Teriparatide treatment increases Hounsfield units in the lumbar spine out of proportion to DEXA changes

OBJECTIVE

The authors sought to assess whether Hounsfield units (HU) increase following teriparatide treatment and to compare HU increases with changes in bone mineral density (BMD) as measured by dual-energy x-ray absorptiometry (DEXA).

METHODS

A retrospective chart review was performed from 1997 to 2018 across all campuses at our institution. The authors identified patients who had been treated with at least 6 months of teriparatide and compared HU and BMD as measured on DEXA scans before and after treatment.

RESULTS

Fifty-two patients were identified for analysis (46 women and 6 men, average age 67 years) who underwent an average of 20.9 ± 6.5 months of teriparatide therapy. The mean ± standard deviation HU increase throughout the lumbar spine (L1-4) was from 109.8 ± 53 to 133.9 ± 61 HU (+22%, 95% CI 1.2-46, p value = 0.039). Based on DEXA results, lumbar spine BMD increased from 0.85 to 0.93 g/cm2 (+9%, p value = 0.044). Lumbar spine T-scores improved from -2.4 ± 1.5 to -1.7 ± 1.5 (p value = 0.03). Average femoral neck T-scores improved from -2.5 ± 1.1 to -2.3 ± 1.0 (p value = 0.31).

CONCLUSIONS

Teriparatide treatment increased both HU and BMD on DEXA in the lumbar spine, without a change in femoral BMD. The 22% improvement in HU surpassed the 9% improvement determined with DEXA. These results support some surgeons' subjective sense that intraoperative bone quality following teriparatide treatment is better than indicated by DEXA results. To the authors' knowledge, this is the first study demonstrating an increase in HU with teriparatide treatment.

Unrecognized Osteoporosis Is Common in Patients With a Well-Functioning Total Knee Arthroplasty

BACKGROUND

Peri-prosthetic fractures after total knee arthroplasty (TKA) are associated with poorer outcomes and high costs. We hypothesize that osteoporosis is under-recognized in the TKA population. The purpose of this study is to report osteoporosis prevalence in a healthy cohort of patients with well-functioning TKA and to compare prevalence between males and females.

METHODS

This study is a cross-sectional study of 30 adults (15 males/15 females) aged 59-80 years without known bone health issues who volunteered to undergo routine dual-energy X-ray absorptiometry 2-5 years (average 3.2 ± 0.8) after primary unilateral TKA. These data plus clinical risk factors were used to estimate fracture risk via the Fracture Risk Assessment Tool and skeletal status (normal, osteopenic, osteoporotic) was determined based on the World Health Organization definition. The National Osteoporosis Foundation criteria for treatment were applied to all patients.

RESULTS

Six of 30 (20%) patients had T-score ≤ -2.5. Eighteen of 30 (60%) patients had T-score between -1 and -2.5 and 6 (20%) patients had T-score ≥ -1. Five patients with normal or osteopenic bone mineral density (BMD) had occult vertebral fractures. Eleven of 30 (36.7%) patients met National Osteoporosis Foundation criteria for pharmacologic treatment.

CONCLUSION

The prevalence of occult osteoporosis meeting treatment guidelines after TKA is substantial in this sample (36.7%). BMD and osteoporosis prevalence are similar between men and women. This underappreciated prevalence of osteoporosis may contribute to peri-prosthetic fracture risk. Arthroplasty surgeons and bone health specialists must be aware of post-operative changes in bone density. These data support the further study of post-operative osteoporosis and consideration of routine BMD screening after TKA.

LEVEL OF EVIDENCE

III.

