Periprosthetic fractures are osteoporotic fractures: missed opportunities for osteoporosis diagnosis

Joint replacement surgery is common in older adults, leading to increasing periprosthetic fracture (PPFx) occurrence. We reviewed all PPFx seen over a 4-year period at an academic hospital. Clinical osteoporosis could be diagnosed based on existing data in 104 (67%) at the time of PPFx. Periprosthetic fractures are generally osteoporosis-related.

PURPOSE

Periprosthetic fractures (PPFx) cause morbidity, mortality, and cost. This study's purpose was to describe osteoporosis-related data available at the time of PPFx.

METHODS

The electronic medical record (EMR) of PPFx patients seen over 4 years in a university orthopedic practice were reviewed. Demographic data and osteoporosis relevant parameters were collected. Prior DXA studies were reviewed, and L1 Hounsfield unit (HU) measurements were performed on CT scans obtained within 2 years before PPFx. Clinical osteoporosis was defined as prior diagnosis, prescribed osteoporosis treatment, T-score ≤  - 2.5, HU ≤ 100, or prior fracture.

RESULTS

Records of 156 PPFx patients (115 F/41 M), mean (SD) age 75.4 (11.9), were reviewed. Almost all 153/156 (98%) of these fractures were femoral. Falls caused 139 (89%); 12 (8%) were spontaneous. Mean time post-arthroplasty was 7.9 (6.3) years. Prior fragility fracture(s) occurred in 72 (46%); 14 were PPFx. Osteoporosis was previously diagnosed in 45 (29%) and medications prescribed in 41 (26%). Prior to PPFx, DXA data were available in 62, mean (SD) lowest T-score was - 1.9 (0.9) and was ≤  - 2.5 in 19. CT data were available in 46; mean (SD) L1 HU was 79.0 (29.4) and was ≤ 100 in 35. Based on existing data, clinical osteoporosis could have been diagnosed in 104 (67%) at the time of PPFx.

CONCLUSION

Periprosthetic fractures are osteoporosis-related. They occur in older adults, often female, and result from falls; BMD, when assessed, is low. Data available at the time of PPFx often allows osteoporosis diagnosis; this should prompt evaluation and pharmacologic treatment consideration.

MRI-based vertebral bone quality score: relationship with age and reproducibility

Vertebral bone quality (VBQ) score is an opportunistic measure of bone mineral density using routine preoperative MRI in spine surgery. VBQ score positively correlates with age and is reproducible across serial scans. However, extrinsic factors, including MRI machine and protocol, affect the VBQ score and must be standardized.

PURPOSE

The purposes of this study were to determine whether VBQ score increased with age and whether VBQ remained consistent across serial MRI studies obtained within 3 months.

METHODS

This retrospective study evaluated 136 patients, age 20-69, who received two T1-weighted lumbar MRI within 3 months of each other between January 2011 and December 2021. VBQ(L1-4) score was calculated as the quotient of L1-L4 signal intensity (SI) and L3 cerebral spinal fluid (CSF) SI. VBQ(L1) score was calculated as the quotient of L1 SI and L1 CSF SI. Regression analysis was performed to determine correlation of VBQ(L1-4) score with age. Coefficient of variation (CV) was used to determine reproducibility between VBQ(L1-4) scores from serial MRI scans.

RESULTS

One hundred thirty-six patients (mean ± SD age 44.9 ± 12.5 years; 53.7% female) were included in this study. Extrinsic factors affecting the VBQ score included patient age, MRI relaxation time, and specific MRI machine. When controlling for MRI relaxation/echo time, the VBQ(L1-4) score was positively correlated with age and had excellent reproducibility in serial MRI with CV of 0.169. There was excellent agreement (ICC > 0.9) of VBQ scores derived from the two formulas, VBQ(L1) and VBQ(L1-4).

CONCLUSION

Extrinsic factors, including MRI technical factors and age, can impact the VBQ(L1-4) score and must be considered when using this tool to estimate bone mineral density (BMD). VBQ(L1-4) score was positively correlated with age. Reproducibility of the VBQ(L1-4) score across serial MRI is excellent especially when controlling for technical factors, supporting use of the VBQ score in estimating BMD. The VBQ(L1) score was a reliable alternative to the VBQ(L1-4) score.

Opportunistic CT-Based Hounsfield Units Strongly Correlate with Biomechanical CT Measurements in the Thoracolumbar Spine

STUDY DESIGN

Retrospective cohort study.

OBJECTIVE

Hounsfield units (HUs) are known to correlate with clinical outcomes, no study has evaluated how they correlate with BCT and DXA measurements.

SUMMARY OF BACKGROUND

Low bone mineral density (BMD) represents a major risk factor for fracture and poor outcomes following spine surgery. Dual-energy x-ray absorptiometry (DXA) can provide regional BMD measurements but has limitations. Opportunistic HUs provide targeted BMD estimates; however, they are not formally accepted for diagnosing osteoporosis in current guidelines. More recently, biomechanical computed tomography (BCT) analysis has emerged as a new modality endorsed by the International Society for Clinical Densitometry (ISCD) for assessing bone strength.

METHODS

Consecutive cases from 2017-2022 at a single institution were reviewed for patients who underwent BCT in the thoracolumbar spine. BCT-measured vertebral strength, trabecular BMD, and the corresponding American College of Radiology (ACR) Classification were recorded. DXA studies within three months of the BCT were reviewed. Pearson Correlation Coefficients were calculated, and receiver-operating characteristic curves were constructed to assess the predictive capacity of HUs. Threshold analysis was performed to identify optimal HU values for identifying osteoporosis and low BMD.

RESULTS

Correlation analysis of 114 cases revealed a strong relationship between HUs and BCT vertebral strength (r=0.69; P<0.0001; R2=0.47) and trabecular BMD (r=0.76; P<0.0001; R2=0.58). However, DXA poorly correlated with opportunistic HUs and BCT measurements. HUs accurately predicted osteoporosis and low BMD (Osteoporosis: C=0.95, 95% CI 0.89-1.00; Low BMD: C=0.87, 95% CI 0.79-0.96). Threshold analysis revealed that 106 and 122 HUs represent optimal thresholds for detecting osteoporosis and low BMD.

CONCLUSION

Opportunistic HUs strongly correlated with BCT-based measures, while neither correlated strongly with DXA-based BMD measures in the thoracolumbar spine. HUs are easy to perform at no additional cost and provide accurate BMD estimates at non-instrumented vertebral levels across all ACR-designated BMD categories.

Advances in Osteoporosis Therapy: Focus on Osteoanabolic Agents, Secondary Fracture Prevention, and Perioperative Bone Health

PURPOSE OF REVIEW

This review summarizes recently published data and other developments around osteoanabolic osteoporosis therapies in patients with very high fracture risk, including those undergoing bone-related surgery.

RECENT FINDINGS

Two osteoanabolic agents, abaloparatide and romosozumab, were recently approved for treatment of patients with osteoporosis at high fracture risk. These agents, along with teriparatide, are valuable for primary and secondary fracture prevention. Orthopedic surgeons are well positioned to facilitate secondary fracture prevention via referrals to fracture liaison services or other bone health specialist colleagues. This review aims to help surgeons understand how to identify patients with sufficiently high fracture risk to warrant consideration of osteoanabolic therapy. Recent evidence around the perioperative use and potential benefits of osteoanabolic agents in fracture healing and other orthopedic settings (e.g., spinal fusion and arthroplasty) in individuals with osteoporosis is also discussed. Osteoanabolic agents should be considered for patients with osteoporosis at very high fracture risk, including those with prior osteoporotic fractures and those with poor bone health who are undergoing bone-related surgery.

Intraoperative physician assessment of bone: correlation to bone mineral density

This study evaluated the intraoperative physician assessment (IPA) of bone status at time of total knee arthroplasty. IPA was highly correlated with distal femur and overall bone mineral density. When IPA identifies poor bone status, formal bone health assessment is indicated.

PURPOSE

Intuitively, intraoperative physician assessment (IPA) would be an excellent measure of bone status gained through haptic feedback during bone preparation. However, no studies have evaluated the orthopedic surgeon's ability to do so. This study's purpose, in patients undergoing total knee arthroplasty (TKA), was to relate IPA with (1) the lowest bone mineral density (BMD) T-score at routine clinical sites; and (2) with distal femur BMD.

METHODS

Seventy patients undergoing TKA by 3 surgeons received pre-operative DXA. Intraoperatively, bone quality was assessed on a 5-point scale (1 excellent to 5 poor) based on tactile feedback to preparation. Demographic data, DXA results, and IPA score between surgeons were compared by factorial ANOVA. Lowest T-score and distal femur BMD were associated with IPA using Spearman's correlation.

