The Multiplicative Effects of Individual Risk Factors in the Development of Osteonecrosis of the Femoral Head.

BACKGROUND: While individual risk factors, including chronic corticosteroid use, alcohol abuse, and smoking, are implicated in osteonecrosis (ON) of the femoral head (ONFH), the degree to which multiple risk factors increase risk is unknown. This study aimed to: (1) identify demographic characteristics of patients with ONFH; (2) quantify the effects of individual risk factors on ONFH development; (3) quantify the effects of combined risk factors on ONFH development; and (4) determine the prognostic implications of combined risk factors on ONFH development. METHODS: This was a retrospective cohort study. A national insurance database was used to study a population of 2,612,383 adult patients who had a 10-year follow-up period. There were 10,233 patients identified who had a diagnosis of ONFH. We identified patients who had chronic corticosteroid use, tobacco use, and/or alcohol abuse and assessed the risk of developing of ONFH over a 10-year period. Patients with individual and multiple risk factors were grouped for comparison, and Chi-square analyses were performed. RESULTS: Higher proportions of patients who had each individual risk factor developed ONFH compared to proportions of patients who did not have risk factors. Patients who had combined risk factors were at greater risk of developing ONFH compared to patients who had no risk factors and those who had single risk factors. Combined risk factors demonstrated multiplicative effects on the development of ONFH: tobacco-alcohol risk ratio (RR) 5.25, corticosteroid-alcohol RR 10.20, tobacco-corticosteroid RR 8.69, and corticosteroid-tobacco-alcohol RR 12.54. Patients who had combined risk factors developed ONFH at younger ages than those who had single risk factors. Kaplan-Meier curve analyses demonstrated worse 10-year hip survival in the setting of combined risk factors. CONCLUSION: Combined risk factors have a multiplicative effect on the risk of developing of atraumatic ONFH. Orthopaedic surgeons may care for at-risk individuals through modulation of risk factors.

Lower Associated Risk of Revision with All-Polyethylene Tibial Components in Total Knee Arthroplasty: An Analysis of the American Joint Replacement Registry.

BACKGROUND: Despite the potential advantage of all-polyethylene tibial components, modular metal-backed component use predominates the market in the United States for total knee arthroplasty (TKA). This is partially driven by concerns about the associated revision risk due to the lack of modularity with all-polyethylene components. This study utilized the American Joint Replacement Registry (AJRR) to compare the associated risk of all-cause revision and revision for infection for all-polyethylene versus modular metal-backed tibial components. METHODS: An analysis of primary TKA cases in patients aged 65 years and older was performed with AJRR data linked to Centers for Medicare and Medicaid Services data from 2012 to 2019. Analyses compared all-polyethylene to modular metal-backed tibial components. We identified 485,024 primary TKA cases, consisting of 479,465 (98.9%) metal-backed and 5,559 (1.1%) all-polyethylene. Cox proportional hazard regression analyses created hazard ratios (HRs) to evaluate the association of design and the risk of all-cause revision while adjusting for sex, age and the competing risk of mortality. Event-free survival curves evaluate time to revision. RESULTS: The all-polyethylene tibia group demonstrated a decreased risk for all-cause revision (HR = 0.37, 95% CI [confidence interval]: 0.24 to 0.55, P < 0.0001) and revision for infection (HR = 0.41, 95% CI: 0.22 to 0.77, P < 0.0001). Event-free survival curves demonstrated a decreased risk of all-cause revision that persisted across time points until 8 years post-TKA. CONCLUSION: In the United States, all-polyethylene tibial component use for TKA remains low compared to modular metal-backed designs. A decreased associated risk for revision should ease concerns about the use of all-polyethylene components in patients aged 65 years or older, and future investigations should investigate the potential cost and value savings associated with expanded use in this population.

Increased Opioid Use in Patients With Ehlers-Danlos Syndrome Before and After Total Hip Arthroplasty.