Executive Summary of the 2019 ISCD Position Development Conference on Monitoring Treatment, DXA Cross-calibration and Least Significant Change, Spinal Cord Injury, Peri-prosthetic and Orthopedic Bone Health, Transgender Medicine, and Pediatrics

To answer important questions in the fields of monitoring with densitometry, dual-energy X-ray absorptiometry machine cross-calibration, monitoring, spinal cord injury, periprosthetic and orthopedic bone health, transgender medicine, and pediatric bone health, the International Society for Clinical Densitometry (ISCD) held a Position Development Conference from March 20 to 23, 2019. Potential topics requiring guidance were solicited from ISCD members in 2017. Following that, a steering committee selected, prioritized, and grouped topics into Task Forces. Chairs for each Task Force were appointed and the members were co-opted from suggestions by the Steering Committee and Task Force Chairs. The Task Forces developed key questions, performed literature searches, and came up with proposed initial positions with substantiating draft publications, with support from the Steering Committee. An invited Panel of Experts first performed a review of draft positions using a modified RAND Appropriateness Method with voting for appropriateness. Draft positions deemed appropriate were further edited and presented at the Position Development Conference meeting in an open forum. A second round of voting occurred after discussions to approve or reject the positions. Finally, a face-to-face closed session with experts and Task Force Chairs, and subsequent electronic follow-up resulted in 34 Official Positions of the ISCD approved by the ISCD Board on May 28, 2019. The Official Positions and the supporting evidence were submitted for publication on July 1, 2019. This paper provides a summary of the all the ISCD Adult and Pediatric Official Positions, with the new 2019 positions highlighted in bold.

Use of Bone Health Evaluation in Orthopedic Surgery: 2019 ISCD Official Position

This position development conference (PDC) Task Force examined the assessment of bone status in orthopedic surgery patients. Key questions included which orthopedic surgery patients should be evaluated for poor bone health prior to surgery and which subsets of patients are at high risk for poor bone health and adverse outcomes. Second, the reliability and validity of using bone densitometry techniques and measurement of specific geometries around the hip and knee before and after arthroplasty was determined. Finally, the use of computed tomography (CT) attenuation coefficients (Hounsfield units) to estimate bone quality at anatomic locations where orthopedic surgery is performed including femur, tibia, shoulder, wrist, and ankle were reviewed. The literature review identified 665 articles of which 198 met inclusion exclusion criteria and were selected based on reporting of methodology, reliability, or validity results. We recommend that the orthopedic surgeon be aware of established ISCD guidelines for determining who should have additional screening for osteoporosis. Patients with inflammatory arthritis, chronic corticosteroid use, chronic renal disease, and those with history of fracture after age 50 are at high risk of osteoporosis and adverse events from surgery and should have dual energy X-ray absorptiometry (DXA) screening before surgery. In addition to standard DXA, bone mineral density (BMD) measurement along the femur and proximal tibia is reliable and valid around implants and can provide valuable information regarding bone remodeling and identification of loosening. Attention to positioning, selection of regions of interest, and use of special techniques and software is required. Plain radiographs and CT provide simple, reliable methods to classify the shape of the proximal femur and to predict osteoporosis; these include the Dorr Classification, Cortical Index, and critical thickness. Correlation of these indices to central BMD is moderate to good. Many patients undergoing orthopedic surgery have had preoperative CT which can be utilized to assess regional quality of bone. The simplest method available on most picture archiving and communications systems is to simply measure a regions of interest and determine the mean Hounsfield units. This method has excellent reliability throughout the skeleton and has moderate correlation to DXA based on BMD. The prediction of outcome and correlation to mechanical strength of fixation of a screw or implant is unknown.

