive Technique for Healing Assessment of Internally Fixated Femur.

The lack of a quantitative method to adequately assess fractured bone healing that has undergone fixation limits prognostic capabilities on patients' optimal return to work. This paper addresses the use of vibrational analysis to monitor the state of healing of a plate-screw fixated femur and supplement the current clinical radiographic assessment. This experimental study involves an osteotomised composite femur specimen enclosed by modelling clay to simulate the damping effect of overlying soft tissues. Epoxy adhesives are applied to the fractured region and to simulate the healing process. With the instrumentation described, the cross-spectrum and coherence are obtained and analysed in the frequency domain over a period of time. The results suggest that it is crucial to analyse the cross-spectrum and proposed healing index to quantitatively assess the stages of healing. The results also show that the mass loading effect due to modelling clay did not influence the proposed healing assessment technique. The findings indicate a potential non-intrusive technique to evaluate the healing of fractured femur by utilising the vibrational responses.

Anatomy-based MRI assessment of the iliopsoas muscle complex after pertrochanteric femoral fracture.

OBJECTIVE: To evaluate the quality of the iliopsoas muscle complex after pertrochanteric femoral fracture, using MRI; to propose an anatomy-based evaluation of the iliopsoas muscle complex; and to determine the inter-reader reliability of two classifications of fatty muscle degeneration. MATERIALS AND METHODS: We included adult patients with a displaced lesser trochanter following pertrochanteric femoral fracture. Muscle quality was evaluated using the Goutallier and Slabaugh classifications at three levels (L4/L5, L5/S1, and the anterior inferior iliac spine). Two radiologists independently reviewed the MRIs, and force measurement was performed on both hips. Linear mixed-effects models were used to determine the effect of fracture on muscle quality and strength, and Cohen's kappa statistic was used to assess inter-reader agreement. RESULTS: In the 18 patients included, the iliopsoas muscle complex showed higher grades of fatty muscle degeneration on the fractured side than on the non-fractured side. The mean difference between muscle strength on the fractured vs the non-fractured side was -12 N (p > 0.05). Inter-reader agreement for the Goutallier and Slabaugh classifications was good and very good respectively (weighted K = 0.78 and 0.85 respectively). CONCLUSION: Fatty muscle degeneration of the iliopsoas muscle complex after pertrochanteric femoral fracture was evident using both classification systems; however, fatty muscle degeneration resulted in only a minimal reduction of muscle strength. To provide a thorough assessment of iliopsoas muscle complex quality, we suggest evaluating it at different anatomical levels. Regarding inter-reader agreement, the Slabaugh classification was superior to the Goutallier classification.

Current Understanding of Epidemiology, Pathophysiology, and Management of Atypical Femur Fractures.

PURPOSE OF REVIEW: To summarize reports published since the 2013 American Society of Bone and Mineral Research Task Force Report on atypical femoral fractures (AFF). RECENT FINDINGS: The absolute incidence of AFFs remains low. AFFs are primarily associated with prolonged bisphosphonate (BP) exposure, but have also been reported in unexposed patients and those receiving denosumab for osteoporosis and metastatic bone disease. Asians may be more susceptible to AFFs. Lateral femoral bowing and varus hip geometry, which increase loading forces on the lateral femoral cortex, may increase AFF risk. Altered bone material properties associated with BP therapy may predispose to AFFs by permitting initiation and increasing propagation of micro-cracks. Relevant genetic mutations have been reported in patients with AFFs. Single X-ray absorptiometry femur scans permit early detection of incomplete and/or asymptomatic AFFs. Orthopedists recommend intramedullary rods for complete AFFs and for incomplete, radiologically advanced AFFs associated with pain and/or marrow edema on MRI. Teriparatide may advance AFF healing but few data support its efficacy. Greater understanding of biological and genetic predisposition to AFF may allow characterization of individual risk prior to initiating osteoporosis therapy and help allay fear in those at low risk for this complication, which remains rare in comparison to the osteoporotic fractures prevented by antiresorptive therapy.

Trial of Acute Femoral Fracture Fixation (TrAFFix): study protocol for a randomised controlled feasibility trial.

