Seven-Year Revision Rates for Cochlear Implants in Pediatric and Adult Populations of an Integrated Healthcare System.

OBJECTIVE: We assessed three cochlear implant (CI) suppliers: Advanced Bionics, Cochlear Limited, and MED-EL, for implant revision requiring reoperation after CI placement. STUDY DESIGN: Retrospective cohort study of integrated-health-system database between 2010 and 2021. Separate models were created for pediatric (age <18) and adult (age ≥18) cohorts. PATIENTS: Pediatric (age <18) and adult (age ≥18) patients undergoing cochlear implantation within our integrated healthcare system. MAIN OUTCOME MEASURE: Revision after CI placement. Cox proportional hazard regression was used to evaluate revision risk and adjust for confounding factors. Hazard ratios (HRs) and 95% confidence intervals (CIs) are presented. RESULTS: A total of 2,347 patients underwent a primary CI placement, and Cochlear Limited was most implanted (51.5%), followed by Advanced Bionics (35.2%) and MED-EL (13.3%). In the pediatric cohort, the 7-year crude revision rate was 10.9% for Advanced Bionics and 4.8% for Cochlear Limited, whereas MED-EL had insufficient cases. In adults, the rates were 9.1%, 4.5%, and 3.3% for Advanced Bionics, MED-EL, and Cochlear Limited, respectively. After 2 years of postoperative follow-up, Advanced Bionics had a significantly higher revision risk (HR = 8.25, 95% CI = 2.91-23.46); MED-EL had no difference (HR = 2.07, 95% CI = 0.46-9.25). CONCLUSION: We found an increased revision risk after 2 years of follow-up for adults with Advanced Bionics CI devices. Although we found no statistical difference between manufacturers in the pediatric cohort, after 2 years of follow-up, there were increasing trends in the revision probability for Advanced Bionics. Further research may determine whether patients are better suited for some CI devices.

Are there differences in the reoperation rates for operative adjacent-segment disease between ALIF+PS, PLIF+PS, TLIF+PS, and LLIF+PS? An analysis of a cohort of 5291 patients.

OBJECTIVE: Biomechanical factors in lumbar fusions accelerate the development of adjacent-segment disease (ASD). Stiffness in the fused segment increases motion in the adjacent levels, resulting in ASD. The objective of this study was to determine if there are differences in the reoperation rates for symptomatic ASD (operative ASD) between anterior lumbar interbody fusion plus pedicle screws (ALIF+PS), posterior lumbar interbody fusion plus pedicle screws (PLIF+PS), transforaminal lumbar interbody fusion plus pedicle screws (TLIF+PS), and lateral lumbar interbody fusion plus pedicle screws (LLIF+PS). METHODS: A retrospective study using data from the Kaiser Permanente Spine Registry identified an adult cohort (≥ 18 years old) with degenerative disc disease who underwent primary lumbar interbody fusions with pedicle screws between L3 to S1. Demographic and operative data were obtained from the registry, and chart review was used to document operative ASD. Patients were followed until operative ASD, membership termination, the end of study (March 31, 2022), or death. Operative ASD was analyzed using Cox proportional hazards models. RESULTS: The final study population included 5291 patients with a mean ± SD age of 60.1 ± 12.1 years and a follow-up of 6.3 ± 3.8 years. There was a total of 443 operative ASD cases, with an overall incidence rate of reoperation for ASD of 8.37% (95% CI 7.6-9.2). The crude incidence of operative ASD at 5 years was the lowest in the ALIF+PS cohort (7.7%, 95% CI 6.3-9.4). In the adjusted models, the authors failed to detect a statistical difference in operative ASD between ALIF+PS (reference) versus PLIF+PS (HR 1.06 [0.79-1.44], p = 0.69) versus TLIF+PS (HR 1.03 [0.81-1.31], p = 0.83) versus LLIF+PS (HR 1.38 [0.77-2.46], p = 0.28). CONCLUSIONS: In a large cohort of over 5000 patients with an average follow-up of > 6 years, the authors found no differences in the reoperation rates for symptomatic ASD (operative ASD) between ALIF+PS and PLIF+PS, TLIF+PS, or LLIF+PS.

Utilization of Total Joint Arthroplasty by Rural-Urban Designation in Patients With Osteoarthritis in a Universal Coverage System.

BACKGROUND: Utilization of total joint arthroplasty (TJA) is affected by differences linked to sex, race, and socioeconomic status; there is little information about how geographic variation contributes to these differences. We sought to determine whether discrepancies in TJA utilization exist in patients diagnosed with osteoarthritis (OA) based upon urban-rural designation in a universal coverage system. METHODS: We conducted a cohort study using data from a US-integrated healthcare system (2015 to 2019). Patients aged ≥50 years who had a diagnosis of hip or knee OA were included. Total hip arthroplasty and total knee arthroplasty utilization (in respective OA cohorts) was evaluated by urban-rural designation (urban, mid, and rural). Incidence rate ratios (IRRs) for urban-rural regions were modeled using multivariable Poisson regressions. RESULTS: The study cohort included 93,642 patients who have hip OA and 275,967 patients who had knee OA. In adjusted analysis, utilization of primary total hip arthroplasty was lower in patients living in urban areas (IRR = 0.87, 95% confidence interval = 0.81 to 0.94) compared to patients in rural regions. Similarly, total knee arthroplasty was used at a lower rate in urban areas (IRR = 0.88, 95% confidence interval = 0.82 to 0.95) compared with rural regions. We found no differences in the hip and knee groups within the mid-region. CONCLUSIONS: In hip and knee OA patients enrolled in a universal coverage system, we found patients living in urban areas had lower TJA utilization compared to patients living in rural areas. Further research is needed to determine how patient location contributes to differences in elective TJA utilization. LEVEL OF EVIDENCE: III.