Bone Health Optimization: Beyond Own the Bone: AOA Critical Issues

Worldwide, osteoporosis management is in crisis because of inadequate delivery of care, competing guidelines, and confusing recommendations. Additionally, patients are not readily accepting the diagnosis of poor bone health and often are noncompliant with treatment recommendations. Secondary fracture prevention, through a program such as Own the Bone, has improved the diagnosis and medical management after a fragility fracture. In patients who undergo elective orthopaedic procedures, osteoporosis is common and adversely affects outcomes. Bone health optimization is the process of bone status assessment, identification and correction of metabolic deficits, and initiation of treatment, when appropriate, for skeletal structural deficits. The principles of bone health optimization are similar to those of secondary fracture prevention and can be initiated by all orthopaedic surgeons. Patients who are ≥50 years of age should be assessed for osteoporosis risk and, if they are in a high-risk group, bone density should be measured. All patients should be counseled to consume adequate vitamin D and calcium and to discontinue use of any toxins (e.g., tobacco products and excessive alcohol consumption). Patients who meet the criteria for pharmaceutical therapy for osteoporosis should consider delaying surgery for a minimum of 3 months, if feasible, and begin medication treatment. Orthopaedic surgeons need to assume a greater role in the care of bone health for our patients.

A Review and Clinical Perspective of the Impact of Osteoporosis on the Spine

Introduction

Osteopenia and osteoporosis are common conditions in the United States. The health consequences of low bone density can be dire, from poor surgical outcomes to increased mortality rates following a fracture.

Significance

This article highlights the impact low bone density has on spine health in terms of vertebral fragility fractures and its adverse effects on elective spine surgery. It also reviews the clinical importance of bone health assessment and optimization.

Results

Vertebral fractures are the most common fragility fractures with significant consequences related to patient morbidity and mortality. Additionally, a vertebral fracture is the best predictor of a subsequent fracture. These fractures constitute sentinel events in osteoporosis that require further evaluation and treatment of the patient's underlying bone disease. In addition to fractures, osteopenia and osteoporosis have deleterious effects on elective spine surgery from screw pullout to fusion rates. Adequate evaluation and treatment of a patient's underlying bone disease in these situations have been shown to improve patient outcomes.

Conclusion

With an increased understanding of the prevalence of low bone mass and its consequences as well an understanding of how to identify these patients and appropriately intervene, spine surgeons can effectively decrease the rates of adverse health outcomes related to low bone mass.

Osteoporosis Is Common and Undertreated Prior to Total Joint Arthroplasty

BACKGROUND

Osteoporosis is common in total joint arthroplasty (TJA) patients and likely contributes to the increasing incidence of periprosthetic fracture. Despite this, the prevalence of osteoporosis in patients undergoing elective TJA is inadequately studied. We hypothesize that preoperative osteoporosis is underrecognized and undertreated in the TJA population. The purpose of this study is to report preoperative osteoporosis screening rates and prevalence prior to TJA and rates of pharmacologic osteoporosis treatment in the TJA population.

METHODS

This is a retrospective case series of 200 consecutive adults (106F, 94M) aged 48-92 years who underwent elective TJA (100 total hip, 100 total knee) at a single tertiary-care center. Charts were retrospectively reviewed to determine preoperative osteoporosis risk factors, prior dual-energy X-ray absorptiometry (DXA) testing, and prior osteoporosis pharmacotherapy. Fracture risk was estimated using the Fracture Risk Assessment Tool and the National Osteoporosis Foundation criteria for screening and treatment were applied to all patients.

RESULTS

One hundred nineteen of 200 patients (59.5%) met criteria for DXA testing. Of these 119, 21 (17.6%) had DXA testing in the 2 years prior to surgery, and 33% had osteoporosis by T-score. Forty-nine patients (24.5%) met National Osteoporosis Foundation criteria for pharmacologic osteoporosis treatment, and 11 of these 49 received a prescription for pharmacotherapy within 6 months before or after surgery.

CONCLUSION

One quarter of TJA patients meet criteria to receive osteoporosis medications, but only 5% receive therapy preoperatively or postoperatively. This lack of preoperative osteoporosis screening and treatment may contribute to periprosthetic fracture risk.

Changes in femoral bone mineral density after total knee arthroplasty: a systematic review and meta-analysis

BACKGROUND

Bone loss after total knee arthroplasty (TKA) may lead to periprosthetic fractures that are associated with significant costs (morbidity, economic, etc.) and pose a challenge to operative fixation. This meta-analysis quantifies the change in bone mineral density (BMD) of the distal femur after primary TKA.

