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.

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.

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 < 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 < 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.

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.

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.

What Are the 30-day Readmission Rates Across Orthopaedic Subspecialties?

BACKGROUND: The Centers for Medicare & Medicaid Services (CMS) now include hip and knee replacements in the Hospital Readmission Reduction Program. The 30-day readmission rate is an important quality metric; however, the incidence has not yet been defined across the numerous orthopaedic subspecialties. Elucidating the readmission rate for each subspecialty may indicate that certain services are being disincentivized by the CMS reimbursement program. Furthermore, the "planned" and "unplanned" definitions of readmission have not been well examined to determine their clinical relevance and representation of safe patient care. Therefore, reducing the 30-day readmission rate has become a top priority in orthopaedic quality assurance. QUESTIONS/PURPOSES: (1) What are the 30-day readmission rates for the different orthopaedic subspecialties? (2) What are the risk factors associated with readmission within 30 days? (3) What are the causes of 30-day readmissions? (4) What is the interrater agreement among CMS, hospital, and clinician definitions of planned and unplanned readmissions? METHODS: We retrospectively examined one tertiary care academic hospital's quality improvement database and identified 4792 discharges from the department of orthopaedics during a continuous 24-month period. Discharges were divided and analyzed according to the subspecialty of orthopaedic care. Demographics and comorbidities were extracted from the database and subjected to univariate and multivariate analysis to determine risk factors for 30-day readmission. Further chart review was conducted on all cases of 30-day readmission to identify causes. The authors' determination of planned versus unplanned was compared with two other definitions (hospital and CMS) and analyzed for agreement by using Fleiss' kappa for multiple rater. RESULTS: The all-cause 30-day readmission rate was 4% (95% confidence interval [CI], 3.8-4.8). The unplanned readmission rate was 3% (95% CI, 2.8-3.8). After controlling for relevant confounding variables, we found that length of stay (odds ratio [OR], 1.10 per day; p < 0.001), American Society of Anesthesiologists score (OR, 1.89 per point; p < 0.001), and care under trauma (OR, 2.55; p < 0.001) or "other" (OR, 1.65; p = 0.009) as compared with joint subspecialty were associated with increased risk of readmission. Of the 160 unplanned readmissions, 93 (58%) were surgical and 67 (42%) were medical. The most common surgical cause was surgical site infection (38% of surgical readmissions) and the most common medical causes were gastrointestinal bleed, pulmonary embolus, and unrelated trauma (each 9% of medical readmissions). There was poor agreement (Fleiss' kappa = 0.120) among the three definitions of planned readmission. CONCLUSIONS: There are important differences in the risk of readmission by subspecialty across orthopaedics and the CMS-driven disincentives may be applied unequally across these subspecialties. This could result in hospitals deemphasizing those service lines and could potentially limit access to care for the patients most in need. Avenues of readmission reduction should be further studied including telephone followup programs and outpatient management of threatened wounds. Clinical, hospital, and CMS definitions of planned readmission have poor agreement, suggesting that hospitals are being unnecessarily penalized. The CMS should develop a more clinically relevant definition of 30-day readmission to more accurately evaluate the rate of readmissions. LEVEL OF EVIDENCE: Level III, therapeutic study.

Thirty-day readmission rates in spine surgery: systematic review and meta-analysis.

OBJECT The rate of 30-day readmissions is rapidly gaining significance as a quality metric and is increasingly used to evaluate performance. An analysis of the present 30-day readmission rate in the spine literature is needed to aid the development of policies to decrease the frequency of readmissions. The authors examine 2 questions: 1) What is the 30-day readmission rate as reported in the spine literature? 2) What study factors impact the rate of 30-day readmissions? METHODS This study was registered with Prospera (CRD42014015319), and 4 electronic databases (PubMed, Cochrane Library, Web of Science, and Google Scholar) were searched for articles. A systematic review and meta-analysis was performed to assess the current 30-day readmission rate in spine surgery. Thirteen studies met inclusion criteria. The readmission rate as well as data source, time from enrollment, sample size, demographics, procedure type and spine level, risk factors for readmission, and causes of readmission were extrapolated from each study. RESULTS The pooled 30-day readmission rate was 5.5% (95% CI 4.2%-7.4%). Studies from single institutions reported the highest 30-day readmission rate at 6.6% (95% CI 3.8%-11.1%), while multicenter studies reported the lowest at 4.7% (95% CI 2.3%-9.7%). Time from enrollment had no statistically significant effect on the 30-day readmission rate. Studies including all spinal levels had a higher 30-day readmission rate (6.1%, 95% CI 4.1%-8.9%) than exclusively lumbar studies (4.6%, 95% CI 2.5%-8.2%); however, the difference between the 2 rates was not statistically significant (p = 0.43). The most frequently reported risk factors associated with an increased odds of 30-day readmission on multivariate analysis were an American Society of Anesthesiology score of 4+, operative duration, and Medicare/Medicaid insurance. The most common cause of readmission was wound complication (39.3%). CONCLUSIONS The 30-day readmission rate following spinal surgery is between 4.2% and 7.4%. The range, rather than the exact result, should be considered given the significant heterogeneity among studies, which indicates that there are factors such as demographics, procedure types, and individual institutional factors that are important and affect this outcome variable. The pooled analysis of risk factors and causes of readmission is limited by the lack of reporting in most of the spine literature.