BACKGROUND: Distal femoral fractures are a source of considerable morbidity and best treatment is currently uncertain. The Trial of Acute Femoral Fracture Fixation (TrAFFix) is a randomised, parallel-group feasibility study designed to inform the design of a later, definitive clinical trial comparing intramedullary nails and locking plates for the treatment of distal femoral fractures. METHODS/DESIGN: Patients aged 50 years and older with a femoral fracture within the distal two Müller squares are potentially eligible for inclusion. Participants are randomly allocated to receive fixation with either an intramedullary nail or a distal locking plate. Measurements (EuroQol 5 Dimensions, Dementia Quality of Life, Disability Rating Index) are collected at baseline, 6 weeks and 4 months. The recruitment rate will be assessed across seven participating centres over a total of 52 centre-months which is expected after 10 months of recruitment. Objectives are - feasibility phase, to assess recruitment rate and completion rate of the primary outcome measure; process evaluation, to assess the generalisability and likely success of a future trial; definitive trial, quantify and draw inferences on observed differences in health-related quality of life at 4 months between the study intervention groups (nail versus plate). A favourable opinion was granted by the Wales Research Ethics Committee (16/WA/0225), study-wide NHS approval was given by the Health Research Authority (IRAS 206745), and participating NHS trusts provided local approvals. This study was funded by the National Institute for Health Research Health Technology Assessment (HTA 15/59/22). DISCUSSION: This is the protocol for a feasibility study conducted prior to any future definitive trial. The estimates of participant recruitment rate and proportion of data completion will be coupled with outputs from the process evaluation to make a final decision regarding feasibility TRIAL REGISTRATIONS: The study is registered with the National Institute for Health Research Portfolio (CPMS ID: 32536) and the ISRCTN registry ( ISRCTN92089567 ) on 26 May 2016.

A new, low cost, locking plate for the long-term fixation of a critical size bone defect in the ratfemur: in vivo performance, biomechanical and finite element analysis.

BACKGROUND: The optimum fixation device for the critical size bone defect is not established yet. OBJECTIVE: A reliable, feasible and low-cost fixation device for the long-term maintenance of a critical bone defect. METHODS: A custom-made plate made of poly-methyl-methacrylate was used for the fixation of a critical defect of rats' femurs. The screws were securely fixing both on the plate and the bone. A three point bending test, aimed to resemble the in vivo loading pattern, a Finite Element Analysis and a 24-week in vivo monitoring of the integrity of the plate fixation were utilized. RESULTS: The plate has linear and reproducible behavior. It presents no discontinuities in the stress field of the fixation. Its properties are attributed to the material and the locking principle. It fails beyond the level of magnitude of the normal ambulatory loads. In vivo, 100% of the plates maintained the bone defect intact up to 12 weeks and 85% of them at 24 weeks. CONCLUSION: This novel locking plate shows optimal biomechanical performance and reliability with high long-term in vivo survival rate. It is fully implantable, inexpensive and easily manufactured. It can be qualified for long term critical defect fixation in bone regeneration studies.

Determination of Radiographic Healing: An Assessment of Consistency Using RUST and Modified RUST in Metadiaphyseal Fractures.

OBJECTIVE: To determine the reliability of the Radiographic Union Scale for Tibia (RUST) score and a new modified RUST score in quantifying healing and to define a value for radiographic union in a large series of metadiaphyseal fractures treated with plates or intramedullary nails. DESIGN: Healing was evaluated using 2 methods: (1) evaluation of interrater agreement in a series of radiographs and (2) analysis of prospectively gathered data from 2 previous large multicenter trials to define thresholds for radiographic union. INTERVENTION: Part 1: 12 orthopedic trauma surgeons evaluated a series of radiographs of 27 distal femur fractures treated with either plate or retrograde nail fixation at various stages of healing in random order using a modified RUST score. For each radiographic set, the reviewer indicated if the fracture was radiographically healed. Part 2: The radiographic results of 2 multicenter randomized trials comparing plate versus nail fixation of 81 distal femur and 46 proximal tibia fractures were reviewed. Orthopaedic surgeons at 24 trauma centers scored radiographs at 3, 6, and 12 months postoperatively using the modified RUST score above. Additionally, investigators indicated if the fracture was healed or not healed. MAIN OUTCOME MEASURES: The intraclass correlation coefficient (ICC) with 95% confidence intervals was determined for each cortex, the standard and modified RUST score, and the assignment of union for part 1 data. The RUST and modified RUST that defined "union" were determined for both parts of the study. RESULTS: ICC: The modified RUST score demonstrated slightly higher ICCs than the standard RUST (0.68 vs. 0.63). Nails had substantial agreement, whereas plates had moderate agreement using both modified and standard RUST (0.74 and 0.67 vs. 0.59 and 0.53). UNION: The average standard and modified RUST at union among all fractures was 8.5 and 11.4. Nails had higher standard and modified RUST scores than plates at union. The ICC for union was 0.53 (nails: 0.58; plates: 0.51), which indicates moderate agreement. However, the majority of reviewers assigned union for a standard RUST of 9 and a modified RUST of 11, and >90% considered a score of 10 on the RUST and 13 on the modified RUST united. CONCLUSIONS: The ICC for the modified RUST is slightly higher than the standard RUST in metadiaphyseal fractures and had substantial agreement. The ICC for the assessment of union was moderate agreement; however, definite union would be 10 and 13 with over 90% of reviewers assigning union. These are the first data-driven estimates of radiographic union for these scores.