METHODS

A systematic review of six databases was performed by two independent reviewers. Studies that reported bone density after knee arthroplasty were identified and inclusion/exclusion criteria was applied. Data were extracted and analyzed using the Comprehensive Meta-Analysis Software.

RESULTS

Fourteen studies were included in the analysis. The average decrease in BMD was 0.09 [0.05, 0.13], 0.14 [0.08, 0.20], 0.16 [0.10, 0.23], and 0.16 [0.12, 0.20] g/cm² at 3, 6, 12, and 24 months, respectively, corresponding to a 9.3%, 13.2%, 15.8%, and 15.4% BMD loss. A high degree of heterogeneity existed between the studies (I² > 90% at most time points).

CONCLUSION

In summary, there is a rapid and significant 15% decrease in BMD in the first 6 months after TKA that is sustained to 24 months. Better understanding regarding how perioperative optimization of bone health may affect BMD loss and the incidence of periprosthetic fracture is essential.

LEVEL OF EVIDENCE

Therapeutic Level II.

Congress of Neurological Surgeons Systematic Review and Evidence-Based Guidelines on the Evaluation and Treatment of Patients With Thoracolumbar Spine Trauma: Classification of Injury

QUESTION 1

Are there classification systems for fractures of the thoracolumbar spine that have been shown to be internally valid and reliable (ie, do these instruments provide consistent information between different care providers)?

RECOMMENDATION 1

A classification scheme that uses readily available clinical data (eg, computed tomography scans with or without magnetic resonance imaging) to convey injury morphology, such as Thoracolumbar Injury Classification and Severity Scale or the AO Spine Thoracolumbar Spine Injury Classification System, should be used to improve characterization of traumatic thoracolumbar injuries and communication among treating physicians. Strength of Recommendation: Grade B.

QUESTION 2

In treating patients with thoracolumbar fractures, does employing a formally tested classification system for treatment decision-making affect clinical outcomes?

RECOMMENDATION 2

There is insufficient evidence to recommend a universal classification system or severity score that will readily guide treatment of all injury types and thereby affect outcomes. Strength of Recommendation: Grade Insufficient The full version of the guideline can be reviewed at: https://www.cns.org/guideline-chapters/congress-neurological-surgeons-systematic-review-evidence-based-guidelines/chapter_2.

Congress of Neurological Surgeons Systematic Review and Evidence-Based Guidelines on the Evaluation and Treatment of Patients With Thoracolumbar Spine Trauma: Radiological Evaluation

BACKGROUND

Radiological evaluation of traumatic thoracolumbar fractures is used to classify the injury and determine the optimal treatment plan. Currently, there remains a lack of consensus regarding appropriate radiological protocol. Most clinicians use a combination of plain radiographs, 3-dimensional computed tomography with reconstructions, and magnetic resonance imaging (MRI).

OBJECTIVE

To determine, through evidence-based guidelines review: (1) whether the use of MRI to identify ligamentous integrity predicted the need for surgical intervention; and (2) if there are any radiological findings that can assist in predicting clinical outcomes.

METHODS

A systematic review of the literature was performed using the National Library of Medicine/PubMed database and the Cochrane Library for studies relevant to thoracolumbar trauma. Clinical studies specifically addressing the radiological evaluation of thoracolumbar spine trauma were selected for review.

RESULTS

Two of 2278 studies met inclusion criteria for review. One retrospective review (Level III) and 1 prospective cohort (Level III) provided evidence that the addition of an MRI scan in acute thoracic and thoracolumbar trauma can predict the need for surgical intervention. There was insufficient evidence that MRI can help predict clinical outcomes in patients with acute traumatic thoracic and thoracolumbar spine injuries.

