Treatment strategies for proximal femur fractures in osteoporotic patients

Mapping the Spatial Evolution of Proximal Femur Osteoporosis: A Retrospective Cross-Sectional Study Based on CT Scans

Purpose

The purpose of this study was to quantify the modifications occurring in osteoporosis at the level of the human proximal femur throughout the trabecular structure, along with the identification of certain anatomic regions preferentially affected by osteoporosis. Another goal was to map the evolution of the radiodensity of the trabecular bone as osteoporosis progresses to an advanced stage.

Methods

The study included CT scans (right femur) from 51 patients, out of which 40 had various degrees of osteoporosis, but no other local pathology. Ten regions of interest in two orthogonal slices have been identified and the differences in radiodensity as well as their evolution have been statistically analyzed in terms of relative and absolute changes.

Results

A detailed spatial map showing the evolution of osteoporosis was obtained. As osteoporosis evolved, the relative decrease in radiodensity was inversely correlated to the radiodensity of the healthy bone. In particular, the region covering the Ward triangle decreased the most, by an average 61-62% in osteopenia and 101-106% in advanced osteoporosis, while the principal compressive group was affected the least, showing a decrease by an average 14-15% in osteopenia and 29-32% in advanced osteoporosis. The absolute decrease in radiodensity was not correlated to the radiodensity of the healthy bone and was shifted to the inferior-posterior edge of the femur. Inside the femoral head, the upper region was affected the most in absolute terms, while the greater trochanter was less affected than the femoral neck. The maximum metaphyseal cortical bone density was unaffected by the progression of osteoporosis.

Conclusion

Significant differences were noticed in terms of the absolute and relative osteoporotic changes in radiodensity related to different anatomical regions of the human femoral bone. These differences become more pronounced as the disease progresses.

Plain radiographic indices are reliable indicators for quantitative bone mineral density in male and female patients before total hip arthroplasty

Osteoporosis is underdiagnosed in patients undergoing total hip arthroplasty (THA). Bone mineral density measurement by dual-energy X-ray absorptiometry (DXA) is the gold standard, but indices on plain hip radiographs also seemed to be reliable screening tools in female or Asian ethnicities in previous studies. Given the lack of knowledge about male patients and Caucasian ethnicities, this study was conducted to evaluate plane hip radiographic indices as a screening tool for osteopenia and osteoporosis in Caucasian female and also male patients before undergoing THA. A retrospective analysis of 216 elderly patients with pre-existing DXA before hip arthroplasty was performed and four indices were calculated on plain hip radiographs: Canal-Flare-Index (CFI), Canal-Calcar-Ratio (CCR), Canal-Bone-Ratio (CBR) 7 and 10 cm below the lesser trochanter. They were correlated with femoral neck DXA T-scores by Pearson's correlation and intraclass correlation coefficient, and a ROC analysis was performed. A total of 216 patients (49.5% male) were included. CBR-7 and -10 were highly correlated (p < 0.001) with femoral neck T-score in males (Pearson's correlation CBR-7 r = - 0.60, CBR-10 r = - 0.55) and females (r = - 0.74, r = - 0.77). CBR-7 and -10 also showed good diagnostic accuracy for osteoporosis in the ROC analysis in males (CBR-7: AUC = 0.75, threshold = 0.51; CBR-10: 0.63; 0.50) and females (CBR-7: AUC = 0.87, threshold = 0.55; CBR-10: 0.90; 0.54). Indices such as the Canal Bone Ratio (CBR) 7 or 10 cm below the lesser trochanter on plain hip radiographs are a good screening tool for osteopenia and osteoporosis on plain hip radiographs and can be used to initiate further diagnostics like the gold standard DXA. They differ between male and female patients.

The bone-protective benefits of amino-conjugated calcium in an ovariectomized (OVX) rat model

Low bone density, fragility, and microarchitectural disintegration are the symptoms of osteoporosis. An imbalance between bone growth and resorption can lead to osteoporosis. This study evaluated the effects of amino-calcium (AC) on bone protection in ovariectomized control group (NC) rats. Amino-calcium (AC) was characterized using Fourier-transform infrared spectroscopy (FT-IR), energy-dispersive X-ray spectroscopy (EDS), and nuclear magnetic resonance spectroscopy analyses (NMR). After determining the biocompatibility of amino-calcium (AC) with MC3T3-E1 cells, alkaline phosphatase staining revealed significant changes on day 7. Three of the four groups underwent ovariectomy, whereas one group received a placebo. On micro-computed tomography, in vivo, data showed increased bone volume fraction in the femoral head and shaft areas in the amino-calcium (AC) group. Hematoxylin and eosin staining showed a bone mass and architectural protection in the amino-calcium (AC) group compared with the calcium carbonate and OVX control group. RNA sequencing analysis revealed high expression of osteogenesis-related genes in MC3T3-E1 cells. RNA sequencing revealed a significant fold change in the expression of integrin-binding sialoprotein (IBSP), bone gamma-carboxyglutamate proteins 1 and 2(BGLAP1 and BGLAP2), and periostin (POSTN). The study concluded that supplementing the OVX rats with calcium enhanced bone protection.

A comparative analysis of distal locked and unlocked long proximal femoral nail antirotation (PFNA-II) in the fixation of stable intertrochanteric fractures

PURPOSE

Long proximal femoral nail anti-rotation (PFNA-II) is a preferred implant in recent years for fixation of pertrochanteric fractures, especially in osteoporotic patients. The purpose of this study is to prospectively investigate the effect of distal locking in long PFNA-II fixation of stable intertrochanteric fractures.

METHODS

A total of 58 patients with isolated stable intertrochanteric fractures and treated in our hospital during the study period of 2017-2019 by distal locked or unlocked long PFNA-II fixation were included in this study. Patients who had multiple injuries or open fractures were excluded. There were 40 female and 18 male patients, with 33 affecting the left side and 25 the right side. Of them, 31 belonged to the distal locked group (group A) and 27 to the unlocked group (group B). Surgical procedures and implants used in both groups were similar except for the distal locking of the nails. General data (age, gender, fracture side, etc.) showed no significant difference between two groups (all p > 0.05). The intraoperative parameters like operative time, radiation exposure and follow-up parameters like functional and radiological outcomes were recorded and compared. Statistical tests like the independent samples t-test Fischer's exact and Chi-square test were used to analyze association.

RESULTS

The distribution of the fractures according to AO/OTA classification and 31A1.2 type of intertrochanteric fractures were most common in our study. All the included fractures united and the average functional outcome in both groups were good and comparable at the end of one year. The operative time (mL, 107.1 ± 12.6 vs. 77.0 ± 12.0, p < 0.001) and radiation exposure (s, 78.6 ± 11.0 vs. 40.3 ± 9.3, p < 0.001) were significantly less among the patients in group B. Fracture consolidation, three months after the operative procedures, was seen in a significantly greater proportion of patients in group B (92.6% vs. 67.7%, p = 0.025). Hardware irritation because of distal locking bolt was exclusively seen in group A, however this was not statistically significant (p = 0.241).

CONCLUSION

We conclude that, in fixation of stable intertrochanteric fractures by long PFNA-II nail, distal locking not only increases the operative time and radiation exposure but also delays the fracture consolidation and increases the chances of hardware irritation, and hence is not required.

Biomechanical analysis analyzing association between bone mineral density and lag screw migration

A proximal femoral nail using a helical blade (HB) is commonly utilized to treat proximal femoral fracture but cut through failure of the lag screws is one of the devastating complications following the surgery. While controversial, one of the potential risk factors for cut through failure is poor bone strength which can be predicted by measuring bone mineral density (BMD). In this study, we performed a biomechanical test on the fractured femoral head to validate whether the indirectly measured BMD from the contralateral hip or that measured directly from the retrieved femoral head can elucidate the structural strength of the fractured femoral head and thereby can be used to predict migration of lag screws. Our result showed that directly measured BMD has a significant correlation with the HB migration on the osteoporotic femoral head. However, while the BMDs measured from the contralateral femoral neck or total hip is the most widely used parameter to predict the bone strength of the fractured femur, this may have limited usability to predict HB migration.

Orthogeriatric co-management for the care of older subjects with hip fracture: recommendations from an Italian intersociety consensus

BACKGROUND

Health outcomes of older subjects with hip fracture (HF) may be negatively influenced by multiple comorbidities and frailty. An integrated multidisciplinary approach (i.e. the orthogeriatric model) is, therefore, highly recommended, but its implementation in clinical practice suffers from the lack of shared management protocols and poor awareness of the problem. The present consensus document has been implemented to address these issues.

AIM

To develop evidence-based recommendations for the orthogeriatric co-management of older subjects with HF.