RESULTS

The mean (SD) age and BMI were 65.8 (7.6) years and 31.4 (5.1) kg/m², respectively. Patient demographic data, BMD, and IPA (mean [SD] = 2.74 [1.2]) did not differ between surgeons. IPA correlated with the lowest T-score (R = 0.511) and distal femur BMD (R = 0.603-0.661). Based on the lowest T-score, no osteoporotic patients had an IPA above average, and none with normal BMD was classified as having poor bone.

CONCLUSIONS

IPA is highly correlated with local (distal femur) and overall BMD. This study supports the International Society for Clinical Densitometry position that surgeon concern regarding bone quality should lead to bone health assessment. As IPA is comparable between surgeons, it is logical this can be widely applied by experienced orthopedic surgeons. Future studies evaluating IPA at other anatomic sites are indicated.

Periprosthetic fractures: an unrecognized osteoporosis crisis

Total joint replacement is common and increasing. Many of these patients have low bone mineral density preoperatively, and arthroplasty leads to bone loss. As falls are common before and after arthroplasty, it is unsurprising that periprosthetic fractures, defined as those associated with an orthopedic device, whether a joint replacement or other internal fixation devices, are not rare. These fractures engender morbidity and mortality comparable to osteoporosis-related hip fractures but remain largely unrecognized and untreated by osteoporosis/metabolic bone disease clinicians. Indeed, recent osteoporosis guidelines are silent regarding periprosthetic fractures. The purposes of this clinical review are to briefly describe the epidemiology of arthroplasty procedures and periprosthetic fractures, raise awareness that these fractures are osteoporosis-related, and suggest approaches likely to reduce their occurrence. Notably, bone health evaluation is essential following the occurrence of a periprosthetic fracture to reduce subsequent fracture risk. Importantly, in addition to such secondary fracture prevention, primary prevention, i.e., bone health assessment and optimization prior to elective orthopedic procedures, is appropriate.

CT required to perform robotic-assisted total hip arthroplasty can identify previously undiagnosed osteoporosis and guide femoral fixation strategy

Osteoporosis can determine surgical strategy for total hip arthroplasty (THA), and perioperative fracture risk. The aims of this study were to use hip CT to measure femoral bone mineral density (BMD) using CT X-ray absorptiometry (CTXA), determine if systematic evaluation of preoperative femoral BMD with CTXA would improve identification of osteopenia and osteoporosis compared with available preoperative dual-energy X-ray absorptiometry (DXA) analysis, and determine if improved recognition of low BMD would affect the use of cemented stem fixation. Retrospective chart review of a single-surgeon database identified 78 patients with CTXA performed prior to robotic-assisted THA (raTHA) (Group 1). Group 1 was age- and sex-matched to 78 raTHAs that had a preoperative hip CT but did not have CTXA analysis (Group 2). Clinical demographics, femoral fixation method, CTXA, and DXA data were recorded. Demographic data were similar for both groups. Preoperative femoral BMD was available for 100% of Group 1 patients (CTXA) and 43.6% of Group 2 patients (DXA). CTXA analysis for all Group 1 patients preoperatively identified 13 osteopenic and eight osteoporotic patients for whom there were no available preoperative DXA data. Cemented stem fixation was used with higher frequency in Group 1 versus Group 2 (28.2% vs 14.3%, respectively; p = 0.030), and in all cases where osteoporosis was diagnosed, irrespective of technique (DXA or CTXA). Preoperative hip CT scans which are routinely obtained prior to raTHA can determine bone health, and thus guide femoral fixation strategy. Systematic preoperative evaluation with CTXA resulted in increased recognition of osteopenia and osteoporosis, and contributed to increased use of cemented femoral fixation compared with routine clinical care; in this small study, however, it did not impact short-term periprosthetic fracture risk.

Fracture in Patients with Normal Bone Mineral Density: An Evaluation of the American Orthopaedic Association's Own the Bone Registry

BACKGROUND

Fractures often occur in patients with normal dual x-ray absorptiometry (DXA)-measured bone mineral density (BMD). DXA does not consider clinical fracture risk factors or bone quality. We hypothesized that patients with normal BMD who sustain a fracture have other characteristics suggesting abnormal bone and an elevated fracture risk requiring additional bone health evaluation and potential anti-osteoporotic treatment.

METHODS

A total of 7,219 patients who were ≥50 years of age, had sustained a fracture from July 2016 to July 2021, and had DXA data in the American Orthopaedic Association's Own the Bone (AOA OTB) registry were included in this study. The index and prior fracture site data were obtained. BMD status was classified by the World Health Organization T-score criteria. The Fracture Risk Assessment Tool (FRAX) scores with and without BMD were calculated in patients with normal BMD. An elevated risk was defined as a major osteoporotic fracture risk of ≥20% or a hip fracture risk of ≥3%.

RESULTS

The mean patient age (and standard deviation) was 70.8 ± 9.71 years, 84% of patients were female, and 92% of patients were Caucasian. Normal BMD was present in 8.6% of patients. The index fracture was a major osteoporotic fracture in 68.6% of patients with normal BMD and 75.6% of patients with osteoporosis. The most common site for index and prior fractures other than major osteoporotic fractures was the foot and ankle; of patients with normal BMD, 13.9% had this as the most common index site and 17.4% had this as the most common prior site. The FRAX risk calculated without BMD was elevated in 72.9% of patients with normal BMD, and the FRAX risk calculated with BMD was elevated in 12.0% of patients.

CONCLUSIONS

Most patients with a fracture and normal BMD met indications, including a prior fracture or elevated FRAX risk, for anti-osteoporotic therapies. Most patients were Caucasian and therefore potentially had a higher baseline fracture risk. The FRAX risk calculated without BMD was elevated more often than the FRAX risk with BMD, implying that clinical risk factors, which highlight multiple opportunities for non-pharmacologic secondary fracture prevention, should be considered along with DXA. Fractures other than major osteoporotic fractures were more common in patients with normal BMD, suggesting that minor fractures in adults who are ≥50 years of age should be considered sentinel events warranting further evaluation. Surgeons must recognize that other important risk factors apart from BMD may help to guide further bone health evaluation.

LEVEL OF EVIDENCE

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

Proposed bone health screening protocol to identify total knee arthroplasty patients for preoperative DXA

This study evaluates a novel, simple bone health screening protocol composed of patient sex, age, fracture history, and FRAX risk to identify total knee arthroplasty patients for preoperative DXA. Findings supported effectiveness, with sensitivity of 1.00 (CI 0.92-1.00) and specificity of 0.54 (CI 0.41-0.68) when evaluating for clinical osteoporosis.

PURPOSE

Bone health optimization is a process where osteoporotic patients are identified, evaluated via modalities such as dual-energy X-ray absorptiometry (DXA), and treated when indicated. There are currently no established guidelines to determine who needs presurgical DXA. This study evaluates the effectiveness of a simple screening protocol to identify TKA patients for preoperative DXA.

METHODS

This prospective cohort study began on September 1, 2019, and included 100 elective TKA patients. Inclusion criteria were ≥ 50 years and primary TKA. All patients obtained routine clinical DXA. The screening protocol defining who should obtain DXA included meeting any of the following: female ≥ 65, male ≥ 70, fracture history after age 50, or FRAX major osteoporotic fracture risk without bone mineral density (BMD) adjustments ≥ 8.4%. Osteoporosis was defined by the World Health Organization (WHO) criteria (T-score ≤  - 2.5) or clinically (T-score ≤  - 2.5, elevated BMD-adjusted FRAX risk, or prior hip/spine fracture). Sensitivity and specificity were calculated.

RESULTS

The study included 68 females and 32 males, mean age 67.2 ± 7.7. T-score osteoporosis was observed in 16 patients while 43 had clinical osteoporosis. Screening criteria recommending DXA was met by 69 patients. Screening sensitivity was 1.00 (CI 0.79-1.00) and specificity was 0.37 (CI 0.27-0.48) for identifying patients with T-score osteoporosis. Similar sensitivity of 1.00 (CI 0.92-1.00) and specificity of 0.54 (CI 0.41-0.68) were found for clinical osteoporosis.

CONCLUSIONS

A simple screening protocol identifies TKA patients with T-score and clinical osteoporosis for preoperative DXA with high sensitivity in this prospective cohort study.

Secondary Fracture Rate After Vertebral Osteoporotic Compression Fracture Is Decreased by Anti-Osteoporotic Medication but Not Increased by Cement Augmentation

BACKGROUND

Painful vertebral osteoporotic compression fractures (OCFs) are often treated with cement augmentation, although controversies exist as to whether or not this increases the secondary fracture risk. Prevention of secondary fracture includes treatment of underlying osteoporosis. The purposes of this study were to determine (1) whether cement augmentation increases the rate of secondary fracture compared with nonoperative management, (2) whether anti-osteoporotic medications reduce the rate of secondary fracture, and (3) the rate of osteoporosis treatment with medications following vertebral OCF.