Association Between Race/Ethnicity and 90-Day Emergency Department Visits in Patients Undergoing Elective Total Knee Arthroplasty or Total Hip Arthroplasty in a Universally Insured Population.

BACKGROUND: Research has identified disparities in returns to care by race/ethnicity following primary total joint arthroplasty. We sought to identify risk factors for 90-day emergency department (ED) returns following primary total knee arthroplasty (TKA) or total hip arthroplasty (THA) for these populations. METHODS: Black, Hispanic, and non-Hispanic White patients who underwent elective primary unilateral TKA and THA in an integrated US healthcare system were identified. Risk factors for 90-day postoperative ED visits including patient demographics, household income and education, comorbidities, preoperative healthcare utilization, and copay data were identified with multivariable logistic regression. RESULTS: Postoperative 90-day ED visits occurred in 13.3% of 79,565 TKA patients (17.2% Black; 14.9% Hispanic; 12.5% White) and 11.0% of THA patients (13.4% Black; 12.1% Hispanic; 10.7% White). Across racial/ethnic categories, patients who had an ED visit within 1 year of their TKA or THA date were more likely to have a 90-day ED return. Shared risk factors for TKA patients were chronic lung disease and outpatient utilization (25th and 75th percentile), while peripheral vascular disease was a shared risk factor for THA patients. Risk factors for multiple races of TKA and THA patients included depression, drug abuse, and psychosis. Prior copay for White (TKA) and Hispanic (TKA and THA) patients was protective, while preoperative primary care was protective for Black THA patients. CONCLUSION: Future strategies to reduce postoperative ED returns should include directed patient outreach for patients who had ED visits and mental health in the year prior to TKA and THA. LEVEL OF EVIDENCE: III.

Risk of Aseptic Revision and Periprosthetic Fracture Following Bipolar Versus Unipolar Hemiarthroplasty.

Hemiarthroplasty is currently the most common treatment for displaced femoral neck fractures in the elderly. While bipolar hemiarthroplasty was developed to reduce the risk of acetabular erosion that is associated with traditional unipolar hemiarthroplasty, meta-analyses have reported similar outcomes for bipolar and unipolar hemiarthroplasty devices. The primary objective of this study was to evaluate the risks of aseptic revision and periprosthetic fracture following bipolar versus unipolar hemiarthroplasty in a large integrated health-care system in the United States. Methods: We conducted a retrospective cohort study using data from the hip fracture registry of an integrated health-care system. Patients aged ≥60 years who underwent hemiarthroplasty for hip fracture between 2009 and 2019 were included. The primary outcome measure was aseptic revision, and the secondary outcome measure was revision for periprosthetic fracture. Cause-specific Cox proportional hazards regression was performed, with mortality considered as a competing event. In the multivariable analysis, estimates were adjusted for potential confounders such as age, sex, race/ethnicity, body mass index, American Society of Anesthesiologists classification, femoral fixation, surgeon volume, type of anesthesia, and discharge disposition. Results: The study sample included 13,939 patients who had been treated with hemiarthroplasty by 498 surgeons at 35 hospitals. The mean follow-up time was 3.7 ± 2.9 years. The overall incidence of aseptic revision at 5 years following hemiarthroplasty was 2.8% (386). In the multivariable analysis controlling for potential confounders, bipolar hemiarthroplasty was associated with a lower risk of aseptic revision than unipolar hemiarthroplasty (hazard ratio [HR], 0.74; 95% confidence interval [CI], 0.59 to 0.94; p = 0.012). Rates of revision for periprosthetic fracture were similar between the bipolar and unipolar devices (HR, 0.79; 95% CI, 0.58 to 1.10; p = 0.16). Conclusions: In this study of hemiarthroplasty for hip fracture in elderly patients, bipolar designs were associated with a lower risk of aseptic revision than unipolar designs. In contrast to prior research, we did not find any difference in the risk of periprosthetic fracture between the 2 designs. Level of Evidence: Therapeutic Level III. See Instructions for Authors for a complete description of levels of evidence.

No difference in revision risk between autologous hamstring graft less than 8 mm versus hybrid graft 8 mm or larger in anterior cruciate ligament reconstruction.