METHODS

A 20-member Expert Task Force of geriatricians, orthopaedics, anaesthesiologists, physiatrists, physiotherapists and general practitioners was established to develop evidence-based recommendations for the pre-, peri-, intra- and postoperative care of older in-patients (≥ 65 years) with HF. A modified Delphi approach was used to achieve consensus, and the U.S. Preventive Services Task Force system was used to rate the strength of recommendations and the quality of evidence.

RESULTS

A total of 120 recommendations were proposed, covering 32 clinical topics and concerning preoperative evaluation (11 topics), perioperative (8 topics) and intraoperative (3 topics) management, and postoperative care (10 topics).

CONCLUSION

These recommendations should ease and promote the multidisciplinary management of older subjects with HF by integrating the expertise of different specialists. By providing a convenient list of topics of interest, they might assist in identifying unmet needs and research priorities.

Impact of Bone Cement Augmentation on the Fixation Strength of TFNA Blades and Screws

Background and Objectives: Hip fractures constitute the most debilitating complication of osteoporosis with steadily increasing incidences in the aging population. Their intramedullary nailing can be challenging because of poor anchorage in the osteoporotic femoral head. Cement augmentation of Proximal Femoral Nail Antirotation (PFNA) blades demonstrated promising results by enhancing cut-out resistance in proximal femoral fractures. The aim of this study was to assess the impact of augmentation on the fixation strength of TFN-ADVANCEDTM Proximal Femoral Nailing System (TFNA) blades and screws within the femoral head and compare its effect when they are implanted in centre or anteroposterior off-centre position. Materials and Methods: Eight groups were formed out of 96 polyurethane low-density foam specimens simulating isolated femoral heads with poor bone quality. The specimens in each group were implanted with either non-augmented or cement-augmented TFNA blades or screws in centre or anteroposterior off-centre positions, 7 mm anterior or posterior. Mechanical testing was performed under progressively increasing cyclic loading until failure, in setup simulating an unstable pertrochanteric fracture with a lack of posteromedial support and load sharing at the fracture gap. Varus-valgus and head rotation angles were monitored. A varus collapse of 5° or 10° head rotation was defined as a clinically relevant failure. Results: Failure load (N) for specimens with augmented TFNA head elements (screw/blade centre: 3799 ± 326/3228 ± 478; screw/blade off-centre: 2680 ± 182/2591 ± 244) was significantly higher compared with respective non-augmented specimens (screw/blade centre: 1593 ± 120/1489 ± 41; screw/blade off-centre: 515 ± 73/1018 ± 48), p < 0.001. For both non-augmented and augmented specimens failure load in the centre position was significantly higher compared with the respective off-centre positions, regardless of the head element type, p < 0.001. Augmented off-centre TFNA head elements had significantly higher failure load compared with non-augmented centrally placed implants, p < 0.001. Conclusions: Cement augmentation clearly enhances the fixation stability of TFNA blades and screws. Non-augmented blades outperformed screws in the anteroposterior off-centre position. Positioning of TFNA blades in the femoral head is more forgiving than TFNA screws in terms of failure load.

A novel method for intraoperative osseomechanical strength measurements: a biomechanical ex vivo evaluation on proximal femora

INTRODUCTION

The increasing number of geriatric traumatology cases has intensified the need to reliably and objectively evaluate local bone quality, the latter poses a decisive factor for the choice of an optimal approach to treat osteoporotic fractures. Osteodensitometry imaging techniques are not routinely available in acute operative settings, nor do they provide objective information on local bone properties specifically needed for the prognosis of implant stability.

MATERIALS AND METHODS

This study sought to verify ex vivo the feasibility and sensitivity of a novel method for the determination of local bone strength in the acute operative setting (intraoperative osseomechanical strength measurement; IOSM) that is based on the principle of material displacement resistance against the force of a rotary indenter. Samples consisted of human femoral heads obtained after total hip replacement. Comparisons were made with results obtained via conventional dual-energy X-ray absorptiometry (DXA) and quantitative computed tomography (qCT).

RESULTS

Regression analyses of the results showed a highly significant correlation between the IOSM and the control methods (r = 0.61 and r = 0.56; p < 0.01), indicating that this new approach qualifies as a reliable tool for the intraoperative evaluation of the intrinsic local bone strength.

CONCLUSIONS

The intraoperative integration of this method may support surgeon on taking proper decisions in terms of optimal surgical approaches and prevention of complications inherent to osteoporotic bone.

Clinical outcomes of PFNA-II in the Asian intertrochanteric fracture patients: Comparison of clinical results according to proximal nail protrusion

PURPOSE

This study intended to explore the clinical outcomes of PFNA-II, one of the commonly used fixation devices for intertrochanteric fractures and the association of clinical results with the extent of proximal nail protrusion.

MATERIALS AND METHODS

Of 315 cases that underwent internal fixation using PFNA-II between September 2010 and June 2018 among intertrochanteric fracture patients aged over 65 years, a total of 86 patients with an ability to communicate clearly and a minimum follow-up of 6 months were retrospectively reviewed. We classified the subjects according to PFNA-II protrusion over the greater trochanter area on anteroposterior radiographs. Differences between the two groups were examined by comparing demographic characteristics including gender, age, height, weight and BMI, instrumental characteristics including PFNA nail size, nail diameter, blade length and blade position, radiologic characteristics including reduction quality, Dorr type and bone union, and clinical characteristics including GT pain,VAS score and Harris Hip Score (HHS).

RESULTS

A total of 86 cases were divided into 30 (34.9%) in the protrusion group (group A) and 56 (65.1%) in the non-protrusion group (group B). No significant difference was found in demographic characteristics such as gender, age, height, weight and BMI between the two groups. Two groups had no statistically significant difference in PFNA nail length, nail diameter and blade length, but showed a statistically significant difference in blade position. At the latest follow-up, the mean HHS shows no statistically significant difference between the two groups. On the contrary, the number of patients complaining of GT pain and VAS score were statistically significantly higher in group A. Removal of metal implants was performed in two patients in the protrusion group due to a complaint of persistent GT pain.

CONCLUSION

Nail protrusion over the greater trochanter area occurs frequently after the surgical treatment of intertrochanteric fracture using PFNA-II. When the nail protruded into the greater trochanter, the number of patients who clinically complained of pain was statistically significantly high. We recommend a modification to the PFNA-II that would further shorten the proximal nail end suitable for the Asian population to achieve better clinical results in the fixation of intertrochanteric fractures.

Hepatitis C is an Independent Risk Factor for Perioperative Complications and Nonroutine Discharge in Patients Treated Surgically for Hip Fractures

OBJECTIVE

To evaluate the relationship between noncirrhotic hepatitis C virus (HCV) infection, perioperative complications, and discharge status in patients undergoing surgical procedures for hip fractures.

METHODS

A retrospective epidemiological study was performed, querying the National Hospital Discharge Survey. Patients were selected using the International Classification of Diseases-9 diagnostic codes for hip fracture and primary procedural codes for open reduction internal fixation, hemiarthroplasty, total hip arthroplasty, or internal fixation. Patients with concurrent cirrhosis, HIV, hepatitis A, B, D, or E were excluded. Pearson χ tests, independent-samples t test, and multivariable binary logistic regression were used for data analysis.

RESULTS

Two cohorts surgically treated for a hip fracture were identified and compared. The first cohort included 5377 patients with a concurrent diagnosis of noncirrhotic HCV infection (HCV+) and the second included 4,712,159 patients without a diagnosis of HCV (HCV-). The HCV+ cohort was younger and had fewer medical comorbidities, yet was found to have a longer length of hospital stay, higher rates of nonroutine discharge, and higher rates of complications than the HCV- cohort. Multivariate regression analysis demonstrated that HCV+ is an independent risk factor for perioperative complications and nonroutine discharge.

CONCLUSIONS

In conclusion, our study demonstrates a negative association between noncirrhotic HCV infection and hip fracture surgery outcomes. Caution and appropriate preparation should be taken when surgically treating hip fractures in HCV+ patients because of higher risk of perioperative complications and nonroutine discharge.

LEVEL OF EVIDENCE

Prognostic Level III. See Instructions for Authors for a complete description of levels of evidence.

Better is the foe of good: Outcome of operatively treated ankle fractures in the elderly

BACKGROUND

Ankle fractures are the second most common fractures of the lower extremities. Nonetheless, no standardized treatment protocol for unstable ankle fractures of the elderly exists today. Choices to treat ankle fractures are debated controversially, including (1) conservative treatment, (2) open reduction and internal fixation (ORIF), and (3) primary hind-foot arthrodesis. This retrospective study aimed to examine the healing result in patients treated by ORIF after unstable ankle fractures.

METHODS

The study was designed as a retrospective comparative series. The American Orthopaedic Foot and Ankle Society (AOFAS) score was followed to assess the postsurgical outcome. Data was obtained from 66 patients younger than 65 (median age, 42 years; range, 18-63) and 28 patients aged 65 or older (median age, 71 years; range, 65-81). The mean follow-up period for the younger-than-65 group was 48 months; for patients older than 65, it was 49 months.