METHODS

The PearlDiver database was queried for all patients with a diagnosis of OCF from 2015 to 2019. Patients were excluded if they were <50 years old, had a diagnosis of spinal neoplasm or infection, or underwent lumbar fusion in the perioperative period. Secondary fracture risk was assessed using univariate and multivariate logistic regression analysis, with kyphoplasty, vertebroplasty, anti-osteoporotic medications, age, gender, and Elixhauser Comorbidity Index as variables.

RESULTS

A total of 36,145 patients were diagnosed with an OCF during the study period. Of those, 25,904 (71.7%) underwent nonoperative management and 10,241 (28.3%) underwent cement augmentation, including 1,556 who underwent vertebroplasty and 8,833 who underwent kyphoplasty. Patients who underwent nonoperative management had a secondary fracture rate of 21.8% following the initial OCF, compared with 14.5% in the vertebroplasty cohort and 18.5% in the kyphoplasty cohort, which was not a significant difference on multivariate analysis. In the entire cohort, 2,833 (7.8%) received anti-osteoporotic medications and 33,312 (92.2%) did not. The rate of secondary fracture was 10.1% in patients who received medications and 21.9% in those who did not, which was a significant difference on multivariate analysis (odds ratio = 1.23, p < 0.001).

CONCLUSIONS

Cement augmentation did not alter the rate of secondary fracture, whereas anti-osteoporotic medications significantly decreased the risk of subsequent OCF by 19%. Only 7.8% of patients received a prescription for an anti-osteoporotic medication following the initial OCF.

LEVEL OF EVIDENCE

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

Humeral BMD can be Measured With DXA and Is Lower in the Surgical Arm After Total Shoulder Arthroplasty

BACKGROUND

As arthroplasty leads to bone loss, we hypothesized that humeral bone mineral density (BMD) is lower after total shoulder arthroplasty (TSA) in the operative versus non-operative arm. However, there is no clinical approach to measure humeral BMD with dual-energy x-ray absorptiometry (DXA). The purposes of this pilot study were to develop DXA methodology to measure humerus BMD, propose humerus regions of interest (ROIs), compare TSA BMD to the non-operative arm, correlate humeral BMD with standard sites, and evaluate measurement reproducibility.

METHODOLOGY

Thirty-eight adults 1-5 years post-TSA had standard clinical DXA scans plus full humerus scans using the atypical femur fracture feature; precision was assessed in a subset (n = 32). Six custom ROIs were used to measure BMD throughout the humerus. Radius and humeral BMD were compared between arms by paired t-test and correlated ipsilaterally using Pearson's Correlation. Custom ROI BMD precision was assessed using the International Society for Clinical Densitometry (ISCD) advanced precision calculator.

RESULTS

Study included 38 subjects (24M/14F), with mean (SD) age and time post-surgery of 69.6 (7.7) years and 2.5 (1.3) years respectively. BMD was lower (p &lt; 0.01) at all custom humerus sites (3.8% to 8.2%) on the surgical side but not different at radius sites. Humeral BMD correlated positively with ipsilateral ultra-distal and 1/3 radius (r = 0.54 to 0.86; p &lt; 0.05). Custom BMD precision (%CV) ranged from 6.0-16.0%.

CONCLUSIONS

Humerus BMD can be measured using DXA and is lower in the TSA arm. Radius BMD correlated with humeral BMD but was not lower in the surgical arm. BMD precision was worse than usual clinical sites; use of software optimized for the femur is a notable limitation and likely contributes to suboptimal precision. Further study to assess the clinical utility of humeral BMD is needed. Automation and optimization of these measurements should improve precision.

Clinical risk factor status in patients with vertebral fracture but normal bone mineral density

BACKGROUND CONTEXT

Normal bone mineral density (BMD) as measured by dual-energy x-ray absorptiometry (DXA) is present in approximately 10% of older adults with fracture. BMD alone does not evaluate bone quality or clinical risk factors, and therefore, may not adequately capture a patient's fracture risk. Thus, despite a normal DXA-measured BMD, the underlying bone may be abnormal, suggesting that further bone health evaluation, and potentially, pharmacologic treatment may be warranted.

PURPOSE

To determine the prevalence of normal BMD, clinical fracture risk factors, and quantitative risk of fracture using the Fracture Risk Assessment Tool (FRAX) in vertebral fracture patients with normal BMD enrolled in the Own the Bone registry, thus facilitating identification of those who meet criteria for anti-osteoporosis therapy.

STUDY DESIGN/SETTING

Retrospective, national registry-based cohort.

PATIENT SAMPLE

From July 2016 to July 2021, 1,807 patients age ≥50 who sustained a vertebral fracture and had DXA data available from within 2 years prior to enrollment in the American Orthopaedic Association's Own the Bone (AOA OTB) registry were included.

OUTCOME MEASURES

World Health Organization (WHO) DXA T-score based bone classification criteria; FRAX risk scores of major osteoporotic fracture or hip fracture.

METHODS

Demographic data, prior fracture site, and clinical fracture risk factors were collected. BMD status was classified by the WHO T-score criteria: ≥ -1.0 normal, -1.1 to -2.4 osteopenia, and ≤ -2.5 osteoporosis, with low bone mass including either osteopenia or osteoporosis. In normal BMD patients, FRAX scores were calculated with and without BMD, with the treatment threshold defined as a major osteoporotic fracture risk ≥20% or hip fracture risk ≥3%.

RESULTS

Mean±SD age was 72.0±9.7, 78.1% were female, and 92.4% were Caucasian. Normal BMD was present in 7.9%. Clinical fracture risk factors including alcohol use ≥3 units/day and history of ≥2 falls in the year prior to enrollment were more common in normal BMD (11.2% and 28%, respectively) compared to low bone mass patients (3.4% and 25.2%, respectively). A prior vertebral fracture had occurred in 49.5% with normal BMD compared to 45.8% with low bone mass, while a prior non-major osteoporotic fracture occurred in 28.9% and 29.3% of normal BMD and low bone mass patients, respectively. In normal BMD patients, either a prior fracture or FRAX risk with BMD meeting treatment thresholds was present in 85%.

CONCLUSIONS

Clear indications for receipt of pharmacologic therapy, ie, prior fracture or elevated fracture risk, were present in most patients with vertebral fracture and normal BMD enrolled in the AOA OTB. Prior non-major osteoporotic fractures were common and may be useful indicators of underlying bone disease. Surgeons must recognize that other important risk factors apart from BMD may indicate poor bone health, and thus, help guide further bone health evaluation.

Summary of the FDA virtual public workshop on spinal device clinical review held on September 17, 2021

The mission of Food and Drug Administration (FDA)'s Center for Devices and Radiological Health is to protect and promote public health. It assures that patients and providers have timely and continued access to safe, effective, and high-quality medical devices and safe radiation-emitting products by providing meaningful and timely information about the products we regulate and the decisions we make. On September 17, 2021, an FDA workshop was held to provide information to stakeholders, including members of the spine community, device manufacturers, regulatory affairs professionals, clinicians, patients, and the general public regarding FDA regulations, guidance and regulatory pathways related to spinal device clinical review. It was not intended to communicate any new policies, processes, or interpretations regarding medical device marketing authorizations. This workshop consisted of individual presentations, group discussions, question and answer sessions, and audience surveys. Information-sharing included discussions related to patient-reported outcomes, clinician-reported outcomes, observer-reported outcomes, and performance outcomes. Discussions involving external subject matter experts covered topics related to spinal device clinical studies including definition of a target population, enrollment criteria, strategies for inclusion of under-represented patient groups, reporting of adverse event and secondary surgical procedures, clinical study endpoints, and clinical outcome assessments. A meeting transcript and webcast workshop link are currently posted on the FDA website. Important related issues and challenges were discussed, and an exciting range of new ideas and concepts were shared which hold promise to advance regulatory science, patient care and future innovation related to spinal devices.

A Novel Osteoporosis Screening Protocol to Identify Orthopedic Surgery Patients for Preoperative Bone Health Optimization

Introduction

Osteoporosis is highly prevalent in elective orthopedic surgery. While preoperative bone health optimization decreases osteoporosis-related complications, there is an unmet need to establish who may benefit from preoperative dual-energy x-ray absorptiometry (DXA). This study assesses a novel, simple screening protocol to identify orthopedic surgical patients for preoperative DXA.

Materials/Methods

This retrospective cohort study included 628 patients undergoing total knee, hip, or shoulder arthroplasty or thoracolumbar spine fusion. Inclusion criteria were ≥40 years undergoing primary elective surgery. Screening criteria defining who should obtain DXA due to high osteoporosis risk included: female ≥65, male ≥70, fracture history when ≥50 years, or FRAX major osteoporotic fracture risk (without bone mineral density [BMD]-adjustments) ≥8.4%. Osteoporosis was defined by World Health Organization criteria [T-score ≤ -2.5], clinical National Osteoporosis Foundation (NOF) criteria [T-score ≤ -2.5, elevated BMD-adjusted FRAX risk, or prior hip/spine fracture], and modified clinical criteria [NOF criteria simplified to include any non-traumatic prior fracture and FRAX without BMD].