PURPOSE: Hamstring autograft (HA) is commonly used for primary anterior cruciate ligament reconstruction (ACLR). However, if the harvested HA is inadequate in diameter, it is often augmented with an allograft tendon, forming a hybrid graft (HY). This study sought to evaluate aseptic revision risk following HA versus HY ACLR. METHODS: A retrospective cohort study was performed using data obtained from our healthcare system's ACLR registry. Patients ≤ 25 years of age who underwent primary isolated ACLR were identified (2005-2020). Graft type and diameter size was the primary exposure of interest: < 8 mm HA and ≥ 8 mm HY. A secondary analysis was performed to examine 7 mm HA and 7.5 mm HA vs ≥ 8 mm HY. Propensity score-weighted Cox proportional hazard regression was used to evaluate the risk of aseptic revision. RESULTS: The study sample included 1,945 ACLR: 548 ≥ 8 mm HY, 651 7 mm HA, and 672 7.5 mm HA. The crude cumulative aseptic revision probability at 8-years for ≥ 8 mm HY was 9.1%, 11.1% for 7 mm HA, and 11.2% for 7.5 mm HA. In adjusted analysis, no difference in revision risk was observed for < 8 mm HA (hazard ratio [HR] 1.15, 95% confidence interval [CI] 0.72-1.82), 7 mm HA (HR 1.23, 95% CI 0.71-2.11), or 7.5 mm HA (HR 1.16, 95% CI 0.74-1.82) compared to ≥ 8 mm HY. CONCLUSION: In a US-based cohort of ACLR patients aged ≤ 25 years, we failed to observe any differences in aseptic revision risk for HA < 8 mm compared to HY ≥ 8 mm. Augmentation of a HA as small as 7 mm is not necessary to prevent a revision surgery. LEVEL OF EVIDENCE: Level III.

Association Between Graft Type and Risk of Repeat Revision Anterior Cruciate Ligament Reconstruction: A Cohort Study of 1747 Patients.

BACKGROUND: With an increasing number of primary anterior cruciate ligament reconstructions (ACLRs), the burden of revision ACLR (rACLR) has also increased. Graft choice for rACLR is complicated by patient factors and the remaining available graft options. PURPOSE: To examine the association between graft type at the time of rACLR and the risk of repeat rACLR (rrACLR) in a large US integrated health care system registry while accounting for patient and surgical factors at the time of revision surgery. STUDY DESIGN: Cohort study; Level of evidence, 3. METHODS: Data from the Kaiser Permanente ACLR registry were used to identify patients who underwent a primary isolated ACLR between 2005 and 2020 and then went on to have rACLR. Graft type used at rACLR, classified as autograft versus allograft, was the exposure of interest. Multivariable Cox proportional hazard regression was used to evaluate the risk of rrACLR, with ipsilateral and contralateral reoperation as secondary outcomes. Models included factors at the time of the rACLR (age, sex, body mass index, smoking status, staged revision, femoral fixation, tibial fixation, femoral tunnel method, lateral meniscal injury, medial meniscal injury, and cartilage injury) and a factor from the primary ACLR (activity at injury) as covariates. RESULTS: A total of 1747 rACLR procedures were included. The crude cumulative rrACLR incidence at 8-year follow-up was 13.9% for allograft and 6.0% for autograft. Cumulative ipsilateral reoperation incidence at 8-year follow-up was 18.3% for allograft and 18.9% for autograft; contralateral reoperation cumulative incidence was 4.3% for allograft and 6.8% for autograft. With adjustment for covariates, a 70% lower risk for rrACLR was observed for autograft compared with allograft (hazard ratio [HR], 0.30; 95% CI, 0.18-0.50; P < .0001). No differences were observed for ipsilateral reoperation (HR, 1.05; 95% CI, 0.73-1.51; P = .78) or contralateral reoperation (HR, 1.33; 95% CI, 0.60-2.97; P = .48). CONCLUSION: The use of autograft at rACLR was associated with a 70% lower risk of rrACLR compared with allograft in this cohort from the Kaiser Permanente ACLR registry. When accounting for all reoperations outside of rrACLR after rACLR, the authors found no significant difference in risk between autograft and allograft. To minimize the risk of rrACLR, surgeons should consider using autograft for rACLR when possible.

Lateral Mass Screws Versus Pedicle Screws at C7: Reoperation Rates for Operative Adjacent Segment Disease and Nonunion in Posterior Cervical Fusion.

STUDY DESIGN: A retrospective cohort study. OBJECTIVE: To determine if there is a difference in reoperation rates for symptomatic adjacent segment disease (operative ASD) and symptomatic nonunions (operative nonunions) in posterior cervical fusions (PCFs) stopping at C7 using either lateral mass screws (LMS) or cervical pedicle screws (CPS) at C7. SUMMARY OF BACKGROUND DATA: Stopping PCFs at C7 has been controversial because of the risks of adjacent segment disease or nonunions. The two commonly used fixation techniques at the C7 level are LMS and CPS. MATERIALS AND METHODS: A retrospective analysis from the Kaiser Permanente Spine Registry identified a cohort of patients with cervical degenerative disk disease who underwent primary PCFs stopping at C7 with either LMS or CPS at C7. Demographic and operative data were extracted from the registry, and operative ASD and operative nonunions were adjudicated through chart review. Patients were followed until validated operative ASD or nonunion, membership termination, death, or end of study (March 31, 2022). Descriptive statistics and multivariable Cox proportional hazards models were calculated for operative ASDs and operative nonunions. RESULTS: We found 481 patients with PCFs stopping at C7 with either LMS (n=347) or CPS (n=134) at C7 with an average follow-up time of 5.6 (±3.8) years, time to operative ASD of 3.0 (±2.8) years, and to operative nonunion of 1.2 (±0.7) years. There were 11 operative ASDs (LMS=8, CPS=3) and eight operative nonunions (LMS=4, CPS=4). There was no statistical difference between patients stopping at C7 with LMS versus CPS for operative ASDs (HR: 0.68, 95% CI=0.17-2.77, P =0.60) or operative nonunions (HR: 2.09, 95% CI=0.45-8.58, P =0.37). CONCLUSION: A large cohort of patients with PCFs stopping at C7 with an average follow-up of > 5 years found no statistical difference in reoperation rates for symptomatic ASD (operative ASD) or operative nonunion using either LMS or CPS at C7.