CONCLUSION

This evidence-based guideline provides a Grade B recommendation that radiological findings in patients with acute thoracic or thoracolumbar spine trauma can predict the need for surgical intervention. This evidence-based guideline provides a grade insufficient recommendation that there is insufficient evidence to determine if radiographic findings can assist in predicting clinical outcomes in patients with acute thoracic and thoracolumbar spine injuries.

QUESTION 1

Are there radiographic findings in patients with traumatic thoracolumbar fractures that can predict the need for surgical intervention?

RECOMMENDATION 1

Because MRI has been shown to influence the management of up to 25% of patients with thoracolumbar fractures, providers may use MRI to assess posterior ligamentous complex integrity, when determining the need for surgery. Strength of Recommendation: Grade B.

QUESTION 2

Are there radiographic findings in patients with traumatic thoracolumbar fractures that can assist in predicting clinical outcomes?

RECOMMENDATION 2

Due to a paucity of published studies, there is insufficient evidence that radiographic findings can be used as predictors of clinical outcomes in thoracolumbar fractures. Strength of Recommendation: Grade Insufficient The full version of the guideline can be reviewed at: https://www.cns.org/guideline-chapters/congress-neurological-surgeons-systematic-review-evidence-based-guidelines/chapter_3.

Congress of Neurological Surgeons Systematic Review and Evidence-Based Guidelines on the Evaluation and Treatment of Patients With Thoracolumbar Spine Trauma: Nonoperative Care

BACKGROUND

Thoracic and lumbar burst fractures in neurologically intact patients are considered to be inherently stable, and responsive to nonsurgical management. There is a lack of consensus regarding the optimal conservative treatment modality. The question remains whether external bracing is necessary vs mobilization without a brace after these injuries.

OBJECTIVE

To determine if the use of external bracing improves outcomes compared to no brace for neurologically intact patients with thoracic or lumbar burst fractures.

METHODS

A systematic review of the literature was performed using the National Library of Medicine PubMed database and the Cochrane Library for studies relevant to thoracolumbar trauma. Clinical studies specifically comparing external bracing to no brace for neurologically intact patients with thoracic or lumbar burst fractures were selected for review.

RESULTS

Three studies out of 1137 met inclusion criteria for review. One randomized controlled trial (level I) and an additional randomized controlled pilot study (level II) provided evidence that both external bracing and no brace equally improve pain and disability in neurologically intact patients with burst fractures. There was no difference in final clinical and radiographic outcomes between patients treated with an external brace vs no brace. One additional level IV retrospective study demonstrated equivalent clinical outcomes for external bracing vs no brace.

CONCLUSION

This evidence-based guideline provides a grade B recommendation that management either with or without an external brace is an option given equivalent improvement in outcomes for neurologically intact patients with thoracic and lumbar burst fractures. The decision to use an external brace is at the discretion of the treating physician, as bracing is not associated with increased adverse events compared to no brace.

QUESTION

Does the use of external bracing improve outcomes in the nonoperative treatment of neurologically intact patients with thoracic and lumbar burst fractures?

RECOMMENDATION

The decision to use an external brace is at the discretion of the treating physician, as the nonoperative management of neurologically intact patients with thoracic and lumbar burst fractures either with or without an external brace produces equivalent improvement in outcomes. Bracing is not associated with increased adverse events compared to not bracing. Strength of Recommendation: Grade B The full version of the guideline can be reviewed at: https://www.cns.org/guideline-chapters/congress-neurological-surgeons-systematic-review-evidence-based-guidelines/chapter_8.

DXA Measured Distal Femur Bone Mineral Density in Patients After Total Knee Arthroplasty: Method Development and Reproducibility

INTRODUCTION

Total knee arthroplasty (TKA) is increasingly being performed. Distal femur periprosthetic fracture is a potentially catastrophic complication following TKA and existing data document substantial distal femur bone mineral density (BMD) loss following TKA. However, distal femur BMD is virtually never measured clinically as no consensus approach exists. This pilot study's purpose was to define regional BMD variation throughout the femur, suggest standard dual-energy X-ray absorptiometry (DXA) regions of interest (ROIs) and evaluate BMD reproducibility at these ROIs.