Background: Ehlers-Danlos syndrome (EDS), a disorder affecting synthesis of collagen, typically presents with chronic pain, hypermobility, and early osteoarthritis. EDS patients undergoing total hip arthroplasty (THA) are at risk of dislocation and revision. Opioid use and impact on outcomes among this population remain unknown. Methods: A retrospective review was performed with a large national database querying the International Classification of Disease, tenth revision procedure codes identifying 1,244,368 primary THAs from 2015-2020. Two hundred thirty-eight EDS patients underwent THA and were propensity matched with population control based on age, sex, and obesity when comparing opioid prescription. To compare dislocation and revision outcomes, EDS patients were stratified into those receiving opioid prescriptions and those not. Multivariate analysis evaluated the association. Results: EDS patients were more likely prescribed opioids 90 days before (49.1% vs 34.7.0%, P < .0001) and after THA (59.7% vs 41.2%, P < .0001), with more preoperatively (1163.6 mme ±1562.8, P < .0001) and postoperatively (900.1 mme ±1235.9, P < .0001) than controls. In EDS patients prescribed opioids 90 days before THA, dislocation rate was 12.8% vs 7.1% not prescribed (odds ratio 2.08, 95% confidence interval 0.85-5.1). 14.8% of EDS patients who received opioids 90 days after THA dislocated vs 2.1% not prescribed (odds ratio 8.13, 95% confidence interval 1.87-35.7). Conclusions: EDS patients are more likely prescribed opioids before and after THA. Opioid prescription was associated with risk of dislocation, though we caution interpretation of causation. However, this suggests that the risks of worse outcomes in EDS patients undergoing THA are multifactorial. We should look at strategies to reduce opioid use prior to THA.

Selective Use of Modern Cementless Total Knee Arthroplasty is Not Associated with Increased Risk of Revision in Patients Aged 65 or Greater: An Analysis from the American Joint Replacement Registry.

Modern highly porous surfaces have increased confidence and use of cementless total knee arthroplasty (TKA) in the United States. As cementless TKA use increases, there remains a paucity of literature regarding associated risk of revision in patients aged ≥65 years. We analyzed the American Joint Replacement Registry (AJRR) data from January 2012 to March 2020 identifying patients aged ≥65 years undergoing primary TKA with linked cases to supplemental centers for Medicare and Medicaid data. Patients with hybrid fixation, reverse hybrid fixation, missing component data, highly constrained implants, and stem extension/augmentation were excluded. We identified 442,745 cemented TKAs and 19,841 modern cementless TKAs with a minimum of 2-year follow-up. Cumulative incident function (CIF) curves and cause-specific Cox models evaluated the risk of all-cause revision and revision for mechanical loosening, adjusting for body mass index (BMI), sex, age, cruciate retaining (CR) versus posterior stabilized (PS) femoral design, patellar resurfacing, and Charlson's comorbidity index (CCI). Patients with cementless compared with cemented TKA were younger (mean age: 71.9 vs. 73.2 years, p < 0.001), more likely to be male sex (48.8 vs. 39.0%, p < 0.001), more likely to have a CR femoral design (81.1 vs. 45.7%, p < 0.001), less likely to have patellar resurfacing (92.7 vs. 95.0%, p < 0.001), and had a lower CCI (mean: 2.9 vs. 3.1, p < 0.001). Adjusted hazard ratios (HRs) showed no difference in associated risk for all-cause revision (HR: 1.07; 95% confidence interval [CI]: 0.92-1.24; p = 0.382) or revision for mechanical loosening (HR: 1.38; 95% CI: 0.9-2.12; p = 0.14) for cementless versus cemented TKA. Our results suggest that current selective use of cementless fixation for TKA in patients aged ≥65 years in the United States is not associated with an increased risk of revision. While encouraging, further study is necessary to establish indications for use in this age group prior to broader adoption in this patient population. LEVEL OF EVIDENCE: Therapeutic Level III.

Active Amphetamine Abuse in Total Hip Arthroplasty Carries Increased Risk for Postoperative Surgical and Medical Complications.

Background: The impact of amphetamine abuse on total hip arthroplasty (THA) outcomes has yet to be studied. As the rates of methamphetamine abuse continue to rise, understanding the risk profile of this population is imperative. This study aims to determine the risk of major surgical and medical complications for those with amphetamine abuse undergoing THA, with the hypothesis that amphetamine abuse carries increased risk. Methods: A retrospective review was performed with all-claims data files of a large national database querying International Classification of Disease, tenth revision, procedure codes identifying 333,038 primary THA, and 1027 with active amphetamine abuse. Medical and surgical complications including infection, dislocation, implant failure, periprosthetic fracture, and revision, as well as length of hospital stay and 90-day readmission rate, were identified. Univariate analysis compared rates of dependent outcomes. To account for independent variables, logistic regression was performed using age, Charlson comorbidity index, sex, obesity, tobacco use, and alcohol use. The results were presented as odds ratios (OR) and P values with significance set at <0.05. Results: Patients with active amphetamine abuse carried an increased risk of dislocation (OR 1.82, P ≤ .001), infection (OR 2.37, P ≤ .001), mechanical complications (OR 1.64, P ≤ .001), periprosthetic fracture (OR 1.53, P ≤ .05), revision (OR 1.70, P ≤ .001), 90-day readmission (OR 1.79, P ≤ .001), as well as medical complications (1.43, P = .02) compared to those without documented amphetamine abuse. Conclusions: Patients with amphetamine abuse are at increased risk of postoperative surgical and medical complications following THA. We recommend consideration of these risks prior to primary THA in this patient population.

