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.

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 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 American Joint Replacement Registry 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% confidence interval: 0.24 to 0.55; P < .0001) and revision for infection (HR = 0.41; 95% confidence interval: 0.22 to 0.77, P < .0001). Event-free survival curves demonstrated a decreased risk of all-cause revision that persisted across time points until 8 years post-TKA. CONCLUSIONS: 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. LEVEL OF EVIDENCE: Therapeutic Level III.

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 of the femoral head (ONFH), the degree to which multiple risk factors increase risk is unknown. This study aimed to: (1) identify the demographic characteristics of patients who have 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 ONFH over a 10-year period. Patients who had 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. CONCLUSIONS: 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. LEVEL OF EVIDENCE: Retrospective Cohort Study, Level III.

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.

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.

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.