Staged Bilateral Total Knee Arthroplasty: Differing Results Comparing the First and Second Knees.

BACKGROUND: Patients often prefer one knee over the other following staged bilateral total knee arthroplasty (BTKA). Our study compared patient-reported outcomes scores of each knee following BTKA and identified factors that may contribute to the identified discrepancies. METHODS: All patients who underwent staged BTKA between July 2014 and August 2022 were identified. The patient-reported outcomes were collected preoperatively and at 2 weeks, 6 weeks, 1 year, and 2 years postoperatively. Each knee's results were compared using paired t-tests and McNemar tests. Preoperative Kellgren-Lawrence Grade (KLG), postoperative range of motion (ROM), reoperation rates, and manipulations under anesthesia (MUAs) were collected. Results were stratified based on time between TKAs (< 3 months, 3 to 12 months, 1 to 2 years, and > 2 years). RESULTS: There were 911 patients who underwent staged BTKA, with a mean 4.1-year follow-up. The ROM, patient satisfaction, MUAs, and reoperations were not significantly different between knees. Comparing the KLG of the first and second knees, 71% had the same KLG for both knees, 21% had a lower KLG, and 7% of the second knees had a higher KLG. The first knee had greater pain reduction (-10.6 at 2 weeks, -27.4 at 6 weeks) compared to the second (9.3 at 2 weeks, -8.1 at 6 weeks) (P < .0001) and better improvement in Knee Injury and Osteoarthritis Outcome Score for Joint Replacement (KOOS JR) score (8.5 at 2 weeks, 16.9 at 6 weeks) compared to the second (-5.8 at 2 weeks, 5.0 at 6 weeks) (P < .0001). The 1-year outcomes between first and second knees, or recovery curves, were not different when stratifying by time between TKAs. CONCLUSIONS: The second knee in a staged BTKA has less delta improvement in KOOS JR and pain scores at early follow-up, likely due to higher starting KOOS JR and Patient-Reported Outcomes Measurement Information System scores, despite similar final patient satisfaction and clinical outcome measures. Lower KLG in the second total knee arthroplasty (TKA) may contribute to these findings. An MUA after the first TKA is highly predictive of an MUA after the second TKA.

Discharge to a Skilled Nursing Facility After Hip Fracture Results in Higher Rates of Periprosthetic Joint Infection.

BACKGROUND: Femoral neck fractures (FNFs) in elderly patients are associated with major morbidity and mortality. The influence of postoperative discharge location on recovery and outcomes after arthroplasty for hip fractures is not well understood. METHODS: A multisite retrospective cohort from 9 academic centers identified patients who had FNF treated with hemiarthroplasty or total hip arthroplasty between 2010 and 2019. Patients who had diagnoses of dementia, stroke, age > 80 years, or high energy fracture were excluded. Discharge location was identified, including home-based health services (HHS), inpatient rehabilitation (IPR), or a skilled nursing facility (SNF). Rates of reoperation, periprosthetic joint infection (PJI), and mortality were compared between cohorts. Multivariate logistic regressions were performed, adjusting for age, American Society of Anesthesiologists (ASA) score, body mass index, sex, and tobacco use. Statistical significance was defined as P < .05. RESULTS: A total of 672 patients (315 HHS, 144 IPR, and 213 SNF) were included in this study. The average follow-up was 30 months. The SNF cohort was significantly older (P < .0001) with higher ASA scores (P < .0001) than the HHS cohort. In a logistic regression model adjusting for age, ASA score, and body mass index, the SNF cohort had higher mortality rates than the HHS cohort (P = .0296) and were more likely to have PJI within 90 days (odds ratio = 4.55, 95% confidence interval = 1.40, 4.74) and within 1 year (odds ratio = 3.08, 95% confidence interval = 1.08, 8.78). Time to PJI was significantly shorter in the SNF cohort (SNF 38 versus HHS 231 days, P = .0155). No differences were seen in dislocation or reoperation rates between the SNF and HHS cohorts. No differences were seen in complication rates between the IPR and HHS cohorts. CONCLUSIONS: Discharge to a SNF after arthroplasty for FNF is associated with increased mortality and higher rates of PJI. Hip fracture care pathways that uniformly discharge patients to SNFs may need to be re-evaluated, and surgeons should consider discharge to home with HHS when possible.