Femoral Component Design Is Associated With the Risk of Periprosthetic Femur Fracture After Cementless THA in Patients 65 Years or Older.

BACKGROUND: Periprosthetic femur fracture is a known complication after THA. The associated risk of cementless femoral component design for periprosthetic femur fracture in a registry population of patients older than 65 years has yet to be clearly identified. QUESTIONS/PURPOSES: (1) Is femoral stem geometry associated with the risk of periprosthetic femur fracture after cementless THA? (2) Is the presence or absence of a collar on cementless femoral implant designs associated with the risk of periprosthetic femur fracture after THA? METHODS: We analyzed American Joint Replacement Registry data from 2012 to March 2020. Unique to this registry is the high use of cementless femoral stems in patients 65 years and older. We identified 266,040 primary cementless THAs during the study period in patients with a diagnosis of osteoarthritis and surgeries linked to supplemental Centers for Medicare and Medicaid data where available. Patient demographics, procedure dates, and reoperation for periprosthetic femur fracture with revision or open reduction and internal fixation were recorded. The main analysis was performed comparing the Kheir and Chen classification: 42% (112,231 of 266,040) were single-wedge, 22% (57,758 of 266,040) were double-wedge, and 24% (62,983 of 266,040) were gradual taper/metadiaphyseal-filling cementless femoral components, which yielded a total of 232,972 primary cementless THAs. An additional analysis compared cementless stems with collars (20% [47,376 of 232,972]) with those with collarless designs (80% [185,596 of 232,972]). A Cox proportional hazard regression analysis with the competing risk of death was used to evaluate the association of design and fracture risk while adjusting for potential confounders. RESULTS: After controlling for the potentially confounding variables of age, sex, geographic region, osteoporosis or osteopenia diagnosis, hospital volume, and the competing risk of death, we found that compared with gradual taper/metadiaphyseal-filling stems, single-wedge designs were associated with a greater risk of periprosthetic femur fracture (HR 2.9 [95% confidence interval (CI) 2.2 to 3.9]; p < 0. 001). Compared with gradual taper/metadiaphyseal-filling stems, double-wedge designs showed an increased risk of periprosthetic femur fracture (HR 3.0 [95% CI 2.2 to 4.0]; p < 0. 001). Collarless stems showed an increased risk of periprosthetic fracture compared with collared stems (HR 7.8 [95% CI 4.1 to 15]; p < 0. 001). CONCLUSION: If cementless femoral fixation is used for THA in patients 65 years or older, surgeons should consider using gradual taper/metadiaphyseal-filling and collared stem designs because they are associated with a lower risk of periprosthetic femur fracture. Future investigations should compare gradual taper/metadiaphyseal-filling and collared cementless designs with cemented fixation in this population. LEVEL OF EVIDENCE: Level III, therapeutic study.

Is Timing of Total Hip Arthroplasty and Lumbar Spine Fusion Associated With Risk of Hip Dislocation?

Background: In patients with concomitant hip and lumbar spine disease, the question of which surgery-total hip arthroplasty (THA) or lumbar spine fusion (LSF)-to address first has not been adequately answered. We aimed to evaluate the risk of dislocation after THA in patients with LSF first or after THA. Methods: Retrospective review utilizing the PearlDiver database querying Current Procedural Terminology codes for LSF in the year prior (LSF first) or in the year after primary or revision THA (THA first). International Classification of Disease codes identified postoperative hip dislocation as our primary outcome variable. Demographic data collected included age, sex, and obesity. Dislocation rates were described as a proportion of the cohort and compared with chi-square tests. Results: We identified 280,857 primary THA and 42,314 revision THA cases from 2012-2019. Of these, 2090 underwent primary THA and LSF, and 283 underwent revision THA and LSF within a year of each procedure. No differences in age, sex, or obesity between groups were noted. No difference in rate of all-time dislocation for primary THA was noted for the LSF first 51/1429 (3.6%) compared to the THA first 30/661 (4.0%) groups (P = .34), or for revision THA with LSF first 48/204 (23.5%) compared to THA first 27/117 (23.1%) groups (P = 1.0). Conclusions: There was no difference in the risk of dislocation after primary or revision THA if LSF occurred prior to or after the THA. These findings can help surgeons as they counsel patients with concomitant lumbar spine and hip degeneration.