RESULTS

An AOFAS score of 86.4 in the older and 92.4 in the younger group was determined, p-value<0.05. Elderly patients suffered from significantly more open-ankle fractures and comorbidities than the younger group did, p-value<0.05 each. The duration of hospital stay and the time needed to reach sufficient self-mobilization were both significantly different between the two groups, p-value<0.05.

CONCLUSION

ORIF treatment of ankle fractures resulted in good functional assessment after a mean follow-up of 49 months in the elderly. Pre-fracture health condition positively affected the healing results in younger patients. This study confirms the basic AO Foundation principles for good postsurgical results.

LEVEL OF EVIDENCE

Level III, retrospective comparative series.

Achievable accuracy of hip screw holding power estimation by insertion torque measurement

BACKGROUND

To ensure stability of proximal femoral fractures, the hip screw must firmly engage into the femoral head. Some studies suggested that screw holding power into trabecular bone could be evaluated, intraoperatively, through measurement of screw insertion torque. However, those studies used synthetic bone, instead of trabecular bone, as host material or they did not evaluate accuracy of predictions. We determined prediction accuracy, also assessing the impact of screw design and host material.

METHODS

We measured, under highly-repeatable experimental conditions, disregarding clinical procedure complexities, insertion torque and pullout strength of four screw designs, both in 120 synthetic and 80 trabecular bone specimens of variable density. For both host materials, we calculated the root-mean-square error and the mean-absolute-percentage error of predictions based on the best fitting model of torque-pullout data, in both single-screw and merged dataset.

FINDINGS

Predictions based on screw-specific regression models were the most accurate. Host material impacts on prediction accuracy: the replacement of synthetic with trabecular bone decreased both root-mean-square errors, from 0.54 ÷ 0.76 kN to 0.21 ÷ 0.40 kN, and mean-absolute-percentage errors, from 14 ÷ 21% to 10 ÷ 12%. However, holding power predicted on low insertion torque remained inaccurate, with errors up to 40% for torques below 1 Nm.

INTERPRETATION

In poor-quality trabecular bone, tissue inhomogeneities likely affect pullout strength and insertion torque to different extents, limiting the predictive power of the latter. This bias decreases when the screw engages good-quality bone. Under this condition, predictions become more accurate although this result must be confirmed by close in-vitro simulation of the clinical procedure.

Epidemiology of Bone Fracture in Female Trauma Patients Based on Risks of Osteoporosis Assessed using the Osteoporosis Self-Assessment Tool for Asians Score

Background: Osteoporotic fractures are defined as low-impact fractures resulting from low-level trauma. However, the exclusion of high-level trauma fractures may result in underestimation of the contribution of osteoporosis to fractures. In this study, we aimed to investigate the fracture patterns of female trauma patients with various risks of osteoporosis based on the Osteoporosis Self-Assessment Tool for Asians (OSTA) score. Methods: According to the data retrieved from the Trauma Registry System of a Level I trauma center between 1 January 2009 and 31 December 2015, a total of 6707 patients aged ≥40 years and hospitalized for the treatment of traumatic bone fracture were categorized as high-risk (OSTA < -4, n = 1585), medium-risk (-1 ≥ OSTA ≥ -4, n = 1985), and low-risk (OSTA > -1, n = 3137) patients. Two-sided Pearson's, chi-squared, or Fisher's exact tests were used to compare categorical data. Unpaired Student's t-test and Mann-Whitney U-test were used to analyze normally and non-normally distributed continuous data, respectively. Propensity-score matching in a 1:1 ratio was performed with injury mechanisms as adjusted variables to evaluate the effects of OSTA-related grouping on the fracture patterns. Results: High- and medium-risk patients were significantly older, had higher incidences of comorbidity, and were more frequently injured from a fall and bicycle accident than low-risk patients did. Compared to low-risk patients, high- and medium-risk patients had a higher injury severity and mortality. In the propensity-score matched population, the incidence of fractures was only different in the extremity regions between high- and low-risk patients as well as between medium- and low-risk patients. The incidences of femoral fractures were significantly higher in high-risk (odds ratio [OR], 3.4; 95% confidence interval [CI], 2.73-4.24; p < 0.001) and medium-risk patients (OR, 1.4; 95% CI, 1.24-1.54; p < 0.001) than in low-risk patients. In addition, high-risk patients had significantly lower odds of humeral, radial, patellar, and tibial fractures; however, such lower odds were not found in medium- risk than low-risk patients. Conclusions: The fracture patterns of female trauma patients with high- and medium-risk osteoporosis were different from that of low-risk patients exclusively in the extremity region.

A novel in silico method to quantify primary stability of screws in trabecular bone

Insufficient primary stability of screws in bone leads to screw loosening and failure. Unlike conventional continuum finite-element models, micro-CT based finite-element analysis (micro-FE) is capable of capturing the patient-specific bone micro-architecture, providing accurate estimates of bone stiffness. However, such in silico models for screws in bone highly overestimate the apparent stiffness. We hypothesized that a more accurate prediction of primary implant stability of screws in bone is possible by considering insertion-related bone damage. We assessed two different screw types and loading scenarios in 20 trabecular bone specimens extracted from 12 cadaveric human femoral heads (N = 5 for each case). In the micro-FE model, we predicted specimen-specific Young's moduli of the peri-implant bone damage region based on morphometric parameters such that the apparent stiffness of each in silico model matched the experimentally measured stiffness of the corresponding in vitro specimen as closely as possible. The standard micro-FE models assuming perfectly intact peri-implant bone overestimated the stiffness by over 330%. The consideration of insertion related damaged peri-implant bone corrected the mean absolute percentage error down to 11.4% for both loading scenarios and screw types. Cross-validation revealed a mean absolute percentage error of 14.2%. We present the validation of a novel micro-FE modeling technique to quantify the apparent stiffness of screws in trabecular bone. While the standard micro-FE model overestimated the bone-implant stiffness, the consideration of insertion-related bone damage was crucial for an accurate stiffness prediction. This approach provides an important step toward more accurate specimen-specific micro-FE models. © 2017 Orthopaedic Research Society. Published by Wiley Periodicals, Inc. J Orthop Res 35:2415-2424, 2017.

Association of Osteoporosis Self-Assessment Tool for Asians (OSTA) Score with Clinical Presentation and Expenditure in Hospitalized Trauma Patients with Femoral Fractures

Background: A cross-sectional study to investigate the association of Osteoporosis Self-Assessment Tool for Asians (OSTA) score with clinical presentation and expenditure of hospitalized adult trauma patients with femoral fractures. Methods: According to the data retrieved from the Trauma Registry System between 1 January 2009 and 31 December 2015, a total of 2086 patients aged ≥40 years and hospitalized for treatment of traumatic femoral bone fracture were categorized as high-risk patients (OSTA < -4, n = 814), medium-risk patients (-1 ≥ OSTA ≥ -4, n = 634), and low-risk patients (OSTA > -1, n = 638). Two-sided Pearson's, chi-squared, or Fisher's exact tests were used to compare categorical data. Unpaired Student's t-test and Mann-Whitney U-test were used to analyze normally and non-normally distributed continuous data, respectively. Propensity-score matching in a 1:1 ratio was performed using Number Crunching Statistical Software (NCSS) software (NCSS 10; NCSS Statistical Software, Kaysville, UT, USA), with adjusted covariates including mechanism and Glasgow Coma Scale (GCS); injuries were assessed based on the Abbreviated Injury Scale (AIS), and Injury Severity Score (ISS) was used to evaluate the effect of OSTA-related grouping on a patient's outcome. Results: High-risk and medium-risk patients were predominantly female, presented with significantly older age and higher incidences of co-morbidity, and were injured in a fall accident more frequently than low-risk patients. High-risk patients and medium-risk patients had a different pattern of femoral fracture and a significantly lower ISS. Although high-risk and medium-risk patients had significantly shorter lengths hospital of stay (LOS) and less total expenditure than low-risk patients did, similar results were not found in the selected propensity score-matched patients, implying that the difference may be attributed to the associated injury severity of the patients with femoral fracture. However, the charge of surgery is significantly lower in high-risk and medium-risk patients than in low-risk patients, regardless of the total population or the selected propensity score-matched patients. This lower charge of surgery may be attributed to a less aggressive surgery applied for older patients with high or medium risk of osteoporosis. Conclusions: This study of hospitalized trauma patients with femoral fracture according to OSTA risk classification revealed that high-risk and medium-risk patients had significantly higher odds of sustaining injury in a fall accident than low-risk patients; they also present a different pattern of femoral bone fracture as well as a significantly lower ISS, shorter hospital LOS, and less total expenditure. In addition, the significantly lower charge of surgery in high-risk and medium-risk patients than in low-risk patients may be because of the preference of orthopedists for less aggressive surgery in dealing with older patients with osteoporotic femoral bone fracture.