Results

The study included 100 TKAs, 100 THAs, 251 TSAs, and 177 spine fusions, average age 65.6 ± 9.8. DXA was available for 209 patients. Screening criteria recommending DXA was met by 362 patients. For those with DXA, screening sensitivity was .96 (CI: .78 to .99) and specificity was .19 (CI: .14 to .25) for identifying T-score osteoporosis. Similar sensitivity of .99 (CI: .91 to .99) and specificity of .61 (CI: .56 to .66) were found for modified clinical osteoporosis. For modified clinical osteoporosis, 192 patients with osteoporosis met criteria (true pos.), 1 patient with osteoporosis did not meet criteria (false neg.), 170 patients without osteoporosis met criteria (false pos.), and 265 patients without osteoporosis did not meet criteria (true neg.).

Discussion/Conclusion

A simple screening protocol identifies orthopedic surgical candidates at risk of T-score or clinical osteoporosis for preoperative DXA with high sensitivity.

Effect of degeneration on bone mineral density, trabecular bone score and CT Hounsfield unit measurements in a spine surgery patient population

This study investigated the impact of spinal degeneration on bone mineral density (BMD), trabecular bone score (TBS), and CT Hounsfield units in an at-risk population. We found that BMD was increased by degeneration, whereas TBS and HU were unaffected. These findings support that TBS is not adversely affected by spinal degeneration.

INTRODUCTION

This study evaluated the impact of spinal degeneration on BMD and TBS measured by dual-energy x-ray absorptiometry (DXA) and on CT HU in a spine surgery patient population.

METHODS

A retrospective study of 63 patients referred for consideration of spine surgery or with history of spine surgery was performed. Patients were included if a DXA scan and a CT containing the lumbar spine were obtained within 18 months of each other. DXA data were collected and analyzed by vertebral level. Individual vertebrae were assessed for degenerative changes by qualitative evaluation of the anterior and posterior elements using CT. Degeneration scores were compared to BMD T-scores, TBS and CT HU at individual vertebral levels L1-4, and after applying International Society for Clinical Densitometry (ISCD) criteria for excluding vertebrae from diagnostic consideration.

RESULTS

Mean patient age and BMI were 67.2 years and 27.8 kg/m², respectively; 79.4% were female. Mean (SD) lowest T-scores of the hip, spine, and lowest overall T-score were - 1.3 (1.4), - 1.7 (0.9), and - 1.9 (1.0), respectively. Osteoporosis was present by T-score in 38% and osteopenia in 52%; 10% had a history of osteoporotic fracture. The mean degeneration score of individual vertebrae was 4.1 on a 0-6 scale. T-score correlated moderately with degeneration score (Spearman's rho 0.484, p < 0.001), whereas TBS and HU were unrelated. ISCD excluded vertebrae had a higher degeneration score than included vertebrae (p =  < 0.001).

CONCLUSIONS

In a spine surgery population, TBS and CT HU values are unrelated to degeneration score and thus appear unaffected by lumbar vertebral degenerative changes. Additionally, these data support the ISCD criteria for vertebral exclusion.

Femur and Tibia BMD Measurement in Elective Total Knee Arthroplasty Candidates

Distal femur BMD declines ∼20% following total knee arthroplasty (TKA) potentially leading to adverse outcomes. BMD knowledge before and following TKA might allow interventions to optimize outcomes. We hypothesized that distal femur and proximal tibial BMD could be reproducibly measured with existing DXA technology. Elective TKA candidates were enrolled and standard clinical DXA plus bilateral PA and lateral knee scans acquired. Manual regions of interest (ROIs) were placed at distal femur and proximal tibia sites based on required TKA machining and periprosthetic fracture location. Intra- and inter-rater BMD reliability was assessed by intra-class correlation (ICC). Custom and standard proximal femur BMD were correlated by linear regression and paired t test evaluated BMD differences between planned surgical and contralateral side. One hundred subjects (68F/32M), mean (SD) age and BMI of 67.2 (7.7) yr and 30.8 (4.8) kg/m² were enrolled. Lowest clinical BMD T-score was < -1.0 in 65% and ≤ -2.5 in 16%; 34 had prior fracture. BMD reproducibility at all custom ROIs was excellent; ICC > 0.96. Mean BMD at custom ROIs ranged from 0.903 to 1.346 g/cm² in the PA projection and 0.891 to 1.429 g/cm² in the lateral. Lower BMD values were observed at the proximal tibia, while the higher measurements were at the femur condyle. Custom knee ROI BMD was highly correlated (p < 0.0001) with total and femur neck with better correlation at ROIs adjacent to the joint (R² = 0.62-0.67, 0.49-0.55 respectively). In those without prior TKA (n = 76), mean BMD was lower (2.8%-6.6%; p < 0.05) in the planned surgical leg at all custom ROIs except the PA tibial regions. Individual variability was present with 82% having a custom ROI with lower BMD (up to 53%) in the planned operative leg. Distal femur and proximal tibial BMD can be measured using custom ROIs with good reproducibility. Suboptimal bone status is common in TKA candidates and distal femur/proximal tibia BMD is often lower on the planned operative side. Routine distal femur/proximal tibial BMD measurement might assist pre-operative interventions, surgical decision-making, subsequent care and outcomes. Studies to evaluate these possibilities are indicated.

Opportunistic Use of Lumbar Magnetic Resonance Imaging for Osteoporosis Screening

Magnetic resonance imaging (MRI) is a routine assessment before spine surgery. We found that the opportunistic use of MRI with the vertebral bone quality (VBQ) score has good diagnostic ability, with a threshold value of VBQ > 3.0, in recognizing patients who may need further osteoporosis evaluation.

INTRODUCTION

The purpose of this study was to determine whether the opportunistic use of magnetic resonance imaging (MRI) is useful for identifying spine surgical patients who need further osteoporosis evaluation.

METHODS

This retrospective study evaluated 83 thoracolumbar spine surgery patients age ≥ 50 who received T1-weighted MRI. Opportunistic MRI was evaluated with the vertebral bone quality (VBQ) score, VBQ (fat) score, and signal-to-noise ratio (SNR). Each uses the median L1-L4 vertebral body signal intensities (SI) divided by either the L3 cerebrospinal fluid (CSF) SI, average SI of the L1 and S1 dorsal fat, or standard deviation (SD) of the background SI dorsal to the skin. Single-level VBQ was calculated as the ratio of the L1 vertebral body and L1 CSF SIs. Receiver-operator curve analysis was performed to determine diagnostic ability.

RESULTS

The mean age was 70.10, 80% were female, and 96% were Caucasian. The mean ± SD VBQ, single-level VBQ, VBQ (fat), and SNR were 3.39 ± 0.68, 3.56 ± 0.81, 3.95 ± 1.89, and 113.18 ± 77.26, respectively. Using area under the curve, the diagnostic ability of VBQ, single-level VBQ, VBQ (fat), and SNR for clinical osteoporosis were 0.806, 0.779, 0.608, and 0.586, respectively. Diagnostic threshold values identified with optimal sensitivity and specificity were VBQ of 2.95 and single-level VBQ of 3.06.

CONCLUSION

Opportunistic use of MRI is a simple, effective tool that may help recognize patients who are at risk for complications related to bone disease. A VBQ > 3.0 can identify patients who need additional diagnostic evaluation.

Materials discovery and design limits in MDABCO perovskites

Three new structures in the MDABCO perovskite family of ferroelectrics define new design rules for ferroelectric phase discovery.

Proceedings of the 2021 Santa Fe Bone Symposium: Advances in the Management of Osteoporosis and Metabolic Bone Diseases

The 2021 Virtual Santa Fe Bone Symposium was held August 5-8, with over 300 registered attendees from throughout the USA, and at least 18 other countries. This annual meeting focuses on applying advances in basic science and clinical research to the care of patients with osteoporosis and those with inherited and acquired disorders of bone metabolism. Participants represented a broad range of medical disciplines with an interest in skeletal diseases. These included physicians of many specialties and practice settings, fellows, advanced practice providers, fracture liaison service (FLS) coordinators, clinical researchers, and bone density technologists. There were lectures, case presentations, and panel discussions, all followed by interactive discussions. Breakout sessions included an FLS workshop, Bone Health TeleECHO workshop, special interest groups, meet-and-greet the faculty, and satellite symposia. The agenda covered topics of interest such as strategies for the use of osteoanabolic therapy, prevention of periprosthetic fractures, management of atypical femur fractures, what we know and don't know about vitamin D, advances in the use of dual-energy X-ray absorptiometry in the assessment of skeletal health, controversies and conundrums in osteoporosis care, skeletal health in transgender patients, management of patients with hypophosphatasia and hypophosphatemia, and treat-to-target approaches for managing patients with osteoporosis. The Proceedings of the 2021 Virtual Santa Fe Bone Symposium consists of highlights of each presentation with current strategies for optimizing the care of patients with skeletal disorders.