Risk of Revision and Complications After Total Hip Arthroplasty for Acute Treatment of Acetabular Fracture.

BACKGROUND: Total hip arthroplasty (THA) for the treatment of acute acetabular fractures may be indicated where there is high risk for failure of open reduction and internal fixation. This study aimed to determine risks of revision and rates of major complications of THA for acute acetabular fractures. METHODS: A retrospective review was performed (all-claims data files of a large national database) by querying International Classification of Disease, 10th revision procedure codes for THA within 14 days of acetabular fracture. We identified all-cause revision and surgical complications including dislocations, mechanical failures (loosenings or broken prostheses), infections, as well as medical complications. Demographic data collected included age, sex, obesity, and Charlson Comorbidity Index (CCI). Multivariate analyses evaluated the association of revision and major surgical complications after adjusting for demographic characteristics and comorbidities. We identified 956 THAs for the treatment of acute acetabular fracture from 2015 to 2020. Of all acute acetabular fractures treated with THA, 241 were concomitant with open reduction and internal fixation (ORIF), and 715 were THA-alone. RESULTS: All-cause revision risk was 18.2%, overall major surgical complication rate 26.9%, and medical complication rate was 13.2%. Women were associated with increased risk of revision (adjusted odds ratio (aOR) 1.8; confidence interval (CI) 1.3 to 2.6, P = .001), dislocation (aOR 2.0; CI 1.5 to 3.1, P < .001), mechanical complication (aOR 2.1; CI 1.4 to 3.2, P < .001), and infection (aOR 1.6; CI 1.0 to 2.5, P = .044). CONCLUSION: We noted risk of all-cause revision of 18.2%, overall major surgical complication rate of 26.9%, and overall major medical complication rate of 13.2% for THA as the treatment of acute acetabular fracture. We caution against broad expansion of THA for treatment of acute acetabular fractures. Furthermore, increased risks of revision and complications in women warrant additional investigation into patient and fracture characteristics that may contribute to this finding.

Fibromyalgia Increases Post-operative Healthcare Utilization Following total Hip Arthroplasty.

BACKGROUND: Preoperative factors can complicate the postoperative course and increase health care utilization following total hip arthroplasty (THA). Fibromyalgia is not generally recognized as a modifiable risk factor prior to THA. The aim of this investigation was to assess the effect of fibromyalgia on postoperative health care utilization following THA. METHODS: Patients who underwent primary THA from 2018 to 2019 were identified from a large national database using Current Procedural Terminology and International Classification of Diseases, tenth revision (International Classification of Diseases-10) codes. Patient demographics, age, sex, and preoperative opioid use were collected. Analysis compared patients who did and did not have fibromyalgia for postoperative health care utilization metrics; lengths of stay (LOS), 90-day postoperative opioid usages, dislocations, and emergency room visits. Independent t-tests were used to compare LOS and rates of ongoing opioid use. Logistic regression analyses with adjusted odds ratios evaluated the risk of dislocation and emergency room visit after adjusting for demographic characteristics and comorbidities. RESULTS: Compared to those who did not have fibromyalgia, patients who had fibromyalgia experienced longer LOS (P < .0001), increased odds of opioid use 90 days postoperatively (P < .0001) as well as increased odds of hip dislocation (P < .0001) and presentation to the emergency room (P < .0001). Patients who had fibromyalgia were also more likely to be "frequent flyers" with ≥5 emergency room visits after THA (P < .0001). CONCLUSIONS: Fibromyalgia can complicate postoperative care following THA with increased LOS, higher rates of opioid use, and increased odds of dislocation and emergency room visits. As focus shifts to preoperative optimization and risk stratification, more attention should be placed on fibromyalgia prior to THA.

Cemented Femoral Fixation in Total Hip Arthroplasty Reduces the Risk of Periprosthetic Femur Fracture in Patients 65 Years and Older: An Analysis From the American Joint Replacement Registry.