A meta-analysis of percutenous compression plate versus intramedullary nail for treatment of intertrochanteric HIP fractures

INTRODUCTION

Intertrochanteric hip fracture is associated with increased morbidity. Currently, a dramatic change in practice was demonstrated, with the intramedullary fixation rate increasing, despite a lack of evidence in the literature supporting the change. As a minimally invasive technique, percutaneous compression plating (PCCP) has been advocated to reduce blood loss, relieve pain, and lead to faster rehabilitation for treatment of intertrochanteric hip fractures. The purpose of this meta-analysis was to estimate the outcomes and complications of the PCCP versus intramedullary nail (IMN) fixation for intertrochanteric fractures.

METHODS

A comprehensive search of related literature was conducted to identify all articles in Medline, Embase, Scopus, Research Gate, and the Cochrane Central Register of Controlled Trials published on or between January 1998 and January 2016. All studies that compared PCCP with IMN in treating adult patients with intertrochanteric fractures were included. Main outcomes about the two fixation method were collected and analysised using the Review Manager 5.1 provided by The Cochrane Collaboration.

RESULTS

Six trials involving 908 fractures met the inclusion criteria. Compared with IMN, PCCP had similar operation time, intraoperative blood loss, mortality, system complications, function score, function recovery, and reoperation rate (P > 0.05). But hospital stay, transfusion need, and incidence of implant-related complications significantly favored the PCCP (P < 0.05).

CONCLUSIONS

The PCCP was associated with less transfusion need, reduced hospital stay, and fewer incidence of implant-related complications compared with IMN. Although a change in practice was occurred, the patients treated with IMN seemed to face the potential for more complications. Owing to the limitations of this systematic review, more high-quality randomized controlled trials (RCTs) are still needed to confirm this conclusion.

Load distribution between cephalic screws in a dual lag screw trochanteric nail

BACKGROUND

It has been observed clinically that the Z-effect is a potential cause of failure of an intramedullary nail with two cephalic screws. It describes the migration behavior of the cephalic screws in the femoral head. The primary objective was to examine different cephalic screw configurations and test the load distribution between them as a function of their relative placement and their relative movement in the nail. It has been hypothesized that different cephalic screw positions may have an influence on the stress in the implant and bone and therefore on implant failures, such as the Z-effect.

METHODS

To quantify the load distribution of a dual cephalic screw intramedullary femoral nail (Citieffe, Calderara di Reno, BO, Italy), a finite element model of the femur, focusing on the loading of the cephalic screws, was prepared. Four different screw lengths (90-105 mm) were examined. The investigation considered the stresses and strains in the bone and implant as well as the relative movement of the screws.

RESULTS

If the inferior cephalic screw had a shorter length, then the superior one and the femoral nail had to bear higher loads. In that case, the "equivalent von Mises stress" increased up to 10 % at the superior cephalic screw and up to 5 % at the femoral nail. The analysis of the relative movement showed that sliding of the inferior cephalic screw occurred in the nail. The total movement ranged from 0.47 to 0.73 mm for the different screw configurations.

CONCLUSIONS

The stresses were distributed more equally between the two cephalic screws in the bone and the implant if a longer inferior screw was used. The stresses in the bone and implant were reduced with a longer inferior cephalic screw. Therefore, a configuration using a longer inferior cephalic screw is preferable for trochanteric fracture fixation with a dual cephalic screw intramedullary device.

Fast and easy preoperative estimation of cancellous bone mineral density in patients with proximal femur fractures

INTRODUCTION

Postoperative complications after hip fractures in osteoporotic bone such as implant cutout can be reduced by the use of specially designed implants or additional cement augmentation. It is not yet clear at which degree of osteoporosis, patients will profit from implant augmentation or specially designed implants for geriatric patients. As the surgeon ideally should obtain information on local bone quality at the site of implant anchorage already preoperatively, the aim of the study was to develop an easily applicable radiographic method to estimate bone quality in those patients.

MATERIALS AND METHODS

75 patients with unilateral hip fracture were included. Preoperatively, a CT scan with a calibration device was conducted. Postoperatively, DXA scans were performed. The proposed method measures local cancellous bone mineral density in the contralateral and uninjured femoral head. As a control, 15 young and healthy non-osteoporotic subjects were included. Inter- and intraobserver reliability was investigated for a subgroup of 20 patients.

RESULTS

Study group patients had a mean BMD measured by CT scans of 194.2 mg/cm(3) (SD 40.4). There was a statistically significant correlation with data from DXA scans (r = 0.706, p < 0.001). The control group was significantly younger and showed a significantly higher BMD when compared to the study group (p < 0.001). Reliability evaluation showed no statistically significant difference in inter- and intraobserver measurements. Interclass correlation proved to be very high.

CONCLUSION

The proposed method is an easily applicable, reliable and useful tool to estimate bone quality preoperatively using the contralateral hip as a reference. Obtained data may facilitate the decision-making towards the use of further therapeutic measures to improve implant anchorage in osteoporotic bone such as bone cement augmentation. Thus, our method allows for a more individualized surgical treatment of hip fracture patients adapted to the estimated cancellous bone quality of the patient.

Are radiographic indices reliable indicators for quantitative bone mineral density and vitamin D status after femoral neck fractures? A retrospective study in 112 elderly patients

BACKGROUND

Radiographic parameters and indices obtained from hip x-rays are a potential tool to promptly estimate bone quality in elderly hip fracture patients. Preoperative decision in whether to use cemented or cement augmented implants might be supported by this information and thus improve patient safety. Subsequently, this study was conducted to evaluate radiographic parameters as a prescreening tool for bone quality.

METHODS

A retrospective analysis of 112 elderly patients with a femoral neck fracture after low-energy trauma was performed (81 % female, 19 % male). Three radiological indices were calculated on hip x-rays: cortical index antero-posterior CTI (ap), cortical index lateral CTI (lat) and canal to calcar ratio CCR. These indices were analyzed for correlations with DXA T-Scores and serum 25-hydroxyvitamin D (25(OH)D) using the Spearman test.

RESULTS

Median age of patients was 80 (IQR 72-86) years. A linear correlation was found for CTI (lat) and T-Score at the total hip (p < 0.001, r = 0.589), femoral neck (p = 0.005, r = 0.405) and the lumbar spine (p = 0.002, r = 0.299). A significant correlation was also indicated between CTI (lat) and 25(OH)D (p = 0.002, r = 0.293). CTI (lat) at a cut-off level of 0.4 showed a sensitivity of 79 % and a specificity of 56 % in predicting a T-score ≤ -2.5 at the total hip. Gender specific analysis revealed a higher sensitivity (100 %) and specificity (73 %) of CTI (lat) at a cut-off level of 0.4 for men. For severe vitamin D deficiency (<10 ng/ml) sensitivity and specificity were 75 % and 65 %.

CONCLUSION

Radiographic indices as the CTI (lat) exhibit a direct correlation to BMD and serum 25OH vitamin D levels. A CTI (lat) cut-off level of 0.4 is recommended for identifying patients at risk of osteoporosis expressed by T-Scores ≤ -2.5 and severe vitamin D deficiency.

Trabecular bone strength is not an independent predictive factor for dynamic hip screw migration--A prospective multicenter cohort study

This study assessed whether mechanically measured trabecular bone strength is an independent predictor of dynamic hip screw (DHS) stability, i.e., DHS migration (DHSM) after the fixation of proximal femoral fractures. One-hundred and seven patients older than 50 years with proximal femoral fractures were included. During fracture fixation, a mechanical probe (DensiProbe™ Hip) was inserted at the site where the DHS tip would ultimately be positioned. Peak torque to breakaway the trabecular bone was measured. Fracture reduction, primary implant position and postoperative DHSM were assessed by radiographs taken postoperatively, at 6 and 12 weeks after surgery. Univariate regression analysis revealed no association between peak torque and DHSM (R(2) = 0.025, p = 0.135). DHSM correlated with the primary DHS position, i.e., the distance between the DHS and (i) the central femoral neck axis (CNFAD, R(2) = 0.230; p < 0.0001) and (ii) the apex of the femoral head (R(2) = 0.110; p = 0.001). DHSM did not correlate with areal BMD of the contralateral proximal femur. Multivariable regression modeling revealed the CFNAD as predictive factor for screw migration. The primary implant position measured by the CFNAD, rather than DensiProbe™ Hip measured bone strength, is an independent predictor of DHSM.