MRI Vertebral Bone Quality Correlates With Interbody Cage Subsidence After Anterior Cervical Discectomy and Fusion.

STUDY DESIGN: Retrospective observational study of consecutive patients. OBJECTIVE: The purpose of the study was to evaluate VBQ as a predictor of interbody subsidence and to determine threshold values that portend increased risk of subsidence. SUMMARY OF BACKGROUND DATA: Many risk factors have been reported for the subsidence of interbody cages in anterior cervical discectomy and fusion (ACDF). MRI Vertebral Bone Quality (VQB) is a relatively new radiographic parameter that can be easily obtained from preoperative MRI and has been shown to correlate with measurements of bone density such as DXA and CT Hounsfield Units. METHODS: All patients who underwent 1- to 3-level ACDF using titanium interbodies with anterior plating between the years 2018 and 2020 at our tertiary referral center were included. Subsidence measurements were performed by 2 independent reviewers on CT scans obtained 6 months postoperatively. VBQ was measured on pre-operative sagittal T1 MRI by 2 independent reviewers, and values were averaged. RESULTS: Eight-five fusion levels in 44 patients were included in the study. There were 32 levels (38%) with moderate subsidence and 12 levels with severe subsidence (14%). The average VBQ score in those patients with severe subsidence was significantly higher than those without subsidence (3.80 vs. 2.40, P<0.01). A threshold value of 3.2 was determined to be optimal for predicting subsidence (AUC=0.99) and had a sensitivity of 100% and a specificity of 94.1% in predicting subsidence. CONCLUSIONS: VBQ strongly correlates with the subsidence of interbody grafts after ACDF. A threshold VBQ score value of 3.2 has excellent sensitivity and specificity for predicting subsidence. Spine surgeons can use VBQ as a readily available screening tool to identify patients at higher risk for subsidence. LEVEL OF EVIDENCE: Level-IV.

Paraspinal Sarcopenia and Lower Hounsfield Units are Independent Predictors of Increased Risk for Proximal Junctional Complications Following Thoracolumbar Fusions Terminating in the Upper Thoracic Spine.

STUDY DESIGN: Retrospective cohort study. OBJECTIVE: The impact of paraspinal sarcopenia following fusions that extend to the upper thoracic spine remain unknown. The purpose of the present study was to assess the impact of sarcopenia on the development of PJK and PJF following spine fusion surgery from the upper thoracic spine to the pelvis. METHODS: We performed a retrospective review of patients who underwent spine fusion surgery that extended caudally to the pelvis and terminated cranially between T1-6. The cohort was divided into 2 groups: (1) patients without PJK or PJF and (2) patients with PJK and/or PJF. Univariate and multivariate analyses were performed to determine risk factors for the development of proximal junctional complications. RESULTS: We identified 81 patients for inclusion in this study. Mean HU at the UIV was 186.1 ± 47.5 in the cohort of patients without PJK or PJF, which was substantially higher than values recorded in the PJK/PJF subgroup (142.4 ± 40.2) (P < 0.001). Severe multifidus sarcopenia was identified at a higher rate in the subgroup of patients who developed proximal junction pathology (66.7%) than in the subgroup of patients who developed neither PJK nor PJF (7.4%; P < 0.001). Multivariate analysis demonstrated both low HU at the UIV and moderate-severe multifidus sarcopenia to be risk factors for the development of PJK and PJF. CONCLUSIONS: Severe paraspinal sarcopenia and diminished bone density at the UIV impart an increased risk of developing PJK and PJF in following thoracolumbar fusions from the upper thoracic spine to the pelvis.