BACKGROUND: Periprosthetic femur fracture (PPFx) is a devastating complication after total hip arthroplasty (THA). Despite concerns for increased PPFx, cementless fixation predominates in the United States. This study used the American Joint Replacement Registry to compare PPFx risk between cemented and cementless femoral fixation for THA. METHODS: An analysis of primary THA cases in patients aged 65 years and more was performed with the American Joint Replacement Registry data linked to Centers for Medicare and Medicaid Services data from 2012 to 2020. Analyses compared cemented to cementless femoral fixation. We identified 279,052 primary THAs, 266,040 (95.3%) with cementless and 13,012 (4.7%) with cemented femoral fixation. Cox proportional hazard regression analyses evaluated the association of fixation and PPFx risk, while adjusting for sex, age, and competing risk of mortality. Cumulative incidence function survival curves evaluated time to PPFx. RESULTS: Age ≥ 80 years (P < .0001) and women (P < .0001) were associated with PPFx. Compared to cemented stems, cementless stems had an elevated risk of PPFx (Hazards Ratio 7.70, 95% Confidence interval 3.2-18.6, P < .0001). The cumulative incidence function curves demonstrated an increased risk for PPFx across all time points for cementless stems, with equal magnitude of risk to 8 years.` CONCLUSION: Cementless femoral fixation in THA continues to predominate in the United States, with cementless femoral fixation demonstrating increased risk of PPFx in patients aged 65 years or more. Surgeons should consider greater use of cemented femoral fixation in this population to decrease the risk of PPFx.

It is the Opioids Not the Spine Surgeon; Dislocation After Total Hip Arthroplasty is Associated With Opioid Use in Patients Who Have Prior Lumbar Spine Fusion.

BACKGROUND: Patients who have prior lumbar spine fusion (LSF) have an increased risk for dislocation after total hip arthroplasty (THA). These patients also have elevated rates of opioid use. We aimed to evaluate the associated risk of dislocation after THA in patients who have prior LSF comparing those who have opioid use to those who do not. METHODS: This was a retrospective review using a large national database of 246,617 primary and 34,083 revision THA cases from 2012 to 2019. There were 1,903 primary THA and 288 revision THA cases identified with LSF prior to THA. Postoperative hip dislocation was our primary outcome variable and patients were stratified to use or nonuse of opioid at THA. Demographic data including age, sex, and obesity were collected. Multivariate analyses evaluated association of opioid use and dislocation after adjusting for demographics. RESULTS: There was increased odds of dislocation for opioid use at THA for both primary (adjusted Odds Ratio [aOR] = 2.29, 95% Confidence Interval [CI] 1.46 to 3.57, P < .0003) and revision THA (aOR = 1.92, 95% CI 1.62 to 3.08, P < .0003), in patients who have prior LSF. Prior LSF without opioid use was associated with increased odds of dislocation (aOR = 1.38, 95% CI 1.01 to 1.88, P = .04), but this was lower than the associated risk of opioid use without LSF (aOR 1.72, 95% CI 1.63 to 1.81, P < .001). CONCLUSION: Increased odds of dislocation were noted with opioid use at time of THA in patients who have prior LSF. Associated risk of dislocation was higher for opioid use than prior LSF. This suggests that dislocation risk is multifactorial and we should look to strategies to reduce opioid use prior to THA.

The James A. Rand Young Investigator's Award: Increased Revision Risk With Mobile Bearings in Total Knee Arthroplasty: An Analysis of the American Joint Replacement Registry.

BACKGROUND: Mobile-bearing (MB) total knee arthroplasty (TKA) may reduce wear and improve patellar tracking but may increase revision risk due to tibial component design, balance complexity, and bearing dislocation. We utilized the American Joint Replacement Registry to examine risk of revision with MB compared to fixed-bearing (FB) designs. METHODS: An analysis of primary TKA in patients over 65 years was performed with American Joint Replacement Registry data linked to Centers for Medicare and Medicaid Services data from 2012 to 2019. Analyses compared MB to FB designs with a subanalysis of implants from a single company. We identified 485,024 TKAs, with 452,199 (93.2%) FB-TKAs and 32,825 (6.8%) MB-TKAs. Cox proportional hazards regression modeling was used for all-cause revision and revision for infection, adjusting for sex, age, and competing risk of mortality. Event-free survival curves evaluated time to all-cause revision and revision for infection. RESULTS: MB-TKAs were at an increased risk for all-cause revision: hazard ratio (HR) 1.36 ([95% confidence interval (CI) 1.24-1.49], P < .0001) but not revision for infection: HR 1.06 ([95% CI 0.90-1.25], P = .52). When comparing implants within a single company, MB-TKAs were at an increased risk of all-cause revision: HR 1.55 ([95% CI 1.38-1.73], P < .0001). Event-free survival curves demonstrated increased risk for all-cause revision for MB-TKA across all time points, with a greater magnitude of risk up to 8 years. CONCLUSION: Although survivorship of both designs was outstanding, MB-TKA designs demonstrated increased risk for all-cause revision. Additional investigation is needed to determine if this is related to patient selection factors, surgical technique, bearing, or implant design.