Radiological outcome and intraoperative evaluation of a computer-navigation system for femoral nailing: a retrospective cohort study.

AIM: Intraoperative determinations of femoral antetorsion and leg length during fixation of femoral shaft fractures present a challenge. In femoral shaft fracture fixations, a computer-navigation system has shown promise in determining antetorsion and leg length discrepancies. This retrospective cohort study aimed to determine whether the use of computer navigation during femoral nailing procedures reduced postoperative femoral malrotation and leg length discrepancy, as well as the number of revision cases. We also sought to determine whether radiation exposure time was reduced when computer navigation was used. MATERIALS AND METHODS: Of 246 patients treated for femoral shaft fractures between 2004 and 2012, we selected those that received postoperative computed tomography for rotation and leg length control. We included 24 patients who received navigation-assisted treatments and 48 who received unassisted treatments, matched for age, sex, and fracture type. All patients were treated by femoral nailing. RESULTS: The groups showed significant differences in the mean (standard deviation (SD) delay before surgery (navigation-assisted vs. unassisted groups: 8.5 ± 3.2 vs. 5.2 ± 5.8 days; P<0.05) and surgery times (163.7 ± 43.94 vs. 98.3 ± 28.13 min; P<0.001). The groups were significantly different in the mean (SD) radiation exposure time (4.43 ± 1.35 vs. 3.73 ± 1.5 min; P=0.042), and were not significantly different in the postoperative femoral antetorsion difference (8.83 ± 5.52° vs. 12.4 ± 9.2°; P=0.056), or in the postoperative length discrepancy (0.92 ± 0.75 vs. 0.95 ± 0.94 cm; P=0.453). Four (16.7%) navigation-assisted and 15 (31.25%) unassisted surgeries got revision for torsion and/or length corrections. CONCLUSION: Our results showed that, compared to unassisted femoral surgery, the computer-navigation system did not improve postoperative results or reduce radiation exposure. In the future, improvements in handling and application could facilitate the workflow and may provide better postoperative results. Currently, computer navigation may provide advantages for complicated or sophisticated cases, such as complex three-dimensional deformity corrections. LEVEL OF EVIDENCE: Level III.

Comparing femoral version after intramedullary nailing performed by trauma-trained and non-trauma trained surgeons: is there a difference?

INTRODUCTION: As with some procedures, trauma fellowship training and greater surgeon experience may result in better outcomes following intramedullary nailing (IMN) of diaphyseal femur fractures. However, surgeons with such training and experience may not always be available to all patients. The purpose of this study is to determine whether trauma training affects the post-operative difference in femoral version (DFV) following IMN. MATERIALS AND METHODS: Between 2000 and 2009, 417 consecutive patients with diaphyseal femur fractures (AO/OTA 32A-C) were treated via IMN. Inclusion criteria for this study included complete baseline and demographic documentation as well as pre-operative films for fracture classification and post-operative CT scanogram (per institutional protocol) for version and length measurement of both the nailed and uninjured femurs. Exclusion criteria included bilateral injuries, multiple ipsilateral lower extremity fractures, previous injury, and previous deformity. Of the initial 417 subjects, 355 patients met our inclusion criteria. Other data included in our analysis were age, sex, injury mechanism, open vs. closed fracture, daytime vs. nighttime surgery, mechanism of injury, and AO and Winquist classifications. Post-operative femoral version of both lower extremities was measured on CT scanogram by an orthopaedic trauma fellowship trained surgeon. Standard univariate and multivariate analyses were performed to determine statistically significant risk factors for malrotation between the two cohorts. RESULTS: Overall, 80.3% (288/355) of all fractures were fixed by trauma-trained surgeons. The mean post-operative DFV was 8.7° in these patients, compared to 10.7° in those treated by surgeons of other subspecialties. This difference was not statistically significant when accounting for other factors in a multivariate model (p>0.05). The same statistical trend was true when analyzing outcomes of only the more severe Winquist type III and IV fractures. Additionally, surgeon experience was not significantly predictive of post-operative version for either trauma or non-trauma surgeons (p>0.05 for both). CONCLUSIONS: Post-operative version or percentage of DFV >15° did not significantly differ following IMN of diaphyseal femur fractures between surgeons with and without trauma fellowship training. However, prospective data that removes the inherent bias that the more complex cases are left for the traumatologists are required before a definitive comparison is made.