Association Between Race/Ethnicity and Total Joint Arthroplasty Utilization in a Universally Insured Population.

INTRODUCTION: Previous studies have documented racial and ethnic disparities in total joint arthroplasty (TJA) utilization in the United States. A potential mediator of healthcare disparities is unequal access to care, and studies have suggested that disparities may be ameliorated in systems of universal access. The purpose of this study was to assess whether racial/ethnic disparities in TJA utilization persist in a universally insured population of patients enrolled in a managed healthcare system. METHODS: This retrospective cohort study used data from a US integrated healthcare system (2015 to 2019). Patients aged 50 years and older with a diagnosis of hip or knee osteoarthritis were included. The outcome of interest was utilization of primary total hip arthroplasty and/or total knee arthroplasty, and the exposure of interest was race/ethnicity. Incidence rate ratios (IRRs) were modeled using multivariable Poisson regression controlling for confounders. RESULTS: There were 99,548 patients in the hip analysis and 290,324 in the knee analysis. Overall, 10.2% of the patients were Black, 20.5% were Hispanic, 9.6% were Asian, and 59.7% were White. In the multivariable analysis, utilization of primary total hip arthroplasty was significantly lower for all minority groups including Black (IRR, 0.55, 95% confidence interval [CI], 0.52-0.57, P < 0.0001), Hispanic (IRR, 0.63, 95% CI, 0.60-0.66, P < 0.0001), and Asian (IRR, 0.64, 95% CI, 0.61-0.68, P < 0.0001). Similarly, utilization of primary total knee arthroplasty was significantly lower for all minority groups including Black (IRR, 0.52, 95% CI, 0.49-0.54, P < 0.0001), Hispanic (IRR, 0.72, 95% CI, 0.70-0.75, P < 0.0001), and Asian (IRR, 0.60, 95% CI, 0.57-0.63, P < 0.0001) (all in comparison with White as reference). CONCLUSIONS: In this study of TJA utilization in a universally insured population of patients enrolled in a managed healthcare system, disparities on the basis of race and ethnicity persisted. Additional research is required to determine the reasons for this finding and to identify interventions which could ameliorate these disparities.

Are Octogenarians at Higher Risk of Complications After Elective Lumbar Spinal Fusion Surgery? Analysis of a Cohort of 7880 Patients From the Kaiser Permanente Spine Registry.

STUDY DESIGN: A retrospective cohort study with chart review. OBJECTIVE: To determine if there is a difference in risk of adverse outcomes following elective posterior instrumented lumbar spinal fusions for patients aged 80 years and above compared with patients aged 50 to 79 years. SUMMARY OF BACKGROUND DATA: Patients aged 80 years and above are undergoing elective lumbar spinal fusion surgery in increasing numbers. There are conflicting data on the risks of intraoperative and postoperative complications in these patients. MATERIALS AND METHODS: Patients aged 80 years and above were compared with 50 to 79 years (reference group) using time-dependent multivariable Cox proportional hazards regression with a competing risk of death for longitudinal outcomes and multivariable logistic regression for binary outcomes. Outcome measures used were: (1) intraoperative complications (durotomy), (2) postoperative complications: 30-day outcomes (pneumonia); 90-day outcomes (deep vein thrombosis, pulmonary embolism, emergency room visits, readmission, reoperations, and mortality); and two-year outcomes (reoperations and mortality). RESULTS: The cohort consisted of 7880 patients who underwent primary elective posterior instrumented lumbar spinal fusion (L1-S1) for degenerative disk disease or spondylolisthesis. This was subdivided into 596 patients were aged 80 years and above and 7284 patients aged 50 to 79. After adjustment, patients aged 80 years and above had a higher likelihood of durotomy [odds ratio (OR)=1.43, 95% confidence interval (CI)=1.02-2.02] and 30-day pneumonia (OR=1.81, 95% CI=1.01-3.23). However, there was a lower risk of reoperation within two years of the index procedure (hazard ratio=0.69, 95% CI=0.48-0.99). No differences were observed for mortality, readmissions, emergency room visits, pulmonary embolism, or deep vein thrombosis. CONCLUSIONS: In a cohort of 7880 elective posterior instrumented lumbar fusion patients for degenerative disk disease or spondylolisthesis, we did not observe any significant risks of adverse events between patients aged 80 years and above and those aged 50 to 79 except for higher durotomies and 30-day pneumonia in the former. We believe octogenarians can safely undergo lumbar fusions, but proper preoperative screening is necessary to reduce the risks of 30-day pneumonia.

