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1.  A Guide to Improving the Care of Patients with Fragility Fractures, Edition 2 
Over the past 4 decades, much has been learned about the pathophysiology and treatment of osteoporosis, the prevention of fragility fractures, and the perioperative management of patients who have these debilitating injuries. However, the volume of published literature on this topic is staggering and far too voluminous for any clinician to review and synthesize by him or herself. This manuscript thoroughly summarizes the latest research on fragility fractures and provides the reader with valuable strategies to optimize the prevention and management of these devastating injuries. The information contained in this article will prove invaluable to any health care provider or health system administrator who is involved in the prevention and management of fragility hip fractures. As providers begin to gain a better understanding of the principles espoused in this article, it is our hope that they will be able to use this information to optimize the care they provide for elderly patients who are at risk of or who have osteoporotic fractures.
doi:10.1177/2151458515572697
PMCID: PMC4430408  PMID: 26246957
geriatric medicine; geriatric trauma; metabolic bone disorders; nonoperative spine; osteoporosis; systems of care; upper extremity surgery; trauma surgery; foot and ankle surgery; fragility fractures
2.  Sedation Depth During Spinal Anesthesia and Survival in Elderly Patients Undergoing Hip Fracture Repair 
Anesthesia and analgesia  2014;118(5):977-980.
Low intraoperative Bispectral Index (BIS) values may be associated with increased mortality. In a previously reported trial to prevent delirium, we randomized patients undergoing hip fracture repair under spinal anesthesia to light (BIS>80) or deep (BIS~50) sedation. We analyzed survival of patients in the original trial. Among all patients, mortality was equivalent across sedation groups. However, among patients with serious comorbidities (Charlson score >4), 1-year mortality was reduced in the light (22.2%) versus deep (43.6%) sedation group (Hazard Ratio [HR], 0.43; 95% CI, 0.19–0.97; P=0.04) during spinal anesthesia. Similarly, among patients with Charlson score >6, 1-year mortality was reduced in the light (28.6%) versus deep (52.6%) sedation group (HR 0.33; 95%CI 0.12–0.94; P=0.04) during spinal anesthesia. Further research on reduced mortality after light sedation during spinal anesthesia is needed.
doi:10.1213/ANE.0000000000000157
PMCID: PMC4090014  PMID: 24781567
3.  Early Results of a Geriatric Hip Fracture Program in India for Femoral Neck Fracture 
Geriatric hip fractures are a challenging clinical problem throughout the world. Hip fracture services have been shown to shorten time to surgery, decrease the cost of admissions, and improve the outcomes. We instituted a geriatric hip fracture program for comanagement of these injuries by orthopedic and internal medicine teams at our hospital in India. From January 2010 till December 2011, 119 patients with a femoral neck fracture were treated with cemented modular hemiarthroplasty under this program using a cost-effective Indian implant. The cohort included 63 males and 56 females with a mean age of 70.7 years (range 55-98 years). Hypertension (n = 42) and diabetes mellitus (n = 29) were the most common comorbidities. The follow-up period ranged from 12 to 37 months with an average of 24 months. The surgery was performed within 24 hours of admission in 60.5% (n = 72) patients. The use of antiplatelet drugs was the most common reason for delay of surgery. The mean length of hospital stay was 10.4 days (range 3-24 days) with 77% (n = 92) of patients discharged within 1 week of admission. On follow-up, good to excellent Harris hip scores were seen in 88% of patients with 76% of patients returning to the preinjury ambulatory status. The mortality rate was 6% at 6 months follow-up and 10.9% at 2 years. Our study shows that a hip fracture program can be instituted in India. The program helped us in achieving the goal of early surgery, mobilization, and discharge from hospital with decreased mortality.
doi:10.1177/2151458514567314
PMCID: PMC4318811  PMID: 26246953
geriatric fracture; hip fracture program; fracture neck femur; hemiarthroplasty; India
4.  Subject-Specific Planning of Femoroplasty: An Experimental Verification Study 
Journal of biomechanics  2014;48(1):59-64.