External fixation in the elderly

Orthopaedic trauma is an increasingly common problem in geriatric patients. As demands of daily life and recreational activities are increasing in these patients, surgeons need to be able to manage geriatric fractures to achieve good functional results. Reduced bone quality in the elderly presents a considerable challenge and may preclude the use of established surgical stabilisation techniques that are performed in younger trauma patients. Furthermore, pre-existing medical conditions and considerable comorbidities in the elderly could complicate standard surgical procedures that younger patients would be offered. In this respect, application of external fixators represents a validated, minimally-invasive treatment opportunity. This review article summarises the use of external fixation in geriatric trauma patients for wrist fractures, proximal femoral fractures, pelvic fractures, and ankle fractures. Modern modifications, like pin coating with hydroxyapatite, and aspects of pin care will be discussed.

Assessing Bone Mineral Density Following Acute Hip Fractures: The Role of Computed Tomography Attenuation

OBJECTIVES

In older patients, bone mineral density (BMD) diminishes with age, increasing susceptibility to femoral neck fractures. Evidence has emerged that patients who should have dual x-ray absorptiometry scans to evaluate their bone health are not doing so. Because computed tomography (CT) attenuation has now been correlated with BMD thresholds relating to osteoporosis, virtually any existing CT scan that includes the L1 vertebra can be used to assess BMD. This study evaluates the utility of CT attenuation in characterizing BMD in patients after femoral neck fractures.

METHODS

The electronic medical records of adults who presented to a level I trauma center with hip fractures were evaluated for eligibility. Those with a CT scan of the abdomen or other CT scan with a complete view of the L1 vertebra were included. To measure attenuation, a region of interest was selected to include the body of the L1 vertebra in the axial plane and exclude the cortices and posterior venous complex.

RESULTS

Of the 589 patients reviewed, 217 met inclusion criteria; 112 were aged 18 to 64, while 105 were ≥65. Eight (7.1%) patients in the younger cohort had a mean CT attenuation below the 110-HU threshold set for 90% specificity, whereas 31 (29.5%) patients in the older cohort had a mean CT attenuation below this threshold. Using the 160-HU threshold set for 90% sensitivity, 39 (34.8%) patients of the younger cohort and 74 (70%) patients of the older cohort were osteoporotic; all differences in CT attenuation by age were strongly significant (P < .0001).

CONCLUSIONS

A significantly larger proportion of older patients with hip fractures had osteoporosis, helping validate the utility of CT attenuation in this context. In addition, a large proportion of these patients already had these images available, thus potentially helping limit cost and unnecessary medical investigations.

Distal locked and unlocked nailing for perthrochanteric fractures--a prospective comparative randomized study

PURPOSE

Intramedullary nailing is widely used in the treatment of stable pertrochanteric fractures. However, it remains controversial whether the distal locking with intramedullary nailing is necessary.

METHOD

In this study, 70 patients over the age of 65 with pertrochanteric fractures (AO/OTA 31-A1 and A2) were enrolled and randomly divided into two groups for treatment by intramedullary nails either with or without distal locking. Intra-operative variables such as operation time, volume of blood loss, total fluoroscopy time, total length of incision, postoperative complications and clinical outcomes were recorded and compared between the two groups.

RESULTS

A total of 29 patients in the locking group and 30 patients in the unlocking group completed one year of follow up. Operation time (39.2 ± 7.6 min), blood loss (158.6 ± 63.6 ml), fluoroscopy time (53.7 ± 3.9 s), and total length of incision (13.1 ± 2.1 cm) in the unlocking group were significantly decreased compared with the locking group (48.5 ± 9.0 min; 194.3 ± 61.6 ml; 57.8 ± 4.3 s; 10.9 ± 1.7 cm) (p < 0.05). No significant differences in postoperative complications and fracture union were identified between the two groups. Most patients in the locking group (80.0 %) and the unlocking group (77.1 %) recovered to their pre-injury activity levels.

CONCLUSION

This study suggests that intramedullary nails without distal locking may be a reliable and acceptable option for treating stable pertrochanteric fractures (AO/OTA 31-A1 and A2) in elderly people. Distal unlocked nails showed subtle advantages in reducing blood loss, operation time, fluoroscopy exposure time, and size of the incision.

Outcomes of Geriatric Hip Fractures Treated with AFFIXUS Hip Fracture Nail

Geriatric hip fractures are one of the commonest fractures worldwide. The purpose of this study was to report the outcomes of a series of unstable geriatric hip fractures treated with AFFIXUS hip fracture nail. A retrospective study of 100 unstable geriatric hip fractures treated with AFFIXUS hip fracture nail is presented. The mean follow-up duration was 8 months (range 3-32). Of the patients 83% were female. The average age was 85 years. The fracture was treated by closed reduction and intramedullary fixation. The mean acute hospital stay was 17.6 days. Systemic complications occurred in 29 patients (29%) and local complications in 3 patients (3%) including lag screw cutout in one patient (1%), lag screw backout in one patient (1%), and deep infection in one patient (1%). Mechanical failures and periprosthetic fractures were not observed in our series. Fractures united in all patients. Preinjury activity level was recovered in 78% of the patients. The results of AFFIXUS hip fracture nail were satisfactory in most elderly patients. The unique design of the lag screw and its thread spacing had effectively reduced cut-out rate.

The PFNA® Augmented in Revision Surgery of Proximal Femur Fractures

Objectives:

Modern implants for proximal femur fracture treatment have clearly improved clinical results. However, complications, including cut-out and loss of reduction, requiring revision surgery still occur. A major challenge in these cases is a loss of bone stock due to the existing implant, which is usually exacerbated by osteoporosis. A potential solution is the augmentation of implants, for example, of the femoral neck blade using bone cement.

Materials and Methods:

Ten patients (five loosening of femoral neck implant, two pseudarthrosis, two implant failures and one acute fracture) were included. The initial hardware was removed and a PFNA augmented was implanted. The perforated femoral neck blade was augmented using polymethyl methacrylate cement. Clinical and radiological follow-up was performed at a mean of 5.4 months (SD ±4.34). The main outcome parameters were fracture healing and implant-related complications.

Results:

Technical handling was uneventful in all cases. No cement leakage into the joint occurred in any of the cases. The mean amount of cement injected was 5.3 ml. The fracture healed during follow-up in all cases except two patients who died from causes unrelated to the procedure and prior to complete consolidation. Problem-free elective hardware removal of the PFNA augmented was performed in two cases.

Discussion:

The PFNA augmented is a potential implant for joint-preserving revision surgery in proximal femur fractures. The augmentation improves implant anchorage in the impaired bone stock. In this preliminary series, no negative biological side effects of the cement (i.e. osteonecrosis) were observed.

Outcomes of trochanteric femoral fractures treated with proximal femoral nail: an analysis of 100 consecutive cases

Purpose

In this study, we aimed to report the results of a retrospective study carried out at our institute regarding cases of patients who had suffered proximal femoral fractures between January 2002 and February 2007, and who were treated with a proximal femoral nail.

Materials and methods

One hundred consecutive cases were included in the study. A case documentation form was used to obtain intraoperative data including age, sex, mechanism of injury, type of fracture according to Association for Osteosynthesis/Association for the Study of Internal Fixation (AO/ASIF) classification and the American Society of Anesthesiologists’ (ASA) physical status classification (ASA grade). Clinical and radiographic examinations were performed at the time of admission and at the 6th week; subsequent visits were organized on the 3rd month, 6th month, and 12th month, and in patients with longer follow-up and annually postoperatively. The Harris score of hip function was used, and any change in the position of the implants and the progress of the fracture union, which was determined radiologically, was noted.

Results

The mean age of the patients was 77.66 years (range: 37–98 years), and the sex distribution was 32 males and 68 females. Seventy-three fractures were reduced by closed means, whereas 27 needed limited open reduction. The mean follow-up time for the study group was 31.3 months (range: 12–75 months). Postoperative radiographs showed a near-anatomical fracture reduction in 78% of patients. The Harris hip score was negatively correlated with the ASA score and patient age. No cases of implant failure were observed. Three patients died before discharge (one due to pulmonary embolism, two due to cardiac arrest), and five patients died due to unrelated medical conditions within the first 3 months of the follow-up.

Conclusion

Our study showed that proximal femoral nail is a reliable fixation with good fracture union, and it is not associated with major complications in any type of trochanteric femoral fracture.

Percutaneous compression plate versus dynamic hip screw for treatment of intertrochanteric Hip fractures: a meta-analyse of five randomized controlled trials

BACKGROUND

Percutaneous compression plating (PCCP) has been advocated to reduce blood loss, relieve pain, and lead to faster rehabilitation for the treatment of intertrochanteric fractures. The purpose of this meta-analysis was to estimate the outcomes and complications of the PCCP versus dynamic hip screw (DHS) fixation for intertrochanteric fractures.

METHODS

All randomized controlled trials (RCT) that compared PCCP with DHS in treating adult patients with intertrochanteric fractures were included. Main outcomes were collected and analysed using the RevMan 5.1 version.