Risk and incidence of head and neck cancers in veterans living with HIV and matched HIV-negative veterans.

BACKGROUND: Persons living with HIV/AIDS have a higher incidence of virus-related and tobacco/alcohol-related cancers. This study is the first to estimate the effect of HIV versus HIV-negative veterans on the risk of head and neck squamous cell carcinoma incidence in a large retrospective cohort study. METHODS: The authors constructed a retrospective cohort study using patient data from 1999 to 2016 from the National Veterans Administration Corporate Data Warehouse and the VA Central Cancer Registry. This cohort study included 45,052 veterans living with HIV/AIDS and 162,486 HIV-negative patients matched by age, sex, and index visit (i.e., HIV diagnosis date or clinic visit date). The age-standardized incidence rates and estimated adjusted hazard ratios were calculated with a Cox proportional hazards regression for oropharyngeal and nonoropharyngeal head and neck cancer squamous cell carcinoma (HNSCC). The authors also abstracted human papillomavirus (HPV) status from oropharyngeal HNSCC diagnosed after 2010. RESULTS: Veterans living with HIV/AIDS (VLWH) have 1.71 (95% confidence interval [CI], 1.36, 2.14) times the risk of oropharyngeal cancer and 2.06 (95% CI, 1.76, 2.42) times the hazard of nonoropharyngeal cancer compared with HIV-negative veterans. VLWH with oropharyngeal squamous cell carcinoma (OPSCC) were more likely to be HPV-positive (N = 30 [81.1%]) than the HIV-negative veterans with OPSCC (N = 50 [67.6%]), although this difference was not significant (p = .135). For nonoropharyngeal cancer, the increased risk of oral cavity cancer among VLWH drove the increased risk. CONCLUSIONS: The study results suggest that HIV may play a role in virally mediated and nonvirally mediated HNSCC. As the HIV prevalence rises in the United States due to better survival and the incidence of HPV-positive oropharyngeal HNSCC increases, the interaction between HPV and HIV becomes increasingly relevant.

Revision Risk in a Cohort of US Patients Younger Than 55 Undergoing Primary Elective Total Hip Arthroplasty.

BACKGROUND: As indications for elective total hip arthroplasty (THA) expand to younger patients, we sought to (1) compare revision risk following primary elective THA in patients <55 years at the time of their THA to patients aged ≥65 years and (2) identify specific risk factors for revision in patients <55 years. METHODS: A Kaiser Permanente's total joint replacement registry was used to conduct a cohort study including primary elective THA patients aged ≥18 (2001-2018). In total, 11,671 patients <55 years and 53,106 patients ≥65 years were included. Multiple Cox regression was used to evaluate cause-specific revision risk, including septic revision, aseptic loosening, instability, and periprosthetic fracture. Stepwise Cox regression was used to identify patient and surgical factors associated with cause-specific revision in patients <55 years. RESULTS: Patients <55 years had a higher risk of septic revision (hazard ratio [HR] = 1.30, 95% confidence interval [CI] = 1.02-1.66), aseptic loosening (HR = 2.60, 95% CI = 1.99-3.40), and instability (HR = 1.35, 95% CI = 1.09-1.68), but a lower risk of revision for periprosthetic fracture (HR = 0.36, 95% CI = 0.22-0.59) compared to patients aged ≥65 years. In the <55 age group, risk factors for septic revision included higher body mass index, drug abuse, and liver disease. Hypertension, anterior approach, and ceramic-on-ceramic were associated with aseptic loosening. White race, American Society of Anesthesiologists classification ≥3, smoker, paralysis, posterior approach, ceramic-on-ceramic, and smaller head diameter were associated with instability. CONCLUSION: Identified risk factors varied depending on the cause for revision. Although septic revisions were related to patient characteristics, more modifiable factors, such as implant or surgical approach, were associated with revision due to aseptic loosening and instability. LEVEL OF EVIDENCE: III.

No Difference in Reoperation Rates for Adjacent Segment Disease (Operative Adjacent Segment Disease) in Posterior Cervical Fusions Stopping at C7 Versus T1/T2: A Cohort of 875 Patients-Part 1.

STUDY DESIGN: A retrospective cohort study with chart review. OBJECTIVE: To determine whether there is a difference in reoperation rates for adjacent segment disease ([ASD] operative ASD) in posterior cervical fusions (PCFs) that stop at -C7 versus -T1/T2. SUMMARY OF BACKGROUND DATA: There are surgical treatment challenges to the anatomical complexities of the cervicothoracic junction. Current posterior cervical spine surgery is based on the belief that ASD occurs if fusions are stopped at C7 although there is varying evidence to support this assumption. METHODS: Patients were followed until validated reoperations for ASD, membership termination, death, or March 31, 2020. Descriptive statistics and 5-year crude incidence rates and 95% confidence intervals for operative ASD for PCF ending at -C7 or -T1/T2 were reported. Time-dependent crude and adjusted multivariable Cox-Proportional Hazards models were used to evaluate operative ASD rates with adjustment for covariates or risk change estimates more than 10%. RESULTS: We identified 875 patients with PCFs (beginning at C3 or C4 or C5 or C6) stopping at either -C7 (n = 470) or -T1/T2 (n = 405) with average follow-up time of 4.6 (±3.3) years and average time to operative ASD of 2.7 (±2.8) years. Crude overall incidence rates for stopping at -C7 (2.12% [1.02%-3.86%]) and -T1/T2 (2.48% [1.25%-4.40%]) were comparable with no statistical difference in risk (adjusted hazard ratio = 1.47, 95% confidence interval = 0.61-3.53, P = 0.39). In addition, we observed no differences in the probability of operative ASD in competing risk time-dependent models (Grey test P  = 0.448). CONCLUSION: A large cohort of 875 patients with PCFs stopping at -C7 or -T1/T2 with an average follow-up of more than 4 years found no statistical difference in reoperation rates for ASD (operative ASD).Level of Evidence: 3.