Own the Fall: AOA Critical Issues

Falls are the most common cause of injury to older patients, resulting in >3 million emergency room visits per year and 290,000 hip fractures annually in the United States. Orthopaedic surgeons care for the majority of these patients; however, they are rarely involved in the assessment of fall risk and providing prevention strategies. Falls also occur perioperatively (e.g., in patients with arthritis and those undergoing arthroplasty). Preoperatively, up to 40% of patients awaiting joint arthroplasty sustain a fall, and 20% to 40% have a fall postoperatively. Risk factors for falls include intrinsic factors such as age and comorbidities that are not modifiable as well as extrinsic factors, including medication reconciliation, improvement in the environment, and the management of modifiable comorbidities that can be optimized. Simple in-office fall assessment tools are available that can be adapted for the orthopaedic practice and be used to identify patients who would benefit from rehabilitation. Orthopaedic surgeons should incorporate these strategies to improve care and to reduce fall risk and associated adverse events.

Cervical fusion for treatment of degenerative conditions: development of appropriate use criteria

BACKGROUND CONTEXT

High quality evidence is difficult to generate, leaving substantial knowledge gaps in the treatment of spinal conditions. Appropriate use criteria (AUC) are a means of determining appropriate recommendations when high quality evidence is lacking.

PURPOSE

Define appropriate use criteria (AUC) of cervical fusion for treatment of degenerative conditions of the cervical spine.

STUDY DESIGN/SETTING

Appropriate use criteria for cervical fusion were developed using the RAND/UCLA appropriateness methodology. Following development of clinical guidelines and scenario writing, a one-day workshop was held with a multidisciplinary group of 14 raters, all considered thought leaders in their respective fields, to determine final ratings for cervical fusion appropriateness for various clinical situations.

OUTCOME MEASURES

Final rating for cervical fusion recommendation as either "Appropriate," "Uncertain" or "Rarely Appropriate" based on the median final rating among the raters.

METHODS

Inclusion criteria for scenarios included patients aged 18 to 80 with degenerative conditions of the cervical spine. Key modifiers were defined and combined to develop a matrix of clinical scenarios. The median score among the raters was used to determine the final rating for each scenario. The final rating was compared between modifier levels. Spearman's rank correlation between each modifier and the final rating was determined. A multivariable ordinal regression model was fit to determine the adjusted odds of an "Appropriate" final rating while adjusting for radiographic diagnosis, number of levels and symptom type. Three decision trees were developed using decision tree classification models and variable importance for each tree was computed.

RESULTS

Of the 263 scenarios, 47 (17.9 %) were rated as rarely appropriate, 66 (25%) as uncertain and 150 (57%) were rated as appropriate. Symptom type was the modifier most strongly correlated with the final rating (adjusted ρ2 = 0.58, p<.01). A multivariable ordinal regression adjusting for symptom type, diagnosis, and number of levels and showed high discriminative ability (C statistic = 0.90) and the adjusted odds ratio (aOR) of receiving a final rating of "Appropriate" was highest for myelopathy (aOR, 7.1) and radiculopathy (aOR, 4.8). Three decision tree models showed that symptom type and radiographic diagnosis had the highest variable importance.

CONCLUSIONS

Appropriate use criteria for cervical fusion in the setting of cervical degenerative disorders were developed. Symptom type was most strongly correlated with final rating. Myelopathy or radiculopathy were most strongly associated with an "Appropriate" rating, while axial pain without stenosis was most associated with "Rarely Appropriate."

A Multicenter Evaluation of the Feasibility, Patient/Provider Satisfaction, and Value of Virtual Spine Consultation During the COVID-19 Pandemic

Objective

To assess the feasibility, patient/provider satisfaction, and perceived value of telehealth spine consultation after rapid conversion from traditional in-office visits during the COVID-19 pandemic.

Methods

Data were obtained for patients undergoing telehealth visits with spine surgeons in the first 3 weeks after government restriction of elective surgical care at 4 sites (March 23, 2020, to April 17, 2020). Demographic factors, technique-specific elements of the telehealth experience, provider confidence in diagnostic and therapeutic assessment, patient/surgeon satisfaction, and perceived value were collected.

Results

A total of 128 unique visits were analyzed. New (74 [58%]), preoperative (26 [20%]), and postoperative (28 [22%]) patients were assessed. A total of 116 (91%) visits had successful connection on the first attempt. Surgeons felt very confident 101 times (79%) when assessing diagnosis and 107 times (84%) when assessing treatment plan. The mean and median patient satisfaction was 89% and 94%, respectively. Patient satisfaction was significantly higher for video over audio-only visits (P < 0.05). Patient satisfaction was not significantly different with patient age, location of chief complaint (cervical or thoracolumbar), or visit type (new, preoperative, or postoperative). Providers reported that 76% of the time they would choose to perform the visit again in telehealth format. Sixty percent of patients valued the visit cost as the same or slightly less than an in-office consultation.

Conclusions

This is the first study to demonstrate the feasibility and high patient/provider satisfaction of virtual spine surgical consultation, and appropriate reimbursement and balanced regulation for spine telehealth care is essential to continue this existing work.

Teriparatide Treatment Increases Hounsfield Units in the Thoracic Spine, Lumbar Spine, Sacrum, and Ilium Out of Proportion to the Cervical Spine

STUDY DESIGN

This was a retrospective chart review.

OBJECTIVE

The objective of this study was to compare the effect of teriparatide on Hounsfield Units (HU) in the cervical spine, thoracic spine, lumbar spine, sacrum, and pelvis. Second, to correlate HU changes at each spinal level with bone mineral density (BMD) on dual-energy x-ray absorptiometry (DXA).

SUMMARY OF BACKGROUND DATA

HU represent a method to estimate BMD and can be used either separately or in conjunction with BMD from DXA.

MATERIALS AND METHODS

A retrospective chart review included patients who had been treated with at least 6 months of teriparatide. HU were measured in the vertebral bodies of the cervical, thoracic, and lumbosacral spine and iliac crests. Lumbar and femoral neck BMD as measured on DXA was collected when available.

RESULTS

One hundred twenty-five patients were identified for analysis with an average age of 67 years who underwent a mean (±SD) of 22±8 months of teriparatide therapy. HU improvement in the cervical spine was 11% (P=0.19), 25% in the thoracic spine (P=0.002), 23% in the lumbar spine (P=0.027), 17% in the sacrum (P=0.11), and 29% in the iliac crests (P=0.09). Lumbar HU correlated better than cervical HU with BMD as measured on DXA.

CONCLUSIONS

Teriparatide increased average HU in the thoracolumbar spine to a proportionally greater extent than the cervical spine. The cervical spine had a higher baseline starting HU than the thoracolumbar spine. Lumbar HU correlated better than cervical and thoracic HU with BMD as measured on DXA.

Osteoporosis in spine surgery patients: what is the best way to diagnose osteoporosis in this population?

OBJECTIVE

The goal of this study was to compare different recognized definitions of osteoporosis in patients with degenerative lumbar spine pathology undergoing elective spinal fusion surgery to determine which patient population should be considered for preoperative optimization.

METHODS

A retrospective review of patients in whom lumbar spine surgery was planned at 2 academic medical centers was performed, and the rate of osteoporosis was compared based on different recognized definitions. Assessments were made based on dual-energy x-ray absorptiometry (DXA), CT Hounsfield units (HU), trabecular bone score (TBS), and fracture risk assessment tool (FRAX). The rate of osteoporosis was compared based on different definitions: 1) the WHO definition (T-score ≤ -2.5) at total hip or spine; 2) CT HU of < 110; 3) National Bone Health Alliance (NBHA) guidelines; and 4) "expanded spine" criteria, which includes patients meeting NBHA criteria and/or HU < 110, and/or "degraded" TBS in the setting of an osteopenic T-score. Inclusion criteria were adult patients with a DXA scan of the total hip and/or spine performed within 1 year and a lumbar spine CT scan within 6 months of the physician visit.

RESULTS

Two hundred forty-four patients were included. The mean age was 68.3 years, with 70.5% female, 96.7% Caucasian, and the mean BMI was 28.8. Fracture history was reported in 53.8% of patients. The proportion of patients identified with osteoporosis on DXA, HUs, NBHA guidelines, and the authors' proposed "expanded spine" criteria was 25.4%, 36.5%, 75%, and 81.9%, respectively. Of the patients not identified with osteoporosis on DXA, 31.3% had osteoporosis based on HU, 55.1% had osteoporosis with NBHA, and 70.4% had osteoporosis with expanded spine criteria (p < 0.05), with poor correlations among the different assessment tools.