The risk of osteoporotic hip fractures may be reduced by augmenting susceptible femora with acrylic polymethylmethacrylate (PMMA) bone cement. Grossly filling the proximal femur with PMMA has shown promise, but the augmented bones can suffer from thermal necrosis or cement leakage, among other side effects. We hypothesized that, using subject-specific planning and computer-assisted augmentation, we can minimize cement volume while increasing bone strength and reducing the risk of fracture. We mechanically tested eight pairs of osteoporotic femora, after augmenting one from each pair following patient-specific planning reported earlier, which optimized cement distribution and strength increase. An average of 9.5(±1.7)ml of cement was injected in the augmented set. Augmentation significantly (P<0.05) increased the yield load by 33%, maximum load by 30%, yield energy by 118%, and maximum energy by 94% relative to the non-augmented controls. Also predicted yield loads correlated well (R2=0.74) with the experiments and, for augmented specimens, cement profiles were predicted with an average surface error of <2mm, further validating our simulation techniques. Results of the current study suggest that subject-specific planning of femoroplasty reduces the risk of hip fracture while minimizing the amount of cement required.
doi:10.1016/j.jbiomech.2014.11.002
PMCID: PMC4274194  PMID: 25468663
Femoroplasty; Cement Augmentation; Planning; Mechanical Test
5.  Patient-specific finite element modeling for femoral bone augmentation 
Medical engineering & physics  2013;35(6):860-865.
The aim of this study was to provide a fast and accurate finite element (FE) modeling scheme for predicting bone stiffness and strength suitable for use within the framework of a computer-assisted osteoporotic femoral bone augmentation surgery system. The key parts of the system, i.e. preoperative planning and intraoperative assessment of the augmentation, demand the finite element model to be solved and analyzed rapidly. Available CT scans and mechanical testing results from nine pairs of osteoporotic femur bones, with one specimen from each pair augmented by polymethylmethacrylate (PMMA) bone cement, were used to create FE models and compare the results with experiments. Correlation values of R2 = 0.72–0.95 were observed between the experiments and FEA results which, combined with the fast model convergence (~3 min for ~250,000 degrees of freedom), makes the presented modeling approach a promising candidate for the intended application of preoperative planning and intraoperative assessment of bone augmentation surgery.
doi:10.1016/j.medengphy.2013.01.003
PMCID: PMC4476497  PMID: 23375663
Femoroplasty; Finite element analysis; Biomechanics; Bone cement
6.  Development of a biomechanical guidance system for periacetabular osteotomy 
Purpose
This paper presents and validates a computer-navigated system for performing periacetabular osteotomy (PAO) to treat developmental dysplasia of the hip. The main motivation of the biomechanical guidance system (BGS) is to plan and track the osteotomy fragment in real time during PAO while simplifying the procedure for less-experienced surgeons. The BGS aims at developing a platform for comparing biomechanical states of the joint with the current gold standard geometric assessment of anatomical angles. The purpose of this study was to (1) determine the accuracy with which the BGS tracks the hip joint through repositioning and (2) identify improvements to the workflow.
Methods
Nineteen cadaveric validation studies quantified system accuracy, verified system application, and helped to refine surgical protocol. In two surgeries, navigation and registration accuracy were computed by affixing fiducials to two cadavers prior to surgery. All scenarios compared anatomical angle measurements and joint positioning as measured intraoperatively to postoperatively.
Results
In the two cases with fiducials, computed fragment transformations deviated from measured fiducial transformations by 1.4 and 1.8 mm in translation and 1.0° and 2.2° in rotation, respectively. The additional seventeen surgeries showed strong agreement between intraoperative and postoperative anatomical angles, helped to refine the surgical protocol, and demonstrated system robustness.