Similar Efficacy and Lower Cost Associated With Ceftazidime Compared to Tobramycin Coupled With Vancomycin in Antibiotic Spacers in the Treatment of Periprosthetic Joint Infection.

BACKGROUND: Vancomycin and tobramycin have traditionally been used in antibiotic spacers. In 2020, our institution replaced tobramycin with ceftazidime. We hypothesized that the use of ceftazidime/vancomycin (CV) in antibiotic spacers would not lead to an increase in treatment failure compared to tobramycin/vancomycin (TV). METHODS: From 2014 to 2022, we identified 243 patients who underwent a stage I revision for periprosthetic joint infection. The primary outcome was a recurrent infection requiring antibiotic spacer exchange. We were adequately powered to detect a 10% difference in recurrent infection. Patients who had a prior failed stage I or two-stage revision for infection, acute kidney injury prior to surgery, or end-stage renal disease were excluded. Given no other changes to our spacer constructs, we estimated cost differences attributable to the antibiotic change. Chi-square and t-tests were used to compare the two groups. Multivariable logistic regressions were utilized for the outcomes. RESULTS: The combination of TV was used in 127 patients; CV was used in 116 patients. Within one year of stage I, 9.8% of the TV group had a recurrence of infection versus 7.8% of the CV group (P = .60). By final follow-up, results were similar (12.6 versus 8.6%, respectively, P = .32). Adjusting for potential risk factors did not alter the results. Cost savings for ceftazidime versus tobramycin are estimated to be $68,550 per one hundred patients treated. CONCLUSIONS: Replacing tobramycin with ceftazidime in antibiotic spacers yielded similar periprosthetic joint infection eradication success at a lower cost. While larger studies are warranted to confirm these efficacy and cost-saving results, our data justifies the continued investigation and use of ceftazidime as an alternative to tobramycin in antibiotic spacers.

Rheumatoid Arthritis Is Not a Contraindication to Unicompartmental Knee Arthroplasty.

BACKGROUND: Rheumatoid arthritis (RA) has historically been considered a contraindication for unicompartmental knee arthroplasty (UKA). However, the widespread use of disease-modifying antirheumatic drugs has substantially improved the management of RA and prevented disease progression. The objective of this study was to ascertain whether RA impacts UKA revision-free survivorship. METHODS: Patients undergoing UKA from 2010 to 2021 were identified in an administrative claims database (n = 105,937) using Current Procedural Terminology code 27446. All patients who underwent UKA who had a diagnosis of RA with a minimum of 2-year follow-up (n = 1,422) were propensity score matched based on age, sex, and Elixhauser Comorbidity Index to those who did not have RA (n = 1,422). Laterality was identified using the 10th Revision of International Classification of Diseases codes. The primary outcome was ipsilateral revision to total knee arthroplasty (TKA) within 2 years, and the secondary outcome was ipsilateral revision at any time. RESULTS: Among the 1,422 patients who had a UKA and a diagnosis of RA, 37 patients (2.6%) underwent conversion to TKA within 2 years, and 48 patients (3.4%) underwent conversion to TKA at any point. In comparison, 28 patients (2.0%) in the propensity-matched control group underwent conversion to TKA within 2 years, and 40 patients (2.8%) underwent conversion to TKA at any point. Statistical analysis revealed no significant difference in conversion to TKA between patients who had and did not have RA, either within 2 years (P = .31) or anytime (P = .45). CONCLUSIONS: Patients who had RA and underwent UKA did not have an increased risk of revision to TKA compared to those who did not have RA. This may indicate that modern management of RA could allow for expanded UKA indications for RA patients.

Risk Factors for Return to the Emergency Department and Readmission After Same-Day Discharge Total Joint Arthroplasty.