The assessment of trabecular bone parameters and cortical bone strength: a comparison of micro-CT and dental cone-beam CT.

This study compared the capabilities of micro-computed tomography (micro-CT) and dental cone-beam computed tomography (CBCT) in assessing trabecular bone parameters and cortical bone strength. Micro-CT and CBCT scans were applied to 28 femurs from 14 rats to obtain independent measurements of the volumetric cancellous bone mineral density (vCanBMD) in the femoral head, volumetric cortical bone mineral density (vCtBMD) in the femoral diaphysis, cross-sectional moment of inertia (CSMI), and bone strength index (BSI) (=CSMI×vCtBMD). Five structural parameters of the trabecular bone of the femoral head were calculated from micro-CT images. A three-point bending test was then conducted to measure the fracture load of each femur. Bivariate linear Pearson analysis was conducted to calculate the correlation coefficients (r values) of the micro-CT, dental CBCT, and three-point bending measurements. The statistical analyses showed a strong correlation between vCanBMD values obtained using micro-CT and dental CBCT (r=0.830). There were strong or moderate correlation between vCanBMD measured using dental CBCT and five parameters of trabecular structure measured using micro-CT. Additionally, the results were satisfactory regardless of whether micro-CT or dental CBCT was used to measure the femoral diaphysis vCtBMD (r=0.733 and 0.680, respectively), CSMI (r=0.756 and 0.726, respectively), or BSI (r=0.846 and 0.847, respectively) to predict fracture loads. This study has yielded a new method for using dental CBCT to evaluate bone parameters and bone strength; however, further studies are necessary to validate the use of dental CBCT on humans.

Micro-computed tomography assessment of the progression of fracture healing in mice.

The mouse fracture model is ideal for research into the pathways of healing because of the availability of genetic and transgenic mice and the ability to create cell-specific genetic mutations. While biomechanical tests and histology are available to assess callus integrity and tissue differentiation, respectively, micro-computed tomography (µCT) analysis has increasingly been utilized in fracture studies because it is non-destructive and provides descriptions of the structural and compositional properties of the callus. However, the dynamic changes of µCT properties that occur during healing are not well defined. Thus, the purpose of this study was to determine which µCT properties change with the progression of fracture repair and converge to values similar to unfractured bone in the mouse femur fracture model. A unilateral femur fracture was performed in C57BL/6 mice and intramedullary fixation performed. Fractured and un-fractured contralateral specimens were harvested from groups of mice between 2 and 12 weeks post-fracture. Parameters describing callus based on µCT were obtained, including polar moment of inertia (J), bending moment of inertia (I), total volume (TV), tissue mineral density (TMD), total bone volume fraction (BV/TV), and volumetric bone mineral density (vBMD). For comparison, plain radiographs were used to measure the callus diameter (D) and area (A); and biomechanical properties were evaluated using either three-point bending or torsion. The µCT parameters J, I, TV, and TMD converged toward their respective values of the un-fractured femurs over time, although significant differences existed between the two sides at every time point evaluated (p<0.05). Radiograph measurement D changed with repair progression in similar manner to TV. In contrast, BV/TV and BMD increased and decreased over time with statistical differences between callus and un-fractured bone occurring sporadically. Similarly, none of the biomechanical properties were found to distinguish consistently between the fractured and un-fractured femur. Micro-CT parameters assessing callus structure and size (J, I, and TV) were more sensitive to changes in callus over time post-fracture than those assessing callus substance (TMD, BV/TV, and BMD). Sample size estimates based on these results indicate that utilization of µCT requires fewer animals than biomechanics and thus is more practical for evaluating the healing femur in the mouse fracture model.