No Reduction in Revision Risk Associated With Highly Cross-linked Polyethylene With or Without Antioxidants Over Conventional Polyetheylene in TKA: An Analysis From the American Joint Replacement Registry.

BACKGROUND: Highly cross-linked polyethylene (HXLPE) can improve wear properties in TKA, but it can also lead to decreased mechanical properties. Antioxidants were added to HXLPE to improve its mechanical properties while retaining the improved wear characteristics. However, it remains unclear whether these modifications to conventional polytheylene used in TKA have resulted in a change in the revision risk. QUESTIONS/PURPOSES: We used American Joint Replacement Registry data to ask: (1) Is there a difference in all-cause revision in patients who underwent TKA using HXLPE with or without an antioxidant doping compared with conventional polyethylene? (2) Is there a difference in revision for aseptic failure in patients who underwent TKA using HXLPE with or without an antioxidant doping compared with conventional polyethylene? METHODS: We analyzed American Joint Replacement Registry data from 2012 to 2019. We identified 339,366 primary TKAs over the study period in patients older than 65 years and linked procedures to supplemental Centers for Medicare & Medicaid data where available. Patient total number of reported comorbidities, gender, age, region, polyethylene characteristics, procedure dates, and indication for revision were recorded. Median follow-up was 34 months. We compared HXLPE with or without antioxidants to conventional polyethylene. Event-free percent survival curves and Cox proportional hazard regression modeling was used for all-cause revision and revision for aseptic failure. RESULTS: Compared with conventional polyethylene, there was no difference in all-cause revision with HXLPE with an antioxidant (HR 1.06 [95% CI 0.98 to 1.14]; p = 0.13) or HXLPE without an antioxidant (HR 1.04 [95% CI 0.97 to 1.11]; p = 0.28). Compared with conventional polyethylene, there was no difference in revision for aseptic failure with HXLPE with an antioxidant (HR 1.07 [95% CI 0.99 to 1.14]; p = 0.08) or HXLPE without an antioxidant (HR 1.03 [95% CI 0.97 to 1.01]; p = 0.30). CONCLUSION: We found no difference in revision risk between HXLPE with or without an antioxidant and conventional polyethylene during this time frame. HXLPE polyethylene, with or without an antioxidant, should not be widely adopted until or unless it is shown to be superior to conventional polyethylene in TKA. LEVEL OF EVIDENCE: Level III, therapeutic study.

Revision Risk for Total Knee Arthroplasty Polyethylene Designs in Patients 65 Years of Age or Older: An Analysis from the American Joint Replacement Registry.

BACKGROUND: Polyethylene bearing design may influence the risk of revision after total knee arthroplasty (TKA). Previous investigations from outside of the United States have suggested the potential for an increased risk of all-cause revision and revision for infection with the use of posterior-stabilized bearings. We examine the risk of revision based on the polyethylene bearing design selection for primary TKA. METHODS: An analysis of the American Joint Replacement Registry (AJRR) data from 2012 to 2019 was performed. We identified all primary TKAs over the study period and linked cases to supplemental U.S. Centers for Medicare & Medicaid Services (CMS) data where available. Patient demographic characteristics, polyethylene characteristics, procedure dates, and cause for revision were recorded. Analysis was performed to compare minimally stabilized implants (cruciate-retaining, anterior-stabilized, or pivot bearing designs) with posterior-stabilized implants. Cumulative incidence function (CIF) curves and Cox proportional hazard ratios (HRs) were created for all-cause revision and revision for infection in each group. RESULTS: We identified 305,279 cases with reported minimally stabilized or posterior-stabilized implant characteristics. There were 161,486 cases (52.9%) that utilized posterior-stabilized bearings compared with 143,793 cases (47.1%) with minimally stabilized bearings. For minimally stabilized bearings, 1,693 cases (1.18%) had all-cause revision and 334 cases (0.23%) had revision for infection. For posterior-stabilized bearings, 2,406 cases (1.49%) had all-cause revision and 446 cases (0.28%) had revision for infection. The use of posterior-stabilized bearings had HRs of 1.25 (95% confidence interval [CI], 1.2 to 1.3; p < 0.0001) for all-cause revision and 1.18 (95% CI, 1.0 to 1.4; p = 0.02) for revision for infection. CONCLUSIONS: Similar to investigations from international registries, we found an increased risk of all-cause revision and revision for infection when using posterior-stabilized bearings in TKA in the United States. Surgeons should consider this finding when considering bearing selection for primary TKA. LEVEL OF EVIDENCE: Therapeutic Level III . See Instructions for Authors for a complete description of levels of evidence.