BACKGROUND: Same-day discharge (SDD) after total joint arthroplasty (TJA) is safe and cost effective. However, benefits may be offset by the potential cost of emergency department (ED) visits and readmissions. We identified risk factors for return to the ED and readmission in patients who underwent SDD and inpatient (IP) stays after TJA. METHODS: We performed a retrospective review of patients who underwent primary TJA at an academic institution over the course of one year. There were 1,708 consecutive TJAs (721 THA [total hip arthroplasty] and 987 TKA [total knee arthroplasty]) included. A SDD occurred after 1,199 (70%) TJAs, 523 THAs, and 676 TKAs. We compared the demographics and comorbidities of patients who have SDD or IP who stayed following TJA. We documented rates of return to the ED or readmission within 90 days of surgery. Cohorts were compared using the Student's t-test or Chi-square test. Significant findings were those with P value < .05. RESULTS: The SDD cohort had a significantly higher rate of young, non-White men who had a lower body mass index and fewer comorbidities than the IP cohort. Rates of return to ED and readmission were similar between SDD and IP cohorts after TJA and similar between THA and TKA. Factors that significantly influenced return to ED included a higher American Society of Anaesthesiologists score (SDD, IP), a higher Charlson Comorbidity Index score (SDD, IP), a lower body mass index (IP), and a psychological diagnosis (SDD, IP). Factors that significantly influenced readmission rates included a higher American Society of Anaesthesiologists score (SDD), older age (SDD), and psychological diagnosis (SDD, IP). CONCLUSIONS: Patients who discharged the same day after primary TJA have similar rates of return to the ED and readmission as those admitted as an IP. Patients who had a psychological diagnosis, and particularly a diagnosis of depression, are at higher risk for return to the ED and readmission after primary TJA, regardless of discharge the same-day or IP admission. Improved measures that attempt to further treat and optimize this patient population could reduce unnecessary postoperative ED visits.

Decreased Patellar Fractures and Subluxation With Patellar Component Replacement at Stage-One Spacer.

BACKGROUND: Periprosthetic joint infection is a devastating complication of total knee arthroplasty and is often treated with 2-stage revision. We retrospectively assessed whether replacing the patellar component with articulating stage-one spacers was associated with improved outcomes compared to spacers without patellar component replacement. METHODS: A total of 139 patients from a single academic institution were identified who underwent an articulating stage-one revision total knee arthroplasty and had at least 1-year follow-up. Of the 139 patients, 91 underwent patellar component removal without replacement, while 48 had a patellar component replaced at stage-one revision. Patellar fracture and reinfection at any point after stage-one were recorded. Knee range of motion (ROM), patellar thickness, lateral tilt, and lateral displacement were measured at 6-weeks post stage-one. Chi-square, Fisher's exact, and t-tests were utilized for comparisons. There were no significant demographic differences between groups. RESULTS: Patellar component replacement at stage-one revision was associated with fewer patellar fractures (2.1 versus 12.1%, P = .046), less lateral patellar displacement (1.7 versus 16.0 mm, P < .01), and improved pre to postoperative knee ROM 6 weeks after stage-one (+5.9 versus -11.4°, P = .03). There was no difference in reinfections after stage-2 revision for the replaced or unreplaced patellar groups (15.4 versus 15%, P = 1.000). While the mean time between stage-one and stage-2 was not different (5.2 versus 4.5 months, P = .50), at one-year follow-up, significantly more patients in the patellar component replacement group were satisfied and refused stage-2 revision (45.8 versus 3.3%, P < .001). CONCLUSIONS: Replacing the patellar component at stage-one revision is associated with a decreased rate of patellar fracture and lateral patellar subluxation, improved ROM, and possible increased patient satisfaction, as reflected by nearly half of these patients electing to keep their spacer. There was no difference in reinfection rates between the cohorts.

Outpatient Total Joint Arthroplasty at a High-Volume Academic Center: An Analysis of Failure to Launch.

BACKGROUND: Unanticipated failure to discharge home (failure to launch, FTL) following scheduled same-day discharge (SDD) total joint arthroplasty (TJA) is problematic for the surgical facility with respect to staffing, care coordination, and reimbursement concerns. The aim of this study was to review rates, etiologies, and contributing factors for FTL in SDD TJA at an inpatient academic medical center. METHODS: All patients who underwent primary TJA between February 2021 and February 2023 were retrospectively reviewed. Of those scheduled for SDD, risk factors for FTL were compared with successful SDD. Readmission and emergency department (ED) visits were compared with historical cohorts. There were 3,093 consecutive primary joint arthroplasties performed, of which 2,411 (78%) were scheduled for SDD. RESULTS: Overall, SDD was successful in 94.2% (n = 2,272) of patients who had an FTL rate of 5.8%. Specifically, SDD was successful in 91.4% with total hip arthroplasty, 96.0% with total knee arthroplasty, and 98.6% with unicompartmental knee arthroplasty. Factors that significantly increased the risk of FTL included general anesthesia versus spinal anesthesia (P < .0001), later surgery start time (P < .0001), longer surgical time (P = .0043), higher estimated blood loss (P < .0001), women (P = .0102), younger age (P = .0079), and lower preoperative mental health patient-reported outcomes scores (P = .0039). Readmission and ED visit rates were not higher in the SDD group when compared to historical controls (P = .6830). CONCLUSIONS: With a comprehensive multidisciplinary approach dedicated to improving SDDs at an academic medical center, we have seen successful SDD in nearly 80% of primary TJA, with an FTL rate of 5.8%, and no increased risk of readmission or ED visits. Without adding many personnel, hospital recovery units, or other resources, simple interventions to help decrease FTL have included enhanced preoperative education and expectation settings, improved perioperative communications, reallocating personnel from the inpatient to the outpatient setting, the use of short-acting spinal anesthetics, and earlier scheduled surgery times.