CONCLUSIONS

Limitations in the use of DXA T-scores alone to diagnose osteoporosis in patients with lumbar spondylosis has prompted interest in additional methods of evaluating bone health in the spine, such as CT HU, TBS, and FRAX, to inform guidelines that aim to reduce fracture risk. However, no current osteoporosis assessment was developed with a focus on improving outcomes in spinal surgery. Therefore, the authors propose an expanded spine definition for osteoporosis to identify a more comprehensive cohort of patients with potential poor bone health who could be considered for preoperative optimization, although further study is needed to validate these results in terms of clinical outcomes.

Lower Hounsfield Units at the Upper Instrumented Vertebrae are Significantly Associated With Proximal Junctional Kyphosis and Failure Near the Thoracolumbar Junction

BACKGROUND

Low bone mineral density (BMD) on dual energy x-ray absorptiometry (DXA) is likely a risk factor for proximal junctional kyphosis (PJK) and proximal junctional failure (PJF). However, prior instrumentation and degenerative changes can preclude a lumbar BMD measurement. Hounsfield units (HU) represent an alternative method to estimate BMD via targeted measurements at the intended operative levels.

OBJECTIVE

To determine if patients with lower HU at the upper instrumented vertebrae (UIV) and vertebral body superior to the UIV (UIV + 1) are at greater risk for PJK and PJF.

METHODS

A retrospective chart review identified patients at least 50 yr of age who underwent instrumented lumbar fusion with pelvic fixation, a UIV from T10 to L2, and a preoperative computed tomography (CT) encompassing the UIV. HU were measured at the UIV, UIV + 1, and the L3-L4 vertebral bodies.

RESULTS

A total of 150 patients (80 women and 70 men) were included with an average age of 66 yr and average follow-up of 32 mo. Multivariable logistic regression analysis with an area under the curve (AUC) of 0.89 demonstrated HU at the UIV/UIV + 1 as the only independent predictor of PJK/PJF with an odds ratio of 0.94 (P-value = .031) for a change in a single HU. Patients with HU at UIV/UIV + 1 of <110 (n = 35), 110 to 160 (n = 73), and >160 (n = 42) had a rate of PJK/PJF of 63%, 27%, and 12%, respectively (P-value < .001).

CONCLUSION

Patients with lower HU at the UIV and UIV + 1 were significantly associated with PJK and PJF, with an optimal cutoff of 122 HU that maximizes sensitivity and specificity.

Osteoporosis: Recent Recommendations and Positions of the American Society for Bone and Mineral Research and the International Society for Clinical Densitometry

➤

Osteoporosis is common in orthopaedic patients, not only in those sustaining fragility fractures but also in patients ≥50 years old who are having elective orthopaedic surgery.

➤

The American Society for Bone and Mineral Research (ASBMR) has developed consensus-based recommendations for secondary fracture prevention for all patients who are ≥65 years old with a hip or spine fracture.

➤

The ASBMR encourages orthopaedic surgeons to "Own the Bone," by beginning prevention of a secondary fracture during hospitalization for a fragility fracture, if practicable, and arranging follow-up for continued bone health care after discharge.

➤

The International Society for Clinical Densitometry (ISCD) recognized that many poor outcomes and complications of elective orthopaedic surgery are related to osteoporosis.

➤

The ISCD used an evidence-based approach to create official positions to identify which patients ≥50 years old who are having elective orthopaedic surgery should undergo assessment of bone health and how this should be performed.

Raman spectroscopy insights into the α- and δ-phases of formamidinium lead iodide (FAPbI3)

Solar perovskites have received phenomenal attention and success over the past decade, due to their high power conversion efficiencies (PCE), ease of fabrication and low cost which has enabled the prospect of them being a real commercial contender to the traditional silicon technology. In one of the several developments on the archetypal MAPbI3 perovskite absorber layer, FAPbI3 was found to obtain a higher PCE, likely due to its more optimum band gap, with doping strategies focusing on the inclusion of MA+/Cs+ cations to avoid the unfavourable phase transformation to a photoinactive phase. To better understand the phase change from the photoactive cubic (Pm3[combining macron]m) black (α) phase to the unwanted photoinactive (P63/mmc) yellow (δ) phase, we make use of variable temperature Raman spectroscopy to probe the molecular species and its relationship to the inorganic framework. We show for the first time there to be no Raman active modes for the α phase up to 4000 cm-1, which can be correlated to the Pm3[combining macron]m cubic symmetry of that phase. Our detailed studies suggest that previous reports of the observation of Raman peaks for this phase are likely associated with degradation reactions from the localised laser exposure and the formation of Raman active lead oxide. In addition, we have identified water as a contributing factor to the transformation, and observed a corresponding signal in the Raman spectra, although confirmation of its exact role still remains inconclusive.

Opportunistic use of dual-energy X-ray absorptiometry to evaluate lumbar scoliosis

Low bone mineral density is associated with spinal deformity. Dual-energy X-ray absorptiometry (DXA), a modality that assesses bone density, portends a theoretical means to also assess spinal deformity. We found that DXA can reliably assess spine alignment. DXA may permit surveillance of spine alignment, i.e., scoliosis in the clinical setting.

PURPOSE

Osteoporosis and scoliosis are interrelated disease processes. Dual-energy X-ray absorptiometry (DXA), used to assess bone density, can also be used to evaluate spinal deformity since it captures a posteroanterior (PA) image of the lumbar spine. We assessed the use of DXA to evaluate lumbar spine alignment.

METHODS

A lumbar spine DXA phantom was used to assess the effects of axial and sagittal plane rotation on lumbar bone mineral content (BMC), density (BMD), and L1-L4 Cobb angle measurements. Using two subject cohorts, intra- and inter-observer reliability and validity of using DXA for L1-L4 Cobb angle measurements in the coronal and sagittal planes were assessed.

RESULTS

Axial and sagittal plane rotation greater than 15° and 10°, respectively, significantly reduced measured BMD and BMC; there was minimal effect on Cobb angle measurement reliability. In human subjects, excellent intra- and inter-observer reliability was observed using lumbar PA DXA images for Cobb angle measurements. Agreement between Cobb angles derived from lumbar PA DXA images and AP lumbar radiographs ranged from good to excellent. The mean difference in Cobb angles between supine lumbar PA DXA images and upright AP lumbar radiographs was 2.8° in all subjects and 5.8° in those with scoliosis.

CONCLUSIONS

Lumbar spine rotation does not significantly affect BMD and BMC within 15° and 10° of axial and sagittal plane rotation, respectively, and minimally affects Cobb angle measurement. Spine alignment in the coronal plane can be reliably assessed using lumbar PA DXA images.

The Basics of Bone Physiology, Healing, and Osteoporosis

Osteoporosis is a skeletal condition characterized by decreased bone mineral density and poor bone quality with resultant greater fracture risk. There has been a focus on bone mineral density deficiency, which is easily measured with dual-energy x-ray absorptiometry and managed with pharmaceutic medications. More recently, impaired bone quality independent of bone mineral density has been recognized as a potential cause of fragility fracture and poor bone healing. Many conditions lead to poor bone quality; the most common is vitamin D deficiency and others are genetic causes and other nutritional deficits. In addition, the cellular and molecular changes associated with osteoporosis are being investigated and are potential targets for treatment. Treatment of patients with poor bone health include nutritional supplementation with vitamin D and calcium, weight-bearing exercises, and antiosteoporotic medications when warranted. Antiosteoporotic medications include antiresorptive drugs such as diphosphonate and denosumab that inhibit osteoclastic bone resorption. Anabolic agents such as teriparatide, abaloparatide, and romosozumab stimulate osteoblastic differentiation and bone formation. All these agents are effective in reducing fracture risk.

Rationale for Bone Health Optimization in Patients Undergoing Orthopaedic Surgery

Osteoporosis is common, affecting more than 40 million people, and is associated with increased fracture risk, loss of independence, chronic pain, and disability. Osteoporosis is underdiagnosed and undertreated even after fracture where secondary fracture prevention has been shown to be cost effective in reducing further fracture risk and mortality. Osteoporosis is also undiagnosed in patients undergoing orthopaedic and spine surgery in up to one-third of cases and negatively affects outcomes, need for revision surgery, and risk of complications. The diagnosis of osteoporosis was previously based on bone mineral density; however, recent clinical definitions include T-scores less than -2.5, the presence of hip and spine fractures, and high fracture risk. Surgeons should adopt bone health optimization for elective surgery. This program screens patients to determine whether a bone mineral density test is indicated and provides counseling for nutritional supplements, elimination of toxins, fall risk assessment, and education regarding bone health. Following assessment, patients meeting the criteria for osteoporosis are referred to a bone health specialist or a fracture liaison program. Both antiresorptive and anabolic antiosteoporotic medications appear effective at improving outcomes and reducing complications of orthopaedic and spine surgery, although a delay in surgery may be required.

Association of Perioperative Computed Tomography Hounsfield Units and Failure of Femoral Neck Fracture Fixation

OBJECTIVES

To determine whether Hounsfield units (HUs) measured on perioperative computed tomographic scans are associated with radiographic outcomes and reoperations after femoral neck fracture fixation.