Telemetric assessment of bone healing with an instrumented internal fixator: a preliminary study.

In an interdisciplinary project involving electronic engineers and clinicians, a telemetric system was developed to measure the bending load in a titanium internal femoral fixator. As this was a new device, the main question posed was: what clinically relevant information could be drawn from its application? As a first clinical investigation, 27 patients (24 men, three women) with a mean age of 38.4 years (19 to 66) with femoral nonunions were treated using the system. The mean duration of the nonunion was 15.4 months (5 to 69). The elasticity of the plate-callus system was measured telemetrically until union. Conventional radiographs and a CT scan at 12 weeks were performed routinely, and healing was staged according to the CT scans. All nonunions healed at a mean of 21.5 weeks (13 to 37). Well before any radiological signs of healing could be detected, a substantial decrease in elasticity was recorded. The relative elasticity decreased to 50% at a mean of 7.8 weeks (3.5 to 13) and to 10% at a mean of 19.3 weeks (4.5 to 37). At 12 weeks the mean relative elasticity was 28.1% (0% to 56%). The relative elasticity was significantly different between the different healing stages as determined by the CT scans. Incorporating load measuring electronics into implants is a promising option for the assessment of bone healing. Future application might lead to a reduction in the need for exposure to ionising radiation to monitor fracture healing.

Three-dimensional high frequency power Doppler ultrasonography for the assessment of microvasculature during fracture healing in a rat model.

We aimed to establish a novel approach with 3D high frequency power Doppler ultrasonography (3D-HF-PDU) to assess microvasculature at the fracture site in rat femurs by comparing with microCT-based microangiography. Twenty-four 9-month-old ovariectomized (OVX) osteoporotic rats and age-matched sham-ovariectomized (Sham) rats were used for establishing closed fracture models on right femora. At 2, 4, and 8 weeks post-operatively, four rats in each group underwent in vivo 3D-HF-PDU scanning for evaluation of vascularization and blood flow at the fracture site. Then the fractured femora were harvested for ex vivo microangiography, and neovasculatures within the callus were reconstructed for vascular volume analysis. Correlation between the vascular volumes of the two methodologies was examined. Both 3D-HF-PDU and microangiography showed a decline of vascular volume at the fracture site from 2 to 8 weeks and a significantly larger volume in the Sham group than the OVX group. A significant linear positive correlation (r = 0.87, p < 0.001) was detected between the volumes measured by the two methodologies. Osteoporotic rats had a diminished angiogenic response and lower blood perfusion than Shams. We believe 3D-HF-PDU is feasible and reproducible for in vivo assessment of microvasculature during femoral fracture healing in rats.

Multiscale modelling and nonlinear finite element analysis as clinical tools for the assessment of fracture risk.

The risk of osteoporotic fractures is currently estimated based on an assessment of bone mass as measured by dual-energy X-ray absorptiometry. However, patient-specific finite element (FE) simulations that include information from multiple scales have the potential to allow more accurate prognosis. In the past, FE models of bone were limited either in resolution or to the linearization of the mechanical behaviour. Now, nonlinear, high-resolution simulations including the bone microstructure have been made possible by recent advances in simulation methods, computer infrastructure and imaging, allowing the implementation of multiscale modelling schemes. For example, the mechanical loads generated in the musculoskeletal system define the boundary conditions for organ-level, continuum-based FE models, whose nonlinear material properties are derived from microstructural information. Similarly microstructure models include tissue-level information such as the dynamic behaviour of collagen by modifying the model's constitutive law. This multiscale approach to modelling the mechanics of bone allows a more accurate characterization of bone fracture behaviour. Furthermore, such models could also include the effects of ageing, osteoporosis and drug treatment. Here we present the current state of the art for multiscale modelling and assess its potential to better predict an individual's risk of fracture in a clinical setting.

Assessment of a mechano-regulation theory of skeletal tissue differentiation in an in vivo model of mechanically induced cartilage formation.