Conclusion
Estimated accuracy with BGS appeared acceptable for future surgical applications. Several major system requirements were identified and addressed, improving the BGS and making it feasible for clinical studies.
doi:10.1007/s11548-014-1116-7
PMCID: PMC4476510  PMID: 25234421
Periacetabular osteotomy; Developmental dysplasia; Computer-assisted surgery; Orthopedics
7.  Role of Fracture and Repair Type on Pain and Opioid Use After Hip Fracture in the Elderly 
Background and Purpose:
Pain after hip fracture repair is related to worse functional outcomes and higher fracture care costs than that for patients with no or less pain. However, to our knowledge, few studies have examined the roles of hip fracture type or surgical procedure as factors influencing postoperative pain or opioid analgesic requirements. Our goal was to determine whether the type of hip fracture or hip fracture repair affects postoperative pain or opioid analgesic requirements in the elderly patient.
Methods:
We conducted a retrospective review of 231 patients ≥65 years old admitted to a hip fracture center for surgical repair. Fracture patterns were classified into femoral neck (FN) versus intertrochanteric (IT), stable versus unstable, and type of surgical repair. Demographic and intraoperative variables, postoperative pain scores, and opioid analgesic use data were collected and analyzed according to the type of hip fracture and type of surgical repair.
Results:
There were no differences in postoperative pain when comparing FN versus IT fractures, stable versus unstable fractures, or type of surgical repair. Patients with FN fractures had higher analgesic requirements on postoperative days 1, 2, and 3. There was no difference in postoperative analgesic requirements among patients with stable versus unstable fractures or type of surgical repair. Otherwise, there were no differences in postoperative pain or opioid analgesic use based on the surgical repair or fracture type. Overall, patients with hip fracture experienced low levels of pain.
doi:10.1177/2151458513518343
PMCID: PMC3943362  PMID: 24600530
hip fracture; pain; postoperative management; femoral neck fracture; intertrochanteric fracture
8.  Factors Associated With Emergency Department Length of Stay for Patients With Hip Fracture 
Time to surgery, which includes time in the emergency department (ED), is important for all patients with hip fracture. We hypothesized that patients with hip fracture spend significantly more time in the ED than do patients with the top 5 most common conditions. In addition, we hypothesized that there are patient, physician, and hospital factors that affect the length of time spent in the ED. We retrospectively reviewed our institution’s hip fracture database and identified 147 elderly patients with hip fractures who presented to our ED from December 18, 2005, through April 30, 2009. We reviewed their records for patient, practitioner, and hospital factors of interest associated with ED time and for 6 specified time intervals. Average working, boarding (waiting for an inpatient room), and total times were calculated and compared with respective averages for admitted ED patients with the top 5 most common conditions. Univariate and multivariate analyses were performed before and after adjusting for confounders (significance, P = .05). The mean total ED time (7 hours and 25 minutes) and working time (4 hours and 31 minutes) for patients with hip fracture were similar to the respective overall averages for admitted ED patients. However, the average boarding time for patients with hip fracture was 2 hours 44 minutes, longer than that for other patients admitted through the ED. Factors significantly associated with longer ED times were a history of hypertension, history of atrial fibrillation, the number of computed tomography scans ordered, and the occupancy rate. Admission to the hip fracture service decreased working time but not overall time. Substantial multidisciplinary work among the ED, hospital admission services, and physicians is needed to dramatically decrease the boarding time and thus the overall time to surgery.
doi:10.1177/2151458513502038
PMCID: PMC3848330  PMID: 24319619
hip fracture; emergency department; occupancy rate; wait time; admitting service
9.  Predisposing Factors for Post-Operative Delirium After Hip Fracture Repair Among Patients With and Without Dementia 
OBJECTIVES
Based on a multi-factorial model of delirium, we compared the types and magnitude of pre- and intra-operative predisposing factors for incident delirium in a stratified sample of acute hip fracture repair patients with and without pre-operative dementia.
DESIGN and SETTING
A prospective cohort study based in an academic medical center.
PARTICIPANTS
425 non-delirious, acute hip fracture patients (mean age: 80.2 +/− 6.8; female: 73.2%; “probable dementia”: 33.1%) admitted to the multi-disciplinary hip fracture repair service.
MEASUREMENTS
Each participant was assessed for delirium by a research nurse based on the Confusion Assessment Method (CAM) before study enrollment and from the second postoperative day until hospital discharge.