RESULTS

Five trials met the inclusion criteria. Compared with DHS, PCCP had similar operation time (95% CI: -26.01~4.05, P = 0.15), length of hospitalization (95% CI: -1.79~1.25, P = 0.73), mortality (95% CI: 0.37~1.02, P = 0.06), incidence of implant-related complications (95% CI: 0.29~1.82, P = 0.49), and reoperation rate (95% CI: 0.41~3.05, P = 0.83). But blood loss (95% CI: -173.84~-4.81, P = 0.04) and transfusion need (95% CI: -0.53~-0.07, P = 0.01) significantly favored the PCCP.

CONCLUSIONS

The PCCP was associated with reduced blood loss and less transfusion need, but similar to DHS in other respects. Owing to the limitations of this systematic review, more high-quality RCTs are still needed to assess the clinical efficiency of PCCP.

Low bone mineral density is not related to failure in femoral neck fracture patients treated with internal fixation

BACKGROUND AND PURPOSE

Internal fixation (IF) in femoral neck fractures has high reoperation rates and some predictors of failure are known, such as age, quality of reduction, and implant positioning. Finding new predictors of failure is an ongoing process, and in this study we evaluated the importance of low bone mineral density (BMD).

PATIENTS AND METHODS

140 consecutive patients (105 females, median age 80) treated with IF had a dual-energy X-ray absorptiometry (DXA) scan of the hip performed median 80 days after treatment. The patients' radiographs were evaluated for fracture displacement, implant positioning, and quality of reduction. From a questionnaire completed during admission, 2 variables for comorbidity and walking disability were chosen. Primary outcome was low hip BMD (amount of mineral matter per square centimeter of hip bone) compared to hip failure (resection, arthroplasty, or new hip fracture). A stratified Cox regression model on fracture displacement was applied and adjusted for age, sex, quality of reduction, implant positioning, comorbidity, and walking disability.

RESULTS

49 patients had a T-score below -2.5 (standard deviation from the young normal reference mean) and 70 patients had a failure. The failure rate after 2 years was 22% (95% CI: 12-39) for the undisplaced fractures and 66% (CI: 56-76) for the displaced fractures. Cox regression showed no association between low hip BMD and failure. For the covariates, only implant positioning showed an association with failure.

INTERPRETATION

We found no statistically significant association between low hip BMD and fixation failure in femoral neck fracture patients treated with IF.

Failure after osteosynthesis of trochanteric fractures. Where is the limit of osteoporosis?

SUMMARY

The aim of this study is to identify osteoporosis values, beyond which there is a high risk of osteosynthesis failure. Bone mineral density (BMD) of 30 cadaveric femora with a pertrochanteric fracture osteotomy was correlated to the risk of cut out after osteosynthesis on a biomechanical testing approach. For a BMD less than 250 mg/cm(3), there is a high risk of fixation failure after surgical treatment of pertrochanteric fractures. This value can be regarded as a reference value for future experimental and clinical studies.

INTRODUCTION

Despite continuous modification of intramedullary load carriers for the surgical stabilization of trochanteric fractures, cut out remains the most frequent complication. The aim of this experimental study was to identify threshold osteoporosis values, beyond which there is a high risk of osteosynthesis failure.

METHODS

Bone mineral density (BMD) of 30 cadaveric femora was recorded for the femoral head by QCT measurement. Subsequently, a standardized osteotomy mimicking an unstable trochanteric type fracture was stabilized by intramedullary nailing. The constructs were loaded axially at a force of 2,100 N up to 20,000 cycles. Cut out at the femoral head was documented by radiograph. Statistical evaluation of the cohort group was performed by calculation of relative risk in relation to the BMD values.

RESULTS

In total, there were six cases of cut out after 10,000 cycles. The incidence of cut out for BMD less than 250 mg/cm(3) was 0.55 (5 of 9) and for BMD greater than 250 mg/cm(3), it was 0.05 (1 of 21). Therefore, the relative risk of cut out for BMD <250 mg/cm(3) is 11× greater than for a BMD >250 mg/cm(3). After 20,000 cycles, an additional test caused one cut out (relative risk of cut out for a BMD <250 mg/cm(3) 5.8).

CONCLUSIONS

For a BMD less than 250 mg/cm(3), there is a high risk of fixation failure after surgical treatment of pertrochanteric fractures. Although this value is based on an experimental in vitro study design with all its associated limitations, it can be regarded as a reference value for future experimental and clinical studies.

ToF-SIMS analysis of osteoblast-like cells and their mineralized extracellular matrix on strontium enriched bone cements

Commonly used implants for therapeutic approaches of non-systemically impaired bone do not sufficiently support the healing process of osteoporotic bone. Since strontium (II) has been proven as an effective anti-osteoporotic drug new types of strontium enriched calcium phosphate bone cements were developed. As osteoporosis is characterized by an imbalance of osteoblast and osteoclast activity the influence of this newly generated strontium enriched biomaterials on the cellular behavior of osteoblast-like cells was investigated by time of flight secondary ion mass spectrometry (ToF-SIMS). ToF-SIMS is used to analyze whether strontium is incorporated in the mineralized extracellular matrix (mECM) and whether there is strontium uptake by osteogenically differentiated human mesenchymal stem cells (hMSCs). Therefore hMSCs were cultured in osteogenic differentiation medium for 21 days on two different strontium enriched bone cements (S100 and A10) and for reference also on the pure calcium phosphate cement (CPC) and on a silicon wafer. The distribution of strontium in the osteoblast-like cells and within their mineralized extracellular matrix was analyzed. A higher intensity of the strontium signal could be detected in the region of the mECM, synthesized by cells cultivated on the Sr- substituted bone cement (S100) in comparison to the reference groups. The osteoblast-like cells used the released strontium from the biomaterial to synthesize their mECM. Apart from that a uniform strontium distribution was measured within all investigated cells. However, different amounts of strontium were found in cells cultured on different biomaterials and substrates. Compared to the negative controls the strontium content in the cells on the strontium enriched biomaterials was much higher. A higher concentration of strontium inside the cells means that more strontium can take part in signaling pathways. As strontium is known for its beneficial effects on osteoblasts by promoting osteoblastic cell replication and differentiation, and reducing apoptosis, the newly developed strontium enriched calcium phosphate cements are promising implant materials for osteoporotic bone.

Mechanical torque measurement in the proximal femur correlates to failure load and bone mineral density ex vivo

Knowledge of local bone quality is essential for surgeons to determine operation techniques. A device for intraoperative measurement of local bone quality has been developed by the AO-Research Foundation (Densi - Probe®). We used this device to experimentally measure peak breakaway torque of trabecular bone in the proximal femur and correlated this with local bone mineral density (BMD) and failure load. Bone mineral density of 160 cadaver femurs was measured by ex situ dualenergy X-ray absorptiometry. The failure load of all femurs was analyzed by side-impact analysis. Femur fractures were fixed and mechanical peak torque was measured with the DensiProbe® device. Correlation was calculated whereas correlation coefficient and significance was calculated by Fisher’s Ztransformation. Moreover, linear regression analysis was carried out. The unpaired Student’s t-test was used to assess the significance of differences. The Ward triangle region had the lowest BMD with 0.511 g/cm² (±0.17 g/cm²), followed by the upper neck region with 0.546 g/cm² (±0.16 g/cm²), trochanteric region with 0.685 g/cm² (±0.19 g/cm²) and the femoral neck with 0.813 g/cm² (±0.2 g/cm²). Peak torque of DensiProbe® in the femoral head was 3.48 Nm (±2.34 Nm). Load to failure was 4050.2 N (±1586.7 N). The highest correlation of peak torque measured by Densi Probe® and load to failure was found in the femoral neck (r=0.64, P<0.001). The overall correlation of mechanical peak torque with T-score was r=0.60 (P<0.001). A correlation was found between mechanical peak torque, load to failure of bone and BMD in vitro. Trabecular strength of bone and bone mineral density are different aspects of bone strength, but a correlation was found between them. Mechanical peak torque as measured may contribute additional information about bone strength, especially in the perioperative testing.

Cement augmentation of the proximal femoral nail antirotation for the treatment of osteoporotic pertrochanteric fractures--a biomechanical cadaver study

INTRODUCTION

Proximal femoral fractures will gain increasing importance in the future due to the epidemiological development. Osteoporosis is often a limiting factor in the achievement of implant stability. New nailing systems offer the possibility of augmentation of the femoral neck component with cement. The aim of this study was to perform a biomechanical comparison of implant stability in osteoporotic pertrochanteric fractures using the proximal femoral nail antirotation (PFNA, Synthes GmbH, Umkirch, Germany) with cement augmented and non-augmented blades.