Impact of Demographic Variables on Recovery After Total Hip Arthroplasty.

BACKGROUND: Several patient factors affect recovery after total hip arthroplasty (THA). However, the impact of these variables on patient-reported outcome measure recovery curves following THA has not been defined. Our goal was to quantify the influence of multiple variables on recovery after primary THA. METHODS: There were 1,724 patients in a multicenter study included. Variables included sex, race/ethnicity, anxiety/depression, body mass index, tobacco, and preoperative opioid use. The Hip disability and Osteoarthritis Score for Joint Replacement (HOOS JR) was recorded at multiple time points. Recovery curves were created using longitudinal estimating equations. RESULTS: Patients who were women, obese, or smokers demonstrated lower HOOS JR scores at all time points. Preoperative opioid use was also correlated with lower HOOS JR scores, but this difference diminished after 6 months. Black patients demonstrated lower HOOS JR scores compared to Caucasians, and this relative difference increased out to 1-year postoperatively (P = .018). Hispanics also had lower HOOS JR scores, but scores recovered at similar rates compared to non-Hispanics. Patients who had only anxiety or depression had similar HOOS JR scores compared to patients who did not have anxiety or depression. However, patients who had both anxiety and depression had lower HOOS JR scores compared to patients who had neither (P = .049), and this relative difference became greater at 1-year postoperatively (P = .002). CONCLUSIONS: Several factors including race/ethnicity, opioid use, and mental health influence recovery trajectory following THA. This information helps provide more individualized counseling about expectations after THA and focus targeted interventions to improve outcomes in at-risk groups.

Motivations and Barriers for Women Orthopaedic Surgeons Considering Arthroplasty Fellowship.

BACKGROUND: Arthroplasty is one of the least gender-diverse orthopaedic subspecialties. While previous studies have looked at factors influencing fellowship choices for women, few studies have attempted to understand the decision for or against arthroplasty specifically. Working to better understand fellowship choice is a critical step in the process of increasing women recruitment. METHODS: An anonymous survey was distributed using REDCap to women orthopaedic surgeons and trainees through listservs, social media groups, and residency programs. Surgeons who had decided on a specific subspecialty or already completed fellowship were included. Responses were obtained from 164 surgeons (72 arthroplasty surgeons, 92 other subspecialties). Chi-squared and Fisher's Exact tests were then performed. RESULTS: The most important factor for those who chose arthroplasty was enjoyment of the surgeries. The biggest concerns from those in the arthroplasty group about the field were work-life balance, ability to become pregnant and/or have a healthy pregnancy, and sex bias from referring physicians. Of those who ultimately chose another subspecialty, 30.4% considered arthroplasty "a little" and 8.7% considered it "strongly." The most important dissuaders for the group that considered arthroplasty were concerns about "boy's club" culture, concerns about the physicality of the surgeries, and a lack of mentors. CONCLUSION: While the decision to choose a career path is multifactorial, our hope is that through the identification of modifiable factors we can increase women representation in arthroplasty. Increasing mentorship, implementing practical solutions to improve work-life balance, supporting healthy pregnancies, and mitigating the physical demands of surgery could help address current disparities.

Metallosis and Corrosion Associated With Revision Total Knee Arthroplasties With Metaphyseal Sleeves.