RESULTS
The incidence of delirium was higher in the Probable Dementia Group than in the No Dementia Group (54% vs. 26%; p≤ 0.001). In the No Dementia group (n = 284), age (OR: 1.07; 95% CI: 1.02-1.13), male gender (OR: 2.81; 95% CI: 1.40-5.64), BMI (OR: 0.92; 95% CI: 0.86-0.99), number of medical comorbidities (OR: 1.15; 95% CI: 1.01-1.32), and duration of surgery longer than two hours (OR: 2.53; 95% CI: 1.20-4.88) were independently associated with a post-operative delirium. In the Probable Dementia group, only the lag time from emergency room to operation room was significantly associated (OR: 2.83; 95% CI: 1.24-2.25) with delirium.
CONCLUSION
Pre-operative determination of dementia status is important for risk stratification for incident delirium after acute hip fracture repair surgery because types and magnitude of predisposing risk factors for post-operative delirium substantially differ based on their pre-operative dementia status.
doi:10.1111/j.1532-5415.2011.03725.x
PMCID: PMC3302355  PMID: 22188077
dementia; delirium; hip fracture; surgery; risk factor
10.  Management and Prevention of Recurrent Clostridium Difficile Infection in Patients After Total Joint Arthroplasty 
Clostridium difficile infection (CDI) is the most common infectious cause of nosocomial diarrhea in elderly patients, accounting for 15% to 25% of all cases of antibiotic-induced diarrhea in those patients. Virulent forms of this organism have developed, increasing the associated morbidity, mortality, and complication rates. The average patient undergoing total joint arthroplasty is at particular risk of CDI because of advanced age, the use of prophylactic antibiotic coverage in the perioperative period, multiple comorbid conditions, and length of hospital stay. In addition, patients who have had one CDI are at risk of another; the rate of recurrent CDI (RCDI) is 15% to 30%. To review the available information on RCDI, we conducted an extensive literature search, focusing on its epidemiology and the management strategies for its treatment and prevention. We found the management of RCDI is a controversial topic, with as yet no consensus regarding specific treatment guidelines. Several experienced clinicians have published suggested treatment algorithms, but they are based on anecdotal experience. With regard to the prevention of RCDI, the literature is scarce, and currently, the only effective strategies remain judicious use of perioperative antibiotics and appropriate implementation of infection control procedures. There are several vaccination medications that are currently being studied but are not yet ready for clinical use. We agree with the approach to management of RCDI that has been proposed in several articles, that is, on confirmation of a first recurrence of CDI by a stool toxin assay and clinical symptoms, a 14-day course of metronidazole or vancomycin; for a second recurrence, a tapered-pulsed course of vancomycin; and, for 3 or more recurrences, a repeat course of the tapered-pulsed vancomycin and adjunctive Saccharomyces boulardii or cholestyramine.
doi:10.1177/2151458513479023
PMCID: PMC3598518  PMID: 23569710
recurrent; Clostridium difficile; infection; arthroplasty
11.  The Johns Hopkins Delirium Consortium: One Model for Collaborating Across Disciplines and Departments for Delirium Prevention and Treatment 
Delirium is an important syndrome affecting inpatients in various hospital settings. This article focuses on multidisciplinary and interdepartmental collaboration for advancing efforts in delirium clinical care and research. One model for such collaboration is represented by the Johns Hopkins Delirium Consortium, which includes members from the disciplines of Nursing, Medicine, Rehabilitation Therapy, Psychology, and Pharmacy within the Departments/Divisions of Anesthesiology, Geriatrics, Oncology, Orthopedic Surgery, Psychiatry, Critical Care Medicine, and Physical Medicine and Rehabilitation at both the Johns Hopkins Hospital and Johns Hopkins Bayview Medical Center. This paper describes the process involved in developing functional collaboration around delirium, and highlights projects, opportunities, and challenges resulting from them.