METHODS

Thirty volunteers 2-5 yr post TKA had both entire femurs imaged twice using a Lunar iDXA with subject repositioning between scans; the atypical femur fracture feature of enCORE software was utilized. To define femoral BMD distribution, custom 1 cm ROIs were stacked one atop the other starting at the intercondylar notch and continuing to the base of the lesser trochanter. Femur length was measured with the ruler tool to calculate distance at 5% increments. ROIs encompassing each 5% increment were utilized to measure BMD at each location. Descriptive statistics were used to determine mean BMD at each ROI and reproducibility at the 15%, 25%, 45%, 60%, and 80% ROIs.

RESULTS

The 5 and 10% ROIs included prosthetic and/or patella, causing high BMD values. Distal femur BMD was lowest at the 15% ROI and was higher (p < 0.05) at each more proximal ROI to 45%, then plateaued from 45% to 75%. BMD reproducibility at these regions was excellent; coefficient of variation (CV) from ∼1% to 3.5%. As periprosthetic fractures generally occur in the distal femur, we propose measuring femur BMD using ROIs placed at 15% and 25%. A 60% region could also be used as a highly cortical site.

CONCLUSION

Existing DXA capabilities allow distal femur BMD measurement with good reproducibility. Further research using standardized ROIs to assess distal femur BMD loss after TKA, and interventions to mitigate this loss, is indicated.

Congress of Neurological Surgeons Systematic Review and Evidence-Based Guidelines on the Evaluation and Treatment of Patients with Thoracolumbar Spine Trauma: Operative Versus Nonoperative Treatment

QUESTION 1

Does the surgical treatment of burst fractures of the thoracic and lumbar spine improve clinical outcomes compared to nonoperative treatment?

RECOMMENDATION 1

There is conflicting evidence to recommend for or against the use of surgical intervention to improve clinical outcomes in patients with thoracolumbar burst fracture who are neurologically intact. Therefore, it is recommended that the discretion of the treating provider be used to determine if the presenting thoracic or lumbar burst fracture in the neurologically intact patient warrants surgical intervention. Strength of Recommendation: Grade Insufficient.

QUESTION 2

Does the surgical treatment of nonburst fractures of the thoracic and lumbar spine improve clinical outcomes compared to nonoperative treatment?

RECOMMENDATION 2

There is insufficient evidence to recommend for or against the use of surgical intervention for nonburst thoracic or lumbar fractures. It is recommended that the decision to pursue surgery for such fractures be at the discretion of the treating physician. Strength of Recommendation: Grade Insufficient The full version of the guideline can be reviewed at: https://www.cns.org/guideline-chapters/congress-neurological-surgeons-systematic-review-evidence-based-guidelines/chapter_1.

Congress of Neurological Surgeons Systematic Review and Evidence-Based Guidelines on the Evaluation and Treatment of Patients With Thoracolumbar Spine Trauma: Neurological Assessment

QUESTION 1

Which neurological assessment tools have demonstrated internal reliability and validity in the management of patients with thoracic and lumbar fractures (ie, do these instruments provide consistent information between different care providers)?

RECOMMENDATION 1

Numerous neurologic assessment scales (Functional Independence Measure, Sunnybrook Cord Injury Scale and Frankel Scale for Spinal Cord Injury) have demonstrated internal reliability and validity in the management of patients with thoracic and lumbar fractures. Unfortunately, other contemporaneous measurement scales (ie, American Spinal Cord Injury Association Impairment Scale) have not been specifically studied in patients with thoracic and lumbar fractures. Strength of Recommendation: Grade C.

QUESTION 2

Are there any clinical findings (eg, presenting neurological grade/function) in patients with thoracic and lumbar fractures that can assist in predicting clinical outcomes?