Mechanical cues are known to regulate tissue differentiation during skeletal healing. Quantitative characterization of this mechano-regulatory effect has great therapeutic potential. This study tested an existing theory that shear strain and interstitial fluid flow govern skeletal tissue differentiation by applying this theory to a scenario in which a bending motion applied to a healing transverse osteotomy results in cartilage, rather than bone, formation. A 3-D finite element mesh was created from micro-computed tomography images of a bending-stimulated callus and was used to estimate the mechanical conditions present in the callus during the mechanical stimulation. Predictions regarding the patterns of tissues--cartilage, fibrous tissue, and bone--that formed were made based on the distributions of fluid velocity and octahedral shear strain. These predictions were compared to histological sections obtained from a previous study. The mechano-regulation theory correctly predicted formation of large volumes of cartilage within the osteotomy gap and many, though not all patterns of tissue formation observed throughout the callus. The results support the concept that interstitial fluid velocity and tissue shear strain are key mechanical stimuli for the differentiation of skeletal tissues.

Bone-muscle interaction of the fractured femur.

The interaction forces of a fractured femur among the bone, muscle, and other soft tissues are not well understood. Only a small number of in vivo measurements have been made and with many limitations. Mathematical modeling is a useful alternative, overcoming limitations and allowing investigation of hypothetical simulated reductions. We aimed to develop a model to help understand best practices in fracture reduction and to form a base to develop new technologies and procedures. The simulation environment allows muscle forces and moments to deform a fractured femur, and the behavior of forces during reduction can be found. Visual and numerical output of forces and moments during simulated reduction procedures are provided. The output can be probed throughout the reduction procedure down to the individual muscle's contribution. This is achieved by construction of an anatomically correct three-dimensional mathematical model of the lower extremity and muscles. Parameters are fully customizable and can be used to investigate simple, oblique, and some comminuted fractures. Results were compared with published in vivo measurements and were of the same magnitude. A simple midshaft fracture had a maximum resulting force of 428 N, whereas traction from the hip reached a maximum value of 893 N at 60 mm of displacement. Monte Carlo analysis revealed that the deforming force was most sensitive to the muscles' rest lengths. The developed model provides greater understanding and detail than in vivo measurements have to date. It allows new treatment procedures to be developed and importantly to assess the outcome.

Análise de fraturas diafisárias do fêmur em crianças menores de 3 anos de idade / Femoral shaft fractures: an assessment in children younger than 3 years old

Este estudo consiste na reavaliação ortopédica e psicossocial de crianças que sofreram fratura do fêmur até a idade dos três anos e objetiva a análise de suas causas prováveis e detecção de indícios de ocorrência de Síndrome de Maus Tratos. Trinta e cinco crianças menores de três anos de idade sofreram fratura diafisária de fêmur e foram atendidas no Pronto Socorro do Serviço de Ortopedia e Traumatologia da Santa Casa de São Paulo, no período de janeiro de 1996 a agosto de 2002, sendo que 18 compareceram para reavaliação. Como causa relatada das fraturas observamos: queda em 13 (72,2 por cento) casos, queda de objetos sobre o membro em três (16,7 por cento) e fratura no parto em dois (11,1 por cento). Constatamos suspeita de Síndrome dos Maus Tratos em nove (maus tratos físicos em seis [33,3 por cento] e negligência em três [16,7 por cento]) casos, fratura patológica em quatro (22,2 por cento), causa acidental em três (16,7 por cento), e outras causas em dois (11,1 por cento) casos. Maus tratos constituem uma importante causa a ser investigada nos casos de fratura do fêmur em crianças com menos de três anos de idade, sendo o provável mecanismo responsável por metade das fraturas aqui estudadas.

This study consists of an orthopaedic and psychosocial re-evaluation of children who experienced femur fractures as young as 3 years old and aims to analyze potential causes and detect Child Abuse rates. Thirty-five children under the age of three years who experienced femoral shaft fractures received care at the Emergency Department of the Orthopaedics and Traumatology Service of Santa Casa de São Paulo within the period ranging from January, 1996 to August, 2002. Eighteen patients returned to the hospital for re-evaluation. The reported causes for fractures were: fall in 13 cases (72.2 percent), object fall on the limb in 2 cases (11.1 percent). Child abuse was suspected in 9 cases (physical abuse in 6 cases (33.3 percent), negligence in 3 cases (16.7 percent), pathological fracture in 4 cases (22.2 percent), accidental causes in 3 cases (16.7 percent), and other causes in 2 cases (11.1 percent). Child abuse constitutes an important cause that needs to be investigated in cases of femur fracture in children under the age of three years and this has possibly been the mechanism responsible for half of the fractures investigated in the current study.