doi:10.1111/j.1532-5415.2011.03672.x
PMCID: PMC4305431  PMID: 22091568
Delirium care and prevention; inpatient care; interdisciplinary; collaboration
12.  A Review of Periprosthetic Femoral Fractures Associated With Total Hip Arthroplasty 
Periprosthetic fractures of the femur in association with total hip arthroplasty are increasingly common and often difficult to treat. Patients with periprosthetic fractures are typically elderly and frail and have osteoporosis. No clear consensus exists regarding the optimal management strategy because there is limited high-quality research. The Vancouver classification facilitates treatment decisions. In the presence of a stable prosthesis (type-B1 and -C fractures), most authors recommend surgical stabilization of the fracture with plates, strut grafts, or a combination thereof. In up to 20% of apparent Vancouver type-B1 fractures, the femoral stem is loose, which may explain the high failure rates associated with open reduction and internal fixation. Some authors recommend routine opening and dislocation of the hip to perform an intraoperative stem stability test to rule out a loose component. Advances in plating techniques and technology are improving the outcomes for these fractures. For fractures around a loose femoral prosthesis (types B2 and 3), revision using an extensively porous-coated uncemented long stem, with or without additional fracture fixation, appears to offer the most reliable outcome. Cement-in-cement revision using a long-stem prosthesis is feasible in elderly patients with a well-fixed cement mantle. It is essential to treat the osteoporosis to help fracture healing and to prevent further fractures. We provide an overview of the causes, classification, and management of periprosthetic femoral fractures around a total hip arthroplasty based on the current best available evidence.
doi:10.1177/2151458512462870
PMCID: PMC3598446  PMID: 23569704
periprosthetic fracture; femur; total hip arthroplasty; Vancouver type; stem
13.  Pain Reporting, Opiate Dosing, and the Adverse Effects of Opiates After Hip or Knee Replacement in Patients 60 Years Old or Older 
Our goal was to determine whether there were age-related differences in pain, opiate use, and opiate side effects after total hip or knee arthroplasty in patients 60 years old or older. We hypothesized that there would be no significant differences between age groups in (1) mean pain score, (2) opiate use after adjusting for pain, or (3) opiate side effects after adjusting for opiate use and pain score. We retrospectively reviewed the electronic and paper charts of all patients undergoing total joint replacements at our institution over 3 years who met the following criteria: (1) 60 years old or older, (2) primary single total knee or total hip replacement, and (3) no preoperative dementia. Preoperative, intraoperative, and postoperative course data were collected using a customized data entry process and database. We divided the patients into 2 age groups, those 60 to 79 years old and those 80 years old or older. Using a marginal model with the panel variable of postoperative day, we investigated the associations between age group and pain, age group and pain adjusting for opiate use, and age group and complications (respiratory depression, naloxone usage as a measure of respiratory arrest, delirium, constipation, and urinary retention) adjusting for opiate use (Xtgee, Stata10, Stata Corp. LP, College Station, Texas). Significance was set at P < .05. We found no significant difference in pain scores between groups, but the older group had significantly fewer opiates prescribed yet significantly more side effects, including delirium (odds ratio 4.2), than did the younger group, even after adjusting for opiate dose and pain score.
doi:10.1177/2151458511432758
PMCID: PMC3617902  PMID: 23569691
opiates; pain; hip replacement; knee replacement; elderly
15.  Inadvertent Screw Stripping During Ankle Fracture Fixation in Elderly Bone 
Poor screw purchase because of osteoporosis presents difficulties in ankle fracture fixation. The aim of our study was to determine if cortical thickness, unicortical versus bicortical purchase, and bone mineral density are predictors of inadvertent screw stripping and overtightening. Ten paired cadaver ankles (average donor age, 81.7 years; range, 50-97 years) were used for the study. Computed tomography scanning with phantoms of known density was used to determine the bone density along the distal fibula. A standard small-fragment, 7-hole, one-third tubular plate was applied to the lateral surface of the fibula, with 3 proximal bicortical cortical screws and 2 distal unicortical cancellous screws. A posterior plate, in which all 5 screws were cortical and achieved bicortical purchase, was subsequently applied to the same bones and positioned so that the screw holes did not overlap. A torque sensor was used to measure the torque of each screw during insertion (Ti) and then stripping (Ts). The effect of bone density, screw location, cortical thickness, and unicortical versus bicortical purchase on Ti and Ts was checked for significance (P < .05) using a general linearized latent and mixed model. We found that 9% of the screws were inadvertently stripped and 12% were overtightened. Despite 21% of the screws being stripped or being at risk for stripping, we found no significant predictors to warn of impending screw stripping. Additional work is needed to identify clinically useful predictors of screw stripping.