Metallosis and corrosion have been associated with metal-on-metal and modular total hip arthroplasty but are rarely described in the setting of primary or revision total knee arthroplasty (TKA). In this series, we report on cases of metallosis due to mechanically assisted crevice corrosion at modular junctions of machined trunnion-bore tapers in a revision TKA system with metaphyseal sleeves. The unique design of metal modular junctions used in sleeve-based revision TKA, along with potential patient and surgical factors, may predispose these designs to fretting, corrosion, and adverse reaction to metal debris. We now consider metallosis and corrosion in the workup of painful or failed revision TKAs with sleeves. Future studies that investigate the incidence of this phenomenon may be warranted.

The Microbiome of Osteoarthritic Hip and Knee Joints: A Prospective Multicenter Investigation.

BACKGROUND: Recent advances in high-throughput DNA sequencing technologies have made it possible to characterize the microbial profile in anatomical sites previously assumed to be sterile. We used this approach to explore the microbial composition within joints of osteoarthritic patients. METHODS: This prospective multicenter study recruited 113 patients undergoing hip or knee arthroplasty between 2017 and 2019. Demographics and prior intra-articular injections were noted. Matched synovial fluid, tissue, and swab specimens were obtained and shipped to a centralized laboratory for testing. Following DNA extraction, microbial 16S-rRNA sequencing was performed. RESULTS: Comparisons of paired specimens indicated that each was a comparable measure for microbiological sampling of the joint. Swab specimens were modestly different in bacterial composition from synovial fluid and tissue. The 5 most abundant genera were Escherichia, Cutibacterium, Staphylococcus, Acinetobacter, and Pseudomonas. Although sample size varied, the hospital of origin explained a significant portion (18.5%) of the variance in the microbial composition of the joint, and corticosteroid injection within 6 months before arthroplasty was associated with elevated abundance of several lineages. CONCLUSIONS: The findings revealed that prior intra-articular injection and the operative hospital environment may influence the microbial composition of the joint. Furthermore, the most common species observed in this study were not among the most common in previous skin microbiome studies, suggesting that the microbial profiles detected are not likely explained solely by skin contamination. Further research is needed to determine the relationship between the hospital and a "closed" microbiome environment. These findings contribute to establishing the baseline microbial signal and identifying contributing variables in the osteoarthritic joint, which will be valuable as a comparator in the contexts of infection and long-term arthroplasty success. LEVEL OF EVIDENCE: Diagnostic Level II. See Instructions for Authors for a complete description of levels of evidence.

Displaced Versus Nondisplaced Femoral Neck Fractures: Is Arthroplasty the Answer for Both?

BACKGROUND: Traditionally, nondisplaced geriatric femoral neck fractures (FNFs) have undergone operative fixation, while displaced geriatric FNFs have undergone hip arthroplasty. The purpose of this study was to evaluate differences between outcomes in patients with nondisplaced (Garden I and II) fractures and displaced (Garden III and IV) fractures that were treated with arthroplasty. METHODS: This was a retrospective review of patients who had a minimum of 1 year follow-up from nine academic medical centers who underwent arthroplasty for FNFs between 2010 and 2020. Chi-square, Fisher's Exact, and t-tests were used to compare demographics and outcomes between patients who had a displaced fracture and those who had a nondisplaced fracture. We included 1,620 patients, with 131 in the nondisplaced cohort and 1,497 in the displaced cohort. The mean follow-up in the study was 26.4 months. Both groups were similar in terms of demographic variables. RESULTS: At 1-year follow-up, the overall reoperation rate was 7% and was not different between patients who had nondisplaced compared to displaced FNFs who underwent arthroplasty. Heterotopic ossification (HO) was significantly higher in displaced (23.6%) versus nondisplaced fractures (11.7%) (P = .0021). Operative times and blood loss were higher in nondisplaced than displaced fractures that underwent arthroplasty. CONCLUSION: Hip arthroplasty is an excellent treatment option for nondisplaced and displaced geriatric FNFs with relatively low and similar reoperation rates at 1 year. Compared to previously published reoperation rates of internal fixation of nondisplaced FNFs, hip arthroplasty is a reasonable treatment option for nondisplaced FNFs to potentially decrease reoperations in a frail patient population.

Recovery Curve for Patient Reported Outcomes and Objective Physical Activity After Primary Total Knee Arthroplasty-A Multicenter Study Using Wearable Technology.