No difference in reoperation rates for nonunions (operative nonunions) in posterior cervical fusions stopping at C7 versus T1/2: a cohort of 875 patients.

OBJECTIVE: The challenges of posterior cervical fusions (PCFs) at the cervicothoracic junction (CTJ) are widely known, including the development of adjacent-segment disease by stopping fusions at C7. One solution has been to cross the CTJ (T1/T2) rather than stopping at C7. This approach may have undue consequences, including increased reoperations for symptomatic nonunion (operative nonunion). The authors sought to investigate if there is a difference in operative nonunion in PCFs that stop at C7 versus T1/T2. METHODS: A retrospective analysis identified patients from the authors' spine registry (Kaiser Permanente) who underwent PCFs with caudal fusion levels at C7 and T1/T2. Demographics, diagnoses, operative times, lengths of stay, and reoperations were extracted from the registry. Operative nonunion was adjudicated via chart review. Patients were followed until validated operative nonunion, membership termination, death, or end of study (March 31, 2020). Descriptive statistics and 2-year crude incidence rates and 95% confidence intervals for operative nonunion for PCFs stopping at C7 or T1/T2 were reported. Time-dependent crude and adjusted multivariable Cox proportional hazards models were used to evaluate operative nonunion rates. RESULTS: The authors identified 875 patients with PCFs (beginning at C3, C4, C5, or C6) stopping at either C7 (n = 470) or T1/T2 (n = 405) with a mean follow-up time of 4.6 ± 3.3 years and a mean time to operative nonunion of 0.9 ± 0.6 years. There were 17 operative nonunions, and, after adjustment for age at surgery and smoking status, the cumulative incidence rates were similar between constructs stopping at C7 and those that extended to T1/T2 (C7: 1.91% [95% CI 0.88%-3.60%]; T1/T2: 1.98% [95% CI 0.86%-3.85%]). In the crude model and model adjusted for age at surgery and smoking status, no difference in risk for constructs extended to T1/T2 compared to those stopping at C7 was found (adjusted HR 1.09 [95% CI 0.42-2.84], p = 0.86). CONCLUSIONS: In one of the largest cohort of patients with PCFs stopping at C7 or T1/T2 with an average follow-up of > 4 years, the authors found no statistically significant difference in reoperation rates for symptomatic nonunion (operative nonunion). This finding shows that there is no added risk of operative nonunion by extending PCFs to T1/T2 or stopping at C7.

The effect of a statewide COVID-19 shelter-in-place order on shoulder arthroplasty for proximal humerus fracture volume and length of stay.

BACKGROUND: Although the COVID-19 pandemic has disrupted elective shoulder arthroplasty throughput, traumatic shoulder arthroplasty procedures are less apt to be postponed. We sought to evaluate shoulder arthroplasty utilization for fracture during the COVID-19 pandemic and California's associated shelter-in-place order compared to historical controls. METHODS: We conducted a cohort study with historical controls, identifying patients who underwent shoulder arthroplasty for proximal humerus fracture in California using our integrated electronic health record. The time period of interest was following the implementation of the statewide shelter-in-place order: March 19, 2020-May 31, 2020. This was compared to three historical periods: January 1, 2020-March 18, 2020, March 18, 2019-May 31, 2019, and January 1, 2019-March 18, 2019. Procedure volume, patient characteristics, in-hospital length of stay, and 30-day events (emergency department visit, readmission, infection, pneumonia, and death) were reported. Changes over time were analyzed using linear regression adjusted for usual seasonal and yearly changes and age, sex, comorbidities, and postadmission factors. RESULTS: Surgical volume dropped from an average of 4.4, 5.2, and 2.6 surgeries per week in the historical time periods, respectively, to 2.4 surgeries per week after shelter-in-place. While no more than 30% of all shoulder arthroplasty procedures performed during any given week were for fracture during the historical time periods, arthroplasties performed for fracture was the overwhelming primary indication immediately after the shelter-in-place order. More patients were discharged the day of surgery (+33.2%, P = .019) after the shelter-in-place order, but we did not observe a change in any of the corresponding 30-day events. CONCLUSIONS: The volume of shoulder arthroplasty for fracture dropped during the time of COVID-19. The reduction in volume could be due to less shoulder trauma due to shelter-in-place or a change in the indications for arthroplasty given the perceived higher risks associated with intubation and surgical care. We noted more patients undergoing shoulder arthroplasty for fracture were safely discharged on the day of surgery, suggesting this may be a safe practice that can be adopted moving forward. LEVEL OF EVIDENCE: Level III; Retrospective Case-control Comparative Study.