RECOMMENDATION 2

Entry American Spinal Injury Association Impairment Scale grade, sacral sensation, ankle spasticity, urethral and rectal sphincter function, and AbH motor function can be used to predict neurological function and outcome in patients with thoracic and lumbar fractures (Table I https://www.cns.org/guideline-chapters/congress-neurological-surgeons-systematic-review-evidence-based-guidelines/chapter_4_table1). Strength of Recommendation: Grade B The full version of the guideline can be reviewed at: https://www.cns.org/guideline-chapters/congress-neurological-surgeons-systematic-review-evidence-based-guidelines/chapter_4.

Dinuclear Ternary Copper(II) Complex: Synthesis, Characterization, Structure and DNA-Binding Studies

A dinuclear centrosymmetric copper(II) complex has been prepared and characterized via FT-IR, UV-Visible and electron spin resonance spectroscopy, electrochemical method, and powder and single crystal XRD techniques. The two copper(II) ions are connected by two μ-1,1-O atoms belonging to para-fluorophenyl acetate ligands. Each copper(II) ion is coordinated by two other carboxylate ligands in monodentate and a 2,2'-bipyridine molecule in bidentate manner. Thus the geometry around each penta-coordinated copper(II) ion is square pyramidal with distortion factor τ = 0.04. Purity and uniform crystalline nature of the complex was assessed from powder XRD spectrum. ESR signal consisted of partially resolved hyperfine splitting pattern while electrochemical studies revealed diffusion controlled electron transfer processes with diffusion co-efficient of 1.628×10-7 cm2 s-1. The results of all spectroscopic experiments support each other. The complex afforded mixed binding mode with DNA yielding DNA-binding constant values of 3.667×104and 1.438×104 M-1 using cyclic voltammetry and absorption spectroscopy, respectively. The preliminary studies heralded good structural and biological importance of the synthesized complex.

The Unstable Spine: A Surgeon's Perspective

Instability of the spine is a complex clinical entity that exists on a wide spectrum encompassing many aspects of spinal pathology including traumatic, neoplastic, infectious, and degenerative processes. The importance of determining stability is paramount in the decision-making process regarding the need for operative or nonoperative care. Defining clinical instability can be a challenging and requires careful attention to the pathology involved, findings of necessary imaging, and a thorough clinical exam. Several classification systems have been developed to aid in surgical decision making, but certain limitations exist. Various imaging modalities play a crucial role in the evaluation of suspected instability. Computed tomography is the initial imaging modality of choice in the traumatic setting. Magnetic resonance imaging is an important adjunct in the setting of suspected ligamentous injury and the modality of choice in suspected infectious and neoplastic processes. Upright radiographs can be particularly useful in the setting of acute or subacute instability to glean information about how the spine responds to gravity and weightbearing. The clinical exam is also of critical importance in the determination of stability. The presence of a neurologic deficit is highly suggestive of a potentially unstable spine and appropriate spinal precautions should be maintained until instability and injury has been ruled out. Certain clinical entities, such as ankylosing spondylitis and diffuse idiopathic skeletal hyperostosis, are at high risk for instability particularly in the traumatic setting. In these situations, the spine should be considered unstable until proven otherwise. Ultimately, the determination of spinal stability, and subsequent need for surgical treatment, should be based on the individual case. Combining information from the clinical exam and imaging findings, including upright radiographs when appropriate, allows for the appropriated determination of spinal stability.

Introduction of New Technologies in Orthopaedic Surgery

The introduction of new devices, biologics, and combination products to the orthopaedic marketplace is increasing rapidly. The majority of these new technologies obtain clearance to market by demonstrating substantial equivalence to a predicate (previously approved device) according to the U.S. Food and Drug Administration (FDA) 510(k) process. Surgeons play a critical role in the introduction of new technologies to patients and must take a leadership role in promoting safe, efficacious, appropriate, and cost-effective care, especially for operative procedures. Surgeons should monitor and document their patients' clinical outcomes and adverse events when using new technology, to ensure that the new technology is performing as desired.