BACKGROUND: This study aimed to describe the trajectory of recovery based on patient-reported outcomes (PROs) and objective metrics of physical activity measures over the first 12 months post-total knee arthroplasty (TKA). METHODS: In total, 1,005 participants who underwent a primary unilateral TKA surgery between November 2018 and September 2021 from a multisite prospective study were analyzed. Generalized estimating equations were used to evaluate PROs and objective physical activity measures over time. RESULTS: All Knee Injury and Osteoarthritis Outcome Score for Joint Replacement (KOOS JR), EuroQol-5D (EQ-5D), and steps per day scores were greater than preoperative scores (P < .05). The flights of stairs per day, gait speed, and walking asymmetry all declined at 1 month (all, P < .001). However, all subsequent scores improved by 6 months (all, P < .01). The greatest clinically important differences from previous visit in KOOS JR (ß = 18.1; 95% Confidence Interval (CI) = 17.2, 19.0), EQ-5D (ß = 0.11; 95% CI = 0.10, 0.12), steps per day (ß = 1,169.3; 95% CI = 1,012.7, 1,325.9), gait speed (ß = -0.05; 95% CI = -0.06, -0.03), and walking asymmetry (ß = 0.00; 95% CI = -0.03, 0.03) were observed at 3 months. CONCLUSION: The KOOS JR, EQ-5D, and steps per day measures showed earlier improvements than other physical activity metrics, with the greatest magnitude of improvement within the first 3 months post-TKA. The greatest magnitude of improvement in walking asymmetry was not observed until 6 months, while gait speed and flights of stairs per day were not observed until 12 months. This data may further help provide expectation setting information to patients before surgery, and may aid in identifying outliers to the normal recovery curve who may benefit from targeted interventions.

Extensor Mechanism Disruption Remains a Challenging Problem.

BACKGROUND: Extensor mechanism disruption (EMD) following total knee arthroplasty (TKA) is a devastating problem commonly treated with allograft or synthetic reconstruction. Understanding of reconstruction success rates and patient recorded outcomes is lacking. METHODS: Patients who have an EMD after TKA undergoing mesh or whole-extensor allograft reconstruction between 2011 and 2019, with minimum 2-year follow-up were reviewed at two tertiary care centers. Functional failure was defined as extensor lag >30 degrees, amputation, or fusion, as well as revision extensor mechanism reconstruction (EMR). Survivorship was assessed using Kaplan-Meier curves, and factors for success were determined with logistic regressions. RESULTS: Of fifty-six EMRs (49 patients), 50.0% (28/56) were functionally successful at 3.2 years of mean follow-up (range, 0.2 to 7.4). In situ survivorship of the reconstructions at 36 months was 75.0% (42 of 58). There were 50.0% (14 of 28) of functionally failed EMRs that retained their reconstruction at last follow-up. Mean extensor lag among successes and failures was 5.4 and 71.0° (P = .01), respectively. Mean Knee Injury and Osteoarthritis Outcome Score, Joint Replacement scores were 67.1 and 48.8 among successes and failures (P = .01). There were 64.0% (16 of 25) of successes and 1 of 19 failures that obtained a Knee Injury and Osteoarthritis Outcome Score, Joint Replacement score above the minimum patient-acceptable symptom state for TKA. Survivorship and success rates were similar between reconstruction methods (P = .86; P = .76). All-cause mortality was 8.2% (4 of 49), each with EMR failure prior to death. All-cause reoperation rate was 42.9% (24 of 56), with a 14.3% (8 of 56) rate of revision EMR and 10.7% (6 of 56) rate of above-knee-amputation or modular fusion. CONCLUSIONS: This multicenter investigation of mesh or allograft EMR demonstrated modest functional success at 3.2 years. Complication and reoperation rates were high, regardless of EMR technique. Therefore, EMD after TKA remains problematic.

The Role of Dual-Mobility Components in Total Hip Arthroplasty.

➤: Dual mobility (DM) refers to a now widely available option for total hip articulation. DM implants feature a small inner head, a hard bearing, that connects via a taper fit onto the femoral trunnion. This head freely rotates but is encased inside a larger, outer polyethylene head that articulates with a smooth acetabular component. ➤: DM acetabular components are available in the form of a monoblock shell or as a liner that is impacted into a modular shell, providing a metal articulation for the polyethylene outer head. ➤: DM is designed to increase hip stability by providing the arthroplasty construct with a higher jump distance, head-to-neck ratio, and range of motion prior to impingement. ➤: The use of DM in total hip arthroplasty continues to increase in the United States for both primary and revision arthroplasty. Surgeons should be aware of the potential benefits and pitfalls. ➤: Long-term data are lacking, especially for modular DM implants. Points of concern include a potential for accelerated polyethylene wear, intraprosthetic dislocation, and modular backside fretting corrosion.