MATERIALS AND METHODS

Bone mineral density (BMD) was measured by dual-energy X-ray absorptiometry (DEXA) in six pairs of fresh-frozen human femurs. Standardised pertrochanteric fractures (AO31-A2.3) were treated with a PFNA. Cement augmentation was performed in six constructs. Axial loading was applied according to a single-leg-stance model using a hydraulic testing machine increasing to 1400N over 10,000 cycles. Biomechanical comparisons between the two groups that were comparable concerning BMD, tip-apex-distance and native stiffness were made with regard to postoperative stiffness, survived cycles, load to failure, failure mechanism and axial displacement.

RESULTS

The stiffness of all stabilised femurs was significantly lower than for native specimens (native 702.5±159.6N/mm vs. postoperative 275.4±53.8N/mm, p<0.001). Stiffness after instrumentation was significantly greater for the cement augmented group than for the non-augmented group (300.6±46.7N/mm vs. 250.3±51.6N/mm, respectively, p=0.001). Five of the twelve constructs survived cyclic testing. Statistically significant differences of the BMD were detected between survived and failed constructs (0.79±0.17g/cm(2) vs. 0.45±0.12g/cm(2), respectively, p=0.028). The failure loads for specimens surviving 10,000 cycles were 4611.9±2078.9N in the cement augmented group (n=3) and 4516.3N and 3253.5N in the non-augmented group (n=2). Postoperative stiffness was found to be a positive predictor of maximum force to failure (R(2)=0.83, p=0.02).

CONCLUSIONS

The results of this biomechanical study show that cement augmentation of the PFNA increases the implant stability in osteoporotic pertrochanteric fractures. Further studies are necessary to evaluate this procedure in providing long term clinical results.

Managing atrophic nonunion in the geriatric population: incidence, distribution, and causes

Osteoporosis is a systemic disease that affects millions of people worldwide. It is estimated that 50% of women and approximately 20% of men more than 50 years of age will sustain a fragility fracture. The cause of nonunion in patients with osteoporosis is likely multifactorial, and includes age-related changes in fracture repair as well as challenges in achieving stable internal fixation. This article discusses fracture healing in patients with osteoporosis and the principles of fixation. Pharmacotherapy for the patient with osteoporosis is also discussed.

Is augmentation a possible salvage procedure after lateral migration of the proximal femur nail antirotation?

INTRODUCTION

Failed fracture fixation of proximal femur fractures in the elderly usually results in prosthetic replacement. In case of the proximal femur nail antirotation (PFNA), during lateral blade migration or periimplant fracture at the femoral shaft, the femoral head remains intact and therefore a joint preserving procedure might be performed. However, implant anchorage in the femoral head after the second blade implantation generally results in reduced anchorage in the remaining cancellous bone. Therefore, we hypothesize that in the above mentioned cases augmentation of the PFNA blade could be a treatment option before prosthetic surgery has to be performed.

MATERIALS

Biomechanical investigations were performed in eight fresh frozen femoral heads. Implant anchorage in case of blade extraction and reinsertion was investigated by rotation and pull out of a PFNA blade with a servohydraulic testing machine. After reinsertion of the blade and augmentation with bone-cement, the anchorage of the blade was investigated again to observe changes in torque and pull-out force.

RESULTS

Rotational stability of the implant significantly increased after augmentation of the prior extracted PFNA blade. Pull-out strength was higher in the revised case than in the initial tests but without statistical significance. After augmentation, correlation between bone mineral density and pull-out strength which was found during initial pull-out disappeared.

DISCUSSION

Augmentation of simulated blade exchange after lateral blade migration demonstrated a good anchorage. There was superior rotational stability in the revised case and no inferiority during pull out for the investigated specimens. Furthermore, augmentation could compensate for destroyed trabeculae and poor bone stock. It could furthermore be an option when a failed implant has to be replaced by a long PFNA in case of shaft fracture at the tip of the implant to increase anchorage in the femoral head. From a biomechanical point of view, reosteosynthesis and augmentation in selected cases of PFNA revision could be an alternative to initial prosthetic replacement. In the case of cut-out or medial implant protrusion, the suggested salvage technique is not feasible.

The effect of osteoporosis on outcomes of operatively treated distal radius fractures

PURPOSE

We hypothesized that postmenopausal osteoporotic women with distal radius fractures treated with open reduction internal fixation had worse functional outcomes than women without osteoporosis sustaining similar injuries.

METHODS

We retrospectively reviewed prospectively collected data for 64 postmenopausal women treated with open reduction internal fixation for distal radius fractures between 2006 and 2010 with known bone mineral density measured by dual-energy x-ray absorptiometry at the time of injury (osteopenia, n = 44; osteoporosis, n = 20). Data collected included age, mechanism of injury, fracture severity, and associated comorbidities. Outcomes included range of motion, Disabilities of the Arm, Shoulder, and Hand (DASH) scores, and radiographic parameters of fracture reduction. We calculated patients' Charlson Comorbidity Index and tabulated complications. The primary outcome was DASH score at 12 months after injury. We applied multiple linear regression to determine whether bone mineral density status was predictive of functional outcomes 12 months after injury. We used logistic regression analysis to identify factors independently associated with poor outcomes and applied likelihood estimation to determine predictors of a high DASH score at 12 months.

RESULTS

At 1 year postoperatively, women with osteoporosis had average DASH scores 15 points higher than those with osteopenia. Both osteoporosis and the Charlson Comorbidity Index were strong positive independent predictors of higher DASH scores (ie, poorer functional outcomes). There were no significant differences in range of motion or radiographic data between groups. Patients with osteoporosis had a higher rate of major complications.

CONCLUSIONS

Osteoporosis had a negative impact on functional outcomes for women with distal radius fractures treated with open reduction internal fixation. Surgeons should identify high-risk patients, ensure close monitoring, and initiate appropriate preventative measures in this patient population.

TYPE OF STUDY/LEVEL OF EVIDENCE

Prognostic II.

Mechanical torque measurement for in vivo quantification of bone strength in the proximal femur

INTRODUCTION

Bone strength determines fracture risk and fixation strength of osteosynthesis implants. In vivo, bone strength is currently measured indirectly by quantifying bone mineral density (BMD) which is however only one determinant of the bone's biomechanical competence besides the bone's macro- and micro-architecture and tissue related parameters. We have developed a measurement principle (DensiProbe™ Hip) for direct, mechanical quantification of bone strength within the proximal femur upon hip fracture fixation. Previous cadaver tests indicated a close correlation between DensiProbe™ Hip measurements, 3D micro-CT analysis and biomechanical indicators of bone strength. The goal of this study was to correlate DensiProbe™ Hip measurements with areal bone mineral density (BMD).

METHODS

Forty-three hip fracture patients were included in this study. Intraoperatively, DensiProbe™ Hip was inserted to the subsequent hip screw tip position within the femoral head. Peak torque to breakaway of local cancellous bone was registered. Thirty-seven patients underwent areal BMD measurements of the contralateral proximal femur. Failure of fixation was assessed radio graphically 6 and 12 weeks postoperatively.

RESULTS

Peak torque and femoral neck BMD showed significant correlations (R=0.60, P=0.0001). In regression analysis, areal BMD explained 46% of femoral neck BMD variance in a quadratic relationship. Throughout the 12-week follow-up period, no failure of fixation was observed.

CONCLUSIONS

DensiProbe™ Hip may capture variations of bone strength beyond areal BMD which are currently difficult to measure in vivo. A multicenter study will clarify if peak torque predicts fixation failure.

[Treatment results after cemented hemiprosthesis for care of unstable pertrochanteric femoral fractures in the elderly]

BACKGROUND

The optimal treatment strategy for unstable trochanteric fractures in the elderly is still controversial because of the frequent failure of osteosynthesis.

METHODS

A cohort of patients with unstable trochanteric fractures who were treated with cemented hemiarthroplasty and presented in our department during the period 2003-2009 was analyzed. Complications, reoperations, walking ability and full weight bearing were documented.

RESULTS

A total of 91 patients were included (mean age 87.7±6.8 years) and predominantly 31A2 fractures (89%) were treated. There were 3.3% reoperations in the cohort and the 30 day mortality was 5.5%. At least 1 general complication occurred in over 50% of the patients. However, 30% of the patients had lower urinary tract infections, disturbances of electrolyte balance or transitory psychotic symptoms. On average full weight bearing could be performed at 3.5 (±3) days after the operation.

CONCLUSION

Cemented hemiarthroplasty is a safe treatment strategy for unstable trochanteric fractures in the elderly, which allows early full weight bearing. Because of frequent general complications, more interdisciplinary units and centres of excellence are needed to handle this challenging cohort.

Functional outcome and mortality in geriatric distal femoral fractures

BACKGROUND

Fragility fractures are a major health care problem worldwide. Due to the ageing population an increase of distal femoral fractures is to be expected. We studied the long-term functional outcome and their influencing factors in geriatric patients with LISS-plated distal femoral fractures.