doi:10.1177/2151458511401352
PMCID: PMC3597310  PMID: 23569675
insertion torque; stripping torque; bone density; inadvertent stripping; ankle fracture
16.  Anatomical Variance in Acetabular Anteversion Does Not Predict Hip Fracture Patterns in the Elderly 
It has been suggested that variances in the anatomy of the acetabulum determine the type of hip fracture in elderly patients. Based on this concept, an overly anteverted acetabulum would lead to impingement of the femoral neck against the posterior rim of the acetabulum, causing a femoral neck fracture, whereas with a retroverted acetabulum, external rotation of the hip would be limited by the capsular tissues attached to the trochanteric region, causing a trochanteric fracture. To test the hypothesis that acetabular version predicts hip fracture type in elderly patients, we measured acetabular version using computed tomography scans for 135 patients with hip fracture. Logistic regression analysis was used to check for an association between version angle and fracture type. No significant relationship between acetabular version and fracture type was found. Therefore, we conclude that acetabular version angle does not predict hip fracture type in the elderly, and our data do not support the impingement concept as the mechanism of hip fractures.
doi:10.1177/2151458510391985
PMCID: PMC3597302  PMID: 23569672
hip fracture; elderly; femoral neck fracture; trochanteric fracture
17.  Biomechanical Comparison of 2 Different Locking Plate Fixation Methods in Vancouver B1 Periprosthetic Femur Fractures 
Locking plates are commonly used to treat fractures around a well-fixed femoral component. The optimal construct should provide sufficient fixation while minimizing soft-tissue dissection. The purpose of the current study was to determine whether plate length, working length, or bone mineral density affects survival of locking plate fixation for Vancouver type B1 periprosthetic hip fractures. A transverse osteotomy was created just distal to cemented femoral prostheses in 9 pairs of cadaveric femurs. Fractures were stabilized with long (20-hole) or short (12-hole) locking plates that were secured proximally with cables and screws and distally with screws only. Specimens were then cycled 10 000 times at 2500 N of axial force and 15 Nm of torque to simulate full weightbearing. A motion capture system was used to record fracture displacement during cycling. Failure occurred in 5 long and 3 short plates, with no significant differences found in the number of cycles to failure. For the specimens that survived, there were no significant differences found between long and short plates for displacement or rotation observed at the fracture site. A shorter working length was not associated with increased failure rate. Lower bone mineral density was significantly associated with failure (P = .02). We concluded that long locked plates do not appear to offer a biomechanical advantage over short locking plates in terms of fixation survival, and that bone mineral density was a better predictor of failure than was the fixation construct type.
doi:10.1177/2151458510397609
PMCID: PMC3597304  PMID: 23569670
periprosthetic fracture; femur; locking plate; working length; fixation
18.  A Biomechanical Evaluation of Femoroplasty under Simulated Fall Conditions 
Objectives
To test the hypotheses that, compared with controls 1) femoroplasty (the injection of bone cement into the proximal femur in an attempt to prevent fragility fracture) increases the yield and ultimate loads, yield and ultimate energies, and stiffness of the proximal osteoporotic femur in a simulated fall model; and 2) the manner in which the cement distributes in the proximal femur affects the extent to which those mechanical properties are altered.
Methods
In 10 pairs of osteoporotic human cadaveric femora, we injected 1 femur of each pair with 40 -- 50 mL of polymethylmethacrylate bone cement; the noninjected femur served as the control. The filling percentage was calculated in 4 anatomical regions of the femur: head, neck, trochanter, and subtrochanter. All specimens were biomechanically tested in a configuration that simulated a fall on the greater trochanter. Student's t test, linear regression, and multinomial logistic regression statistical analyses were conducted where appropriate, with significant difference defined as P < 0.05.