An Enhanced Understanding of Culture-Negative Periprosthetic Joint Infection with Next-Generation Sequencing: A Multicenter Study.

BACKGROUND: The challenges of culture-negative periprosthetic joint infection (PJI) have led to the emergence of molecular methods of pathogen identification, including next-generation sequencing (NGS). While its increased sensitivity compared with traditional culture techniques is well documented, it is not fully known which organisms could be expected to be detected with use of NGS. The aim of this study was to describe the NGS profile of culture-negative PJI. METHODS: Patients undergoing revision hip or knee arthroplasty from June 2016 to August 2020 at 14 institutions were prospectively recruited. Patients meeting International Consensus Meeting (ICM) criteria for PJI were included in this study. Intraoperative samples were obtained and concurrently sent for both routine culture and NGS. Patients for whom NGS was positive and standard culture was negative were included in our analysis. RESULTS: The overall cohort included 301 patients who met the ICM criteria for PJI. Of these patients, 85 (28.2%) were culture-negative. A pathogen could be identified by NGS in 56 (65.9%) of these culture-negative patients. Seventeen species were identified as common based on a study-wide incidence threshold of 5%. NGS revealed a polymicrobial infection in 91.1% of culture-negative PJI cases, with the set of common species contributing to 82.4% of polymicrobial profiles. Escherichia coli, Cutibacterium acnes, Staphylococcus epidermidis, and Staphylococcus aureus ranked highest in terms of incidence and study-wide mean relative abundance and were most frequently the dominant organism when occurring in polymicrobial infections. CONCLUSIONS: NGS provides a more comprehensive picture of the microbial profile of infection that is often missed by traditional culture. Examining the profile of PJI in a multicenter cohort using NGS, this study demonstrated that approximately two-thirds of culture-negative PJIs had identifiable opportunistically pathogenic organisms, and furthermore, the majority of infections were polymicrobial. LEVEL OF EVIDENCE: Diagnostic Level II . See Instructions for Authors for a complete description of levels of evidence.

Total Hip Arthroplasty in Patients With Severe Chronic Pubic Diastasis.

Background: Total hip arthroplasty (THA) in patients with severe chronic pubic diastasis from either congenital or acquired causes presents an exceptionally difficult challenge that has rarely been addressed in the arthroplasty literature. The purpose of this paper is to present a series of THAs in patients with severe chronic pubic diastasis, asking the following research questions: (1) What is the survivorship and clinical outcomes after THA in patients with severe chronic pubic diastasis? And (2) What is the rate of complications after THA surgery in this challenging patient population? We additionally describe our algorithm for preoperative planning and rationale for surgical technique and implant position. Material and methods: We retrospectively queried the prospective arthroplasty database of 2 high-volume referral centers, yielding 6 THA in 4 patients with severe chronic pubic diastasis (minimum 8 cm) with a mean follow-up of 2.7 years. We recorded baseline demographic and intraoperative variables, as well as survivorship, patient-reported outcomes (Hip disability and Osteoarthritis Outcome Score for Joint Replacement score), and incidence of complications. Results: There were no failures reported (100% survivorship) at a mean follow-up of 2.7 years. Mean Hip disability and Osteoarthritis Outcome Score for Joint Replacement scores improved from 36.0 preoperatively to 82.8 postoperatively. There were no infections, dislocations, fractures, or any major complications in the postoperative period. Conclusion: THA for patients with severe chronic pubic diastasis remains a rare but challenging reconstructive procedure. Excellent outcomes can be achieved with adequate preparation, particularly regarding the acetabular component position. Understanding the nature of the hemipelvis deformity and meticulous templating using "normalized" views of the hip are important components to a successful preoperative plan.

Occupational Hazards to the Joint Replacement Surgeon: Radiation Exposure.