PATIENTS AND METHODS

A cohort study with functional long-term follow up examination was carried out in a level one trauma centre on distal femoral fracture patients 65 years and older. Of 53 consecutive patients who were treated in our hospital, 43 patients with a mean age of 80 years met our inclusion criteria. 48.8% died within the study period of 5.3 years. On the remaining patients the residential status, the Barthel index and the Parker score were assessed.

RESULTS

The mean Barthel index was 47.7 and the mean Parker score was 3.5. 23% were found to be totally housebound and 26% were not able to perform any social activity. Only 18% were able to walk unaided. Patients with any medical complication had significantly higher mortality rates. Patients with extraarticular fractures had better mobility scores. Nursing home residents showed higher mortality rates but compared to patients coming from their own home the difference regarding Barthel and Parker scores remained non-significant.

CONCLUSION

This study documents the poor functional long-term outcome of geriatric patients with distal femoral fractures. In comparison to other fragility fracture patients it seems that this population is at higher risk to die in-hospital during their perioperative course. Medical complications have to be avoided as they were found to be associated with worse functional outcome and higher mortality rates. An osteoporosis therapy may be associated with reduced mortality rates also in these patients.

Osteoporosis is not a risk factor for the development of nonunion: A cohort nested case-control study

INTRODUCTION

Osteoporosis (OP) is one of the most prevalent metabolic bone disorders worldwide and it is associated with a higher incidence of fractures. The aim of this study was to identify OP as a risk factor for the development of nonunion.

METHODS

In a prospective database all patients aged >50 years with an acute fracture were screened for osteoporosis from September 13, 2004 till February 9, 2009. Bone mineral density measurements (T-scores, Z-scores and absolute values in g/cm(2)) were performed. The selected patients were matched (1:2 ratio) to control patients based on gender, age (±5 years) and type of fracture according to the AO-criteria. Other parameters including diabetes mellitus, corticosteroid use, rheumatoid arthritis, smoking, alcohol use, and body mass index were recorded. Follow-up for the patients in the matched group was at least one year.

RESULTS

This study included a total of 1498 patients who were screened for the presence of osteoporosis. In total 40 patients were treated for nonunion. After 1:2 matching this resulted in a total number of 120 patients for analysis. Logistic regression analysis including all covariates in the model demonstrated no correlation between the standardised regression coefficients and the development of nonunion (r(2)=0.10, p=0.6). The patients that developed an atrophic nonunion, according to radiographic results, were analysed separately and compared to matched patients. The presence of osteoporosis, osteopenia and normal bone density and the related independent BMD measurements did not differ significantly between the atrophic nonunion group and the matched controls.

CONCLUSION

We conclude that although bone quality may be diminished in the elderly this does not influence the occurrence of nonunion. These results indicate that the use of BMD measurements preoperatively to identify osteoporosis as a possible risk factor of nonunion has no clinical value.

Long-term functional outcome in geriatric hip fracture patients

BACKGROUND

Fragility fractures are a major health care problem worldwide. The proportion of the geriatric population and the overall life expectancy will increase. Hip fractures are the most common fragility fractures needing surgery and nowadays treatment concepts are changing. We studied the long-term functional outcome and their influencing factors in patients treated without any interdisciplinary aspects.

DESIGN AND SETTING

A retrospective cohort study with functional long-term follow-up examination was carried out in a level one trauma centre on hip fracture patients 80 years old and above treated without any formalized interdisciplinary aspects ("usual care").

PATIENTS

Of 281 consecutive patients who were treated 2005 and 2006 with usual care, 246 patients with a mean age of 86.8 years met our inclusion criteria. 69.1% died within the study period of 4.9 years. On the remaining patients, the residential status, the Barthel Index and the Parker Score were assessed.

RESULTS

The mean Barthel Index was 49.6 and the mean Parker Score was 2.7. More than one-fourth of the survivors were found to be bedridden and 45% were not able to walk outside. 88% are bound to one floor and only 8% are able to walk unaided. Patients with more comorbidities and patients with subsequent fractures had significant higher mortality rates. Patients with trochanteric fractures had significant better functional outcome scores compared to patients with femoral neck fractures. Nursing home residents showed significant higher mortality rates and lower functional outcome scores. Patients who were transferred to a nearby acute geriatric hospital for further treatment had significantly higher functional outcome scores.

CONCLUSION

This paper shows the frustrating long-term outcome of geriatric hip fracture patients but it also suggests that an early geriatric intervention may lead to better function.

Determination of composition and structure of spongy bone tissue in human head of femur by Raman spectral mapping

Biomechanical properties of bone depend on the composition and organization of collagen fibers. In this study, Raman microspectroscopy was employed to determine the content of mineral and organic constituents and orientation of collagen fibers in spongy bone in the human head of femur at the microstructural level. Changes in composition and structure of trabecula were illustrated using Raman spectral mapping. The polarized Raman spectra permit separate analysis of local variations in orientation and composition. The ratios of ν₂PO₄³⁻/Amide III, ν₄PO₄³⁻/Amide III and ν₁CO₃²⁻/ν₂PO₄³⁻ are used to describe relative amounts of spongy bone components. The ν₁PO₄³⁻/Amide I ratio is quite susceptible to orientation effect and brings information on collagen fibers orientation. The results presented illustrate the versatility of the Raman method in the study of bone tissue. The study permits better understanding of bone physiology and evaluation of the biomechanical properties of bone.

Internal fixation of femoral neck fractures with posterior comminution: a biomechanical comparison of DHS® and Intertan nail®

BACKGROUND AND PURPOSE

Internal fixation is a therapeutic mainstay for treatment of undisplaced femoral neck fractures and fractures without posterior comminution. The best treatment for unstable and comminuted fractures, however, remains controversial, especially in older patients. The present study was designed to assess the utility of the Intertan Nail® (IT) for stabilization of comminuted Pauwels type III fractures compared to dynamic hips screw (DHS).

METHODS

Randomized on the basis of bone mineral density, 32 human femurs were assigned to four groups. Pauwels type III fractures were osteomized with a custom-made saw guide. In 16 specimens the posteromedial support was removed and all femurs were instrumented with an IT or a DHS. All constructs were tested with nondestructive axial loading to 700N, cyclical compression to 1,400N (10,000 cycles), and loading to failure. Outcome measures included number of survived cycles, mechanical stiffness, head displacement and load to failure.

RESULTS

Postoperative mechanical stiffness and stiffness after cyclical loading were significantly reduced in all constructs regardless of the presence of a comminution defect (p = 0.02). Specimens stabilized with the IT had a lower construct displacement (IT, 8.5 ± 0.5 mm vs. DHS, 14.5 ± 2.2 mm; p = 0.007) and sustained higher failure loads (IT, 4929 ± 419 N vs. DHS, 3505 ± 453 N; p = 0.036) than the DHS constructs.

INTERPRETATION

In comminuted Pauwels type III fractures, the fixation with the IT provided sufficient postoperative mechanical strength, comparable rate of femoral head displacement, and a similar tolerance of physiological loads compared to fractures without comminution. The absence of the posteromedial support in comminuted fractures tended to reduce the failure load regardless of the fixation method.

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.

Clinical comparison of the second and third generation of intramedullary devices for trochanteric fractures of the hip--Blade vs screw

With industrial societies getting older the incidence of femoral fractures is increasing. Complication rates up to 20% have led to a continuous improvement of intramedullar nailing systems and the third generation of implants is in clinical application. They seem superior to the second generation. But as clinical data is still fragmentary, we wanted to compare a second generation implant, the Proximal Femur Nail with three devices of the third generation: the Gleitnagel, Trochanter Fixation Nail and the Proximal Femur Nail Antirotation with a clinical study. We analysed whether fracture reduction and implant position could possibly be indicators for implant complications. Patients with a trochanteric fracture type A1-A3 (AO/ASIF classification) admitted at the department of traumatology Augsburg were enrolled. Postoperative X-rays were analysed in the matter of fracture reduction for the fracture gap, the Garden Alignment Index and for the matter of implant position in the femur head with the cleaveland zones and the Tip Apex Distance. 322 patients were enrolled. Most frequent was the A2 (n=240) and the A3 type of fracture (n=80) followed by A1 (n=29). Time to hospital discharge was 17 days (9/25), 12 patients died (3.2%). The complication rate (cutting out) in the third generation was lower (2.5-7%) than in the second generation (14%). The postoperative range of mobilisation compared to the old social status was in the groups with 34% similar after 3 months. The third generation nails are safe and reliable implants. Compared with second generation devices, fewer complications are observed. A correlation might be seen in the postoperative X-rays between the fracture reduction or implant position and implant related mechanical complications (cutting out).