DESIGN

Retrospective cohort study.

SETTING

Level I trauma center.

PATIENTS

One hundred fourteen patients age ≥18 years, who presented to a Level I trauma center, and who underwent surgical fixation of intracapsular femoral neck fracture and had perioperative computed tomographic scans and adequate follow-up.

INTERVENTION

None.

MAIN OUTCOME MEASUREMENTS

Screw penetration, femoral neck shortening >5 mm, and revision surgery.

RESULTS

A median follow-up was 23 months. An HU measurement of the femoral head was significantly associated with screw penetration and femoral neck shortening but not revision surgery. Patients with middle femoral head HU measurements <146 had 17 times (95% confidence interval: 4.32-78.9, P < 0.001) increased odds of screw penetration. Greater than 5 mm shortening was seen in patients with HUs <212.5 in the low head section by an odds ratio of 7.8 (95% confidence interval: 2.15-33.0, P = 0.014).

CONCLUSION

Outcome differences regarding screw penetration and femoral neck shortening related to the HU or densities of femoral head and neck at the time of fracture are significant. These findings can help the clinician with developing a treatment plan for either arthroplasty or fixation of a femoral neck fracture based on objective bone quality measurements rather than relying on an arbitrary age recommendation.

LEVEL OF EVIDENCE

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

Biomechanical Analysis of an Anterior Cervical Discectomy and Fusion Pseudarthrosis Model Revised With Machined Interfacet Allograft Spacers

STUDY DESIGN

Biomechanics study.

OBJECTIVES

To evaluate the biomechanical advantage of interfacet allograft spacers in an unstable single-level and 2-level anterior cervical discectomy and fusion (ACDF) pseudoarthrosis model.

METHODS

Nine single-level and 8 two-level ACDF constructs were tested. Range of motion in flexion-extension (FE), lateral bending (LB), and axial rotation (AR) at 1.5 N m were collected in 4 testing configurations: (1) intact spine, (2) ACDF with interbody graft and plate/screw, (3) ACDF with interbody graft and plate/loosened screws (loose condition), and (4) ACDF with interbody graft and plate/loosened screws supplemented with interfacet allograft spacers (rescue condition).

RESULTS

All fixation configurations resulted in statistically significant decreases in range of motion in all bending planes compared with the intact spine (P < .05). One Level. Performing ACDF with interbody graft and plate on the intact spine reduced FE, LB, and AR 60.0%, 64.9%, and 72.9%, respectively. Loosening the ACDF screws decreased these reductions to 40.9%, 44.6%, and 52.1%. The addition of interfacet allograft spacers to the loose condition increased these reductions to 74.0%, 84.1%, and 82.1%. Two Level. Performing ACDF with interbody graft and plate on the intact spine reduced FE, LB, and AR 72.0%, 71.1%, and 71.2%, respectively. Loosening the ACDF screws decreased these reductions to 55.4%, 55.3%, and 51.3%. The addition of interfacet allograft spacers to the loose condition significantly increased these reductions to 82.6%, 91.2%, and 89.3% (P < .05).

CONCLUSIONS

Supplementation of a loose ACDF construct (pseudarthrosis model) with interfacet allograft spacers significantly increases stability and has potential applications in treating cervical pseudarthrosis.

Preoperative bone health assessment and optimization in spine surgery

OBJECTIVE

The purpose of this investigation was to characterize the bone health in preoperative spine surgery patients. This information will provide a framework to understand the needs and methods for providing bone health optimization in elective spine surgery patients.

METHODS

A retrospective study of 104 patients undergoing bone health optimization was performed. Patients were selected based on risk factors identified by the surgeon and suspected compromised bone health. Evaluation included history and examination, laboratory investigations, and bone mineral density (BMD) at 3 sites (femoral neck, lumbar spine, and radius). Patients' bone status was classified using WHO criteria and expanded criteria recommended by the National Osteoporosis Foundation (NOF). The 10-year Fracture Risk Assessment Tool (FRAX) scores of the hip and major osteoporotic fracture (MOF) were calculated with and without femoral neck BMD, with spine BMD, and with the trabecular bone score (TBS). Antiresorptive and anabolic agents were provided in accordance with meeting NOF criteria for treatment of osteoporosis.

RESULTS

The mean patient age was 69.0 years, and 81% of patients were female. The mean historical height loss was 5.6 cm, and 54% of patients had a history of fracture. Secondary osteoporosis due to chronic renal failure, inflammatory arthritis, diabetes, and steroid use was common (51%). The mean 25-hydroxy vitamin D was 42.4 ng/ml and was normal in 81% of patients, with only 4 patients being deficient. The mean T-scores were -2.09 (SD 0.71) of the femoral neck, -0.54 (1.71) of the lumbar spine, and -1.65 (1.38) of the distal radius. These were significantly different. The 10-year FRAX MOF score was 20.7%, and that for hip fracture was 6.9% using the femoral neck BMD and was not significantly different without the use of BMD. The FRAX risk-adjusted score using the lumbar spine BMD and TBS was significantly lower than that for the hip. Osteoporosis was present in 32.1% according to WHO criteria compared with 81.6% according to NOF criteria. Antiresorptive medications were recommended in 31 patients and anabolic medications in 44 patients.

CONCLUSIONS

Surgeons can reliably identify patients with poor bone health by using simple criteria, including historical height loss, history of fracture, comorbidities associated with osteoporosis, analysis of available imaging, and calculation of FRAX score without BMD. High-risk patients should have BMD testing and bone health assessment. In patients with osteoporosis, a comprehensive preoperative bone health assessment is recommended and, if warranted, pharmacological treatment should be started.

Regional improvements in lumbosacropelvic Hounsfield units following teriparatide treatment

OBJECTIVE

Opportunistic Hounsfield unit (HU) determination from CT imaging has been increasingly used to estimate bone mineral density (BMD) in conjunction with assessments from dual energy x-ray absorptiometry (DXA). The authors sought to compare the effect of teriparatide on HUs across different regions in the pelvis, sacrum, and lumbar spine, as a surrogate measure for the effects of teriparatide on lumbosacropelvic instrumentation.

METHODS

A single-institution retrospective review of patients who had been treated with at least 6 months of teriparatide was performed. All patients had at least baseline DXA as well as pre- and post-teriparatide CT imaging. HUs were measured in the pedicle, lamina, and vertebral body of the lumbar spine, in the sciatic notch, and at the S1 and S2 levels at three different points (ilium, sacral body, and sacral ala).

RESULTS

Forty patients with an average age of 67 years underwent a mean of 20 months of teriparatide therapy. Mean HUs of the lumbar lamina, pedicles, and vertebral body were significantly different from each other before teriparatide treatment: 343 ± 114, 219 ± 89.2, and 111 ± 48.1, respectively (p < 0.001). Mean HUs at the S1 level for the ilium, sacral ala, and sacral body were also significantly different from each other: 124 ± 90.1, −10.7 ± 61.9, and 99.1 ± 72.1, respectively (p < 0.001). The mean HUs at the S2 level for the ilium and sacral body were not significantly different from each other, although the mean HU at the sacral ala (−11.9 ± 52.6) was significantly lower than those at the ilium and sacral body (p = 0.003 and 0.006, respectively). HU improvement occurred in most regions following teriparatide treatment. In the lumbar spine, the mean lamina HU increased from 343 to 400 (p < 0.001), the mean pedicle HU increased from 219 to 242 (p = 0.04), and the mean vertebral body HU increased from 111 to 134 (p < 0.001). There were also significant increases in the S1 sacral body (99.1 to 130, p < 0.05), S1 ilium (124 vs 165, p = 0.01), S1 sacral ala (−10.7 vs 3.68, p = 0.04), and S2 sacral body (168 vs 189, p < 0.05).

CONCLUSIONS

There was significant regional variation in lumbar and sacropelvic HUs, with most regions significantly increasing following teriparatide treatment. The sacropelvic area had lower HU values than the lumbar spine, more regional variation, and a higher degree of correlation with BMD as measured on DXA. While teriparatide treatment resulted in HUs > 110 in the majority of the lumbosacral spine, the HUs in the sacral ala remained suggestive of severe osteoporosis, which may limit the effectiveness of fixation in this region.

Cervical Kyphosis in Spinal Muscular Atrophy: A Case Report

CASE

A 12-year-old boy with spinal muscular atrophy (SMA) Type II presented 5 years after undergoing spinal growing rod placement with cervical kyphosis at C2-3. He underwent anterior cervical discectomy and fusion but 6 years later developed significant kyphosis at the adjacent C3-4 level.

CONCLUSION

We describe a rare adjacent segment kyphotic condition in a young man with SMA Type II. Clinicians should be cognizant of the risk of cervical kyphosis in adolescent patients with SMA.