PLF+PS or ALIF+PS: which has a lower operative nonunion rate? Analysis of a cohort of 2,061 patients from a National Spine Registry.

BACKGROUND CONTEXT: Although fusion rates in posterolateral lumbar fusions with pedicle screws (PLF+PS) and anterior lumbar interbody fusions with pedicle screws (ALIF+PS) have been reported, there has been no consensus on superiority with respect to clinical outcome and nonunion rates. Most studies determine nonunion rates based on radiographic studies; however, many of these nonunions are asymptomatic and may not require reoperations. Hence, a potentially more clinically useful measure is the reoperation rate for symptomatic nonunions, which we term the operative nonunion rate. PURPOSE: To determine if there is a difference in operative nonunion rates between PLF+PS versus ALIF+PS. STUDY DESIGN: Retrospective cohort study. PATIENT SAMPLE: Adult patients (≥18 years old) with the diagnosis of lumbar spondylolisthesis or lumbar spinal stenosis who underwent primary elective PLF+PS and ALIF+PS for 1-level and 2-level fusions (L4-S1) between 2009 and 2018. OUTCOME MEASURES: Reoperation rates for symptomatic nonunions (ie, operative nonunion rates). METHODS: Patients were followed until validated operative nonunions, membership termination, death, or 03/31/2019. Descriptive statistics and 2-year incidence rates for operative nonunions were calculated by fusion-level, fusion type, and levels fused. Time-dependent multivariable Cox-Proportional Hazards regression was used to evaluate operative nonunion rates with adjustment for covariates or risk change estimates more than 10%. RESULTS: We identified 2,061 patients (PLF+PS:1,491, ALIF+PS:570) with average follow-up time of 4.8 (±3.1) years and average time to operative nonunion of 1.3 (±1.2) yrs. Comparatively, unadjusted 1-level and 2-level incidence rates for operative nonunions were higher in PLF+PS versus ALIF+PS. For 1-level procedures these were 0.9% (95% CI=0.4-1.6) versus 0.6% (95% CI=0.1-2.1); 2-level, 2.0% (95% CI=0.8-4.0) versus 0.9% (95% CI=0.1-3.3). However, there were no observed significant differences in risks for operative nonunions in multivariable models comparing PLF+PS versus ALIF+PS (HR=0.3, 95% CI=0.1-1.1), 1-level versus 2-level fusions (HR=1.8, 95% CI=0.8-4.3), or by fusion level (L4-L5: HR=1.0, 95% CI=0.4-2.7; L5-S1: HR=2.0, 95% CI=0.7-5.4). CONCLUSIONS: A large cohort of patients with lumbar fusions between L4 to S1 and an average follow-up of >4 years found that although there was a trend for higher operative nonunions in PLF+PS compared with ALIF+PS, this was not statistically significant. The role of spinal alignment was not investigated.

The Association Between Cement Viscosity and Revision Risk After Primary Total Knee Arthroplasty.

BACKGROUND: Recent case series have reported early failure with the use of high-viscosity cement (HVC) in total knee arthroplasty (TKA). We evaluated revision risk after TKA with HVC compared with medium-viscosity cement (MVC) in a large cohort. METHODS: We conducted a cohort study using data from Kaiser Permanente's Total Joint Replacement Registry. Patients who underwent fully cemented primary TKA for osteoarthritis were identified (2001-2018). Only posterior-stabilized, fixed-mobility designs of the 3 highest-volume implant systems (DePuy PFC, Zimmer NexGen, and Zimmer Persona) were included to mitigate confounding from implant characteristics. Palacos (Zimmer/Heraeus) and Simplex (Stryker) cements comprised the HVC and MVC exposure groups, respectively. Propensity score-weighted Cox proportional hazards regression was used to evaluate risk for any revision during follow-up and risk for revision from aseptic loosening specifically. RESULTS: The final cohort comprised 76,052 TKAs, 41.1% using MVC. The crude 14-year cumulative revision probability was 4.55% and 5.12% for TKA with MVC and HVC, respectively. In propensity score-weighted Cox models, MVC compared with HVC had a lower risk of any revision (hazard ratio = 0.82, 95% confidence interval = 0.70-0.95) while no difference was observed for revision from aseptic loosening (hazard ratio = 0.80, 95% confidence interval = 0.56-1.13). CONCLUSION: While we observed a lower risk for any revision with the use of Simplex MVC compared with Palacos HVC, we did not observe a difference in revision for aseptic loosening specifically. Given the widespread use of HVC, additional research to investigate other HVC and potential mechanisms for failure outside of loosening is warranted. LEVEL OF EVIDENCE: Level III.

Operative Nonunion Rates in Posterolateral Lumbar Fusions: Analysis of a Cohort of 2591 Patients from a National Spine Registry.