Results
Femoroplasty significantly increased yield load (22.0%), ultimate load (37.3%), yield energy (79.6%), and ultimate energy (154%) relative to matched controls, but did not significantly change stiffness (-10.9%). There was a strong (r2 = 0.7) correlation between yield load and filling percentage in the femoral neck.
Conclusions
This study showed that 1) femoroplasty significantly increased fracture load and energy to fracture when osteoporotic femora were loaded in simulated fall conditions and 2) cement filling in the femoral neck may have an important role in the extent to which femoroplasty affects mechanical strength of the proximal femur.
doi:10.1097/BOT.0b013e3181b5c0c6
PMCID: PMC2813465  PMID: 20101133
femoroplasty; hip fracture; osteoporosis; prophylactic; bone cement
20.  The Effect of Cement Placement on Augmentation of the Osteoporotic Proximal Femur 
Femoroplasty, the augmentation of the proximal femur, has been shown in biomechanical studies to increase the energy required to produce a fracture and therefore may reduce the risk of such injuries. The purpose of our study was to test the hypotheses that: (1) 15 mL of cement was sufficient to mechanically augment the proximal femur, (2) there was no difference in augmentation effect between cement placement in the intertrochanteric region and in the femoral neck, and (3) cement placement in the femoral neck would predispose the proximal femur to an intertrochanteric fracture, whereas trochanteric placement would result in subtrochanteric fractures. In each of 18 pairs of osteoporotic human cadaveric femora, 15 mL of polymethylmethacrylate bone cement was injected into the trochanteric or femoral neck region of 1 femur, and the noninjected femur was used as the control. The augmentation effect of femoroplasty was evaluated under simulated fall conditions using a materials testing machine. Multiple linear regressions incorporating random effects were used to check for associations between covariates (bone mineral density, cement location, and treatment) and the parameters of interest (stiffness, yield energy, yield load, ultimate load, and ultimate energy). Significance was set at P < .05. It was found that femoroplasty with 15 mL of cement did not significantly increase stiffness, yield energy, yield load, ultimate load, or ultimate energy relative to paired controls. There were no significant differences in parameters of interest or fracture patterns in specimens augmented in the femoral neck versus the trochanter. It was concluded that 15 mL of cement was not sufficient to augment the proximal femur and that there was no biomechanical advantage to the placement of cement within the femoral neck versus the trochanter.
doi:10.1177/2151458510378406
PMCID: PMC3597291  PMID: 23569658
femoroplasty; cement augmentation; hip fracture; osteoporosis; fracture prevention
21.  Bone Density and Cortical Thickness in Normal, Osteopenic, and Osteoporotic Sacra 
Journal of Osteoporosis  2010;2010:504078.
It is unclear if a decrease in cancellous bone density or cortical bone thickness is related to sacral insufficiency fractures. We hypothesized that reduction in overall bone density leads to local reductions in bone density and cortical thickness in cadaveric sacra that match clinically observed fracture patterns in patients with sacral insufficiency fractures. We used quantitative computed tomography to measure cancellous density and cortical thickness in multiple areas of normal, osteopenic, and osteoporotic sacra. Cancellous bone density was significantly lower in osteoporotic specimens in the central and anterior regions of the sacral ala compared with other regions of these specimens. Cortical thickness decreased uniformly in all regions of osteopenic and osteoporotic specimens. These results support our hypothesis that areas of the sacrum where sacral insufficiency fractures often occur have significantly larger decreases in cancellous bone density; however, they do not support the hypothesis that these areas have local reduction of cortical bone thickness.
doi:10.4061/2010/504078
PMCID: PMC2951120  PMID: 20948574
22.  Inhibition of TGF–β signaling in subchondral bone mesenchymal stem cells attenuates osteoarthritis 
Nature medicine  2013;19(6):704-712.