Bone micro-damage assessment using non-linear resonant ultrasound spectroscopy (NRUS) techniques: a feasibility study.

Non-linear resonant ultrasound spectroscopy (NRUS) is a technique exploiting the significant non-linear behavior of damaged materials, related to the presence of damage. This study shows for the first time the feasibility of this technique for damage assessment in bone. Two samples of bovine cortical bone were subjected to a progressive damage experiment. Damage accumulation was progressively induced in the samples by mechanical testing. For independent assessment of damage, X-ray CT imaging was performed at each damage step, but only helped in the detection of the prominent cracks. Synchrotron micro-CT imaging and histology using epifluorescence microscopy were performed in one of the two samples at the last damage step and allowed detection of micro-cracks for this step. As the quantity of damage accumulation increased, NRUS revealed a corresponding increase in the non-linear response. The measured change in non-linear response is much more sensitive than the change in elastic modulus. The results suggest that NRUS could be a potential tool for micro-damage assessment in bone. Further work has to be carried out for a better understanding of the physical nature of damaged bone, and for the ultimate goal of in vivo implementation of the technique where bone access will be a challenging problem.

Outcome after femoral shaft fractures in the elderly: the effects of altitude.

BACKGROUND: A paucity of knowledge currently exists surrounding the effects of altitude on femur fracture outcomes. The purpose of this study was to determine if altitude plays a significant role in determining the outcome of femoral shaft fractures in the elderly. The authors hypothesized that the additional cardiopulmonary stress of altitude would promote poorer outcomes of those individuals treated at high altitude, especially those individuals whose home residence was located at low altitude. METHODS: Medicare part A claims data between 1996 and 2000 were searched and patients with open or closed femoral shaft fractures were identified for the study. The treatment altitude and home residence altitude for each patient was recorded by cross-matching Zip Code information provided in the Medicare part A database with a database providing altitude data by Zip Code. The patients were grouped both by the altitude of treatment and by the difference between the altitude of residence and the altitude of treatment. The data was analyzed for outcome measurements. RESULTS: The claims data search identified 30,168 patients for the study. For the entire sample, the in-hospital mortality was 4.2%, 30-day mortality was 8.3%, 1-year mortality was 26.3%, and complication rate was 5.7%. Length of stay results demonstrated that patients treated at medium or high altitude had statistically shorter lengths of stay than those treated at low altitude (p < 0.01). Mortality rates and complications were not statistically different for those treated at high, medium, or low altitude with the exception of a slightly lower in-hospital mortality in the medium treatment altitude group (p = 0.04). Additionally, those patients who resided more than 1000 ft below the treatment altitude had shorter lengths of stay than those who resided more than 1000 ft above the treatment altitude (p < 0.01). Those patients who lived within 1000 ft of the treatment hospital or more than 1000 ft below the treatment hospital had fewer days in the intensive care unit (p < 0.01, p = 0.01; respectively). CONCLUSIONS: Femoral shaft fractures treated at altitude were not associated with increased morbidity and mortality as compared to femoral shaft fractures treated at low altitude. Additionally, patients residing at low altitude and treated at high altitude did not suffer increased morbidity or mortality.

Management of complex tibial and femoral nonunion using the Ilizarov technique, and its cost implications.

We reviewed 78 femoral and tibial nonunions treated between January 1992 and December 2003. Of these, we classified 41 in 40 patients as complex cases because of infection (22), bone loss (6) or failed previous surgery (13). The complex cases were all treated with Ilizarov frames. At a mean time of 14.1 months (4 to 38), 39 had healed successfully. Using the Association for the Study and Application of the Methods of Ilizarov scoring system we obtained 17 excellent, 14 good, four fair and six poor bone results. The functional results were excellent in 14 patients, good in 14, fair in two and poor in two. A total of six patients were lost to follow-up and two had amputations so were not evaluated for final functional assessment. All but two patients were very satisfied with the results. The average cost of treatment to the treating hospital was approximately pound 30,000 per patient. We suggest that early referral to a tertiary centre could reduce the morbidity and prolonged time off work for these patients. The results justify the expense, but the National Health Service needs to make financial provision for the reconstruction of this type of complex nonunion.