OBJECTIVE: Radiographic nonunion rates in the literature for posterolateral lumbar fusions with pedicle screws (PLFs) range from 8.1% to 43.3% but may not represent nonunion rates. A few small studies have reported reoperations for symptomatic nonunions (operative nonunions) to range from 3.2% to 13.9%. The objective of this study is to determine operative nonunion rates for 1-level, 2-level, 3-level, and ≥4-level PLFs and to determine the risks for these nonunions. METHODS: A retrospective cohort study, using data from the Kaiser Permanente Spine Registry, identified adult patients (≥18 years old) who underwent PLFs for degenerative disc disease. Multivariable Cox proportional hazards regression and Kaplan-Meier survival estimates using the log-rank statistic were used to evaluate operative nonunion rates. RESULTS: The cohort consisted of 2591 patients with single-level and multilevel PLFs with mean follow-up of 4.6 years, time to operative nonunion of 1.52 years, and 2-year operative nonunion rate of 1.08%. Compared with single-level fusions, patients with 3-level and ≥4-level fusion had 2.8 and 3.7 times higher risk of operative nonunions. Patients with PLFs involving L5-S1 had 2.5 times the risk of an operative nonunion compared with those without. CONCLUSIONS: Our study reports results from one of the largest cohort of patients for the first time with single-level and multilevel instrumented PLFs and found a 2-year operative nonunion rate of 1.08% with increased risk of nonunion for constructs that included L5-S1 and ≥3-level fusions. Operative nonunion combines clinical and radiographic data and provides an alternative measure of fusion rates.

PLF Versus PLIF and the Fate of L5-S1: Analysis of Operative Nonunion Rates Among 3065 Patients with Lumbar Fusions from a Regional Spine Registry.

STUDY DESIGN: A retrospective cohort study with chart review. OBJECTIVE: The aim of this study was to compare the reoperation rates for symptomatic nonunions (operative nonunion rates) between posterolateral fusions with pedicle screws (PLFs) and posterior interbody fusion with pedicle screws (PLIFs). SUMMARY OF BACKGROUND DATA: Although radiographic nonunions in PLFs and PLIFs are well documented in the literature, there is no consensus on which technique has lower nonunions. Since some radiographic nonunions may be asymptomatic, a more clinically useful measure is operative nonunions, of which there is minimal research. METHODS: A retrospective cohort study, using data from the Kaiser Permanente Spine Registry, identified adult patients (≥18 years' old) who had elective single and multilevel PLFs and PLIFs. Descriptive statistics and 2-year incidence rates for operative nonunions were calculated by fusion-level (1-3), fusion type (PLF vs. PLIF), and levels fused (L3 to S1). Time-dependent multivariable Cox-Proportional Hazards regression was used to evaluate nonunion reoperation rates with adjustment for covariates. RESULTS: The cohort consisted of 3065 patients with PLFs (71.6%) and PLIFs (28.4%). Average age was 65.0 ±â€Š11.7, average follow-up time was 4.8 ±â€Š3.1 years, and average time to operative nonunion was 1.6 (±1.3) years. Single and multilevel incidence rates for nonunions after PLF versus PLIF were similar except for three-level fusions (2.9% [95% confidence interval, CI = 1.0-6.7] vs. 7.1% [95% CI = 0.2-33.9]). In adjusted models, there was no difference in risk of operative nonunions in PLIF compared to PLF (hazard ratio [HR]: 0.8, 95% CI = 0.4-1.6); however, patients with L5-S1 constructs with PLFs had 2.8 times the risk of operative nonunion compared to PLIFs (PLF: HR = 2.8, 95% CI = 1.3-6.2; PLIF: HR = 1.5, 95% CI = 0.4-5.1). CONCLUSION: In a large cohort of patients with >4 years of follow-up, we found no difference in operative nonunions between PLF and PLIF except for constructs that included L5-S1 in which the risk of nonunion was limited to PLF patients.Level of Evidence: 3.

Effect of Body Weight and Other Metabolic Factors on Risk of Non-Small Cell Lung Cancer among Veterans with HIV and a History of Smoking.

Among people living with HIV (PWH), there has been an increasing incidence of non-small cell lung cancer (NSCLC) and metabolic abnormalities, including dyslipidemia, which can modulate NSCLC risk. In this article, we evaluate which metabolic risk factors are associated with incident risk among PWH who smoke. This is done through a retrospective cohort study, using data of HIV+ veterans who smoke from the nationwide Veterans Affairs (VA) healthcare system. Data on diagnostic codes, medication, and laboratory values of 33,351 veterans were obtained using the VA's Corporate Data Warehouse and Central Cancer Registry. We calculated NSCLC incidence and utilized Cox regression to determine metabolic factors associated with NSCLC risk. HIV+ cohort was 97.4% male; median age = 47 years and 20,050 (60.1%) well-controlled (≥80% follow-up time undetectable viral load). Crude incidence rates were lower in well-controlled PWH (1.46 vs. 2.06/1000 PY). Metabolic factors associated with incident NSCLC risk included lower BMI at HIV diagnosis and cachexia history in both groups, while HDL and triglycerides were significant in non-well-controlled smokers only. Our findings that lower BMI at HIV diagnosis, history of cachexia among individuals with well-controlled HIV, and cachexia presence at diagnosis are associated with increased risk of developing NSCLC in PWH with a history of smoking have important implications.