BACKGROUND: Intraoperative fluoroscopy is an essential tool to assist orthopedic surgeons in accurately and safely implanting hardware. In arthroplasty cases, its use is on the rise with the increasing popularity of the direct anterior (DA) approach for THA. However, exposure of ionizing radiation poses a potential health risk to surgeons. While the benefits of intraoperative fluoroscopy in DA THA is becoming clearer, and are well-described in the literature, the potential health dangers associated with career-long cumulative radiation exposure are rarely discussed. METHODS: In this article, we review the available literature to discuss radiation safety in orthopedics with a focus on total joint arthroplasty. We present the basic science of radiation, discuss the amount of radiation exposure in orthopedic surgery, and review the potential health risks associated with long-term exposure. CONCLUSION: Overall, the radiation dose exposure to arthroplasty surgeons is low and within recommendations for occupation exposure limits. However, due to the stochastic health impacts of ionizing radiation, there is no threshold dose below which radiation exposure is truly safe. Therefore, it is imperative that surgeons practice proper fluoroscopy safety habits, such as wearing proper protective equipment, minimizing fluoroscopy time and magnification, and maximizing distance from the radiation source to minimize the life-long cumulative radiation exposure and associated health risks.

Anterior-Based Approaches to Total Hip Arthroplasty: Beyond the Learning Curve.

BACKGROUND: Anterior-based approaches for total hip arthroplasty (THA) have gained popularity over the last decade. At our institution, anterior-based approaches are preferentially utilized, including both anterior-based muscle-sparing (ABMS) and direct anterior (DA) for primary THA. As there are higher complication rates during the transition to an anterior approach, we compared the outcomes and complications between ABMS and DA approaches beyond the learning curve. METHODS: A retrospective study of all ABMS and DA primary THA patients performed at a single institution was performed, excluding the first 100 anterior cases done by any surgeon. In total, 813 DA and 378 ABMS THA cases were included. Demographics, complications, and patient-reported outcomes (PROMIS and HOOS) were obtained for each patient. RESULTS: There was a 4.5% overall complication rate (4.1% in DA and 5.6% in ABMS, P = .248), with the most common complication being infection at 1.7% (1.5% vs 2.1%, P = .423). A revision was performed in 3.4% of cases overall (1.8% aseptic, 1.6% septic). There was no difference in complication rates between approaches. Length of surgery was shorter for ABMS (94.5 vs 116.0 minutes, P < .001). Both DA and ABMS had significant improvements in PROMIS and HOOS Jr. scores, without any significant difference between the groups. CONCLUSIONS: Anterior-based approaches for primary THA demonstrated excellent clinical results and low complication rates overall. Beyond the learning curve, excellent results can be obtained with either ABMS or DA approach for primary THA.

High Survivorship of a Modular Titanium Baseplate Independent of Body Mass Index and Malalignment.

BACKGROUND: Tibial component aseptic loosening remains problematic in primary total knee arthroplasty (TKA). Influential factors include component design, metallurgy, and cement technique. Additionally, reports advocate for longer tibial stem fixation in high body mass index (BMI) patients. We have utilized a single stem length modular titanium baseplate in patients regardless of BMI, bone quality, or malalignment. We report the survivorship of this implant with focus on the impact of elevated BMI and postoperative malalignment. METHODS: We retrospectively reviewed patients who underwent TKA with a single modular titanium baseplate with a cruciate-shaped keel between 2004 and 2018. In total, 2,949 TKAs with a minimum of 1-year follow-up were included. The mean follow-up was 7 years. The primary outcome was component failure stratified by BMI and postoperative malalignment. High viscosity cement was utilized in all cases. Chi-squared and t-tests were used to compare outcome variables across groups. RESULTS: Eighty-five implants (2.8%) were revised with 46 (1.6%) for aseptic loosening. Failure was not associated with BMI, gender, American Society of Anesthesiologists class, or Charlson Comorbidity Index. There was no difference in failure rate by BMI (P = .26) or by malalignment (outside of 3° from neutral mechanical axis) (P = .67). Age was associated with failure as patients with failed TKAs were younger (61 vs 65, P < .01). CONCLUSION: This design of a specific modular titanium base plate with a cruciate-shaped keel and grit blast surface demonstrated 99% survivorship regardless of patient BMI or malalignment over 7-year follow-up period. Consistent cement technique with high viscosity cement indicates that component design remains an important variable impacting survivorship in TKA.