Traditional Versus Digital Media-Based Hand Therapy After Distal Radius Fracture.

PURPOSE: Distal radius fractures (DRFs) are common injuries with a rising incidence. A substantial portion of the cost of care is attributable to therapy services. Our purpose was to evaluate the effectiveness of a self-directed hand therapy program guided by digital media compared with that of traditional therapy. METHODS: We conducted a randomized controlled trial in patients aged 18 years or older who underwent open reduction and internal fixation of a DRF with volar plating. Subjects were randomized to traditional hand therapy using a 12-week protocol or an identical protocol presented in digital videos and performed at home. Disabilities of the Arm, Shoulder, and Hand (QuickDASH) scores were collected as the primary outcome at 2 weeks (baseline), 6 weeks, and 12 weeks or greater. Pain visual analog scale (VAS) scores, Veterans RAND 12-Item Health Survey (VR-12) scores, wrist and forearm range of motion, wrist circumference, and grip strength were recorded as secondary outcomes. RESULTS: Fifty-one patients were enrolled. Forty-nine patients were included in the analysis-21 in the digital media group and 28 in the traditional group. Both groups demonstrated significant improvements in QuickDASH scores between baseline and 12-week or greater time points. The QuickDASH scores in the digital media group were slightly more improved than those in the traditional group at the 6-week and 12-week or greater time points; however, these differences were not statistically significant. Pain VAS and VR-12 scores were comparable between group differences at each time point. CONCLUSIONS: Our digital media program was at least as effective as traditional therapy for patients undergoing volar plating of DRF. These results may help inform the design of future trials investigating the effectiveness of digital media-based hand therapy programs. TYPE OF STUDY/LEVEL OF EVIDENCE: Therapeutic II.

Trends in Polyethylene Design and Manufacturing Characteristics for Total Knee Arthroplasty: An Analysis From the American Joint Replacement Registry.

BACKGROUND: Advances in polyethylene bearing characteristics have led to various options for total knee arthroplasty. We examine trends in use of polyethylene in the United States. METHODS: An analysis of American Joint Replacement Registry data from 2012 to 2019 for primary total knee arthroplasty procedures was conducted. Design and manufacturing characteristics were obtained and validated in the American Joint Replacement Registry dataset. Polyethylene bearing design and manufacturing use characteristics were compared by year, gender, age group, and geographic region of the procedure. Descriptive analysis was performed. RESULTS: We identified 993,292 cases over the study period. In total, 791,233 (80%) cases had complete device data available and were included in analysis. In addition, 366,280 (49.4%) cases utilized minimally stabilized bearings compared to 374,809 (50.6%) for posterior-stabilized bearings. Posterior-stabilized use was stable over the study period and highest in the Northeast (64.5%; P < .0001). Cruciate-retaining use decreased from 29.7% to 20.2% and anterior-stabilized use increased from 17.4% to 25.2%. Conventional polyethylene use decreased from 42.8% to 21.9%, and was highest in the 81+ age group (37.8%; P < .0001) and Northeast (43.0%; P < .0001). Highly cross-linked polyethylene (HXLPE) with antioxidant use increased from 9.08% to 31.8%, while HXLPE without antioxidant use remained constant. CONCLUSION: There was an increase in use of anterior-stabilized and pivot bearings and an increase in use of HXLPE with antioxidant. Additionally, there were noted age group and regional differences in the use of various bearings. Further study should evaluate if these changing utilization trends are related to clinical outcomes, or due to regional training, preferences, or manufacturer pressures. LEVEL OF EVIDENCE: Level III, retrospective.

Disagreement in Readmission Rates After Total Hip and Knee Arthroplasty Across Data Sets.