Abaloparatide and the Spine: A Narrative Review

Osteoporosis is a common and debilitating condition characterized by diminished bone mass and architecture leading to bone fragility. Antiresorptive medicines like bisphosphonates (and less commonly denosumab) are the typical first-line agents for the medical treatment of osteoporosis. However, newer anabolic agents have been shown to improve bone mass and architecture, as well as reduce fracture risk, to a greater degree than traditional antiresorptive therapies. Teriparatide (human recombinant parathyroid hormone (PTH) 1–34, Forteo, Ely Lilly, Indianapolis, IN), which was the first in class to be approved in the United States, is the most widely used anabolic osteoporosis medicine and has shown significant benefit over traditional antiresorptive therapies. However, abaloparatide (synthetic parathyroid-related peptide (PTHrP), Tymlos, Radius Health, Waltham, MA), the second drug in this family, has recently become available for use. In this narrative review, we review the mechanism, effects, and benefits of abaloparatide compared to alternative treatments as well as discuss the current literature in regard to its effect on osteoporosis-related complications in the spine.

Appropriate Management of Vertebral Fragility Fractures: Development of a Pathway Based on a Vertebral Compression Fracture Registry

BACKGROUND

The BenchMarket Medical (BMM) Vertebral Compression Fracture (VCF) Registry, now known as Talosix, is a collaborative effort between Talosix (the authorized registry vendor), Noridian Healthcare Solutions, and clinicians to gather outcomes evidence for cement augmentation treatments in patients with acute painful osteoporotic VCFs. The VCF Registry was designed to provide outcomes evidence to inform the Medicare payer's "coverage with evidence development" decision to authorize reimbursement for cement augmentation treatments.

OBJECTIVES

The purpose of this article was to present a pathway for appropriate use of vertebral augmentation based on the findings of the VCF Registry.

STUDY DESIGN

Prospective observational data, including patient characteristics, diagnosis, process of care, and patient-reported outcomes (PROs) for pain and function, were collected from patients undergoing cement augmentation treatment. The PROs were collected at baseline, 1, 3, and 6 months following the procedure.

SETTING

The VCF Registry is a national ongoing registry with no specified end time or designated sample size.

METHODS

Primary outcomes were pain improvement measured using the Numeric Rating Scale and function improvement, measured using the Roland Morris Disability Questionnaire (RMDQ). Secondary outcomes included cement leakage, new neurologic deficits, adverse events, readmissions, and death.

RESULTS

The VCF Registry delivered outcomes data to support Noridian's "coverage with evidence development" decision. A total of 732 patients were included in this study. Registry outcomes confirmed postmarket evidence of highly significant pain relief with mean pain score improvement of 6.5/10 points at 6 months. Function also improved significantly with mean RMDQ score change of 11.4/24 points 6 months after surgery. Results also showed the safety and reliability of cement augmentation.

LIMITATIONS

The nature of the registry data is that it contains nonrandomized, nonplacebo controlled data and should not be perceived as such. The real-world setting and the large number of patients within the dataset should increase the external validity of the findings.

CONCLUSIONS

Cement augmentation treatments of patients with acute painful VCFs reliably results in highly significant benefits of pain decrease and functional improvement for this Medicare population.

KEY WORDS

Vertebral compression fractures, osteoporosis, kyphoplasty, back pain, registry.

Bone Health Optimization in Orthopaedic Surgery

BACKGROUND

Osteoporosis is associated with adverse orthopaedic surgical outcomes. Bone health optimization is a preoperative intervention intended to reduce the likelihood of postoperative complications. We aimed to characterize a patient cohort referred for bone health optimization to test the hypothesis that poor bone quality is common in orthopaedic surgery and that many such patients meet guidelines for osteoporosis treatment.

METHODS

This retrospective study evaluated 124 patients referred for bone health optimization who were ≥50 years of age and candidates for arthroplasty or thoracolumbar surgery. The Fracture Risk Assessment Tool (FRAX) risk factors and dual x-ray absorptiometry (DXA) results were collected. When available, opportunistic computed tomographic (CT) imaging and the trabecular bone score were evaluated. The World Health Organization (WHO) diagnostic and National Osteoporosis Foundation (NOF) treatment guidelines were applied.

RESULTS

All patients were referred by their orthopaedic surgeon; their mean age was 69.2 years, 83% of patients were female, 97% were Caucasian, and 56% had sustained a previous fracture. The mean historical height loss (and standard deviation) was 5.3 ± 3.3 cm for women and 6.0 ± 3.6 cm for men. The mean lowest T-score of the hip, spine, or wrist was -2.43 ± 0.90 points in women and -2.04 ± 0.81 points in men (p < 0.08). Osteoporosis (T-score of ≤-2.5 points) was present in 45% of women and 20% of men; only 3% of women and 10% of men had normal bone mineral density. Opportunistic CT scans identified 60% of patients as likely having osteoporosis. The trabecular bone score identified 34% of patients with degraded bone microarchitecture and 30% of patients with partially degraded bone microarchitecture. The NOF threshold for osteoporosis treatment was met in 91% of patients. Treatment was prescribed in 75% of patients (45% anabolic therapy and 30% antiresorptive therapy).

CONCLUSIONS

Osteoporosis, degraded bone microarchitecture, prior fracture, and elevated fracture risk were common. Given the high prevalence of impaired bone health in this cohort, we believe that bone health screening, including FRAX assessment, should be considered in selected patients undergoing orthopaedic surgery as part of the preoperative optimization for all adults who are ≥50 years of age.

LEVEL OF EVIDENCE

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

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

QUESTION

Does the choice of surgical approach (anterior, posterior, or combined anterior-posterior) improve clinical outcomes in patients with thoracic and lumbar fractures?

RECOMMENDATIONS

In the surgical treatment of patients with thoracolumbar burst fractures, physicians may use an anterior, posterior, or a combined approach as the selection of approach does not appear to impact clinical or neurological outcomes. Strength of Recommendation: Grade B With regard to radiologic outcomes in the surgical treatment of patients with thoracolumbar fractures, physicians may utilize an anterior, posterior, or combined approach because there is conflicting evidence in the comparison among approaches. Strength of Recommendation: Grade Insufficient With regard to complications in the surgical treatment of patients with thoracolumbar fractures, physicians may use an anterior, posterior, or combined approach because there is conflicting evidence in the comparison among approaches. 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_11.

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

QUESTION 1

Does routine screening for deep venous thrombosis prevent pulmonary embolism (or venous thromboembolism (VTE)-associated morbidity and mortality) in patients with thoracic and lumbar fractures?

RECOMMENDATION 1

There is insufficient evidence to recommend for or against routine screening for deep venous thrombosis in preventing pulmonary embolism (or VTE-associated morbidity and mortality) in patients with thoracic and lumbar fractures. Strength of Recommendation: Grade Insufficient.

QUESTION 2

For patients with thoracic and lumbar fractures, is one regimen of VTE prophylaxis superior to others with respect to prevention of pulmonary embolism (or VTE-associated morbidity and mortality)?

RECOMMENDATION 2

There is insufficient evidence to recommend a specific regimen of VTE prophylaxis to prevent pulmonary embolism (or VTE-associated morbidity and mortality) in patients with thoracic and lumbar fractures. Strength of Recommendation: Grade Insufficient.

QUESTION 3

Is there a specific treatment regimen for documented VTE that provides fewer complications than other treatments in patients with thoracic and lumbar fractures?

RECOMMENDATION 3

There is insufficient evidence to recommend for or against a specific treatment regimen for documented VTE that would provide fewer complications than other treatments in patients with thoracic and lumbar fractures. Strength of Recommendation: Grade Insufficient.

RECOMMENDATION 4

Based on published data from pooled (cervical and thoracolumbar) spinal cord injury populations, the use of thromboprophylaxis is recommended to reduce the risk of VTE events in patients with thoracic and lumbar fractures. Consensus Statement by the Workgroup 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_7.

An Ion-Exchangeable MOF with Reversible Dehydration and Dynamic Structural Behavior (NH4 )2 [Zn2 (O3 PCH2 CH2 COO)2 ]⋅5 H2 O (BIRM-1)

(NH₄ )₂ [Zn₂ (O₃ PCH₂ CH₂ COO)₂ ]⋅5 H₂ O (BIRM-1) is a new metal phosphonate material, synthesized through a simple hydrothermal reaction between zinc nitrate and 3-phosphonopropionic acid, using urea and tetraethylammonium bromide as the reaction medium. In common with other metal-organic framework materials, BIRM-1 has a large three-dimensional porous structure providing potential access to a high internal surface area. Unlike most others, it has the advantage of containing ammonium cations within the pores and has the ability to undergo cation exchange. Additionally, BIRM-1 also exhibits a reversible dehydration behavior involving an amorphization-recrystallization cycle. The ability to undergo ion exchange and dynamic structural behavior are of interest in their own right, but also increase the range of potential applications for this material. Here the crystal structure of this new metal phosphonate and its ion exchange behavior with K⁺ as an exemplar are studied in detail, and its unusual structure-reviving property reported.