Osteoarthritis is a highly prevalent and debilitating joint disorder. There is no effective medical therapy for osteoarthritis due to limited understanding of osteoarthritis pathogenesis. We show that TGF–β1 is activated in the subchondral bone in response to altered mechanical loading in an anterior cruciate ligament transection (ACLT) osteoarthritis mouse model. TGF–β1 concentrations also increased in human osteoarthritis subchondral bone. High concentrations of TGF–β1 induced formation of nestin+ mesenchymal stem cell (MSC) clusters leading to aberrant bone formation accompanied by increased angiogenesis. Transgenic expression of active TGF–β1 in osteoblastic cells induced osteoarthritis. Inhibition of TGF–β activity in subchondral bone attenuated degeneration of osteoarthritis articular cartilage. Notably, knockout of the TGF–β type II receptor (TβRII) in nestin+ MSCs reduced development of osteoarthritis in ACLT mice. Thus, high concentrations of active TGF–β1 in the subchondral bone initiated the pathological changes of osteoarthritis, inhibition of which could be a potential therapeutic approach.
doi:10.1038/nm.3143
PMCID: PMC3676689  PMID: 23685840
23.  Salvaging the Pullout Strength of Stripped Screws in Osteoporotic Bone 
Our goal was to determine whether the pullout strength of stripped screw holes in osteoporotic bone could be increased with readily available materials from the operating room. We inserted 3.5-mm stainless steel nonlocking self-tapping cortical screws bicortically into 5 osteoporotic humeri. Each screw was first stripped by rotating it 1 full turn past maximum torque. In the control group, the screw was pulled out using an MTS machine (858; MTS Inc, Eden Prairie, Minnesota). In the treatment groups, the screw was removed, the hole was augmented with 1 of the 3 materials (stainless steel wire, polysorb suture, or polyethylene terephthalate glycol plastic sheet), and the screws were replaced and then pulled out. The effect of material on pullout strength was checked for significance (P < .05) using a general linearized latent and mixed model (Stata10; StataCorp, College Station, Texas). The mean (95% confidence interval) pullout strength for the unaugmented hole was 138 N (range 88-189), whereas the holes augmented with plastic, suture, or wire had mean pullout strengths of 255 N (range 177-333), 228 N (range 149-308), and 396 N (range 244-548), respectively. Although wire augmentation resulted in pullout strength that was significantly greater than that of the unaugmented screw, it was still below that of the intact construct.
doi:10.1177/2151458513498393
PMCID: PMC3789504  PMID: 24093076
screw stripping; osteoporosis; bone density; inadvertent stripping; ankle fracture; humerus fracture
24.  Case Discussion 
This case presents a discussion of a 92-year-old man with multiple comorbidities, who presents with a subtrochanteric fracture. His course is complicated by large volume blood loss intraoperatively, requiring intensive care unit (ICU) monitoring postoperatively. His course is also complicated by delirium.
doi:10.1177/2151458511426426
PMCID: PMC3609401  PMID: 23569687
dementia; delirium; fragility fractures; systems of care; physical therapy
25.  Case Report: Perioperative Use of Protein C Concentrate for Protein C Deficiency in THA 
Background
Perioperative management of patients with heterozygous protein C deficiency is challenging because of the competing risks of bleeding and recurrent thrombosis.
Case Description
We report the case of a 74-year-old man with protein C deficiency and heterozygous prothrombin G20210A gene mutation who had a successful left THA with perioperative administration of human zymogen protein C concentrate in addition to anticoagulation with enoxaparin.
Literature Review
Several studies have reported the use of protein C concentrate in severe sepsis-associated purpura fulminans in patients with severe congenital protein C deficiency who have had thrombotic events. We reviewed studies and case reports pertinent to the treatment of patients with protein C deficiency, especially in the perioperative setting. We report the case of a patient undergoing THA in whom we used human zymogen protein C concentrate.
Purposes and Clinical Relevance
THA, a particularly high-risk procedure, is associated with a 40% to 70% incidence of venographic deep venous thrombosis and a 2% to 3% incidence of symptomatic deep venous thrombosis. These risks are greater in people with thrombophilic defects such as protein C deficiency. The use of human zymogen protein C in our patient with heterozygous protein C deficiency during the perioperative period of a THA was associated with no evidence of excessive bleeding, hematoma, deep venous thrombosis, or pulmonary embolism.
doi:10.1007/s11999-009-1189-8
PMCID: PMC2882006  PMID: 20012238

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