BACKGROUND: In 2014, the Affordable Care Act Hospital Readmissions Reduction Program began penalizing hospitals for excessive readmission rates 30 days after total hip arthroplasty (THA) and total knee arthroplasty (TKA). Various data sets with nonstandardized validation processes report readmission data, which may provide conflicting outcome values for the same patient populations. METHODS: We queried 4 separate data sets: the American Joint Replacement Registry, Centers for Medicare and Medicaid Services billing data, the Vizient data set, and an advanced analytics integration (Cognos) report from our electronic medical record. We identified 2763 patients who underwent primary TKA and THA at a single academic medical center from June 2016 to June 2019. We then matched 613 surgery encounters in all 4 databases. Our primary outcome metric was 30-day readmissions. Fleiss' Kappa was used to measure agreement among the different data sets. RESULTS: Of the 613 THA and TKA patients, there were 45 (7.3%) readmissions noted. Data collected from the Centers for Medicare and Medicaid Services flagged 41 (6.7%) readmissions, Vizient flagged 11 (1.8%) readmissions, and the American Joint Replacement Registry and Cognos report both flagged 6 (0.98%) readmissions each. None of the readmissions were identified by all 4 data sets. There was significant disagreement among data sets using Fleiss' Kappa (kappa = -0.1318, P = .03). CONCLUSION: There is disagreement in readmission rates in databases receiving the same patient data after THA and TKA. Care must be taken to establish standard validation processes and reporting methods and scrutiny applied when interpreting readmission rates from various data sets.

Does Resident Participation in the Surgical Fixation of Hip Fractures Increase Operative Time or Affect Outcomes?

BACKGROUND: Surgical fixation of hip fractures is a common procedure at teaching hospitals with resident support and in community hospitals. OBJECTIVE: We evaluated to what extent participation by residents in hip fracture fixation affects operative times or outcomes. SETTING: Operations were performed by three surgeons who operate at a teaching hospital with resident support, and at a community hospital without residents in the same metropolitan area. PARTICIPANTS: We performed a retrospective analysis of operative time and early post-operative outcomes on a series of 314 patients with hip fractures (Arbeitsgemeinschaft für Osteosynthesefragen/Orthopaedic Trauma Association A1-3, B1-3) treated with surgical fixation between April 2012 and March 2015; 177 patients at the community hospital, and 137 at the teaching hospital. METHODS: Multivariate regression assessed the effect of hospital type, adjusting for age, gender, American Society of Anesthesiologist classification, and Charlson comorbidity index. RESULTS: We found lower median operative time at the community hospital than the teaching hospital (46 minutes, 95% confidence interval [CI] = [43, 52] versus 75 minutes, 95% CI = [70, 81]) and lower estimated blood loss (177.3 mL, 95% CI=[158.6, 195.1] versus 234.8 mL, 95% CI = [196.4, 273.6]), but no differences in transfusion requirement, length of stay, or discharge to skilled nursing facility. Adjusted odds ratio for thirty-day mortality at the teaching hospital was 5.44 (95% CI = [1.22, 24.1]). CONCLUSION: We found longer operative times and elevated estimated blood loss with resident involvement in surgical fixation of hip fractures. There was a difference in 30-day mortality between the groups, although this cannot simply be attributed to resident involvement as there are many other factors related to mortality.

Compressive osseointegration for endoprosthetic reconstruction.

This review summarizes the biomechanical concepts, clinical outcomes and limitations of compressive osseointegration fixation for endoprosthetic reconstruction. Compressive osseointe - gration establishes stable fixation and integration through a novel mechanism; a Belleville washer system within the spindle applies 400-800 PSI force at the boneimplant interface. Compressive osseointegration can be used whenever standard endoprosthetic reconstruction is indicated. However, its mode of fixation allows for a shorter spindle that is less limited by the length of remaining cortical bone. Most often compressive osseointegration is used in the distal femur, proximal femur, proximal tibia, and humerus but these devices have been customized for use in less traditional locations. Aseptic mechanical failure occurs earlier than with standard endoprosthetic reconstruction, most often within the first two years. Compressive osseointegration has repeatedly been proven to be non-inferior to standard endoprosthetic reconstruction in terms of aseptic mechanical failure. No demographic, device specific, oncologic variables have been found to be associated with increased risk of aseptic mechanical failure. While multiple radiographic parameters are used to assess for aseptic mechanical failure, no suitable method of evaluation exists. The underlying pathology associated with aseptic mechanical failure demonstrates avascular bone necrosis. This is in comparison to the bone hypertrophy and ingrowth at the boneprosthetic interface that seals the endosteal canal, preventing aseptic loosening.